The following posters will be presented at the 2018 LTER All Scientists’ Meeting and are organized here alphabetically by last name. Session A posters (A-F001 to A-K128) will be presented on Monday evening, October 1st and Session B posters (B-F001 to B-K130) will be presented on Tuesday evening, October 2nd. Posters labeled with F are located in Fred Farr, and those with K are in Kiln.

 

Adam, Thomas

B-K108: Drivers and consequences of large-scale patterns of nutrient enrichment in a coral reef ecosystem    

Deron Burkepile, Sally Holbrook, Russell Schmitt, Robert Carpenter

Mo’orea Coral Reef LTER, University of California Santa Barbara

Many coral reefs have undergone shifts from coral-dominated to algae-dominated communities. These ‘phase shifts’ could be related to nutrient loading. We quantify spatial and temporal patterns of nitrogen enrichment on coral reefs around the island of Moorea and test whether patterns of enrichment correlate with recent changes in benthic communities. We find that spatial patterns of enrichment are related to distance from anthropogenic sources and seasonal patterns of rainfall and wave-driven flow. In addition, long-term dynamics of benthic algae indicate that algae have increased in enriched areas. These results suggest that nutrient loading could be a driver of recent coral to macroalgae phase shifts in the lagoons of Moorea.

 

Addis, Brett

B-F027: Effects of environmental variation on dispersal distance in a stream salamander

Winsor Lowe

Hubbard Brook LTER, University of Montana

Dispersal allows organisms to escape fitness costs resulting from environmental variation, among other factors. While there is evidence that active dispersers base emigration decisions on environmental factors relating to habitat quality, it is less well understood how these factors influence dispersal distance. Our goal was to test whether fine-scale or large-scale patterns of environmental variability predict variation in dispersal distance in a stream salamander. Dispersal distances decreased with survival – our index of large-scale variation, but were unrelated to changes in body condition – our index of fine-scale variation. Thus, salamanders disperse further in risky environments characterized by a history of low survival.

 

Ahn, Nahyun

A-F094: Study of phenological research for terrestrial ecosystems in South Korea

National Institute of Ecology, South Korea

Phenology is the study of periodic plant and animal life cycle events and how these are influenced by seasonal and interannual variations in climate, as well as habitat factors. Phenology of plants, insects and birds have been observed and are being continuously monitored in South Korea. Plant phenology data collect using the field research and the time lapse camera. Insects phenology, especially Lepidoptera, collect data using light trap at night and line transect method during the day. Collect bird phenology data using artificial birdhouse, field research and songmeter. This study can be considered as a long-term study to identify the impacts of phenological climate change and ecosystem changes in the future.

 

Alber, Merryl

A-K118: Site Poster

Georgia Coastal Ecosystems LTER

 

Alber, Merryl

B-F062: Phenological variation in a Spartina alterniflora marsh

Jessica O’Connell

Georgia Coastal Ecosystems LTER, University of Georgia

Detailed information on vegetation phenology in salt marshes is useful for understanding patterns in plant production and carbon sequestration. We used the “GCESapelo” PhenoCam, which auto-collects images every 30 min, to characterize the phenophases of Spartina alterniflora. We found spatial and inter-annual differences in green-up onset and growing season length. A spring warm-up model that used elevation-related differences in soil temperature was able to predict the date of green-up onset for S. alterniflora within approximately one week. When we applied this model over a 60-year time span, we estimated that winter soil temperatures have increased by 1.7 degrees C, advancing green-up dates by approximately 11 days.

 

Allenbrand, Jaide

B-F026: Grassland fire and grazing affects soil microbial diversity and heterogeneity

Lydia Zeglin

Konza Prairie LTER, Kansas State University

We asked how direct and interactive burn treatments and grazing treatments affected soil microbial diversity across watersheds. From samples collected in a log-distance design, bacterial and archaeal community composition and key soil factors were measured. We found that watershed scale historical treatments explained more microbial community variation than soil factors. Annually burned, ungrazed watersheds resulted in the highest microbial alpha diversity and that grazed, annually burned watersheds had the lowest distance dissimilarity, indicating that both management practices might promote microbial dispersal. To evaluate how these microbial diversity differences relate to ecosystem function, we also measured nutrient cycling processes.

 

Alteio, Lauren

A-F033: Expanding Microbial Diversity in Harvard Forest Soil

Frederik Schulz, Elizabeth Ryan, Danielle Goudeau, Rex Malmstrom, Tanja Woyke, Jeff Blanchard

Harvard Forest LTER, University of Massachusetts Amherst

Forest soils are teeming with immense biodiversity, much of which remains poorly characterized in the complex soil environment. We used a new approach to sort individual microorganisms directly from soil samples collected at the Harvard Forest LTER warming site. We report data from 2,000 genomes which more than double known diversity across major groups of soil bacteria. Additionally we discovered 13 new giant virus clades which have previously never been found in terrestrial environments. The astonishing genome diversity suggests we are just scratching the surface of the microbial world. These reference genomes provide a more robust context for identifying sentinel microbial taxa and understanding how communities respond to climate change.

 

Aluwihare, Lihini

B-F081: Nitrate isotope fractionation by phytoplankton communities in the California Current Ecosystem

Brandon Stephens, Margot White, Scott Wankel

California Current Ecosystem LTER, UCSD/SIO

Nitrogen isotopes in nitrate can be used to examine changes in nitrate utilization, to establish the provenance of nitrate supporting foodwebs, and to place bounds on the importance of nitrification in aquatic environments. However, interpreting variations in nitrate isotopes can be complicated by food web processes such as nitrate uptake by phytoplankton, that fractionate these isotopes. Here we capitalize on an LTER sample set spanning different climatic conditions to examine how changes in phytoplankton community composition impact the fractionation of nitrate isotopes. The imprint of phytoplankton activity on the nitrate reservoir must be constrained if nitrate isotopes are to be used to study the past and present Nitrogen Cycle.

 

Anderson-Huxley, Jared

A-F001: Functional dominance, not functional diversity, drives ecosystem function in alpine tundra

Niwot Ridge LTER, UC Riverside

There are two non-exclusive hypotheses for how biodiversity may influence ecosystem function: 1) the mass ratio (MR) effect, which holds that species affect ecosystem functions in proportion to their abundance; and 2) niche complementarity (NC), which postulates that increased species diversity will enhance ecosystem functions through complementary resource use. We tested the relative importance of these two hypotheses on net primary production (NPP) over eight years (sampled between 2008 and 2016) in 81 1m2 long term monitoring plots in alpine tundra at the Niwot Ridge LTER, Colorado, USA. We found that MR effects were the dominant mechanism by which biodiversity influenced NPP in this system.

 

Andrade, Riley

B-F088: Connecting an economic crisis to the ecological disturbance of an urban arthropod community

Susannah B. Lerman, Heather L. Bateman, Kelli L. Larson, Julie Ripplinger, Paige S. Warren

Central Arizona-Phoenix LTER, Arizona State University

The effects of urban development on biodiversity are variable, and in part depend on people’s decisions that affect habitat characteristics. In residential yards, habitat is created and maintained by management decisions. When homes are abandoned, landscaping can become neglected and resource inputs such as irrigation get turned off. The sudden shift places economic booms and busts within the framework of ecological disturbance. However, the ways that disturbance plays out in socioecological systems remains relatively understudied. Here, we study the arthropod community in residential yards during an economic recession using data from the CAP LTER project. Our findings suggest that economic processes can create ecological disturbances, interacting with fluctuations in ecological processes to affect rates of species turnover and biodiversity outcomes.

 

Andrus, Robert

A-F004: Different vital rates of spruce and fir explain discordance in understory/overstory dominance

Niwot Ridge LTER, University of Colorado

Studies of forest dynamics commonly assume that species composition of the seedling bank reflects the composition of the future forest canopy. However, many forest types exhibit persistent differences in relative dominance of species in these two strata, and species-specific differences in vital rates (e.g. mortality, height growth) may explain this discrepancy. We tested whether differences in vital rates, quantified from permanent forest plots, explain the shift from seedling bank dominance by subalpine fir (Abies lasiocarpa) to more equal dominance of the main canopy by fir and Engelmann spruce (Picea engelmannii). Our results have important implications for projecting future forest trajectories from seedling bank composition.

 

Aoki, Lillian

B-F061: Temperature drives patterns of seagrass restoration and resilience across spatial scales

Karen McGlathery, Matthew Oreska, Peter Berg, Pat Wiberg, Amelie Berger

Virginia Coast Reserve LTER, University of Virginia

Long-term monitoring of seagrass restoration in the Virginia coastal bays provides insight into the dynamics of meadow expansion and the response of the meadow to disturbance from marine heatwaves. Expansion of the meadow is limited by depth (light limitation) in deeper areas and by warmer temperature in shallower areas. These limits interact with spatial position in the landscape to drive patterns of seagrass resilience. We combined long-term monitoring data (>12 years) with short-term observations before and after high temperature events in 2012 and 2015 to understand the patterns of recovery and adaptability following temperature-induced declines in two restored meadows.

 

Atkins, Rebecca

B-F058: Consumer effects within and across southeastern US salt marshes

Craig W. Osenberg

Georgia Coastal Ecosystems LTER, University of Georgia

Southeastern US salt marshes are some of the most productive ecosystems in the world. In these marshes, the periwinkle snail, Littoraria irrorata, utilizes saltmarsh cordgrass, Spartina alterniflora, as both a refuge and food source. Our research has expanded from the GCE LTER to sites along the Atlantic coast to quantify naturally occurring spatial variation in Littoraria populations and Littoraria consumer effects. We are now working to understand variation across Littoraria populations in the context of metabolic traits, and future work will emphasize the role of temperature in marsh communities. Our research highlights value of working across spatial scales to understand both present and future species interactions.

 

Avolio, Meghan,

B-K115: Global change drivers alter the variability of primary production

Baltimore Ecosystem Study LTER, Konza Prairie LTER, Johns Hopkins University

Global change can alter the stability of ecosystem function. We synthesized 27 global change experiments to investigate whether 1) global change treatments affect temporal and spatial variability in ANPP; 2) a change in ANPP temporal variability relates to change in richness; and 3) sensitivity of ANPP to annual precipitation changes with GCDs. We found that GCDs affect ANPP variability by making less variable sites more variable, and vice versa. Second, for temporal variability, treatments became more variable as they lost species; however, a change in richness only explained 8% of the variation. Lastly, overall GCDs increase the sensitivity of ANPP to precipitation; however, the MAP of a site does not affect its sensitivity.

 

Bachle Seton

A-F022: Physiological and Microanatomical Responses to Extreme Drought in Andropogon gerardii

Rory O’Connor, Jesse Nippert

Konza Prairie LTER, Kansas State University

Current climate models project an enhanced risk of drought in the Tallgrass prairie over the coming century; which will alter productivity, ecosystem functioning, and may promote woody encroachment. To understand the effects of reduced precipitation in this system, rainout shelters were constructed (Drought-Net design) at Konza Prairie LTER, to simulate an extreme multiyear drought (50% rainfall reduction). We measured species composition, aboveground net primary productivity (ANPP), species-specific physiology and microanatomy during the 2016-2018 growing seasons. Results indicate that prolonged drought will negatively impact species’ physiology, decrease productivity, and alter species composition.

 

Baerwald, Melinda

A-K112: Interagency Ecological Program: Enhancing Communication and Collaboration Among Scientific Partners

Larry Brown, Maggie Christman, Louise Conrad, Steve Culberson, Karen Kayfetz, Shruti Khanna, Peggy Lehman, Brian Schreier, Ted Sommer, Vanessa Tobias

California DWR, California Department of Water Resources

Understanding and managing the San Francisco Estuary ecosystem requires coordinated monitoring and research. The Interagency Ecological Program (IEP) consortium brings together scientists and managers from nine government agencies to prioritize and execute scientific studies. Since its inception, IEP has conducted and communicated high-quality science that is driven by synergistic collaboration and the exchange of resources, data and ideas. To fuel increased collaboration, IEP is investing in a monitoring and research facility in the heart of the ecosystem that will also engage with the local community. This initiative will promote open science and energize the collaborative spirit of IEP that enables effective ecosystem management.

 

Báez, Noeli

A-K108: LUQ-LTER schoolyard students assessing vegetation structure after Hurricane María

Steven McGee, Jess K. Zimmerman, Glenda L. Almodóvar, Christopher J. Nytch

Luquillo LTER, University of Puerto Rico – Rio Piedras

Hurricane Maria caused extensive damage to the forests of Puerto Rico, including those studied by the Luquillo LTER. We had established a Schoolyard forest plot near El Verde Field Station for teachers and students to learn forest mensuration practices. We adapted our Schoolyard protocols to post-hurricane conditions, allowing middle and high school students to experience how the forest is recovering. The revised protocol mirrors the one being used throughout the LTER site to assess forest damage and helps ground-truth remote sensing studies. This work builds on a long-term learning program involving K-12 students and teachers at our site and applying that knowledge in forested landscapes near their schools, such as the Guánica Dry Forest.

 

Bahlai  Christie

B-F005: Managing our expectations: can we characterize misleading trajectories in ecological processes?

Sarah Cusser

Kellogg Biological Station LTER, Kent State University

In ecology, we often scale short term data to form long term predictions- with mixed reliability. We developed a method to address the temporal issues of scaling, by iteratively sampling long time series over short periods. Using standard statistical methods at each iteration, we compile results to draw conclusions about the reliability of short term trends. We use a 15y study of fireflies at Kellogg Biological Station as a proof of concept, but will expand to synthesize data from across the LTER to gain insights into how temporal trends behave across ecosystems, and answer the questions: “how often are the trends observed in short term data misleading? Can we use characteristics of these trends to predict our likelihood of being misled?”

 

Barker-Plotkin , Audrey

A-K122: Site Poster

Harvard Forest LTER

 

Bell, Tom

B-F091: Disentangling Global Change Trends from Low Frequency Climate Oscillations in Marine Environments

James Allen, Kyle Cavanaugh, David Siegel

Santa Barbara Coastal LTER, UC Santa Barbara

Giant kelp is a highly dynamic, globally distributed, marine foundation species which supports a diverse community of ecologically and economically important species. Therefore, understanding the drivers of kelp biomass variability is vital for fisheries, ecology, and conservation research. We have developed a multidecadal time series of giant kelp canopy biomass across much of the NE Pacific and have used this dataset to identify several important abiotic and biotic drivers which operate over various time scales. Here we use our multidecadal scale dataset to examine kelp biomass patterns over multiple spatial and temporal scales to tease apart fluctuations associated with marine climate cycles from longer-scale trends.

 

Bell-Dereske, Lukas

A-F005: MMPRNT: Effects of spatial and temporal scale on bacterial communities

Kellogg Biological Station LTER, Michigan State University

Soil bacterial communities vary temporally and spatially, but we are only beginning to understand the scale and drivers of these processes. The MMPRNT (Microbial Mediated Perennial Rhizosphere Nitrogen Transformations) project is exploring the role of the microbial community in the response of the biofuel crop species Panicum virgatum to nitrogen fertilization across spatial scales from <1m to >500km and temporal scales of weeks to years. The bacterial community was sampled across these scales using metabarcoding. We have found that the spatial scale is the largest driver of the soil bacterial communities. On the other hand, the nitrogen fertilization and temporal scale had weak effects on the community.

 

Benjamin, Whitmore

A-F090: Zooglider- a novel autonomous glider capable of resolving micro-scale layers of zooplankton

Mark D. Ohman, Jeffrey S. Ellen, Catherine F. Nickels

California Current Ecosystem LTER, Scripps Institution of Oceanography, UCSD

Thin layers (height < 5 m) are recurring and persistent features in the ocean. These layers have elevated concentrations of organisms compared to ambient conditions. Most conventional zooplankton sampling relies on ship-based methods that require a large amount of effort per sample, yet do not adequately resolve the fine-scale required for the analysis of these thin layers. We present results from the use of the Zooglider, a novel zooplankton-sensing glider, within the CCE LTER site. The Zooglider is capable of optically resolving mesozooplankton at a vertical scale of 5 cm, with concurrent acoustic and physical data. Post-deployment, our original machine learning classifiers rapidly classify Zooglider images into 27 groups.

 

Berbes-Blazquez, Marta

B-F084: Assessing scenario visions: Equity, resilience, and sustainability of the future of South

David Iwaniec, Elizabeth Cook, Melissa Davidson, Nancy B Grimm, Tischa Muñoz-Erickson, Darin Wahl

Central Arizona-Phoenix LTER, Arizona State University

Participatory scenario planning provides an opportunity to co-produce positive visions of the future. We developed an assessment tool to evaluate scenarios in terms of equity, resilience, and sustainability of social-ecological-technological systems. We use scenarios co-produced with urban professionals, researchers, and civic organizations in South Phoenix to illustrate the utility of the qualitative framework. Our framework integrates insights from systems thinking, social innovation, resilience, stewardship, and sustainability to compare not just alternative visions, but also key pathways—and potential obstacles—that participants identified as important to fulfilling their future goals, as well as implicit and explicit tradeoffs.

 

Berger, Amelie

A-F059: Seagrass ecosystem metabolism and resilience measured by aquatic eddy covariance

Peter Berg, Karen McGlathery, Marie Lise Delgard

Virginia Coast Reserve LTER, University of Virginia

Benthic oxygen fluxes in a seagrass meadow at the Virginia Coast Reserve LTER site have been measured seasonally by aquatic eddy covariance over the past 10 years. These in situ measurements cover a period of ecosystem development 6-13 years (2007-2014) after restoration by seeding, a high-temperature-related die-off event in 2015, and recovery in 2016 and 2017. This uniquely extensive dataset covering ~100 full diurnal cycles provides an unprecedented opportunity to study long-term trends and drivers of seagrass metabolism as well as the resilience of seagrass habitats. The VCR LTER site is a model for temperate systems globally, and is an ideal natural laboratory to study the potential impact of warming oceans on seagrass resilience.

 

Bergman, Zoe

B-F072: Precipitation Event Size Controls on Autotrophic and Heterotrophic Respiration in the Jornada LTER

Osvaldo Sala, Laureano Gherardi

Jornada Basin LTER, James Madison University

Soil carbon efflux has two major contributors, autotrophic and heterotrophic respiration. In past studies, it has been found that microbial respiration will peak at small rainfall pulses and level off even as rainfall increases, while plant respiration tends to increase as rainfall size increases. Will small rainfall events stimulate only microbial respiration? Will the size of the rainfall event change the relationship between plant root and microbial respiration? In this study we determined the ratio between plant root respiration and microbe respiration in relation to varying amounts of rainfall in the Chihuahua Desert.

 

Bergstrom, Anna

A-F045: Testing nutrient uptake on glaciers, the headwaters of the McMurdo Dry Valleys ecosystem

McMurdo Dry Valleys LTER, University of Colorado – Boulder

Because glaciers in the McMurdo Dry valleys set the initial geochemical signal of the aquatic system, it is important to understand nutrient cycling and transformations on the glaciers. This has been studied extensively in cryoconite holes, but not the supraglacial streams or ponds, the main drainage network. This study aims to test, under fertilized nutrient conditions, if the biota living in the sediment of the streams and ponds has the potential to take up dissolved nutrients as well as testing which nutrient is limiting uptake. We performed both an in-situ tracer based uptake experiment and a lab-based incubation experiment. We hypothesize that, like the cryoconite holes, these systems may be phosphorous limited.

 

Bestelmeyer, Stephanie

B-F090: Data Jams: Promoting K-12 Data Literacy and Science Engagement Using LTER Data

Alan Berkowitz, Bess Caplan, Rhea Esposito, Michelle Forster, Steven McGee, Noelia Baez Rodriguez

Jornada Basin LTER, Asombro Institute for Science Education

Since Data Jam began in 2012, thousands of middle and high school students have participated in this unique education competition hosted by Jornada Basin LTER, Baltimore Ecosystem Study LTER, Luquillo LTER, and Cary Institute of Ecosystem Studies. In a Data Jam, students learn content information, explore LTER or associated datasets related to that topic, and develop a creative project (such as a song, book, physical model, info-graphic, or game) that communicates a trend in the data to nonscientist audiences. This poster describes the structure of Data Jams, shows sample projects, highlights teacher and student feedback, and offers advice for anyone interested in starting a Data Jam.

 

Bharath Iyengar, Siddharth

A-F008: What can long term nutrient additions in grasslands tell us about ANPP-Precipitation relationships?

Elizabeth T Borer, Eric W Seabloom

Cedar Creek LTER, University of Minnesota

Due to anthropogenic global change, plant communities face increased nutrient loads and greater variation in precipitation. Plant communities are co-limited by both nutrients (which vary in space) and water (whichvary in time). Long term studies have proposed that multiple resource limitation drives the relationship between primary production and precipitation in grasslands. How does alleviation of nutrient limitation change the responsiveness of ANPP to rainfall, and is this dependent upon shifts in plant community structure? We analyse data from long term nutrient addition experiments, in order to understand how co-limitation between nutrients and water drives stability of grassland plant communities.

 

Biel, Reuben

B-F066: Influence of vegetation dynamics, wave climate, and shoreline change on dune field development

Laura J. Moore, Evan Goldstein

Virginia Coast Reserve LTER, University of North Carolina at Chapel Hill

Coastal dunes develop via feedbacks between sediment transport and vegetation processes that cause localized deposition sand. Though this feedback is well-acknowledged, biological processes have only recently been incorporated into geomorphic models that examine dune development. Here we expand upon the vegetation module of the Coastal Dune Model to better represent plant colonization, growth, and propagation for typical dune-building grasses (e.g., Ammophila breviligulata) and parameterize it using VCR LTER long-term datasets and the literature. We then examine how plant population dynamics, wave climate, and shoreline change alter coastal dune development on Virginia barrier Islands over multiple decades.

 

Bolin, Lana

A-F015: Feedbacks between inter- and intra-specific diversity alter the outcome of plant-soil feedbacks

Jennifer A. Lau

Kellogg Biological Station LTER, Michigan State University

Plant-soil feedbacks (PSF) occur when plants alter the soil microbial community in ways that then affect plant growth and can contribute to the maintenance of biodiversity. Theory predicts that inter- and intra-specific diversity may feedback with each other but has never been tested in a PSF framework. We show that the direction of interspecific PSF shifts from negative to positive as intraspecific genetic variation increases, and that intraspecific PSF shifts from negative to neutral as species diversity increases. These results indicate that genetic diversity may minimize the effectiveness of PSF for maintaining species diversity, and reciprocally that species diversity may minimize the capacity for PSF to maintain genetic diversity.

 

Boose, Emery

B-F028: What can provenance do for you?

Orenna Brand, Aaron Ellison, Elizabeth Fong, Matthew Lau, Barbara Lerner, Thomas Pasquier, Margo Seltzer, Joseph Wonsil

Harvard Forest LTER, Harvard University

Provenance is the history of an item of data from its creation to its present state. In this project we have developed tools to collect provenance for scripts written in R. We are now working on applications that use provenance to perform tasks that support scientists in their work. These applications can or will do the following: simplify debugging through direct access to intermediate data values, identify all occurrences of a variable for quality control or error propagation, clean a script to remove all non-essential elements, record the details of the computing environment and versions of all libraries used, and preserve all input and output values (including transient values) needed to reproduce a particular result.

 

Brigham, Laurel

A-F002: Soil pH Indirectly Influences the Overall Interior Root Microbiome, but Not the Dominant Bacterial Families

Clifton P. Bueno de Mesquita, Marko J. Spasojevic, Emily C. Farrer, Dorota L. Porazinska, Jane G. Smith, Steven K. Schmidt, Katharine N. Suding

Niwot Ridge LTER, University of Colorado, Boulder

Although the impacts of soil characteristics and soil microbes on the rhizosphere have been documented, a link between varying edaphic properties and the root interior (endosphere) microbiome remains to be well characterized. We propose that soil properties have either a direct influence on the endosphere microbiome or an indirect influence through the soil microbiome. We used structural equation modeling to partition the direct effects of soil pH and host identity from the indirect effects due to soil microbiome composition. We found varying importance of soil pH and the soil microbiome depending on the aspect of the endosphere microbiome examined—richness, diversity, total community, or the dominant root bacterial families.

 

Broderick, Caitlin

B-F006: Water availability as a short- and long-term ecosystem driver in tallgrass prairie

Konza Prairie LTER, Kansas State University

Using a multi-decadal irrigation experiment combined with new rainfall treatments, we ask: how does climate affect tallgrass prairie structure, function and stability over several timescales? We will 1) describe biogeochemical cycles under different precipitation regimes and 2) explore how precipitation history shapes ecosystem sensitivity to reduced or increased rainfall. This study quantifies responses of soil C and N pools and fluxes to altered precipitation, and how these changes relate to responses in plant communities and functioning. Early results suggest that alleviating water stress accelerates N cycling and increases long-term productivity and C fluxes . Results will offer new insights into grassland responses to climate change.

 

Brooks , Andrew

A-K097: Response of coral reef herbivores to a large-scale reduction in live coral cover

Russell Schmit, Sally Holbrook, Thomas Adam

Mo’orea Coral Reef LTER, UC Santa Barbara

The coral reefs surrounding the island of Moorea, French Polynesia experienced an order of magnitude decline in the cover of live coral on an island-wide scale following the 2007 outbreak of the crown-of-thorns seastar. We report here on the population and individual level responses exhibited by the herbivorous fish community, with an emphasis on parrotfishes, to the decline in live coral cover. Our work demonstrates the ability of the herbivorous fish community described from Moorea to quickly respond to large-scale disturbances that result in significant losses of live coral and highlight the importance of these species to maintaining a high degree of reef resiliency.

 

Brown, Michael

A-F051: Glacial meltwater chemistry along the West Antarctic Peninsula

Colette Feehan, Robert Sherrell, Kaixuan Bu, Vincent Roccanova, Hugh Ducklow, Michael Meredith, Oscar Schofield

Palmer Antarctic LTER, Rutgers University, Montclair State University, Columbia University, British Antarctic Survey

The West Antarctic Peninsula is a rapidly warming polar system. Little is known about the content of runoff in the region, especially macronutrients and trace metals that could impact phytoplankton dynamics. Here we present measurements of macronutrients, trace metals, oxygen isotopes, major ions, and volume transport from two glacial meltwater streams located on Anvers Island collected over the 2016-17 austral summer. Our results indicate these streams have high concentrations of nitrate, phosphate (but low silicate), iron, manganese, and copper. Increasing glacial inputs could alter phytoplankton dynamics that cascade through the food web, e.g. low (high) silicate (copper) inputs could select against diatoms, the preferred food of krill.

 

Brown, Joseph

A-F061: Cross-scale connections explain disturbance response on Virginia Coast Reserve barrier island system

Audrey Kirschner, Ben Nettleton, Julie Zinnert

Virginia Coast Reserve LTER, Virginia Commonwealth University

Climatic drivers of disturbance play a major role in barrier island dynamics globally and across many scales. Our objective was to determine how barrier islands of the VCR LTER respond to disturbance at a landscape scale, and how such changes affect lower spatial scales (i.e. community and organism levels). Observation and manipulation studies at landscape, community, and organism levels show that VCR islands can be described as disturbance reinforcing or disturbance resisting, particularly across island segments (i.e. beach to marsh). Cross-scale effects can be seen at community and organism levels exhibiting functional responses to disturbance. Organism traits may feedback to influence the level of disturbance.

 

Bueno de Mesquita, Cliff

B-F003: Moving uphill: The role of early snowmelt and microbes in plant range shifts

Steven K. Schmidt, Katharine N. Suding

Niwot Ridge LTER, University of Colorado Boulder

Despite their importance, the role of plant-microbe interactions in plant range shifts has rarely been studied. We hypothesized that earlier snowmelt and certain microbial communities enable plant establishment in unvegetated areas. We grew three alpine plant species in different soil inocula collected at various sites across a high-alpine ecosystem, including from unvegetated and vegetated soils. We manipulated the growing season by applying a thin layer of black sand onto the snow surface at peak snowpack, which accelerated snowmelt by one week. After the first growing season in the field, growth of Deschampsia cespitosa was significantly affected by the different soil inoculum treatments but not by the extended growing season.

 

Burruss, Dylan

A-F074: Predicting Lehmann’s lovegrass expansion at the JRN LTER site

Debra P.C. Peters, Steven R. Archer, Haitao Huang

Jornada Basin LTER, New Mexico State University

Lehmann lovegrass (Eragrostis lehmanniana) is a perennial grass introduced across the American Southwest in the 1930s to restore production on grasslands. While climate and soils are known to influence broad distributions of E. lehmanniana, drivers of local patterns, such as patterns at the Jornada Basin LTER site, are less understood. Our objective was to integrate fine-scale maps of soils and climate with multi-scale patterns of E. lehmanniana occurrence through time to improve the spatio-temporal predictions of its expansion into Chihuahuan Desert ecosystems. Our results show climate, soil properties and seedling recruitment (germination, establishment, dispersal) parameters result in non-linear rates and patterns of spread through time.

 

Butitta, Vince

B-F022 linking environmental conditions and annual growth rings in mussels

North Temperate Lakes LTER, University of Wisconsin Madison

Annual rings in bivalve shells frequently correlate with environmental variables important for growth which may make them useful tools to reconstruct historical environmental conditions when direct measurements of environmental conditions don’t exist. We analyzed shell thin-sections of a mussel species from a cool, oligotrophic lake, and quantified population growth rates. Preliminary analyses display a moderately high level of synchrony in annual growth among individuals (n = 19, 30yr, interseries correlation = 0.385). Growth was significantly correlated with total phosphorus (r = 0.50, p < 0.01) and not correlated to water temperature, suggesting that primary productivity is likely a stronger driver than temperature for mussel growth.

 

Caplan, Bess

A-F062: An Integrated Approach to Water Science and Computational Literacy

Alan R. Berkowitz, Garret Love, Randall Boone

Baltimore Ecosystem Study LTER, Cary Institute of Ecosystem Studies

CompHydro is a collaborative research and development project that supports an integrated approach to Water Science and Computational literacy. It combines authentic learning experiences in the schoolyard, physical, conceptual and computational models and data interpretation to enable high school students and teachers to reason about an important local issue: urban runoff and flooding in Baltimore.

 

Caplan, Bess

B-F059: The Baltimore Urban Ecological Young Environmental Scientist (YES) Program

Tanaira Cullens, Alan R. Berkowitz, Deresha Porter

Baltimore Ecosystem Study LTER, Cary Institute of Ecosystem Studies

The Young Environmental Scientist (YES) program is a partnership between the Baltimore Ecosystem Study and the Parks & People Foundation, a local non-profit organization engaged in youth development and urban greening initiatives. YES recruits Baltimore City High School students into a 5 week, paid internship program where team members learn environmental science through authentic research with mentors in real research sites using actual BES protocols. Students also receive job and life skills training and participate in team building activities. BES is exploring these students’ understanding of the outcomes and benefits of scientific study of ecosystems.

 

Castorani, Max

A-F072 Loss of foundation species: disturbance frequency outweighs severity for kelp forest biodiversity

Daniel C. Reed, Robert J. Miller

Santa Barbara Coastal LTER, Virginia Coast Reserve LTER, University of Virginia

Disturbances often cause the disproportionate loss of foundation species but understanding how the frequency and severity of disturbance to such organisms influence communities remains unresolved. We carried out a 9-yr, large-scale, spatially replicated field experiment at Santa Barbara Coastal LTER in which we manipulated disturbance to giant kelp and tracked the response of >200 taxa over time. We discovered that the frequency of disturbance to giant kelp changed the biomass, diversity, and composition of community guilds in a manner commensurate with their dependence on the physical (i.e., light, space), trophic (i.e., living and detrital biomass), and habitat (i.e., biogenic structure) resources mediated by this foundation species.

 

Chamoro, Jannine

B-F078: Ecological epigenetics of marine invertebrates in the Santa Barbara Channel

Logan Kozal, Gretchen Hofmann

Santa Barbara Coastal LTER, University of California-Santa Barbara

Epigenetic mechanisms are thought to be processes that could drive rapid changes in organismal tolerance. I am interested in exploring epigenetic processes in coastal marine invertebrates and an ideal place to first test these hypotheses is the rocky intertidal zone due to the steep environmental stress gradients over small spatial scales. Natural variation in temperatures experienced by sessile California mussels (Mytilus californianus) make them excellent candidates for determining how parental conditioning can affect progeny. In a study associated with the SBC LTER, I will compare mussels from high and low zones of the intertidal region to determine if epigenetic patterns differ in progeny with regard to adult conditioning.

 

Chappell, Jessica

A-K10: Long term changes in habitat connectivity for migratory shrimp in northeastern Puerto Rico

Kyle McKay, Mary Freeman, Cathy Prignle

Luquillo LTER, University of Georgia

We build a picture of long-term changes (over 30 years) in the proportion of habitat connected to the regional freshwater shrimp metapopulation across seven watersheds draining El Yunque National Forest (aka Luquillo Experimental Forest) in the mountains of northeastern Puerto Rico. Specifically, we discuss the impact of season and drought conditions, as well as human water withdrawals, on longitudinal riverine connectivity for freshwater shrimp. While we find stream habitat connectivity declined through time, high quality shrimp habitat connectivity has been consistently low. Examining long-term temporal changes in habitat connectivity demonstrates how differing water intake locations can alter shrimp access to habitat.

 

Charles, Sean

B-K107: Saltwater intrusion and vegetation shifts alter organic carbon storage across the coastal Everglades

Florida Coastal Everglades LTER, Florida International University

Coastal wetlands efficiently store organic carbon (OC), mitigating climate change and increasing soil elevation. Sea level rise alters biogeochemical conditions and drives vegetation shifts across the Everglades landscape, with uncertain OC storage impacts. We manipulated salinity, phosphorus and inundation and found that increasing salinity (0- 9 psu) drove root mortality, OC loss and 2.8 cm of elevation decrease in six months. In field surveys across the marsh to mangrove ecotone we identified similar OC losses during saltwater intrusion, but mangrove encroachment can mitigate OC losses and increase OC storage through time. The interaction of saltwater intrusion and vegetation shifts will drive wetland vulnerability with climate change.

 

Chilcutt, Cameo

B-K129: REU Poster: Disturbance effects on species richness within and across co-located NEON-LTER sites.

Sydne Record, Phoebe Zarnetske, Benjamin Baiser, Kyra Hoerr, Huijie Wei, Beth Gerstner

NEON, Northeastern Illinois University

Disturbance and land-use may produce long-lasting environmental legacies. Quantifying disturbance history of a landscape enables deeper understanding of ecological changes in the past and present, and can help forecast future changes. National Ecological Observatory Network (NEON) sites co-located with Long Term Ecological Research Network (LTER) sites offer an opportunity to contextualize the current cross-continental ecological patterns detected by NEON’s standardized data collection using long-term site history from LTER. In this study, we compiled land-use and disturbance history at co-located NEON-LTER sites to explore how species richness is affected by disturbances within and across sites.

 

Childers, Dan

A-K116: Urban ecology & sustainability through the lens of Urban Ecological Infrastructure (UEI)

Mark Watkins

Central Arizona-Phoenix LTER, Arizona State University

The Central Arizona-Phoenix LTER program has been studying the greater Phoenix region as a social-ecological system for 20 years. A new theoretical focus for CAP IV is on UEI as a critical bridge between the system’s biophysical and human/social domains. UEI acts as the central conceptual framework that guides all CAP research and activities. With this framework, CAP is exploring new frontiers of interdisciplinary urban ecology in residential landscapes, urban waterbodies, desert parks and preserves, the flora, fauna, and climate of a “riparianized” desert city, and urban design and governance. CAP is organized around eight research questions being addressed by eight Interdisciplinary Research Teams. We are continuing to grow urban systems.

 

Childers, Dan

A-K128: Site Poster

Mark Watkins

Central Arizona-Phoenix LTER

 

Ciruzzi, Dominick

A-F006: Groundwater-forest interactions in the sandy temperate forests of NTL-LTER

Steven P. Loheide II

North Temperate Lakes LTER, University of Wisconsin-Madison

This study focuses on the bi-directional interactions between the groundwater and forest systems during drought at the NTL-LTER site in northern Wisconsin. We analyzed tree growth chronologies and forest groundwater use from diurnal water table fluctuations along a depth to groundwater gradient, 1-9m. In general, trees in shallower groundwater areas showed high annual growth and consumed high quantities of groundwater during both wet and dry periods. In deeper groundwater areas, we observed consistently lower annual growth and little to no groundwater use in trees. Our research aims to provide a basis for understanding these groundwater-tree interactions in temperate forests to help guide sustainable water and forest management decisions.

 

Clare, Xochitl

B-F093: Snails on the menu? Investigating ocean acidification impacts on kelp forest predator, K. kelletii

Santa Barbara Coastal LTER, University of California, Santa Barbara

To ensure sustainable shellfish populations, we must understand how various life stages will be affected by predicted increases in environmental variability. A prominent kelp forest predator, the Kellet’s whelk (Kelletia kelletii), is an emerging fishery species. Little is known about the physiological tolerances of its early stages. As part of the SBC LTER effort, I am studying the Kellet’s whelk and their life history. Alongside feeding trials on adults, in Summer 2018, I observed impacts of current and future pCO2 levels on Kelletia kelletii early development. My work represents the first ocean acidification study on this species, contributing to our understanding of future behavior of important kelp forest marine invertebrates.

 

Coleman, Daniel

A-F063: The effect of vegetation dieback on salt marsh sediment transport and surface elevation        

Virginia Coast Reserve LTER, Virginia Institute of Marine Science

Vegetation is a critical component of ecogeomorphic feedbacks that allow a salt marsh to accrete vertically and resist erosion. Vegetation disturbance can have detrimental effects on marsh stability, especially under rising sea levels. Here, we report a variety of sediment transport measurements associated with an unexpected, natural dieback in a rapidly prograding marsh. We find that vegetation mortality led to a significant loss of elevation compared to undisturbed reference areas. Belowground mortality led to reduced soil shear strength, and a switch from a depositional to erosional topographic profile. Vegetation disturbance can temporarily reverse the trajectory of a prograding marsh and produce complex patterns of sediment transport.

 

Connell, Kent

B-F018: Plant-soil history has lasting effects on soil organic matter decomposition

Konza Prairie LTER, Kansas State University

We investigated how species-specific plant-soil feedbacks affect rates of SOM decomposition. We addressed this by conducting a “home vs. away” plant-soil feedback greenhouse experiment using two C3 grass species (Bromus inermis and Pascopyrum smithii). SOM-derived CO2 production and microbial biomass were always significantly higher in soils that were originally conditioned by B. inermis regardless of which plant species was being grown in those soils. Our results are likely due to the differential effects of plant species on soil microbes during the original conditioning phase. This suggests that changes in soil microbial community caused by shifts in plant species composition can have lasting effects on ecosystem processes.

 

Conrad , Louise

A-K111: Interagency Ecological Program: Synthesis for an Environmentally and Economically Vital Estuary

Melinda Baerwald, Larry Brown, Steven Culberson, Maggie Christman, Karen Kayfetz, Shruti Khanna, Peggy Lehman, Brian Schreier, Ted Sommer, Vanessa Tobias

California DWR, California Department of Water Resources,

The Interagency Ecological Program has conducted five decades of monitoring in the San Francisco Estuary and is guided by scientists across multiple resource agencies. The program structure naturally lends itself to synthesis, resulting in numerous reports and publications. IEP synthesis teams are primarily composed of agency scientists and strive for inclusion of experts from academic and private groups. A common theme of synthesis efforts is conceptual models for species’ biology, which in turn prompt new synthesis efforts to inform management. High human demands on this system put ecological synthesis in the spotlight for its ability to inform management decisions that have far-reaching implications for both ecology and human society.

 

Conroy , John

B-F045: Seasonal succession and local surface currents structure a coastal Antarctic zooplankton community

Deborah Steinberg, Leigh West

Palmer Antarctic LTER, Virginia Institute of Marine Science

This study investigates coastal Antarctic zooplankton community structure on a scale of days to months throughout the productive summer season for the first time. Twice-weekly net tows were conducted at time-series sites near Palmer Station from November 2017 to March 2018 as part of the PAL LTER. Over the study period, local abundance of the Antarctic krill Euphausia superba, the pelagic snail Limacina helicina, and the herbivorous copepod Calanoides acutus all declined while abundance of omnivorous calanoid copepods increased. Other taxa peaked mid-season at different times. High-frequency variability will be discussed in the context of tidal regime and wind direction, which control local surface currents.

 

Cook, Dana

A-K100: Effects of Spatial Heterogeneity of Browsing on Coral Reef Community Structure and Dynamics

Mo’orea Coral Reef LTER, UCSB

Coral reefs are dynamic ecosystems that can undergo phase shifts from coral to macroalgae dominance. A key ecological process underpinning these shifts is browsing – the consumption of mature macroalgae that suppresses the growth of corals. In Moorea, French Polynesia, browser species are not only ecologically significant, but also important in a socio-economic context as they are counted in the top three genera caught. In 2017, we observed spatial heterogeneity in browsing along a gradient of sites varying in physical properties and biotic communities. Our goal is to address the underlying drivers causing this variation in browsing pressure, and eventually link fishing practices to spatial patterns of herbivory and coral or algae dominance

 

Cook, Danielle

B-K120: REU Poster: The Effects of Evergreen Understory Shrub Species on Forest Soil Moisture Availability

Christopher Oishi, Paul Bolstad, Chelcey Miniat

Coweeta LTER, University of North Carolina at Chapel Hill

Evergreen understory species Rhododendron maximum and Kalmia latifolia may inhibit the regeneration of canopy trees, perhaps through resource competition for nutrients, lights, or water. This project investigates the impacts of these species on soil moisture in Coweeta Basin. Soil moisture varies by topographic position, and within the same topographic position between open and evergreen coverage. Water use and interception are proposed mechanisms by which this occurs, but further data collection and analysis is required.

 

Cordero Quiros, Nathali

B-F086 A Composite Physical-Biological Enso in the California Current System

Arthur J. Miller, Aneesh C. Subramanian, Jessica Luo, Matthew Long

California Current Ecosystem LTER, Scripps Institution of Oceanography

We show the response of the California Current System (CCS) to ENSO events through composite anomalies of different physical and biogeochemical fields derived from a 67-year long simulation from NCAR. The results show the composite evolution of anomalies of SST, pycnocline depth, vertically integrated chlorophyll and zooplankton, oxygen and one nutrient, during 13 El Niño and 13 La Niña events over the CCS.

 

Cox, Julia

B-K124: REU Poster: Zooplankton Regime Shifts and Spatial Variability  on the Southern New England Shelf

Joel Llopiz

Northeast U.S. Shelf LTER, University of Massachusetts Amherst, Woods Hole Oceanographic Institution

To inform future Long Term Ecological Research, zooplankton data collected by the NOAA NMFS NEFSC Oceanography Branch from 1977 to 2015 was used to investigate long-term spatial and temporal abundance trends for six zooplankton taxa on the Southern New England Shelf. The six selected taxa are important prey species for forage fish on the Northeast US shelf and are vital components of the shelf ecosystem. Principal component analyses and sequential t-tests were used to identify zooplankton regimes, and the onshore-offshore spatial distribution of the six taxa was assessed. Four regimes (1977-1988, 1989-1994, 1995-2002, and 2003-2015) were identified. These shifts were driven by variability in Calanus and Centropages copepods.

 

Crotty, Sinead

A-F068: Foundation species patch configuration mediates marsh biodiversity, stability and multifunctionality

Christine Angelini

Georgia Coastal Ecosystems LTER, University of Florida

Foundation species enhance biodiversity and multifunctionality across many systems; however, whether foundation species patch configuration mediates their ecological effects is unknown. In a 6-month field experiment, we test which attributes of foundation species patch configuration control biodiversity, stability, and multifunctionality by adding a standardized density of mussels in patches of 1, 5, 10, 30, 60, 90, or 180 individuals to a southeastern US salt marsh. We find that mussel configuration—by controlling the relative distribution of multi-dimensional patch interior and edge niche space—critically modulates this foundation species’ effects on ecosystem structure, stability, and function.

 

Culberson, Steven

A-K113: Interagency Ecological Program (IEP): Long-term monitoring science in a multi-agency context

Louise Conrad, Melinda Baerwald, Larry Brown, Maggie Christman, Karen Kayfetz, Shruti Khanna, Peggy Lehman, Brian Schreier, Ted Sommer, and Vanessa Tobias

California DWR, Interagency Ecological Program/Delta Stewardship Council

The history of ecological monitoring within the San Francisco Estuary IEP dates to the 1970s, and includes measurement of a variety of habitats and species. Originally a status-and-trends program for water management, the IEP has evolved onto a policy-relevant scientific enterprise covering dozens of species from the head-of-tide to the near-shore coastal Pacific Ocean. Current efforts at synthesis of long-term data sets are reshaping the direction of future monitoring science, environmental compliance, and innovative, open-science-based research.

 

Currier, Courtney

A-F073: Multi-year rainfall manipulation effects on grass and shrub phenology at the Jornada Basin LTER

Osvaldo Sala

Jornada Basin LTER, Arizona State University

Aboveground net primary production in drylands is tightly linked to annual precipitation amount. We hypothesized that changes in production due to changes in precipitation result from changes in phenology (duration of greenness period), changes in rate of productivity (maximum greenness), or both. We found, using time-lapse cameras across a range of experimental rainfall manipulations at the Jornada LTER that shrubs and grasses respond differently to precipitation changes. Grasses exhibit a fixed phenology response depending on water availability whereas shrubs were not affected by differences in precipitation. Overall, drought had a stronger effect on plant phenology than increased precipitation.

 

Cusser, Sarah

B-F020: Long-term data and community dynamics of important biocontrol agent in agro-ecosystems

Kellogg Biological Station LTER, Michigan State University

Ecosystem services (ESS) delivered by mobile organisms depend on spatially segregated habitats. The loss of natural habitat in agroecosystems can impact mobile organisms and alter the ESS they provide. However, land management, including tillage or chemical use, can mitigate the negative effects of habitat loss and bolster crop yield. Syrphid flies act as biocontrol agents in agroecosystems, suppressing aphid outbreaks. The influence of, and the interaction between, local and landscape management on Syrphid abundance is little known. Here we use a long-term dataset to explore the effect of land management on fly community dynamics within and between years by comparing four management regimes across a gradient of landscape contexts.

 

Danielson, Seth

A-F055: It’s a finescale line: Acrobat® observations from along the Gulf of Alaska hydrographic tightrope

Northern Gulf of Alaska LTER, University of Alaska Fairbanks

Physical and chemical water column structure delineates oceanic habitats that influence planktonic and upper trophic level specie distributions and community compositions. Measurements from the Gulf of Alaska upper water column (0-50 m) using a towed undulating Acrobat® conductivity-temperature-depth profiler equipped with a variety of optical sensors resolve relatively fine-scale (< 1 km) features that are aliased by traditional sampling methods. These new observations reveal details of the contrasting balances in the hydrographic structure and dynamics of fjord, coastal, shelf, slope, and oceanic domains. Such differences may influence system resilience and adaptive behaviors of foraging zooplankton, fishes, seabirds and marine mammals.

 

DeAngelis, Kristen

A-F037: Microbial controls over soil carbon dynamics in a warming world

Grace Pold, Luiz Domeignoz Horta, Xiaojun Liu, Serita Frey, Jerry Melillo

Harvard Forest LTER, University of Massachusetts Amherst

Microbes are key drivers of biogeochemical cycling in terrestrial ecosystems, and inclusion of microbial dynamics can improve Earth system models. We investigate a long-term field warming experiment at the Harvard Forest LTER, where soils have been heated 5 degrees Celsius above ambient temperatures for 27 years. Using field, laboratory, and modeling experiments, our research addresses the questions: How does microbial evolution of bacterial traits versus shifts is dominant actors over time affect soil C cycling? How does diversity, soil moisture and temperature differently affect carbon use efficiency and soil C stability? How does physical versus biochemical protection of soil organic matter change over the course of long-term warming?

 

Denny, Riva

A-F020: Midwest Farmer Perceptions of Cover Crops: Implications for Cover Crop Use

Kellogg Biological Station LTER, Michigan State University

Cover crops are being promoted to improve soil quality and reduce agricultural soil and nutrient run-off. However, the use of cover crops remains substantially lower than the use of other conservation practices such as conservation tillage and no-till (~ 2.5% vs. ~25% of Midwest cropland in 2012). To help better understand the low rate of cover crop use, I analyze farmer survey data collected in spring 2018 in four Midwest states and examine responses on the perceived usefulness of cover crops for topics including: preventing erosion, improving soil quality, controlling weeds, and saving money on inputs. If farmers do not think cover crops will provide them enough benefits to be worth the costs, then they are less likely to use them.

 

DeVan, Rae

B-F053: Fire and fungi in the changing boreal forest

Bonanza Creek LTER, University of New Mexico

We sought to understand how increases in wildfire severity and associated shifts in post-fire trajectories from black spruce self-replacement to deciduous dominance, along with introduction of a non-native host tree, lodgepole pine, effect mycorrhizal fungal communities in the boreal forests of Interior Alaska. We characterized the mycorrhizal fungi on native, and lodgepole pine seedlings from 2004 burn sites, including in Bonanza Creek. There was significantly lower diversity on aspen compared to coniferous hosts, predictable shifts in mycorrhizal fungal guilds with burn severity, and evidence that plantings and potential expansion of non-native lodgepole pine will result in substantial co-introduction of fungi novel to the region.

 

Dickerson, Kevin

A-F049: Using LTER Data in the 7-9th Grade Science Classroom to Achieve Student Science Literacy Objectives

Byron Adams

McMurdo Dry Valleys LTER, American Fork Junior High School

We implemented “Authentic Inquiry” aspects of the Polar Interdisciplinary Coordinated Education (Polar-ICE) program. Throughout the school year students practiced identifying trends and patterns among biological and environmental variables, generating testable hypotheses, and formatting, analyzing, and interpreting MCM and PAL LTER data. The project culminated in a research symposium at BYU where students presented their findings to faculty and graduate students, and received feedback on their hypotheses, analytical design, and interpretation of results. Project assessments imply that the activity was an important component of the overall classroom experience and reinforced Utah state core standards for 9th grade science literacy.

 

DiFiore, Bartholomew

B-F071: How history of disturbance alters the diversity and structure of kelp forest communities.

Adrian Stier, Max Castorani, Tom Bell, Dan Reed, Kyle Cavanaugh, Bob Miller

Santa Barbara Coastal LTER, University of California, Santa Barbara

Disturbance is well known to alter the structure and diversity of communities. However, if disturbance alters communities through niche-based or stochastic processes is an outstanding question. California’s giant kelp forests form an extensive metapopulation where individual patches are regularly disturbed by large waves, sea urchin outbreaks, and declines in nutrients. Using a satellite derived time series of kelp biomass, we identified kelp patches with different histories of disturbance and conducted diver surveys to assess community structure. To determine how disturbance alters kelp communities we examined how beta diversity and the abundance of major functional groups differed between sites along the gradient of disturbance history.

 

DiGregorio, Lina

A-K128: Site Poster

Andrews Forest LTER

 

Dong, Zheng

A-F043: Improved simulations of canopy interception/evapotration in an old-growth Douglas-fir forest

Sherri Johnson

Andrews Forest LTER, Oregon State University

A biogeochemical/hydrological model had been applied in the H. J. Andrews Experimental Forest to examine future dynamics of water, carbon, and nitrogen under climate change scenarios. While being able to capture temporal variations of most elements and processes, the model performed less accurately in streamflow at the start and end of rain seasons in the Pacific Northwest. We attributed this mismatch to current model algorithms on canopy interception/evaporation which used a large but fixed percentage of rainfall to depict the large biomass of needles and epiphytes. We improved model simulations on this process and showed great implications on dynamics of other elements under future climate change in the old-growth Douglas-fir forest.

 

Dudley, Maura

B-F063: Top-down effects of crayfish alter stream ecosystem response to riparian disturbance

Kelsey Solomon, Seth Wenger, Rhett Jackson, Katherine J. Elliott, Chelcy F. Miniat, and Catherine M. Pringle

Coweeta LTER, University of Georgia

In the southern Appalachians, removal of Rhododendron maximum is a potential management strategy to restore hardwood forests. Here, we examine how top-down control by crayfish alters stream ecosystem response to reach-scale rhododendron removal. We conducted 32-day experiments using paired crayfish exclusion and access (control) plots, nested within 300 m stream reaches of a control and rhododendron removal manipulation stream. Our findings suggests that crayfish consumers mediate increased algal growth when rhododendron is removed, and play a dominant role in leaf decomposition in both reach types. Initial response to rhododendron removal may not persist over the long-term if crayfish abundance ultimately declines due to rhododendron loss.

 

Dugan, Jenifer

A-F077: Evaluating responses to trophic connectivity between kelp forest and sandy beach ecosystems

Carter Ohlman, Kyle Emery, David Hubbard, Trenton Koeper, Robert Miller, Jessica Madden

Santa Barbara Coastal LTER, Marine Science Institute, University of California, Santa Barbara

Trophic connectivity across ecosystems can strongly affect recipient food webs. We quantified trophic connectivity between giant kelp forests and sandy beaches in the SBC LTER. Kelp removal from forests and delivery to beaches varied greatly in time and space but drift cards, GPS tracks and model trajectories indicated ~ 25% of kelp plants landed on nearby beaches. Kelp deposition on beaches was strongly influenced by coastal topography, beach conditions, and proximity to kelp forests with the greatest kelp abundance on beaches near headlands. Recipient beach ecosystems responded to spatial dynamics of kelp subsidies, even on a local scale, suggesting spatial variation in trophic connectivity can strongly affect these recipient ecosystems.

 

Eggenberger, Cody

B-K098: Coupling telemetry and stable isotope techniquest to unravel movement

Florida Coastal Everglades LTER, Florida International University

Anthropogenic impacts can alter the quality of coastal habitats, and the ways in which animals move and distribute themselves throughout landscapes. Understanding how these impacts may be altering animal habitat selection mechanisms is critical. Among the most prominent anthropogenic perturbation to coastal ecosystems is nutrient enrichment, known to impact aquatic animal distributions and behaviors. In this study, we coupled acoustic telemetry methods and stable isotope analyses (SIA) to examine the effects of nutrient enrichment on habitat selection and diets of Common Snook (Centropomus undecimalis) in two neighboring subestuaries of varying nutrient enrichment state. We observed both movement and isotopic variation between Snook in both

 

Emery, Kyle

A-F081: Assessing the recovery and resilience of sandy beach consumer populations to disturbance

Nicholas Schooler, Jenifer Dugan, David Hubbard, Kyle Cavanaugh

Santa Barbara Coastal LTER, University of California, Santa Barbara

Evaluating the effects of disturbance on population dynamics yields insights on resilience to environmental change. Disturbance to sandy beach ecosystems occurs during major storms and El Niño events. We used long term data on kelp canopy biomass, macrophyte wrack, beach conditions and intertidal wrack consumers to investigate population responses to variation in kelp subsidies and beach habitat. The availability of both habitat and food resources strongly controlled wrack consumer populations. Recovery of beach ecosystems from major disturbances was a multi-year process and time to recovery varied across SBC beaches. Population dynamics of wrack consumers can be strong indicators of beach food webs and their connectivity to kelp forests.

 

 

Fakhraei, Habibollah

B-F031: Impact of Experimental and Natural Ice Storm on Ecosystem Dynamics in Northen Hardwood Forest

Charles Driscoll, Lindsey Rustad, John Campbell, Peter Groffman, Timothy Fahey

Hubbard Brook LTER, Syracuse University

A novel field experiment was conducted in a northern hardwood forest at the Hubbard Brook Experimental Forest to quantify the influence of ice storms on the ecological processes. During subfreezing conditions in the winters of 2016 and 2017, water from a nearby stream was pumped and sprayed on the canopy of eight experimental plots to accrete ice to a targeted thickness on the canopy. The most notable response of the icing treatments was a marked increase in fine and course litter fall, and the post-treatment openings in the canopy caused short-term increases in soil temperature in the ice-treatment plots. In this study, we compared the ecosystem response to the experimental ice storm and to the 1998 ice storm and we used a biogeochemical model, PnET-BGC, to evaluate the long-term impacts of ice storms on northern hardwood forest.

 

Fisk, Melany

A-F032 Nutrient limitation and interactions of N and P availability in northern hardwood forests

Hubbard Brook LTER, Miami University

Ecosystem productivity is often co-limited by N and P, and we tested the hypothesis that interactions between soil N and P availability contribute to co-limitation in northern hardwood forests. P limitation, but not co-limitation, was indicated by tree growth responses to 5 years of NxP fertilization. P limitation of soil microbial activities was suggested by enzyme activities and microbial growth responses to N and P. Resin-available N was suppressed and N-use efficiency for leaf production increased in response to elevated P. We propose that alleviating microbial P limitation promotes microbial N uptake and induces N limitation of forest productivity, leading to sequential co-limitation over time.

 

Forrester, Chiara

B-F002: The impacts of early snowmelt on alpine plants

Niwot Ridge LTER, University of Colorado at Boulder, Institute of Arctic and Alpine Research

Climate warming is accelerating spring snowmelt, with pronounced effects in mountain ecosystems. Early snowmelt results in an extended summer that may increase stressors for plants, such as water limitation and a higher frequency of frost events. Plant phenology, or the timing of biological life stages, has been shown to be highly sensitive to changes in time of snowmelt. These changes in plant phenology may cause changes in plant fitness (e.g. by altering the length of the growing season). Thus, understanding how plant phenology responds to early snowmelt across heterogeneous landscapes will aid us in predicting the effects of climate warming on alpine plant populations.

 

Forsch, Kiefer

A-F079: Iron limitation of a coastal filament in the southern California Current Ecosystem

Katherine Barbeau

California Current Ecosystem LTER, Scripps Institution of Oceanography

During periods of intense coastal upwelling, the micronutrient iron is supplied to the mixed layer from nearshore sedimentary sources and is an important bottom-up control on the distribution and growth of phytoplankton in the California Current Ecosystem. In this upwelling region, mesoscale filament features distribute iron laterally, leading to distinct iron-influenced ecological zones. Presented here are broad spatial patterns of iron concentrations and proxies of iron-stress of diatoms, including results from microcosm amendment studies conducted during a cruise in June 2017. These results highlight rapid removal of iron from a recently upwelled water mass, leading to diminished supply for downstream, offshore primary producers.

 

Fulton, Kayleen

B-F079: Dynamics of Biogenic Silica in a coastal upwelling filament in the California Current Ecosystem

Katherine A. Barbeau, Michael R. Stukel, Jeffrey W. Krause

California Current Ecosystem LTER, University of California, San Diego – Scripps Institution of Oceanography

Previous studies have shown that iron limitation affects silicic acid to carbon (Si:C) and silicic acid to nitrate (Si:N) uptake ratios in marine diatoms. Changes in these elemental ratios result in enhanced silica ballasting and protection from grazing via thicker frustules. These physiological responses have the potential to increase export, while decreases in organic material growth can counter this effect. Results are presented from a Lagrangian study of the dynamics of biogenic silica throughout the progression, from nutrient-replete to iron-limited, of a coastal upwelling filament in the California Current Ecosystem. Changing Si:N and Si:C ratios were observed in growth and export with the onset of iron limitation.

 

Gallagher, Jordan

B-K121: REU Poster: Application of Photogrammetry and a Geodetic Network for 3D Coral Reef Modeling

Russ Schmitt, Sally Holbroo, Andrew Brooks, Alessandro Capra, Erica Nocerino, Fabio Menna, Serkan Ural, Fabian Neyer, Armin Grun

Mo’orea Coral Reef LTER, UC Santa Barbara

We combined photogrammetric techniques with a geodetic control network to produce high accuracy 3D models of coral reefs at various scales and depths. Highly accurate and reliable measurements create a precise geodetic network capable of estimating coral growth, reef degradation and habitat availability. Use of cameras with varying quality and price allow assessment of model accuracy along a gradient of budgets.

 

Gervasi, Carissa

A-K099: Impacts of Coastal Marine Reserves on Sport Fish Traits: A Case Study in Florida Bay

Florida Coastal Everglades LTER, Florida International University

Numerous studies have shown that marine reserves (areas closed to fishing) can have important benefits for exploited fish populations. This study uses a multi-pronged approach to determine the efficacy of a small, coastal marine reserve in Florida Bay that has been closed to public access for over 30 years. Life history traits, behavior, and movement of the Gray Snapper (Lutjanus griseus) will be compared between the marine reserve and adjacent fished areas to determine how the closure has impacted Gray Snapper traits. We expect that fish inside the marine reserve will exhibit higher growth rates, bolder behavior, and decreased movement in and out of the protected area, all of which could have dramatic effects on recreational anglers.

 

Gherardi, Laureano

B-F082: Precipitation controls above-belowground partitioning of net primary production across biomes

Osvaldo E. Sala

Jornada Basin LTER, Arizona State University – Global Drylands Center

Are BNPP and ANPP responding in synchrony to major drivers of ecosystem functioning across biomes? Or, specifically, does water availability affect ANPP and BNPP in similar ways? Or does the effect of water availability on BNPP offset the ANPP response? Few studies have explored the effect of precipitation on the fraction of total primary production allocated belowground. Our work explores hypotheses regarding how changes in water availability affect the fraction of belowground net productivity relative to total production and how the effect of water availability changes across spatial gradients of long-term mean precipitation from deserts to tropical forests.

 

Giblin, Anne

A-K121: Site Poster

Plum Island Ecosystem LTER

 

Glanville, Kathryn

A-F011: Consequences of Extreme Rainfall Patterns on Nitrous Oxide Fluxes in Midwest Cropping Systems

Kellogg Biological Station LTER, Michigan State University

Nitrous oxide (N2O) is the dominant natural ozone-consuming substance in the stratosphere and a strong greenhouse gas. N2O is produced by soil microbes and fluxes are closely linked with soil moisture. Documented and future changing rainfall patterns due to climate change will likely influence N2O fluxes. Since the majority of anthropogenic N2O produced globally is from agricultural soils, where fluxes are controlled by numerous factors including oxygen, nitrate, and carbon availability (all of which are strongly tied to soil moisture status), it is important to understand the impact of extreme precipitation patterns on N2O emissions. We tested the hypothesis that changing rainfall patterns strongly alter N2O fluxes in agricultural soils.

 

Gooseff, Michael

A-K127: Ecosystem Connectivity in a Polar Desert – the McMurdo Dry Valleys, Antarctica

Byron Adams, Jeb Barrett, Shawn Devlin, Peter Doran, Adrian Howkins, Diane McKnight, Rachael Morgan-Kiss, John Priscu, Cristina Takacs-Vesbach, Kathleen Welch

McMurdo Dry Valleys LTER, University of Colorado

The McMurdo Dry Valleys of Antarctica are dominated by bare soils, glaciers, streams, and ice-covered lakes. The two main physical processes that connect the landscape are aeolean transport (primarily during winter) and hydrologic transport (summer only). We have observed patterns in physical connectivity that directly influence biological communities and community dynamics. For example, streams with intermittent flows tend to have more endemic diatom species in their benthic mats. We postulate that greater connectivity of landscape units (in frequency and magnitude) will homogenize the ecosystem. Here we test this with specific and general monitoring measurements mad in our ecosystem.

 

Gorgas, Maya

B-K130: REU Poster: Seawater Temperature Trends Using Sensors Deployed Around the Island of Mo’orea, French Polynesia

Moorea Coral Reef LTER

 

Gosnell, Hannah

A-F040: Forest Governance, LTER Science, and Landscape Change in the Western Cascades, OR

Jesse Abrams, Tyler Harris, Heidi Huber-Sterns, Julia Jones, Robert Kennedy, Michael Nelson, Fred Swanson

Andrews Forest LTER, Oregon State University

This poster provides an overview of how social science and geospatial science have been integrated to contribute to LTER7 Goal III, which is to understand connections between forest governance and landscape pattern and process, and the ways in which public perceptions and valuations of federal forest landscapes and LTER science influence those connections. Research includes characterization and quantification of a transition in federal forest governance from a ‘dominant federal’ model to a ‘social forestry’ model on Willamette National Forest; geospatial analysis of resulting timber harvest patterns, and consideration of the role that Andrews Forest science has played in governance change and landscape change.

 

Grimm, Nancy

A-F085: A Most Valuable Accident: Accidental Wetlands Provide Ecosystem Services in an Aridland City

M. Handler, M. Lauck, M. M. Palta, A. Suchy

Central Arizona-Phoenix LTER, Arizona State University, School of Life Sciences

Accidental wetlands are unique urban habitats resulting from human activities but not designed or managed for any specific purpose. These understudied wetlands likely provide ecosystem services. The Salt R channel in Phoenix supports several accidental wetlands maintained by storm drains discharging urban baseflow and stormwater into the dry river bed with its compacted sediments. CAP studies have examined the ecosystem services provided, especially related to nutrient cycling. Findings suggest that reduction of nitrate, a potentially problematic nutrient in these wetlands, is occurring without active restoration and management. However, nitrate removal could be augmented through hydrologic management of these accidental wetlands.

 

Guinnip, James

B-F009: Exploring Causes of an Extraordinary Shift in Water Chemistry in a Pristine Grassland Stream Network

Walter Dodds

Konza Prairie LTER, Kansas State University – Division of Biology

An analysis of long-term water chemistry data from Kings Creek has revealed an extraordinary increase in the availability of ammonium (NH4+) on a decadal scale. We used water chemistry data from 1983-2016 from multiple locations within the Kings Creek stream network to characterize trends of NH4+ concentration over time. We hypothesize: 1) atmospheric pollution is increasing the deposition of reduced N, which enters streams; and 2) woody expansion in grasslands stores N and alters N cycling to increase NH4+ in streams. We measured rates of nitrification and denitrification in riparian and benthic habitats of open- and closed-canopy stream reaches to quantify the influence of riparian woody vegetation on rates of N cycling.

 

Gutierrez del Arroyo, Omar

B-K103: The response of soil biogeochemistry to drought and hurricanes in a wet tropical forest

Whendee L. Silver

Luquillo LTER, UC Berkeley

Tropical forests are experiencing novel disturbance regimes with the potential to alter ecosystem processes in ways that could both alleviate or worsen our current climate crisis. To study the response of soil biogeochemistry to drought in a wet tropical forests, we established a throughfall exclusion experiment in the Luquillo Experimental Forest in Puerto Rico. Hourly measurements of soil temperature, volumetric moisture, and oxygen concentration at three depths, as well as quarterly soil samplings, have been ongoing since late 2016. Soil GHG fluxes have also been measured biweekly using manual static flux chambers. Although our results will focus on soil drought, we also captured the impact of two major hurricanes (Irma/Maria).

 

Hamilton, Stephen

A-F025: Nitrate leaching from continuous maize, perennial grasses, restored prairie, and poplar trees

Kellogg Biological Station LTER, Michigan State University

 

Harris, Carolynn

B-F043: Microbial decomposition of photosynthetic carbon in the water column of ice-covered Antarctic Lakes

John C. Priscu, Amy L. Chiuchiolo

McMurdo Dry Valleys LTER, Montana State University

The McMurdo Dry Valley lakes have ice-covered water columns (20-40m deep) and receive <5% of ambient light in summer (no light in winter). Lake food webs contain no crustaceous zooplankton or fish. Phytoplankton photosynthesis, a key source of organic matter (OM), produces 4000-9000 kg C yr-1. Stream microbial mats, flushed into the lakes at high flows, are an external OM source. Loss rates of these OM sources are not well constrained but are likely low (~0.01% day-1). We propose to assess microbial mineralization rates of OM sources in two lakes by measuring 14C-CO2 produced from 14C-labeled phytoplankton and stream mats. We hypothesize that the majority of OM is not mineralized within the water column and is decomposed on the lake bottom.

 

Hedin, Matthew

A-F050: Biogeochemistry and biology of simulated permafrost melt in the McMurdo Dry Valleys

Byron Adams, Michael Gooseff, Diana Wall, Ross Virginia, John Barrett

McMurdo Dry Valleys LTER, Virginia Tech

Climate change models predict that the McMurdo Dry Valleys (MDV) of Antarctica will experience future warming. This warming will result in permafrost thaw within the MDV that will result in a warmer, wetter, and more interconnected system. We simulated two levels of permafrost thaw in soil plots over four years. Plots were monitored for 6 years prior to treatment to establish baseline conditions. One plot was pulsed with water biannually while a second plot was pressed with water annually. A third plot was left as an un-amended control. By examining spatial, temporal, and treatment derived differences in biology, soil chemistry, and hydrology we are able to make predictions about the effect of climate change on the cryosphere.

 

Heindel, Ruth

A-F053: Aerosolization of cyanobacterial cells across ecosystem boundaries in the McMurdo Dry Valleys

Jessica Trout-Haney, Ross Virginia

McMurdo Dry Valleys LTER, University of Colorado Boulder, INSTAAR

Despite their predominance in polar ecosystems, the extent to which cyanobacteria move between terrestrial and aquatic landscape units remains poorly understood. We conducted a field study to examine the transport of aerosolized cyanobacterial cells from ponds and soils in the McMurdo Dry Valleys, Antarctica and in Kangerlussuaq, Greenland. We detected aerosolized picocyanobacterial cells from all ponds and soils sampled, indicating that these cells may be quite mobile and are transported across ecosystem boundaries. Our results highlight the role of aerosolization in mobilizing and transporting cyanobacterial cells, and suggest that even in extreme polar deserts, biological connectivity exists between aquatic and terrestrial habitats.

 

Helms, Jackson

A-F009: Can next-generation biofuel crops support native biodiversity and meet energy needs?

Kellogg Biological Station LTER, Kellogg Biological Station

Biofuel crops are increasingly grown to reduce fossil fuel use. Annual crops like corn displace natural vegetation and have few carbon benefits. But perennial crops, which do not require annual planting or tillage, sequester carbon and may support native biodiversity and associated ecosystem services. We compared biodiversity and ecosystem function in three biofuel crops—annual corn, perennial switchgrass, and perennial prairie—using landscape experiments at the KBS LTER. Using ants as an indicator taxon, we compared ant abundance, diversity, activity, and consumption of pest insects among crop types. Our results illuminate tradeoffs involved in biofuel production and suggest ways to maximize the conservation value of working landscapes.

 

Hewitt, Rebecca

B-F054: Mycobiont contribution to tundra plant acquisition of permafrost-derived nitrogen

Bonanza Creek LTER, Northern Arizona University

As arctic soils warm, newly thawed permafrost releases nitrogen (N) that could stimulate plant productivity and thus offset soil carbon losses from tundra ecosystems. The role of mycorrhizal fungi in plant access to N from newly thawed permafrost soils is unknown. We characterized depth profiles of mycorrhizal fungi on roots and at the thaw front below the maximum rooting depth of host plants in tussock and shrub vegetation communities at Eight Mile Lake, Alaska. We tested the relationships between root and thaw front fungal composition and plant uptake of an isotopically labeled 15N tracer applied at the permafrost boundary at maximum active layer thaw. We explore the role of mycorrhizal fungi as a mechanism for redistribution of deep N.

 

Hogan, Sara

B-F067: Using LiDAR data to map and quantify oyster reefs within the Virginia Coast Reserve

Matthew Reidenbach

Virginia Coast Reserve LTER, University of Virginia

Within the Virginia Coast Reserve (VCR), techniques to locate and map eastern oyster (Crassostrea virginica) populations and potential habitat are needed for continued monitoring and restoration efforts. LiDAR elevation, raw intensity, and derived slope information is input into GIS as layers and used to train maximum likelihood image classification tools to determine if this data can successfully be used to distinguish oysters within the VCR. Classified images are compared with ground truth oysters mapped based on elevation, aerial imagery, and GPS tracks. Data extracted to areas of oyster are also used to understand the physical environment of present oyster reefs to determine suitable habitat and environmental correlations.

 

Holbrook, Sally

B-K100: Recruitment Drives Spatial Variation in Recovery Rates of Resilient Coral Reefs

Thomas Adam, Peter J. Edmunds, Russell J. Schmitt, Robert C.Carpenter, Andrew J. Brooks, Hunter S. Lenihan, Cheryl J. Briggs

Mo’orea Coral Reef LTER, University of California Santa Barbara

Due to increasing threats to coral reefs, it is critical to understand mechanisms driving their recovery following landscape-scale loss of coral. We explored this issue on the fore reef of Moorea following a massive disturbance episode. Re-establishment of coral cover differed systematically around the island, returning most rapidly where the least amount of live coral remained, although all sites showed evidence of re-assembly to their pre-disturbance community. The primary driver of spatial variation in recovery was recruitment of sexually-produced corals. Although resilient, some areas may not attain the coral cover and taxonomic structure they previously had before another landscape-scale perturbation occurs.

 

Holguin, Jennifer

B-K127: REU Poster: Soil microbial and nutrient response to altered seasonal precipitation in two semi-arid grasslands

Scott L Collins, Jennie R. McLaren

Sevilleta LTER, The University of Texas at El Paso

Climate change models predict that arid and semi-aridland ecosystems will become increasingly dry with shifts in magnitude and timing of seasonal precipitation. In this study, we sought to answer how the biogeochemistry of semi-arid grasslands would respond to severe reduction and delay in monsoon season precipitation . In 2012, a precipitation alteration experiment was established in two southwestern semi-arid grasslands at the Sevilleta LTER site in New Mexico. In 2017, soil was collected at three time points: pre-monsoon, mid-monsoon, and post-monsoon.  Poster will display:  available nitrate, phosphate and ammonium, extractable organic carbon, total nitrogen,  soil microbial biomass (CNP) and microbial CNP acquiring enzyme results.

 

Hollibaugh, James

A-F060: Water temperature, rather than hypoxia, controls nitrification in temperate coastal waters

Georgia Coastal Ecosystems LTER, University of Georgia

Nitrification is a two-step process linking the reduced and oxidized sides of the N cycle. These steps are typically tightly coupled with the primary intermediate, NO2-, rarely accumulating. Mid-summer peaks of NO2- in well-mixed, estuarine waters off Georgia coincide with peaks of NH3-oxidizing Archaea. Experiments and analysis of data from 29 coastal sites show that NH3 and NO2- oxidation become uncoupled between 20-30 oC, leading to accumulation of NO2- driven primarily by water temperature, rather than by hypoxia. Potential consequences are increased N2O production, NO2- toxicity and accelerated loss of fixed N. Humans have greatly altered the N biogeochemical cycle and our results suggest that climate warming may alter it further.

 

Hong, Daniel

B-F032: Foliar Resorption of Northern Hardwood Species Indicates Nutrient Limitation

Hubbard Brook LTER, SUNY-ESF

Trees resorb nutrients from their leaves over the litterfall season; the timing of senescence reflects a tradeoff between continuing photosynthesis and risking winter damage. We collected green leaves in August and periodically collected fresh litter of American beech, pin cherry, white birch and yellow birch in fall 2016 from six hardwood stands at Bartlett, Hubbard Brook, and Jeffers Brook of NH, where N and P have been added annually since 2011 in a full factorial design. For most species, resorption of N occurs earlier in the season than P. Resorption efficiencies of N and P are affected by soil N and P availability. Reductions in foliar P concentrations with N addition might reflect vegetative growth or microbial immobilization.

 

Isaak, Ashtyn

A-K098: Interactive effects of ocean acidification and light on a reef-building alga at different depths

Mo’orea Coral Reef LTER, California State University Northridge

Ocean acidification (OA) negatively affects marine calcifying organisms, and can alter many physiological processes. Crustose coralline algae (CCA), such as Porolithon onkodes, are important structural calcifying components on coral reefs and they grow across a range of depths. This study investigated the interactive effects of light quantity (PFD) and spectral quality and pCO2 on P. onkodes to determine if CCA are impacted differentially by OA at depth. Mesocosms were utilized to simulate the light regimes that occur at shallow and deep reefs in Moorea, French Polynesia at both ambient and high pCO2 treatments. Preliminary results suggest that CCA from deeper reefs are impacted proportionally less by OA than CCA on shallow reefs.

 

Jackson, Rhett

A-K129: Site Poster

Coweeta LTER

 

James, Anna

A-F071: Monitoring the Kelp Microbiome

Santa Barbara Coastal LTER, University of California, Santa Barbara

Much like the tens of trillions of microbes that inhabit humans, giant kelp harbor microbial communities that differ phylogenetically from those in the surrounding water column. Our microbiome is essential for proper immune system function and plays a fundamental role in most aspects of our physiology. To assess whether, like the human microbiome, kelp actively produce dissolved organic matter to cultivate specific microbial assemblages that aid in kelp survival, I will show results from large spatial assessments of ‘the kelp microbiome’ (both 16S amplicon and metagenomic sequencing) coupled to concentrations and characterization of the dissolved organic matter released from individual kelp blades.

 

James, W. Ryan

B-K110: Consumer specific energetic landscapes derived from stable isotope analysis and habitat cover

James A. Nelson

Florida Coastal Everglades LTER, University of Louisiana

Habitats are spatial heterogeneous and vary in resource quantity and quality. Resource use varies between consumers within a food web, and areas of high resource quality are not the same for each consumer. Consumers integrate resources over space to fulfill energetic demands. We constructed consumer specific energetic landscapes by combining consumer source contributions derived from stable isotopes and habitat cover across a bay ecosystem. Maps were made of varying spatial resolution depending on the home range of the consumer and represent areas within the bay ecosystem with high resource quality for that consumer. These maps have the potential to explain the movement and spatial distribution of species within a habitat.

 

Jarecke, Karla

A-F044: Quantifying water for streamflow versus vegetation use in the West Cascades

Steve Wondzell, Kevin Bladon

Andrews Forest LTER, Oregon State University

Catchment water storage can be quantified as two functionally distinct pools of water: “direct storage”, which contributes to streamflow generation and “indirect storage”, which is retained in the catchment. The relative volumes and seasonal dynamics of direct and indirect storage provides a modelling framework for streamflow and vegetation response to climate change. We use long-term precipitation and discharge from the HJ Andrews Experimental Forest to estimate direct and indirect storage and quantify the proportion of indirect storage available to trees in the top meter of soil. Our results lead to potential hypotheses of how water storage mechanisms will affect streamflow and forest productivity in a warmer, drier climate.

 

Jevon, Fiona

A-F031: Harvard Forest’s first Data Nugget: Bringing our eddy covariance record to high school classrooms

Pamela Snow, Clarisse Hart

Harvard Forest LTER, Dartmouth College

The Harvard Forest eddy covariance tower has the world’s longest continuous record of net ecosystem CO2 exchange. We have created a Data Nugget activity that utilizes these data to teach about the forest carbon cycle, ecological research, and the scientific process at the high school level. The completion of this activity was an iterative process that involved scientists, education and outreach professionals, and teachers from several grade levels. Working with feedback across these groups presented some challenges, but dramatically improved the accessibility of the activity. We hope to share the activity as well as lessons we have learned about how to approach putting together Data Nuggets and other outreach materials for K-12 classrooms.

 

Ji, Wenjie

B-F092 Relationship between shrub cover and plant available water in a U.S. Southwest desert

Niall P. Hanan, Dawn M. Browning, H. Curtis Monger, Debra C. Peters, Julius Y. Anchang, Sanath S. Kumar, C. Wade Ross, Brianna M. Lind, Lara Prihodko, Steven R. Archer

Jornada Basin LTER, New Mexico State University

The abundance of woody perennial plants in arid ecosystems is constrained by water availability. However, the extent to which maximum canopy cover is limited by rainfall, and the degree to which soil characteristics, runoff and water redistribution impact maximum cover are not well understood. Plant communities at the Jornada LTER in the northern Chihuahuan Desert have experienced a long-term state-change, from herbaceous dominated grassland to woody plant dominated shrubland. To better understand this transformation, and the environmental controls on shrub cover, we created a shrub cover map using high spatial resolution images and explored how mean and maximum shrub cover vary with landform, water availability, and soil characteristics.

 

Jordan, Samuel

A-F087: Pulse regimes and the distribution of biocrusts in drylands

Osvaldo Sala, Sasha Reed

Jornada Basin LTER, Arizona State University

Drylands are ecosystems that are both notably arid and diverse. The large evaporative demand in drylands ensures that water availability will be dominated by pulse dynamics, however, we lack a mechanistic understanding of how changes in climate will influence dryland biota. In particular, biocrusts – a community of autotrophic soil organisms found in drylands– may be sensitive to pulse events. Our research question is: Does the frequency of precipitation and the time in between events affect the distribution of biocrusts? We analyzed the precipitation regimes of drylands of the southwestern US and found distinct patterns in the average time in between events (Tau) and the frequency of events <5mm that may explain distribution of biocrusts.

 

Kalra, Isha

B-F046: Alternative electron flow supports rewired metabolism in Antarctic alga Chlamydomonas sp. UWO241

Xin Wang, Rachael Morgan-Kiss

McMurdo Dry Valleys LTER, Miami University

Photosynthetic organisms respond to extreme environment by either activating short-term or long-term stress responses to deal with reactive oxygen species. The Antarctic alga Chlamydomonas sp. UWO241, isolated from Lake Bonney in McMurdo Dry Valleys, is not only adapted to low temperature but also high salinity. UWO241 has downregulated short-term stress response but has upregulated long-term acclimatory strategies like cyclic electron flow (CEF) through formation of stable supercomplex. Here, using proteomics, we show that UWO241 acclimated to high salinity has upregulated Calvin cycle, Glycerol synthesis and Shikimate pathway enzymes. We hypothesize that increased CEF in UWO241 supplies excess ATP to support its rewired metabolism.

 

Kemmerling, Lindsey

A-F012: Passive and active restoration effects on plant-pollinator-crab spider interactions

Kellogg Biological Station LTER, Michigan State University

Restoration of degraded landscapes is necessary to prevent biodiversity loss. Degraded landscapes can be actively restored by removing the anthropogenic disturbance and aiding in the recovery of the system, or they can be passively restored by removing the disturbance and allowing passive recovery. It is necessary to understand how restoration method affects species interactions over time in order to effectively allocate resources for conservation. We studied how passive and active prairie restorations influenced interactions between crab spiders and their prey, pollinators in passively and actively restored plots established in 2007. This work aims to develop best strategies for restoration management and biodiversity conservation.

 

Kemmitt, Kathrine

B-F080: Stormwater biogeochemistry in an ephemeral, urban stream

Stevan R. Earl, Lauren E McPhillips, Rebecca L Hale, Nancy B Grimm

Central Arizona-Phoenix LTER, Arizona State University, School of Life Sciences

We analyzed stormwater chemistry and export dynamics for 17 of the 90 storms that occurred over a nine-year period in Indian Bend Wash, an urban ephemeral stream that drains a large portion of Scottsdale, Arizona ( ~234 km^2). Our dataset captures both winter and summer-monsoon storms that produced event flow lasting from 1.2-113 h. Export was driven primarily by total event discharge rather than concentration. Patterns of storm hysteresis were not consistent across season, but the pattern exhibited by conservative elements (e.g., Ca, Cl) often was opposite that of the nutrient (N and P) species. Event mean concentration was higher during the monsoon season than winter for conservative elements and organic carbon.

 

Kimmel, Kaitlin

B-F011: Chronic resource addition causes persistent and escalating impacts on plant community structure

Laura Dee, Dave Tilman, Forest Isbell

Cedar Creek LTER, University of Minnesota

It is still unclear whether increases in resource supply will quickly restructure communities, and then have consistent and persistent effects, or instead gradually and increasingly restructure communities over time. Here, we examine how chronic nitrogen and water addition impact grassland plant community structure through time. We found that chronic water and N addition generally cause presence/absence measures of community structure to generally increasingly deviate from ambient plots through time while abundance weighted measures had more idiosyncratic responses. Our results indicate that both water and N can have escalating effects on community structure, while only N has quick, but persistent effects over a decade of resource addition.

 

Kittredge, Heather

A-F013: Dead stuff matters: how bacterial necromass facilitates evolution

Sarah Evans, Kevin Dougherty

Kellogg Biological Station LTER, Michigan State University

Bacteria have the unique ability to evolve by transferring genes between and within species. This process, called horizontal gene transfer (HGT), is often cited as a driving force in bacterial diversification and can facilitate evolution. One mechanism of HGT, known as natural transformation involves the uptake and integration of extracellular DNA (exoDNA) into a recipient’s genome. We find that exoDNA is abundant in soil, averaging around 60% of total DNA, making this genetic source influential in determining rates of transformation – and evolution – in the wild.

 

Kjelvik, Melissa

B-F012: Digital Data Nuggets: free resources that address the challenges of using real data in the classroom

Elizabeth H. Schultheis

Kellogg Biological Station LTER, Michigan State University

As contemporary ecology continues to progress towards an era of large-scale and long-term data collection, we are immersed in opportunities to answer questions about the environment that were limited in the past. To meet the demands of our current transition towards an age of data, we need to train students in analyzing and interpreting large, often complex data sets. To provide students with opportunities for structured inquiry and data exploration we are expanding Data Nugget resources by integrating digital data visualization platforms and large datasets. We have developed and piloted several “Digital” Data Nuggets highlighting LTER data, which allow students to easily explore, analyze, and interpret large, long-term datasets.

 

Kopecky, Kai

A-K104: Effects of density on growth and predation in a reef-building coral

Mo’orea Coral Reef LTER, UC Santa Barbara

Density dependence has yet to be investigated thoroughly in corals, the biogeneic foundation of coral reef ecosystems. Current literature on this key regulatory process outlines both benefits and disadvantages of corals existing in dense aggregations, and the mechanisms underlying these contrasting effects are poorly understood. I am estimating how corallivory interacts with ‘bottom up’ factors (e.g., nutrient flux) to shape density dependent growth responses. These results can provide deeper insight into processes affecting the resilience of coral communities.

 

Kothari, Shan

B-F014: The Physiological Underpinnings of Facilitation in a Tree Diversity Experiment

Jeannine Cavender-Bares, Peter Reich, Sarah Hobbie, Rebecca Montgomery

Cedar Creek LTER, University of Minnesota

One mechanism that could underlie the well-established relationship between diversity and productivity is interspecific facilitation, in which some species promote the growth of others. Facilitation can be caused by amelioration of stress from excess light or unfavorable microclimates. I used an experiment comprising plots planted with 1, 2, 5, or 12 tree species to examine whether facilitation contributes to observed diversity effects. I focused on eight broadleaf deciduous species. To probe the physiological underpinnings of facilitation, I measured photosynthetic light-response curves, chlorophyll fluorescence parameters, and concentrations of photoprotective pigments of these eight species across three treatments: (1) monoculture (full sun); (2) bicultures with fast-growing needleleaf trees (partial shade); and (3) 12-species plots (partial, patchy shade). I found that some species had higher woody biomass growth in more dense plots where they intercepted less sunlight. Among all but one species, leaves in shade had higher light-saturated rates of photosynthesis and fewer signs of photoinhibition. This result is consistent with roles for both photoinhibition and microclimatic factors in reducing photosynthetic efficiency in monocultures. Finally, a survey of phenology in one species, Tilia americana, showed that photosynthetic downregulation and leaf abscission occurred weeks earlier in monoculture, narrowing the window for carbon gain. These results suggest that amelioration of light and climatic stresses could explain why diversity matters for tree communities.

 

Kottler, Emily

A-F064: Reciprocal transplant of a migrating marsh grass; plasticity in response to upland conditions

Keryn Gedan

Virginia Coast Reserve LTER, The George Washington University

In the Mid-Atlantic region, sea-level rise is occurring at three times the global average, provoking rapid habitat shifts in many coastal areas. As salt water intrusion impacts upland habitats, wetland species are colonizing space opened up by upland dieback. One such species is the high marsh foundation species Spartina patens. This plant is known to exhibit multiple growth forms under different environmental conditions in marsh, dune, and swale habitats, and now appears to be colonizing upland coastal forest. This project aims to characterize the relationship between Spartina patens plant traits and environmental conditions along the ecological gradient from marsh to coastal forest.

 

Kozal, Logan

A-F093: Environmental Variability and Transgenerational Plasticity in the Santa Barbara Channel

Terence Leach, Juliet Wong, Umi Hoshijima, Gretchen Hofmann

Santa Barbara Coastal LTER, University of California Santa Barbara

Diurnal cycles, seasonal shifts, and episodic upwelling drive variation in temperature, pH, and oxygen in the Santa Barbara Channel. By changing water chemistry and retention time, kelp forests can influence these cycles on a local scale. In this study, we sought to characterize this environmental variability and investigate whether heterogeneity in temperature, oxygen, or pH can influence transgenerational physiological response of key species such as the purple urchin, Stronglyocentrotus purpuratus. As part of the Santa Barbara Coastal LTER research program, we conducted time series analysis of pH and temperature across LTER sites and conditioned S. purpuratus in lab to assess the effect of parental conditioning on offspring performance.

 

Kuletz, Kathy

A-F048 Seabird distribution relative to biophysical oceanographic properties in North Pacific ecosystems

Russell Hopcroft, Seth Danielson, Jarrod Santora, William Sydeman, Brian Hoover, Dan Cushing

Northern Gulf of Alaska LTER, U.S. Fish and Wildlife Service

Seabirds are indicators of mesoscale changes in oceanographic properties and prey. In the northern Gulf of Alaska LTER, seasonal and long-term shifts in cross-shelf seabird distribution varied among species, with ‘inshore’ species showing greater temporal and spatial changes. The same seabird species, or ecological equivalents, occur in the California Current Ecosystem LTER, where changes in species abundance, richness, and community composition are related to long-term changes in forage fish availability and climate change. A comparison of seabird-oceanographic relationships between these two large offshore marine ecosystems will inform predictions about the impact of rising ocean temperatures on upper trophic levels.

 

La Pierre, Kimberly

B-F015 Trajectories of plant community change with chronic nitrogen manipulation

Meghan Avolio, John Blair, Sally Koerner, Zak Ratajczak, Kevin Wilcox, Lydia Zeglin

Cedar Creek LTER, Konza Prairie LTER, Smithsonian Environmental Research Center

Temporal trajectories of plant community change in response to resource additions are poorly understood. We examine five nutrient addition studies at Konza Prairie LTER to determine the mechanisms underlying the timing of plant community change. We find that the temporal trajectory of plant community change is consistent across all five experiments, taking roughly five years for control and treatment plots to become dissimilar in terms of community composition. The initiation of this change is not driven by yearly precipitation patterns, herbivore outbreaks, or co-limitation by other resources. Rather, it appears that the long-lived dominant species in these experiments take time to lose their dominance.

 

Ladd, Mark

A-K107: Tradeoffs between coral growth and predation vary among and within reef habitats in Moorea, FP

Dana T Cook, Thomas C Adam, Russel J Schmitt, Sally J Holbrook

Mo’orea Coral Reef LTER, University of California Santa Barbara

On tropical reefs, coral predation (i.e. corallivory) can shape attributes of coral communities. I quantified coral growth and corallivory on the north shore of Moorea, French Polynesia by transplanting coral nubbins at 20 sites in two habitats, the fringing reef (FR) and the mid-lagoon (ML). Transplanted corals were either exposed to predation or protected by cages. In the ML, caged corals grew faster while exposed corals experienced intense corallivory, reducing growth rates 6-fold. In contrast, on the FR both caged and exposed corals more than doubled in mass. These findings suggest that tradeoffs between growth and predation vary between habitats, and that corallivory in the ML could impede the recovery of coral following disturbances.

 

Lany, Nina

A-F034: A reproducible workflow for synthesizing disparate LTER data

Max Castorani, Margaret O’Brien

Hubbard Brook LTER, Michigan State University

How can ecologists synthesize disparate datasets that encompass diverse biomes, taxa, and sampling methods? We describe a general approach and demonstrate its utility to the research workflow of two LTER Synthesis Working Groups that are testing community ecology theory using numerous LTER datasets from terrestrial, freshwater, and marine ecosystems. Our coded workflows help to ensure transparency and reproducibility, as well as data versioning to adapt to the changing nature of long-term data. Our workflow integrates an online data repository (EDI), cloud storage, version control, and open-source software for statistics, markup and typesetting. This workflow integrates new data as they become available and facilitates remote collaboration.

 

Leach, Terence

A-F089: Maternal and paternal investments alter offspring phenotype in purple sea urchins

Marie Strader, Gretchen Hofmann

Santa Barbara Coastal LTER, UCSB

As global ocean temperatures and pCO2 levels rise at unprecedented rates, marine organisms face a new suite of abiotic stressors. Transgenerational plasticity (TGP), or the effect of parental environment on offspring phenotype, may represent a robust source of physiological tolerance in a rapidly changing ocean. The exact mechanisms behind TGP remain unknown, but parental contributions of resources or epigenetic marks are thought to play a role. In this project, purple sea urchins (Strongylocentrotus purpuratus) were used to quantify investment from both maternal and paternal sources. As part of SBC LTER research, the results of this study will aid in the development of more holistic climate change models and predictions.

 

Lee, Dong Yoon

B-K099: Will freshwater restoration offset peat collapse in wetlands exposed to salt and phosphorus?

Steve Davis, Tiffany Troxler, Evelyn Gaiser, John Kominoski

Florida Coastal Everglades LTER, Florida International University

Saltwater intrusion is increasing salinity and altering carbon (C) and nutrient (phosphorus, P) cycling in coastal wetlands. Freshwater restoration may recover ecosystem C, but legacy effects of saltwater are uncertain. In experimental wetland mesocosms, we continuously added salinity (~6.9 g salt d-1) and P (~0.5 mg P d-1) to Cladium jamaicense peat monoliths for two years and quantified changes in C partitioning. Although added P stimulated macrophyte biomass, elevated salinity reduced root biomass and soil elevation. Within the first year, net ecosystem productivity (NEP) increased with elevated P but decreased with continued exposure to high salinity. To examine the capacity of wetland ecosystems to recover C losses from saltwater intrusion, we experimentally restored freshwater to previous treatment and control mesocosms. Added freshwater lowered porewater salinity from 10 to <3 ppt and nutrients (P, nitrogen, N) to concentrations comparable to freshwater controls. Contrary, concentrations of surface water dissolved organic C and N elevated by salinity in the first experiment remained high despite freshwater restoration. Legacy effects of P included increases in gross ecosystem productivity and ecosystem respiration, collectively resulting in net heterotrophy (negative NEP). Legacy effects of high salinity included increased marsh litter breakdown and dissolved organic matter flux to water columns, collectively lowering soil organic C. Even with continued freshwater restoration, saltwater intrusion legacies may limit the capacity of restored wetlands to recover salt-induced C losses.

 

Lee, Sanghun

A-F095: Study of climate change research for ecosystems in South Korea

National Institute of Ecology, South Korea

Quantitative long-term monitoring data is needed to identify the climate change threats in various ecotypes. Therefore, this study collects long-term data from terrestrial, freshwater and estuary ecosystems. The terrestrial ecosystem for vegetation dynamics, insect dynamics and material circulation, freshwater ecosystem for water quality and planktonic dynamic, and estuary ecosystem for soil environment and halophyte were investigated. Collected long-term data was analyzed about climate change impact. Especially, the seedlings of Abies Koreana in subalpine region were decreased. The number of species and population of Moth have two picks at June and August. These results will support the adaptation measures of climate change.

 

Liang, Di

B-F024: The seasonal responses of soil nitrifiers to management intensity and season   

G. Philip Robertson

Kellogg Biological Station LTER, Michigan State University

Nitrification is the process that converts ammonia to nitrate with N2O released as a byproduct. Ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) are the two main taxa involved in this process but their relative importance is poorly understood. In this research we evaluated the seasonal abundance of AOA and AOB and their contributions to nitrification from seven ecosystems including two annual crop ecosystems, one perennial crop ecosystem and four native successional ecosystems. Our results showed although AOA are more abundant in soils, AOB are the more important source of nitrate in annual and early successional ecosystems, and more important sources of nitrification-derived N2O in all ecosystems except the forest.

 

Liu, Wenwen

A-F065: Allometric variation of the grass Spartina alterniflora in a nature salt marsh across space and time

Steven C. Pennings

Georgia Coastal Ecosystems LTER, Department of Biology and Biochemistry, University of Houston

Plants adjust their size and reproductive effort in response to numerous selection pressures and constraints. The self-thinning rule describes a well-known tradeoff between size and density. Plants also trade off investment into growth versus sexual reproduction. We examined how these tradeoffs affected allometry and flowering across space and time using the salt marsh grass Spartina alterniflora. We collected data on plant height, density and flowering probability over 16 years at different elevations at 8 different sites in Georgia, USA.

 

Livneh, Ben

B-F001: Controls on Hydrologic Connectivity with a Sensor Array at the Niwot Ridge LTER

Andrew Badger, Elsa Culler, Javier Abad, Eve-Lyn Hinckley, Anna Hermes, Noah Molotch, Oliver Wigmore, Jason Neff, and Katharine Suding

Niwot Ridge LTER, University of Colorado Boulder

Hydrologic connectivity is broadly defined as the water-mediated transfer of matter, energy, and/or organisms within or between elements of the hydrologic cycle. This research will address two current knowledge gaps: (i) identifying dominant connectivity-mediating processes and (ii) quantifying how landscape connections will affect water and nutrient cycling important for ecological response. Connectivity across the landscape will be analyzed using observations from a new 16-sensor array, integrated with a distributed hydrologic model constrained with soil moisture and streamflow measurements. Periods of wetting and drying will be analyzed to evaluate changing connectivity across the landscape and to identify biogeochemical ‘hot spot’ areas.

 

Lottig, Noah

A-K120: Site Poster

North Temperate Lakes

 

Lovett, Gary

A-K132: Site Poster

Hubbard Brook LTER

 

Lowman, Heili

A-F075: Investigating Benthic Marine Sediments as a Nutrient Source to the Overlying Water Column

John Melack

Santa Barbara Coastal LTER, University of California Santa Barbara

Recent research suggests that permeable marine sediments are hotspots of biogeochemical activity whose efflux of nutrients may support primary production. This project aims to quantify the byproducts of organic matter breakdown, specifically dissolved inorganic nitrogen species, that are released from sediments into the overlying water column. To measure nutrient efflux, I use a series of sediment bioreactors with samples collected from estuarine and kelp forest reef sites. Results suggest that sediments surrounding kelp forest reef sites are a net source of ammonium (NH4+) to the overlying water column. The findings from this study will be used to inform nutrient budget calculations for nearshore regions within the SBC LTER program.

 

Maerz, John

B-F060: Integrating Spatial and Temporal Studies to Model Salamander Demographic Responses to Climate

Coweeta LTER University of Georgia

In the face of shifting climates, management for biodiversity and associated ecological services requires mechanistic models of species’ distributions and abundances. Such models require integration of long-term and spatially extensive demographic studies, and are, therefore, relatively uncommon for animals. Here we demonstrate the integration of a long-term robust capture-recapture study with a spatially extensive “unmarked” study to estimate the sensitivity of salamander vital rates and abundance to weather and climate, and to project salamander population growth across a portion of western North Carolina where rapid development may conflict with the capacity to support salamander population growth under future climate scenarios.

 

Malakhoff, Katrina

A-F080: Examining the impacts of fishing and marine protected areas on M. franciscanus and S. purpuratus    

Santa Barbara Coastal LTER, UC Santa Barbara

Grazing sea urchins are key components of the kelp forests studied by the Santa Barbara Coastal LTER. However, little is known about the extent of competition between two common California sea urchin species, purple (S. purpuratus) and red (M. franciscanus) urchins, or how the economically important red sea urchin fishery might impact both populations. Previous research has predicted that an increase in urchin predators within marine reserves would keep urchin populations low. Contrary to this research, our findings demonstrate that both purple and red sea urchins are increasing in biomass inside marine reserves, although they are differentially impacted by environmental factors such as sea surface temperature and wave exposure.

 

Manck, Lauren

A-F082: Microbial Remineralization of Iron in the California Current Ecosystem

Kiefer Forsch, Chris Dupont, Katherine Barbeau

California Current Ecosystem LTER, Scripps Institution of Oceanography

The biological remineralization of iron is an understudied aspect of the iron biogeochemical cycle in the marine environment. The rates of iron ligand production and the activity of heterotrophic bacteria will be important factors in determining the fate of iron being released from organic particulates. Here we present results from a microcosm incubation conducted in the California Current Ecosystem following these dynamics during a stimulated phytoplankton bloom and subsequent remineralization phase. A pronounced ecological succession in the prokaryotic community was observed resulting in an enrichment in copiotrophic species. Iron ligand dynamics and their correlation with bacterial gene expression will also be presented.

 

Massie, Jordan

B-K101: Environmental drivers of large-scale fish movements in the Florida Everglades during Hurricane Irma

Natasha Viadero, Rolondo Santos, and Jennifer Rehage

Florida Coastal Everglades LTER, Florida International University

Extreme weather events have been shown to elicit large-scale movements in coastal fish populations, however, our knowledge of the mechanisms triggering these movements is not fully understood. Here we use acoustic telemetry data to investigate the timing and magnitude of Common Snook movement in relation to Hurricane Irma. Movements are correlated with abiotic data to examine how changing conditions throughout the storm correspond to observed behavior. The frequency with which extreme events occur has increased in recent years, and understanding how fish might respond to future events can provide information that allows natural resource agencies to make informed decisions on how to best manage fish stocks in the face of changing conditions.

 

McDevitt, Andrew

A-F028: Cultural-historical activity theory: A theoretical framework for REU program assessment

Manisha V. Patel, Aaron M. Ellison

Harvard Forest LTER, University of Colorado Denver

REU programs are recognized as a way to strengthen undergraduate participation in STEM fields by providing authentic research opportunities. Unfortunately, our understanding of best practices and long-term impacts is still limited. To address this gap, we advocate for programs to align their assessment strategies with educational theory and suggest the use of cultural-historical activity theory (CHAT). CHAT is a broad educational framework that recognizes learning as a social endeavor, with individuals situated within a learning community and using available resources to accomplish specified goals. CHAT provides a systems perspective and allows researchers to examine the unique dynamics of REU programs at multiple levels of organization.

 

McDonnell, Janice

B-F049: Education Programs at the Palmer LTER

Palmer Antarctic LTER, Rutgers University

The Palmer LTER education and outreach team has designed a variety of programs focused on communicating the research of the Palmer LTER to K-12 educators and their students. We match these efforts with a companion NSF award from the Polar Science Division called Polar Interdisciplinary Coordinated Education or Polar ICE. In this poster we will desribe our Science-Investigator (Sci-I) project, a year-long in school project that consists of a Summer Educator workshop and a follow up Student Polar Research Symposium (SPRS). We will share lessons learned from our efforts in guiding student exploration of Palmer LTER data through interactions with scientists and participation in polar data-focused classroom lessons.

 

McTigue, Nathan

A-K131: Site Poster

Beaufort Lagoon Ecosystem

 

Michaud, Kristen

B-K132: Use of macrophyte subsidies as food and habitat among intertidal consumers

Kyle Emery, Jenifer Dugan, David Hubbard, Robert Miller

Santa Barbara Coastal LTER, UC Santa Barbara

Macrophyte wrack, particularly giant kelp, Macrocystis, from nearshore reefs provides habitat and food for diverse intertidal consumers. To investigate wrack resource use by beach consumers, we measured four talitrid amphipod species’ (Megalorchestia) and an herbivorous beetle’s (Phaleria) consumption of five macrophytes and manipulated wrack patch composition in the field. Macrophyte consumption differed significantly among consumers, but all species preferred feather boa kelp, Egregia, despite its generally lower abundance. In a field experiment, consumers were more diverse under wrack patches containing kelp. Our results highlight the importance of kelps to beach consumers, which coexist despite their similar use of these resources.

 

Millar, Neville

A-K130: Site Poster

Kellogg Biological Station LTER

 

Millar, Neville

B-F025: The influence of winter cover crops on nitrous oxide (N2O) emissions from Midwest row-crops

Philp Robertson

Kellogg Biological Station LTER, Michigan State University

Nitrous oxide is the largest contributor to the greenhouse gas (GHG) burden of cropping systems in the US. Perennializing annual crop systems by adding winter cover crops may provide climate stabilization through N2O mitigation, and could make the difference between abating or raising the overall Global Warming Impact (GWI) of the system. Limited, longer-term N2O emissions data from winter cover crops make this evaluation challenging. We will present 12 site years of N2O emissions data from a corn-soybean rotation, either with or without cover crops at KBS. Including cover crops in annual crop systems had little effect on N2O emissions. There was evidence for decreased emissions in soybean years, but not corn years following cover crops.

 

Modest, Michelle

B-F050: Pre-breeding Ground Migratory Behavior of the Southeastern Pacific Humpback Whale

Palmer Antarctic LTER, UC Santa Cruz

Humpback whale migration is part of an annual cycle consisting of the journey between tropical calving grounds and high latitude feeding grounds. Unfortunately, multitaxon reviews indicate that long distance migrants may be particularly vulnerable to climate change and an understanding of their annual life cycles is needed to make conservation decisions. We are conducting a novel large-scale inter-annual satellite tag investigation of the foraging to breeding grounds migratory path in the Antarctic Peninsula. As the first study to look at the pre-breeding migratory route, it fills a critical knowledge gap in the life history of the species and illuminates areas for conservation focus.

 

Monique, Picon

A-K109: Land-use legacies and extreme events shape species composition in a secondary tropical forest

María Uriarte, Jess Zimmerman

Luquillo LTER, University of Puerto Rico- Rio Piedras

Second-growth forests comprise more than half of all tropical forests, yet shifts in species composition as these forests regenerate are poorly understood. Past human land use and extreme climatic disturbances influence the successional trajectories of recovering forests by favoring certain species over others. Using historical information, a post-hurricane survey, and 6 years of tree census data from a forest chronosequence in the Luquillo Mountains of Puerto Rico, we studied changes in species composition during post-agricultural succession and in response to Hurricanes Irma and María.

 

Motes, Jessie

B-K118: REU Poster: Evidence of high nitrogen fixation in early successional southern Appalachian forests

Nina Wurzburger

Coweeta LTER, University of Georgia

In the southern Appalachians, anthropogenic disturbances triggered forest recovery in the early 20th century. In this region, black locust, a dominant early-successional tree species, supports biological nitrogen fixation (BNF) through an association with symbiotic bacteria, but it is unclear how this species supports BNF over time. We quantified nodule activity and mass per stem and found that BNF peaks at 10 years of age and then declines in a curvilinear fashion. Our results revealed that mass of nodule per stem decreased exponentially, and the proportion of nodulating trees declined linearly with age. Our findings stress the importance of studying early successional periods in order to understand long-term legacy effects of disturbance.

 

Mulder, Christa

A-F047: Fostering Science: using science education to empower youth in foster care

Katie Spellman, Stephen Decina, and Theresa Villano

Bonanza Creek LTER, University of Alaska Fairbanks

When youth participate in “doing science”, they increase connections to the environment and their community. Youth in foster care lack control over their lives and may feel powerless, but they are largely absent from summer science camps. We have developed a science adventure day camp aimed at 12 to 16-year olds in foster care. Campers spend a week at the Bonanza Creek LTER site in a wide range of activities with scientists and artists designed to foster interest in the natural world and increase knowledge of career opportunities in science. The goal is to empower young people in difficult times and help them envision a positive future. We are interested in exploring opportunities within the LTER network to expand this model to other sites.

 

Myers, Madeline

A-F052: Snow and Underwater Photosynthetically Active Radiation in McMurdo Dry Valley Lakes

Peter Doran, Krista Myers

McMurdo Dry Valleys LTER, Louisiana State University

Snow accumulation on McMurdo Dry Valley (MDV) lake ice reduces Underwater Photosynthetically Active Radiation (UWPAR) and acts as an ecological disturbance. Although annual snowfall values in the MDVs are low (3 to 50 mm water equivalent), trends of increasing snowfall and persistence on the under future warming conditions could lead to an increased role for snow in regulating UWPAR. Here, we use methods from previous research augmented with qualitative estimates from time-lapse camera data to extend the current precipitation record. We show that low precipitation events have the potential to suppress UWPAR for weeks and provide insight on snow as an ecological disturbance and the implications for lacustrine primary productivity.

 

Myers, Krista

B-F047: Connectivity of lakes and groundwater since the Last Glacial Maximum, Taylor Valley, Antarctica

Peter T. Doran

McMurdo Dry Valleys LTER, Louisiana State University

During the Last Glacial Maximum, grounded ice in the Ross Sea extended into the otherwise ice-free McMurdo Dry Valleys, creating a series of large ice dammed paleolakes. Grounded ice within the mouth of Taylor Valley allowed for lake levels to reach 300 m above sea level, resulting in regional connectivity throughout Taylor Valley. Airborne electromagnetic survey data reveal an extensive groundwater system which formed during past lake level high stands, connecting modern lakes with subsurface aquifers and the McMurdo Sound. Fluctuating lake levels over time have changed the magnitude and even direction of the hydraulic gradient of the groundwater system, altering biological and chemical exchange between lakes, soils, and groundwater.

 

Nardelli, Schuyler

B-F051: Characterization of phytoplankton species variability at Palmer Station from October 2017-March 2018

Oscar Schofield

Palmer Antarctic LTER, Rutgers University

The West Antarctic Peninsula is experiencing significant change and this has been associated with shifts in phytoplankton biomass and community composition. These shifts in the phytoplankton have broad implications for the food web. While the Palmer LTER has collected taxa specific pigments for several decades, species information has been limited. During the spring and summer of 2018, we added an Imaging FlowCytobot to our sampling which allowed us to measure seasonal and spatial variability in phytoplankton species. Results from October 2017-March 2018 will be presented, with a focus on to what degree specific phytoplankton species are associated with a different water masses near Palmer Station.

 

Nelson, Michael

B-F037: “Is” and “Ought:” Integrating Ecological and Ethical Inquiry at the H.J. Andrews Experimental Forest

Chelsea Batavia

Andrews Forest LTER, Oregon State University

The H.J. Andrews Experimental Forest (HJA) fosters connections not only between various branches of the ecological and social sciences, but also between the sciences and the humanities. A cornerstone of this approach is our work on conservation ethics, which demonstrates the role and significance of ethics in conservation and management. We highlight and critically evaluate ethics at all stages of the science-management interface, from the science to the management, using methods of philosophical analysis in conjunction with other qualitative and quantitative research methods. This poster creatively illustrates the scholarly merit and practical relevance of conservation ethics and describes past, ongoing, and future projects at HJA.

 

Nicolai, Nancy

B-F087: Rodents respond to litter reduction and seed augmentation in grasslands of the Sevilleta LTER

Sevilleta LTER, University of New Mexico

Prairie rodents use prairie dog habitat perhaps due to increased seed production and litter removal. Survival can be affected because rodents must move through structurally complex litter and find seeds bound up in it. Population characteristics were compared between sparse and dense litter plots and seed added and unadded. During the spring breeding season, one species body mass was greater in sparse and two species’ mass and abundance in seeded. As winter approached, more abundance, male counts and offspring were in sparse. Results support the hypothesis that population characteristics increase in sparse litter. Together avoiding predation and levels of available seeds determines how species disparately use prairie dog habitat.

 

Nieland, Matthew

A-F018: Effects of fire and N-cycling soil microbes on ecosystem recovery from chronic fertilization

Priscilla Moley, Janaye Hanschu, Lydia Zeglin

Konza Prairie LTER, Kansas State University

We address whether chronic N fertilization changes soil microbial capacity for N removal following cessation of fertilization, and whether fire history mediates this response. We measured soil N availability, nitrification and denitrification potential rates, microbial biomass, community composition and functional gene abundances monthly over the 2017 growing season at a replicated 30-y fire by nitrogen plot-scale field experiment. This year, fertilization was ceased, except in small comparative sub-plots. In long-term fertilized soils, N-cycling rates were higher, microbial biomass was lower, and microbial communities changed. We detected post-fertilization recovery of N availability and nitrification, but not biomass or denitrification, with corresponding microbial diversity and functional population shifts. Fire reduces the potential for microbial N loss from the ecosystem both during and following cessation of fertilization.

 

Nippert, Jesse

A-K124: Site Poster

Konza Prairie LTER

 

Nordheim, Caitlin

B-K117: REU Poster: Comparing lizards across urban and non-urban riparian habitats in central Arizona

Heather L. Bateman

Central Arizona-Phoenix LTER, The University of Tampa

Urbanization is rapidly increasing, and it is important to understand how urbanization impacts ecosystems, specifically amphibians and reptiles in riparian forests. Using visual encounter surveys in riparian forests along the Salt River, San Pedro River, and Gila River in central Arizona, we compared (1) community diversity and richness between urban and non-urban areas (2) abundance and (3) occupancy of different lizard species in urban and non-urban riparian areas. Diversity did not differ between urban and non-urban sites, but the non-urban sites had a higher species richness. Urban areas support more lizards associated with open area and non-urban areas support more tree-associated species.

 

Nufer, Marissa

B-K125: REU Poster: Collaboration for Conservation: Collaborating with various stakeholders in the agriculture industry

Julie Doll, Adam Reimer

Kellogg Biological Station LTER, Michigan State University

Often when we think about scientific research we associate it with specific lab and field work. While this type of research is certainly important, we also have to think of how this research can be applied, and what effect we want it to have once it leaves the laboratory—this is where communication comes in. Effective communication of science can be done through outreach and engagement—this is the purpose of MSU Extension, as well as the purpose of my team’s research with the LTER. Led by Dr. Julie Doll and Dr. Adam Reimer, this summer I had the opportunity to partake in social science research when we hosted a “Conservation Agriculture Field Day”. During this field day we brought together key stakeholders in the agriculture industry.

 

O’Brien, Margaret

B-K114: ecocomDP: A dataset design pattern for ecological community data to facilitate synthesis and reuse

Colin Smith, Corinna Gries

Environmental Data Initiative, University of California, Santa Barbara

A diverse array of observation and experimental data is available for reuse, integration and synthesis. However, the largest time investment is still in cleaning and combining primary datasets until all data are completely understood and converted to a similar format. There are two approaches to simplifying the process: prescribe the format prior to data collection, or convert primary data to a flexible intermediate for reuse. Prescribed formats are impossible to impose on research studies, so we take the second approach; we define a flexible intermediate, and convert primary data to that model. This poster describes EDI’s process for harmonizing datasets as “design patterns”, with an example for ecological community survey data.

 

O’Connell, Kari

A-F041: Undergraduate Field Experiences Research Network

Alan Berkowitz, Janet Branchaw

Andrews Forest LTER, Oregon State University

The Undergraduate Field Experiences Research Network is building a collaborative network that fosters effective undergraduate field learning experiences by: 1) Identifying and sharing evidence-based practices for engaging undergraduates in effective field learning experiences, 2) Modifying, developing, and sharing assessment tools for understanding the impact of field learning experiences on undergraduate student learning, 3) Investigating how undergraduate field experiences may help broaden the participation and retention of students who are currently underrepresented in field-based sciences, & 4) Establishing undergraduate field learning experiences as “interdisciplinary laboratories” for researching evidence-based practices in undergraduate experiences.

 

O’Connell, Jessica

A-F066: Remote sensing of Spartina alterniflora belowground biomass in salt marshes on the Georgia coast

Merryl Alber, Deepak R. Mishra, Kristin B. Byrd

Georgia Coastal Ecosystems LTER, University of Georgia

We estimated belowground productivity of Spartina alterniflora, the dominant salt marsh macrophyte with 4 sites on the Georgia coast. This effort is important because belowground productivity of marsh plants contributes to coastal marsh resiliency both through sub-surface expansion, allowing marsh surface elevation to keep pace with sea level rise, and through soil stabilization, preventing lateral marsh erosion from wave action. Belowground productivity also contributes to soil organic matter, providing information on so called “Blue Carbon” dynamics. Site-wide estimates of belowground biomass are difficult to obtain because root:shoot ratios vary in response to environmental gradients and other factors that drive biomass partitioning.

 

O’Connell, Kari

B-F036: Andrews Schoolyard LTER Program: Integrating Science, Math, & the Humanities in K-12 STEM Education

Andrews Forest LTER, Oregon State University

In this poster, we describe the Andrews Schoolyard LTER program which draws upon the strengths of the Andrews LTER program – interdisciplinary environmental science research, scientists with interests in collaboration and outreach, and an inspiring place – to build capacity for Oregon K-12 teachers to engage their students in authentic, field-based inquiry about the natural world. An additional and emerging goal is to develop and implement a learning research program that builds upon our Schoolyard LTER activities, in particular building ecological data literacy of teachers and students, the role of creative content on students’ learning of science, and creating effective scientist-educator partnerships.

 

O’Connor, Rory

B-F019: Future of woody plant survival in the Great Plains

Troy Ochletree, Dan Lecain, Dana Blumenthal, Jesse Nippert

Konza Prairie LTER, Kansas State University

Climate projection of the Great Plains region predict increased [CO2] and altered precipitation regimes that reduce soil moisture. These climate predictions should favor deep-rooted woody plants over shallow-rooted grasses and exacerbate woody encroachment. To test this hypothesis, we conducted a greenhouse study to determine how four woody seedling species (Cornus drummondii, Rhus glabra, Gleditsia tricanthos and Juniperus osteosperma) would grow under elevated [CO2] and decreased soil moisture. We found that elevated [CO2] ameliorated the stress of decreased soil moisture for the seedlings, suggesting that woody plant seedlings will be able to cope with the projected climate scenarios for the Great Plains region.

 

Omari, Haneen

B-F077: Spatiotemporal Variations of Microbiota within Biological Soil Crusts at the Jornada LTER

Pietrasiak, N., Ferrenberg, S., De Ley, P., and Nishiguchi, M.K.

Jornada Basin LTER, New Mexico State University

Biological soil crusts (BSCs) are essential features of drylands, and their microbial composition remains poorly understood. Within the Jornada LTER, three BSC types were collected from two vegetation zones within three seasons. A modified extraction for microfauna was used to reveal abundance and diversity patterns. Phospholipid Fatty Acid Analysis of the microflora and soil chemistry data were also obtained and related to microfauna. Data indicates significant spatiotemporal differences in the soil microbiota with notable dissimilarities by BSC type, vegetation zone, and season. Furthermore, protists are linearly correlated with salts and P, while the microflora are linearly correlated with SOM, Ca, Cu, Na, CEC, Zn, and pH. Identifying differences that impact biodiversity, even if microscopic, is crucial in understanding how arid soils respond to desertification.

 

Omiotek, Nicolle

B-K128: REU Poster: Alien and Native Orchids in a Tropical Forest: Benign Coexistence?

James D. Ackerman

Luquillo LTER, University of Puerto Rico at Río Piedras

The objective of this study was to evaluate the population and distribution of the alien orchid Oeceoclades maculata and two native orchids inside the Luquillo Forest Dynamics Plot (LFDP) in Puerto Rico over ten years. The project focused on the ecological implications of the increasing population of the alien orchid. O. maculata had the highest abundance, with a population that more than doubled. Incongruous with previous censuses, the alien orchid now prefers the old growth over the most disturbed areas of the LFDP. O. maculata in previous censuses had a negative correlation with the native orchids, however, in 2017 it did not. This indicates that the increasing population of O. maculata is likely benign to these native orchids.

 

Onwuka, Ikechukwu

A-K102: Modelling phosphorus dynamics in Everglades Ecosystem Canals

Florida Coastal Everglades LTER, Florida International University

Canals were constructed in South Florida to drain portions of the Everglades for agriculture and urban development. Long-term loading of phosphorus into canals and P release from canal sediments are potential sources downstream. Canals can act as P sources or sinks depending on water column and sediment physicochemical characteristics. We propose to quantify the processes that govern the fate and transport of P within identified canal reaches using a mechanistic model, based in STELLA®. Stores will represent major P-forms in water and sediments, which include: particulate and dissolved organic and inorganic species, while flows will represent processes including: entrainment, settling, decomposition, sorption, precipitation, uptake, etc.

 

Parkinson, Lindsey

B-F048 Morphological plasticity of two Arctic berry-producing shrubs: Blueberry and Lingonberry

Christa PH Mulder

Bonanza Creek LTER, University of Alaska Fairbanks

Berries are an important cultural and natural resource to people across the circumpolar north but much of the data in Alaska deal with fire and successional effects on vegetative plant parts rather than on fruit availability. Ultimately, it is fruit availability and the environmental conditions that support it that matter to the humans and animals that rely on berries for food. This study measures resource trade-offs between reproductive and vegetative growth and morphological plasticity in two closely related fruit-bearing shrubs on opposite ends of the leaf economic spectrum, Vaccinium vitis-idaea (lingonberry) and V. uliginosum (blueberry), across a range of boreal forest sites.

 

Pastore, Melissa

A-F016: Photosynthetic responses of 14 grassland species to 20 years of CO2 enrichment and nitrogen addition

Tali Lee, Sarah Hobbie, Peter Reich

Cedar Creek LTER, University of Minnesota

We measured long-term (20 years) leaf gas exchange in monocultures of 14 perennial grassland species exposed to free-air CO2 enrichment (+180 ppm above ambient) and nitrogen addition (4 g N m-2 y-1). Species were classified into four functional groups – C3 grasses, C4 grasses, forbs, and legumes. Over two decades, we found that eCO2 stimulated photosynthesis by 12% on average across species compared to plants exposed to ambient CO2, which is much lower than rates reported in shorter-term studies that included fewer species. Contrary to expectations, responses did not significantly vary by functional group, depend on nitrogen supply, or decline through time.

 

Perng, Lansing

A-K106: Canopy-forming macroalgae may buffer effects of ocean acidification on calcifying algae

Robert C. Carpenter

Mo’orea Coral Reef LTER, California State University, Northridge

Climate change may induce shifts to macroalgal dominance on coral reefs. An increase in atmospheric CO2 causes ocean acidification (OA), and reduces reef calcification. Macroalgal photosynthesis may mitigate OA locally through carbon uptake, resulting in a local increase in pH. This buffering effect on calcifiers was quantified in a mesocosm study and subsequent field study conducted in Moorea, French Polynesia. A common canopy-forming alga and co-occurring crustose coralline alga (CCA) were used to test whether fleshy algae can buffer seawater from OA, and consequently alter CCA physiology. Data from the mesocosm study support this buffering effect, and the in-progress field study will display whether this effect persists in the field.

 

Peters, Joseph

A-F078: Consumer-derived nutrients in kelp forests: identifying consumers bottom-up role in nutrient cycling

Santa Barbara Coastal LTER, University of California, Santa Barbara

Human impacts are fundamentally altering the abundances of marine species. Numerous studies have documented the negative impacts of declining animal abundances on top-down interactions, yet more recent work highlights the consequences of consumer declines in driving bottom-up processes. While evidence is growing that consumer-mediated nutrient dynamics are a major biogeochemical component of coastal marine ecosystems, more work is needed to examine how these drivers vary with spatial and temporal context. The proposed work examines the functional role of consumer nutrients in kelp forests by integrating ammonium excretion rates with an 18-year time series of their standing biomass at 7 sites measured by the SBC-LTER.

 

Peters, Debra

A-K115: Site Poster: Long –Term Research at the Jornada Basin (LTER VII)

Hanan NP, Bestelmeyer BT, Okin GS, Sala OE, Schooley RL, Vivoni ER, Archer SR, Bestelmeyer SV, Brungard C, Garcia-Pichel F, Herrick JE, Monger HC, Pietrasiak N, Tweedie CE

Jornada LTER Program, USDA-ARS

Chihuahuan Desert landscapes exemplify the ecological conditions, vulnerability, and management challenges in arid and semi-arid regions around the world. The goal of the Jornada Basin Long Term Ecological Research program (JRN LTER) is to understand and quantify the key factors and processes controlling ecosystem dynamics in Chihuahuan Desert landscapes. In LTER-VII, we explore how spatial heterogeneity of dryland ecosystems evolves over time in response to disturbance triggers, positive feedbacks, and their interactions with the eco-geomorphic template. Our recent observations indicate the need to conceptually and computationally integrate data and knowledge into a Data Science Integrated System (DSIS).

 

Peters, Debra

A-K119: Site Poster

Jornada Basin LTER

 

Peters, Debra

B-F074: Insights from Long-Term Ecological Research: free EcoTrends books available

Jornada Basin LTER, USDA-ARS

EcoTrends is a project to synthesize long-term data to examine trends in the Earth’s ecosystems. Participants in the data synthesis included scientists and information managers from 50 sites, including 25 LTER sites. The large and diverse collection of long-term ecological datasets can be found through the EcoTrends website (https://ecotrends.info/) or through our book (Peters et al. 2013), Our Changing World: Insights from Long-Term Ecological Research. This book is an excellent compendium of long-term ecological data and trends from long-term research sites. We have a small number of complimentary copies of our book available, and interested persons may sign up to have a free copy shipped to them.

 

Peters, Debra

B-F075: Developing an integrated knowledge landscape map using a trans-disciplinary approach

Bestelmeyer BT, Okin GS, Sala OE, Vivoni ER, Archer SR, Brungard C, Herrick JE, Hannan NP

Jornada Basin LTER, USDA-ARS

Our goal is to develop a trans-disciplinary approach to complex landscapes that facilitates integration of large and diverse types of data and knowledge to: (1) reduce the high spatial heterogeneity in sampling across heterogeneous landscapes and fill data/knowledge gaps for underrepresented locations; (2) characterize the non-stationarity of environmental drivers and ascertain the extent to which knowledge of the past can, or cannot, inform the future; and (3) inform land managers in prioritizing locations. We illustrate the utility of our approach to extend process-based understanding of ANPP at intensively studied locations to dynamics at other under-represented locations, and to predict spatial variability across the landscape.

 

Pierson, Derek

B-F038: Soil carbon turnover and sequestration dynamics at the H.J. Andrews LTER

Kate Lajtha

Andrews Forest LTER, Oregon State University

Soil carbon dynamics are a diverse and complex field of study, where biogeochemical processes and physical conditions coalesce to regulate soil carbon turnover and sequestration. To sort through this complexity and improve understanding of soil carbon dynamics, a multidisciplinary approach is essential. To this end, continued long-term soil carbon research at the H.J. Andrews LTER spans a variety of disciplines and scales; from micron-scale laboratory investigations of the microbial and abiotic controls on carbon turnover and organo-mineral complexation, to long-term landscape scale quantification of detrital effects on soil carbon stocks (DIRT), and finally to facilitating and improving regional to global scale earth system models.

 

Porter, John

A-F027: Making Data Easier to Discover Using the LTER Controlled Vocabulary

Virginia Coast Reserve LTER, University of Virginia

Keywords are a critical aid in discovering LTER Data. In 2011, the LTER network adopted a Controlled Vocabulary for data keywords. This poster reports on how successfully the terms from the LTER Controlled Vocabulary have been incorporated into LTER data packages. It examines use of the controlled vocabulary from the perspective of individual data packages, the LTER site and from the keywords themselves. Examination of all LTER metadata shows that 95% of data packages are discoverable using the controlled vocabulary, and that searches using controlled vocabulary terms yield nine times as many “hits” as uncontrolled terms. Similarly, uncontrolled terms typically returned data from only a single LTER site whereas terms in the controlled vocabulary typically returned data from four or more sites.

 

Potter, Ashley

B-K097: Characterizing the metabolic gradient of two species of reef corals from Moorea, French Polynesia

Peter Edmunds

Mo’orea Coral Reef LTER, California State University, Northridge

To better project survival of reef building corals under anthropogenic stressors, we measured the aerobic scope (AS) of two resilient corals, Pocillopora verrucosa and Acropora pulchra, by measuring metabolic rate (MR) in the presence of a metabolic uncoupler (maximum metabolic rate, MMR) and under starvation (basal metabolic rate BMR). The AS was 136-250% and the MR associated with polyp expansion (94-106% of BMR) and digestion (46-94% of BMR) fell within this range. Relative to other metazoans, the AS reveals a modest ability to up-regulate metabolism and suggests coral activity needs to be considered in measurements of MR that are used to evaluate survival based on use of energy reserves and the capacity of corals to respond to stress.

 

Power, Sarah

A-F056: Remote multispectral characterization of microbial mat communities in Taylor Valley, Antarctica

Mark Salvatore, John Barrett

McMurdo Dry Valleys LTER, Virginia Tech

Microbial mats, dominated by cyanobacteria, are the principal autotrophic communities of terrestrial ecosystems in the McMurdo Dry Valleys (MDV), Antarctica. Currently, there are no systematic estimates of terrestrial productivity in the region. Recent work has demonstrated that microbial mats can be identified along ephemeral melt-water stream margins in the MDV with multispectral satellite imagery. Using WV-2 satellite imagery and ground-based assessments, we’re examining the relationships between multispectral data and microbial mat density, AFDM, chlorophyll a and scytonemin content in multiple wetland systems. Once validated, this method will be scaled up to systematically estimate the terrestrial productivity of Taylor Valley.

 

Puig-Santana, Alessandra

B-K127: REU Poster: Testing Biotic and Abiotic mechanisms of root breakdown along salinity gradients in coastal wetlands  

John S. Kominoski, Matthew Smith, Shelby M. Servais, Benjamin J. Wilson

Florida Coastal Everglades LTER, Florida International University

Saltwater intrusion into coastal wetlands increases nutrient availability, decreases soil carbon, and influences root and soil elevation loss. However, abiotic and biotic mechanisms for soil carbon loss are uncertain. We tested effects of salinity concentration on breakdown of biologically intact and sterilized roots to explain mechanisms of peat collapse. We found that increasing salinity increased root mass loss similarly for both biologically intact and sterilized roots, indicating strong abiotic mechanisms of soil carbon loss. Our results suggest soil carbon loss from saltwater intrusion is largely abiotically driven, but biogeochemical changes in microbial activities likely provide feedbacks to carbon loss at lower salinities.

 

Ramirez, Geovany

B-F076: A machine learning guided system for automatically processing data from an array of wireless sensors

Debra P. C. Peters, John Anderson

Jornada Basin LTER, New Mexico State University

We present a system that automatically processes data from an array of remote sensors in a wireless network and makes these data available online. Our system automatically performs QA/QC using the GCE LTER Data toolbox for Matlab. Additionally, the GCE toolbox help us to manage metadata and data in multiple formats. Users can explore data with tools to graph, select stations, variables, and time. We have connected this QA/QC process with our Knowledge, Learning, and Analysis System (KLAS) to allow users to perform experiments with the data collected. KLAS can learn from users’ behavior using machine learning to serve as a guide during the process of approving provisional data and during the experimentation process by making recommendations.

 

Rastetter, Ed

A-K123: Site Poster

Arctic LTER

 

Rasu, Eeswaran

A-F019: Physical Controls and Stability of Soil Moisture across Different Cropping Systems

Amor V.M. Ines

Kellogg Biological Station LTER, Michigan State University

This study will present an analysis of the temporal and spatial dynamics of soil moisture under different agricultural landscapes using the long-term soil moisture measurements of KBS-LTER. First, we will present the temporal stability analysis of soil moisture using statistical metrics like mean relative difference and the root-mean-square of relative difference. Then we will present an analysis of physical controls of soil moisture using Empirical Orthogonal Function and correlation analysis. Results will help to identify controlling factors of soil moisture variability and resilient agricultural management systems to climate variability.

 

Ray, Chris

B-F004: Demographic trends over four decades in a declining population of the American pika

Niwot Ridge LTER, University of Colorado-Boulder

Climate-mediated range shifts have been documented for many species, but details of the demographic response to climate–useful for inferring causation–are often lacking. We use data from the Niwot LTER (NWT) to explore demographic trends in the American pika, a species that is disappearing from portions of its range. In over 2000 captures during 1981-2018, pikas were weighed and classified by sex and stage, and parturition dates were estimated for each juvenile using a growth curve specific to NWT. Trends in pika demography were estimated using mixed-effect models, allowing for random effects of year and fixed effects of climatic variables trending at NWT, including annual snow-free date and mean summer temperature.

 

Reeves, Ian

A-F067: Impacts of Seagrass Dynamics on the Coupled Long-Term Evolution of Barrier-Marsh-Bay Systems

Virginia Coast Reserve LTER, University of North Carolina at Chapel Hill

Here we incorporate seagrass dynamics of the back-barrier bay into the coupled barrier-marsh model GEOMBEST+. Simulations suggest that for back-barrier environments in which some suspended sediment is exported to the ocean, seagrass reduces marsh edge erosion rates and increases progradation rates. Surprisingly, when sediment export is negligible seagrass increases marsh edge erosion rates. In addition, adding seagrass to the bay subsystem reduces the amount of sediment available to the marsh until the bay reaches its new, shallower equilibrium depth, leading to increased erosion rates for that time period. Removing seagrass liberates previously-sequestered sediment that is then delivered to the marsh, leading to a marsh progradation event.

 

Remillard, Suzanne

B-F040: Archiving Research Data for Discoverability and Secondary Use

Don Henshaw

Andrews Forest LTER, Oregon State University

High quality data and well-documented metadata enable the discovery of data collected at regional and national scales to address new science challenges. LTER Metadata Best Practices provide rules for populating the necessary elements to assure consistency and comparability of information. Andrews LTER data and metadata pass through a series of checks both locally and upon upload to the LTER Network Data Portal to ensure integrity and high quality. These data are then exposed through DataONE for ease of discovery and secondary use.

 

Rhodes, Jennifer

B-F013: The Art and Science of the Prairie Fire

Jill Haukos , Yang Xia

Konza Prairie LTER, Kansas State University

This poster highlights the efforts underway to integrate art into the scientific activities at Konza Prairie. Fire is a major component in the management of any prairie and the dramatic nature of fire naturally inspires the artistic sensibility. This poster briefly profiles three different artists on how they were inspired by fire and the art they produced as a result.

 

Rios, Orlando

B-K126: REU Poster: Bio-reactivity of dissolved organic matter from nutrients along the Rio Grande River      

Sevilleta LTER, Wayne State University

The microbial communities in the Rio Grande river play a critical role in processing organic. Although is known that these organism’s populations thrive over arid climates, the proportions of processing dissolved organic matter (DOM) over the various changes of nutrients availability remain unknown. As the Rio Grande receives significant nutrients input from the agricultural fields, urban runoff, and wastewater treatment; water quality is threatened. In this experiment, we discovered these microbial communities processing aptitude are established over their recurrent nutrient uptake. Therefore, our project is a starting point for the understanding of the contemporary bioreactivity of watersheds considering urban, agricultural disturbances.

 

Rivera, Sara

A-F086: Heterotrophic Bacteria in the CCE LTER between 2006-2017

Lihini Aluwihare

California Current Ecosystem LTER, Scripps Institution of Oceanography, University of California San Diego

Heterotrophic bacteria recycle organic matter into its constituent nutrients through the microbial loop. In this study we quantified the abundance and activity of heterotrophic bacteria in the California Current Ecosystem (CCE) LTER site between 2006-2017. This time period captured significant interannual variability in climatic conditions in the region but we found little temporal variability in bacterial abundance. Instead, the biggest gradients in abundance and activity varied spatially from coastal upwelling sites to open ocean oligotrophic environments. Strong, but distinct, correlations with environmental parameters suggest that regional characteristics may be useful for modeling bacterial characteristics in times of limited sampling.

 

Robinson, David

A-F058: Environmental History: Examining Disturbances in Previously Used Antarctic Field Camps

Adrian Howkins, Stephen Chignell, Byron J. Adams, J.E. Barrett, John C. Priscu, Michael N. Gooseff, Peter T. Doran, Cristina Takacs-Vesbach

McMurdo Dry Valleys LTER, University of New Mexico

Soil community composition is sensitive to disturbance, resulting in potential changes in ecosystem function. We have sampled the soil microbiota (i.e. bacterial 16S rRNA genes, nematodes, tardigrades, rotifers) in five areas that once housed field camps during the 1970s and 80s in the McMurdo Dry Valleys. Site disturbances include researchers, huts, helicopter pads, and outhouses, in addition to the use of other materials for building. We predict differences in diversity and community composition in these former camps compared to other uninhabited areas. We will estimate potential recovery rates of different members of the community and examine if individual types of disturbance have distinct effects on community composition and function.

 

Robison, Andrew

A-F029: Greenhouse gas monitoring in the river networks of the Plum Island Ecosystems LTER

Wilfred Wollheim

Plum Island LTER, University of New Hampshire

River networks are most often sources of greenhouse gases (GHGs), yet uncertainty remains in understanding river network GHG dynamics across space and time. We have begun monitoring GHGs (CO2, CH4, and N2O) within the PIE LTER river networks to address these uncertainties across an urbanization gradient. High frequency in situ dissolved CO2 sensors are deployed at five headwater stream sites; floating chambers in two headwater streams and nearby wetlands are monitoring evasion of the three GHGs; and bubble traps have been deployed along transects at two headwater streams to measure ebullitive fluxes on a greater spatial scale. Together, these measurements will improve our understanding of the controls on GHG emissions from river networks.

 

Roebling, Suzy

B-K123: REU Poster: Testing effects of freshwater restoration following long-term simulated saltwater intrusion on litter breakdown in coastal wetlands        

Florida Coastal Everglades LTER, FIU

The balance of fresh and marine water supplies influences plant-soil carbon (C) storage in coastal wetlands. Saltwater intrusion into freshwater coastal wetlands increases marine-derived nutrient subsidies (e.g., nitrogen, N; phosphorus, P) and salinity stress. We lack sufficient information about the legacies of P and salinity on soil C processing in freshwater wetlands previously exposed to marine water. Further, the capacity for freshwater restoration to affect soil C storage is not well understood. Our objective was to quantify differences in organic matter breakdown rates in freshwater sawgrass (Cladium).

 

Rohr, Tyler

A-F057: Southern Ocean Iron Fertilization: An argument against commercialization but for continued research

Palmer Antarctic LTER, MIT/WHOI Joint Program

Ocean Iron Fertilization is a geoengineering strategy designed to mitigate climate change by attempting to increase the net oceanic drawdown of CO2 by stimulating marine phytoplankton growth in large iron-limited swaths of the Southern Ocean. I argue that measurement challenges, unreliable auditing, ambiguous baselines, high frequency variability, poor enforcement, and severe externalities, would together cripple a market-based approach to implementation and should preclude adoption into emerging compliance offset markets. Continued research, however, is needed to help delegitimize the reckless commercialization of OIF on voluntary markets which is motivated by the relative ease of OIF, market incentives and a loose regulatory framework.

 

Rohwer, Robin

A-F021: Time Scales of Freshwater Microbial Community Change

Katherine McMahon

North Temperate Lakes LTER, University of Wisconsin-Madison

Microbial communities drive freshwater biogeochemical cycling, but identifying ecologically significant changes in microbial community composition remains a defining challenge of microbial ecology. We address this challenge using an 18-year time series of Lake Mendota, a eutrophic lake in WI, USA, analyzed using 16S rRNA gene amplicon sequencing. The temporal frequency of samples ranges from approximately twice-monthly during the first 12 years to twice-weekly during the remaining 6 years, with periods of higher 1-2 day frequencies. In order to differentiate significant changes between temporally-close samples, we sequenced biological duplicates. We used a taxonomy-centric analysis to enable ecological interpretations of community changes.

 

Rugge, Mike

A-K125: Site Poster: Drivers of Abrupt Change in the Florida Coastal Everglades

Florida Coastal Everglades

The Everglades formed over the last 5 millennia but a century of hydrologic alterations have drastically altered its subtropical freshwater wetlands, mangrove forests, and seagrass meadows. The Florida Coastal Everglades (FCE) LTER program has revealed the origins of ecosystem productivity in this iconic landscape, quantifying how variation in water sources interacts with disturbances like tropical storms to drive ecological properties along coastal gradients. Restoration of freshwater to maintain the Everglades competes with human demands for water. Declining fresh water is colliding with accelerated rates of sea-level rise, making vulnerable distinctive food webs and globally significant carbon stores. Preventing these losses is urgent.

 

Santos, Rolando

B-K104: Incorporating animal movement into long-term ecological monitoring: Snook movement in the FCE-LTER

Florida Coastal Everglades LTER, Florida International University

Organisms with varying phenotypes and personality types are known to respond differently to spatiotemporal heterogeneity in foraging, habitat, and mating opportunities; thus, inducing intraspecific movement variability. Whether populations behave as homogeneous or heterogeneous units can have important conservation implications. To inform how intraspecific variability of habitat use influences the stability of mobile populations in the face of a changing environment, we assessed the synchrony in spatial distribution among common snook (Centropomus undecimalis) individuals in Shark River (FCE-LTER) using acoustic telemetry. Our results highlight the importance of incorporating animal movement into long-term ecological monitoring.

 

Sauceda, Marcos

A-K101: Calibrating minirhizotron estimates of belowground productivity in North American grasslands

Osvaldo Sala, Laureano Gherardi

Jornada Basin LTER, Arizona State University

Minirhizotron imaging allows researchers to study root production over time due to the non-destructive nature of the technology. This project seeks to produce a calibration method and metric to improve the accuracy of below ground production estimates created by minirhizotron imaging across three North American grasslands. We sampled the range of root production using minirhizotron imaging on plots under a range of precipitation exclusion treatments. We then physically sampled each plot to produce a comparative physical sample for each minirhizotron measurement. Our results are being used to derive allometric equations that will be useful to researchers who rely on minirhizotron technology to estimate below ground productivity in grassland ecosystems.

 

Savoy, Heather

A-F076: The DASH Portal: a gateway to simplified access and integration for long-term ecological data

Debra P.C. Peters, Geovany Ramirez, Dylan Burruss

Jornada Basin LTER, New Mexico State University

Various LTER projects can rely on the same geospatial data sets (e.g. precipitation across a LTER site) and the work to integrate these data sets into individual workflows can become redundant. The Data Access and Spatiotemporal Harmonization (DASH) portal was created to automate these steps, such as accessing the data, subsetting the data by time and space, and performing statistical analyses. The portal tool allows users to obtain the data they need via a web-based interface that translates their selections into automated scripts so that the user does not need to use GIS software or programming languages themselves. This poster will describe the features of DASH and examples of how the portal benefits current and future LTER projects.

 

Scaife, Charles

A-F070: Linking long-term stormflow threshold variation to ecosystem transpiration at the Coweeta LTER

Lawrence Band

Coweeta LTER, University of Virginia

Ecosystem transpiration rates in humid, temperate forests can compete with actively draining subsurface flows reducing stormflow totals. By simply adding antecedent wetness conditions to total storm event rainfall, one can examine this interaction by identifying stormflow thresholds and examining threshold variation through time. Previous long-term studies utilizing this method could not consider the effects of rainfall intensity, which may generate significant stormflow through pathways too transient to interact with transpiration. Using long-term hydroclimatological data collected at the Coweeta LTER, we examine the formation and variation of stormflow thresholds to better understand these long-term vegetation-climate interactions.

 

Schmidt, Stephanie

B-F039: Air Temperature Instrument Deviations and Consequences for Climate Trend Analysis at H.J. Andrews

Mark Schulze, Sherri Johnson, Lisa Ganio

Andrews Forest LTER, Oregon State University, USFS Pacific Northwest Research Station

Air temperature instruments at the H.J. Andrews LTER have been upgraded over time as new technology has developed, but concurrent and co-located measurements from newer instruments deviate from the measurements of older instruments. These deviations create a potential for bias in long-term temperature records and complications for trend analyses. The objectives of this study are to determine the frequency and extent to which measurements from historic instruments deviate relative to the current standard, the extent to which solar radiation and wind speed are correlated with deviations, and whether temperature metrics typically used in research are sensitive to deviations associated with instrument changes.

 

Schmitt, Russell

B-K105: Experimental support for alternative attractors on coral reefs

Sally J. Holbrook

Mo’orea Coral Reef LTER, University of California Santa Barbara

Ecosystems with multiple basins of attraction can get trapped in an undesired state, yet they are challenging to detect in nature. On coral reefs, it is thought that persistent coral-to-macroalgae ‘phase shifts’ may reflect a regime shift to an alternate attractor. MCR field experiments demonstrated for the first time: (1) hysteresis in the herbivory – macroalgae relationship, creating the potential for coral – macroalgae bistability, and (2) that macroalgae were an alternative attractor under prevailing conditions in the lagoon but not the fore reef. These findings help explain the different dynamical responses of these habitats on Moorea, and reinforce the idea that reversing an undesired shift on coral reefs can be difficult.

 

Schofield, Oscar

A-K117: Site Poster

Palmer Antarctic LTER

 

Schofield, Oscar

B-F057: Changing Sea Ice Dynamics on West Antarctic Peninsula Underlying Ecosystem Alterations

Bay Head

Palmer Antarctic LTER, Rutgers University, COOL

Sea ice of the West Antarctic Peninsula (WAP) has experienced significant change over the last fifty years. Over decadal time scales, the heating on the WAP has been driven by subsurface intrusions of the warm circumpolar current onto the shelf that is topographically steered to the coast terminating near major penguin colonies. Sea ice has steadily declined from the 1980’s until a recent reversal that began in 2008. In the southern WAP, the mixed layer depth has shallowed and is associated with enhanced phytoplankton carbon fixation. Associated with the recent increases in sea ice has been an increase in the photosynthetic efficiency. High chlorophyll years were associated with krill recruitment suggesting a tightly coupled ecosystem.

 

Schooley, Robert

B-F089: Shrub encroachment, productivity pulses, and core-transient dynamics of Chihuahuan Desert rodents

Brandon Bestelmeyer

Jornada Basin LTER, University of Illinois

Drylands worldwide are experiencing shrub encroachment into grasslands with potential consequences for biodiversity and ecosystem services. We used long-term data from the Jornada Basin LTER site in the Chihuahuan Desert to ask whether bottom-up control of desert rodents changes across shrub encroachment gradients. Transitions to shrublands did not produce degraded ecosystems, on average, with reduced net primary production or decreased rodent biomass. However, more rodent biomass was supported on unencroached grasslands following droughts whose frequency may increase in the Southwest. Bottom-up processes for desert rodents were understood by integrating lagged responses to productivity pulses with core-transient structuring of communities.

 

Schreier, Brian

A-K110: Interagency Ecological Program: Supporting science and resource management with long-term monitoring

Melinda Baerwald, Larry Brown, Maggie Christman, J. Louise Conrad, Steven Culberson, Karen Kayfetz, Shruti Khanna, Peggy Lehman, Ted Sommer, Vanessa Tobias

California Department of Water Resources

The San Francisco Estuary is monitored by over 20 distinct programs, some dating back to the 1960s. This ecological monitoring network collects data on hydrology, water quality, phytoplankton, zooplankton, macroinvertebrates, and fishes across multiple habitat types using a suite of sampling methods and technologies. Support and integration of this vast network is coordinated by the Interagency Ecological Program for informing resource management decisions, habitat restoration efforts, and species conservation. We describe the breadth of this monitoring network and how resource managers draw upon multiple programs for information and real-time decision making.

 

Schultz, Cristina

B-F044: Using datasets and model results to understand the ecology of the Palmer region, Antarctica

Palmer Antarctic LTER, Woods Hole Oceanographic Institution

Over the past several decades, the West Antarctic Peninsula (WAP) has undergone physical and ecological changes at a rapid pace, with warming surface ocean and a sharp decrease in the duration of the sea ice season. The impact of these changes in the ocean chemistry and ecosystem are not fully understood and have been investigated by the Palmer-LTER since 1991. Given the data acquisition constraints imposed by weather conditions in this region, an ocean circulation, sea ice and biogeochemistry model was implemented to help fill the gaps in the dataset. The current results indicate that the changing sea ice concentration directly influences the timing of the phytoplankton blooms through changes in light availability and freshwater input.

 

Schwenck, Sarah

A-F088: A look at viral mortality across an upwelling filament within the California Current Ecosystem

Michael Landry, Andrew Allen, Lisa Zeigler Allen

California Current Ecosystem LTER, Scripps Institution of Oceanography

The California Current Ecosystem has numerous short-lived upwelling filaments that introduce limiting nutrients and influence the growth and transport of microbial communities offshore. We investigated mortality along a transect of one such filament via a series of dilution experiments. Samples for chlorophyll, viral counts, flow cytometry, and -omics work were collected. Growth rates indicated that while grazer mortality was present at all stations, viral mortality influences were strongest within the filament. Ongoing investigations via sequencing of viruses and microbes are underway to assess taxonomic and host physiological changes during incubation, providing greater insight into the influences of viral mortality on phytoplankton.

 

Scott, George

B-F056: Comparative Phylogeography of Nematodes in Victoria Land and Southern TAM, Antarctica

McMurdo Dry Valleys LTER, Brigham Young University

The objective of this study is to assess biological connectivity within Southern Victoria Land, Northern Victoria Land, and the Southern Transantarctic Mountain regions. Our hypotheses of population structures are tested with nematode species from four genera, which span a geographic region of ~1100 miles. Areas of endemism as well as potential refugia sites during the Last Glacial Maximum are explored.

 

See, Craig

B-F007: The effects of four global change factors on growing-season CO2 flux from grassland soils

Erin Mittag, Caroline Daws, Sarah Hobbie, Peter Reich

Cedar Creek LTER, University of Minnesota

Globally, the respiration of roots and soil organisms represents the largest terrestrial flux of CO2 to the atmosphere. Despite its importance to the global carbon budget, there remains uncertainty as to how soil respiration rates will respond under global change. We investigated the main effects and interactions of multiple global change factors on 3 years of repeated measurements of soil respiration in the BioCON experiment at Cedar Creek. We found that elevated CO2 and warming treatments independently increased soil respiration. We did not detect an effect of drought, while the effects of nitrogen depended on the presence of warming. We scaled the point respiration rate measurements to seasonal flux using treatment-specific Q10 equations

 

Shaffer, Monica

A-F017: Plant architectural shifts contribute to increased forage density on grazing lawns

David Hartnett, Samantha Grieger

Konza Prairie LTER, Kansas State University

A key feature of many grasslands is the formation of grazing lawns, intensely grazed, short-statured patches maintained by positive feedbacks between grazers and grasses. Different mechanisms may initiate/maintain grazing lawns as an alternate stable state in grasslands. We tested the hypothesis that grazing on tallgrass prairie causes shifts in plant architecture that increase forage density (grams per unit canopy volume), which then promotes further grazing. Grasses on grazing lawns were generally characterized by higher leaf:stem ratios, density of belowground buds and tillers, and shorter internode lengths and height, compared to conspecifics in tallgrass swards. shifts, resulting in higher forage density on lawns.

 

Sherwell, Shasten

A-F054: Response of microbial communities to disturbances in ice-covered lakes in the McMurdo dry valleys

McMurdo Dry Valleys LTER, Miami University

Lakes in the McMurdo Dry Valleys are perennially ice-covered and are always stratified. Increasing air temperature continues to warm the valleys exposing these lakes to a chain of disturbances, such as lake level rise, thinning of ice-cover, and increasing connectivity. To study the response of microbial communities to these disturbances, tLICE was designed. This experiment consists of transplanting under-ice communities to deeper layers in the lake, and into the moat. From the preliminary data we conclude that shallow communities showed low resilience to the disturbance of lake level rise as well as to increasing connectivity, by showing a decrease in biomass, a downregulation of PSII and a shift in community composition.

 

Sibley, Adam

A-F038: Differential canopy wetting dynamics in old growth and second growth Douglas-fir canopies

Christopher Still

Andrews Forest LTER, Oregon State University

Old growth and regrowth Douglas-fir canopies generally have distinct vertical profiles of biomass. This difference in canopy structure leads to distinct patterns of dewfall and rainfall interception, as well as the time it takes for canopy zones to dry out. The persistence of unique microclimates and moisture zones distributed vertically through these canopies has implications for leaf water uptake, endophyte community composition, and epiphyte community distribution. Using two adjacent trees heavily instrumented with environmental sensors, we are able to explore the climatological factors that determine where biotic communities are located vertically as well as water balance feedbacks between these communities and the trees themselves.

Simon, Scott

A-F091: SBC-sLTER: Advancing EcosySTEM Literacy

Santa Barbara Coastal LTER, Marine Science Institute-Univ. Ca at Santa Barbara

With the continued implementation of Next Generation Science Standards (NGSS), SBC sLTER continues to develop content to support relevant science curricula around project-, and place-based learning. Our sLTER programs focus on transforming science content knowledge through strategic undergraduate science education and communication, teacher professional development AND place-based experiential learning for P-20 students in Southern California. This is accomplished through a model of cooperative learning processes, learning progression teaching strategies and the utilization of current research and real-world issues.

 

Sinclair, Michael

B-F068: State change in coastal grasslands: expansion of a nitrogen-fixing shrub

Julie Zinnert, Donald Young, Lauren Wood

Virginia Coast Reserve LTER, Virginia Commonwealth University

Morella cerifera rapidly encroaches barrier island swale grasslands at the Virginia Coast Reserve LTER, establishing a dense monotypic shrub thicket. Increasing winter minimum temperatures may be the primary driver, which previously inhibited the expansion of cold-intolerant M. cerifera. Grass-shrub facilitation may enhance growth at the seedling life stage. Microclimate modification at later stages creates a positive feedback for shrub growth. Morella cerifera encroachment has important implications for ecosystem function and stability as shrub thickets have higher productivity but lower species richness than grasslands. Shrub thickets also limit cross-island sediment transport, possibly leading to increased barrier island erosion.

 

Smith, Colin

A-F026: Data curation services for ecologists

Susanne Grossman-Clarke, Corinna Gries

Environmental Data Initiative, University of Wisconsin

The Long-Term Ecological Research Network has a long history of archiving its monitoring and most research data. The National Science Foundation is now expanding its requirement to make research data products openly accessible to other environmental programs and is joined in this requirement by scientific journals publisher. Ecologists associated with an LTER site are privileged to have the support of a local Information Manager. However, those grappling with this requirement for the first time themselves and for a different funding stream, selecting a data repository, preparing the data for archive, and appropriately documenting their data may be a challenge.

 

Smith, Colin

B-K113: Information Management Code Registry: Discover and share software solutions

Kristin Vanderbilt, Corinna Gries

Environmental Data Initiative, University of Wisconsin

Ecologists and data managers write significant amounts of code for data manipulation in preparation for publication and analysis. However, publishing and sharing this code is not a common practice and is hampered by the lack of thematic code registries that are designed to make code easily discoverable and reusable. In this poster, we introduce a new information management code registry. Its focus is on code or workflow scripts developed for common procedures that ecologists and information managers encounter when organizing, cleaning, manipulating, and harmonizing data. It will live in the niche between scientific analysis and modeling code and short code snippets found on online community help boards.

 

Snow, Pamela

B-F034: Broader Impacts for Land-Use Change Research

Melanie McCracken, Pamela Snow, Clarisse Hart

Harvard Forest LTER, Harvard University

This poster will highlight the educational activities designed by High School teacher, Melanie McCracken, who has developed land-use change lesson plans related to a Harvard Forest led Schoolyard LTER plot-based forest study at her school. These activities make use of a series of companion land-use change maps of her town, developed by and Joshua Plisinski and HFR PI, Jonathan Thompson’s as part of the Scenarios team’s research . The lessons are designed to help students better understand changes in the land in and around their own schoolyards and towns using these sets of maps. Nine-year, HFR Schoolyard Ecology program participant, Melanie McCracken, Groton-Dunstable High School teacher, will work with HFR Schoolyard Coordinator in sharing this poster.

 

Speare, Kelly

A-K105: Evaluating top-down and bottom-up control of coral community recovery across a depth gradient

Deron Burkepile

Mo’orea Coral Reef LTER, University of California, Santa Barbara

Coral communities in Moorea, French Polynesia experienced massive disturbances between 2007-2011 that killed and removed nearly all live coral on the outer reef. The six MCR LTER sites all show signs of coral community recovery, but there are strong spatial patterns in the rates of recovery on the three sides of the island and across a depth gradient. Here we evaluate differences in top-down and bottom-up control on community recovery across depths on the outer reef. We investigate three mechanisms that could drive variation in recovery: 1) differences in recruitment of corals, 2) variation in growth and survival of recruits, and 3) variation in coral growth rates across depths.

 

Stier, Adrian

B-F070: How harvest modifies the role of predation in kelp forest ecosystems

Max Castorani, Tom Bell, Dan Reed, Kyle Cavanaugh, Bob Miller

Santa Barbara Coastal LTER, University of California Santa Barbara

Harvest of species at the top of the food chain can fundamentally alter structure and dynamics of ecosystems. In kelp forest ecosystems, predators such as the California spiny lobster (Panulirus interruptus) are hypothesized to promote the persistence of kelp by consuming dominant play an important role in regulating herbivorous uchins. Heavy fishing pressure can significantly reduce the abundance and average size of lobsters; however, our understanding of how these changes in abundance and size alter the role of predation in kelp forests remains limited. Here we describe the results of a laboratory experiment that quantifies how size selective harvest of lobsters can fundamentally alter the role of predation in kelp forest ecosystems.

 

Stingl, Ulrich

B-K109: Microbial communities in waters of the Florida Coastal Everglades were impacted by Hurricane Irma

Florida Coastal Everglades LTER, University of Florida

Aquatic microbial communities drive biogeochemical cycles and organic matter processing. Surprisingly little is known about structure and spatiotemporal variability of microbial communities in many wetland ecosystems. Here, we show the first detailed snapshots of phylogenetic composition and predicted functions of water column microbes in transects of the Florida Coastal Everglades, and also document their changes after Hurricane Irma. E.g., unicellular cyanobacteria of the genus Synecchococcus contributed 5-10% of oligohaline and estuary communities before Irma, but bloomed in the north-eastern part of Florida Bay after Irma (over 40% of all). Uncultured heterotrophic members of the order Burkholderiales dominated the freshwater marshes.

 

Strom, Suzanne

A-K114: Site Poster: The Northern Gulf of Alaska (NGA) LTER: Resilience Amidst a Sea of Change

Russ Hopcroft, Ana Aguilar-Islas, Seth Danielson, Jerome Fiechter, Andrew McDonnell, Marilyn Sigman

Northern Gulf of Alaska, Western Washington University

The new Northern Gulf of Alaska (NGA) LTER site is exploring the ecological and oceanographic underpinnings of a remote and productive coastal subarctic ecosystem. Our program builds on a multi-decade time series of oceanographic observations on the continental shelf. LTER hypotheses and process work initially focus on major production drivers: the spring bloom, and summer-fall inputs of freshwater to the shelf. Our ecological framework postulates that intense environmental variability has led to the evolution of resilience, as embodied in species- and community-level properties. This poster will share time series data, modeling approaches, and outreach strategies, along with an overview of the site and sampling program.

 

Suchy, Amanda

B-F069 Hotspots of nitrogen transport and retention in residential lawns in Baltimore, MD

Peter M Groffman, Lawrence E Band, Jonathan M Duncan, Arthur J Gold

Baltimore Ecosystem Study LTER, City University of New York

Residential landscapes are considered exporters of nitrogen to downstream ecosystems. However, watershed scale studies have found some residential areas retain more nitrogen than expected and it has been suggested that lawns could be a potential sink for nitrogen in these landscapes. Despite their ubiquity, predicting the environmental performance of residential lawns can be challenging. Variable management practices, complicated land use histories, and underlying geomorphology interplay to affect the ecology and hydrobiogeochemistry of lawns. In this poster, we present preliminary results of a study in which we examined how the topography of lawns and lawn management decisions interact to affect nitrogen transport and retention in lawns.

 

Swartz, Allison

B-F041: Influence of a riparian canopy gap on a forested headwater stream

Dana Warren

Andrews Forest LTER, Oregon State University

In aquatic ecosystems light is a fundamental control on stream temperature, primary production, and nutrient cycling. Old-growth riparian forests contain complex multi-level canopies with canopy gaps that result in patches of elevated light reaching the streams. In contrast, mid-succession riparian forests have uniform closed-canopies lacking structural heterogeneity. To quantify the influence of canopy gaps on primary production, nutrient cycling, and stream food webs, we cut a riparian canopy gap along a second-order stream in the HJ Andrews Experimental Forest LTER. As hypothesized, creating a canopy gap resulted in localized increases in light, with subsequent increases in chlorophyll-a standing stocks, and nutrient uptake velocity.

 

Taylor, Jeff

A-F010: The Flora of Konza Prairie: An Update

Mark Mayfield, Gary Breckon

Konza Prairie LTER  Kansas State University

The vascular flora of Konza Prairie Biological Station, a 3487ha research site located in the Flint Hills of Kansas, has been studied for over 40 years, but new species continue to be reported. In the 16 years since the last published checklist, over 125 additional taxa have been located on Konza. While Konza is a tallgrass prairie site, only 33% of all species occur primarily in prairie habitat. Other important habitat types include woodlands (20%), wetlands (16%), and sites prone to disturbance (29%). Twenty percent of the Konza flora now consists of exotic species.

 

Thibodeau, Patricia

B-F052: Pteropod feeding ecology along the Western Antarctic Peninsula

Deborah K. Steinberg and Bongkeun Song

Palmer Antarctic LTER, Virginia Institute of Marine Science

The pteropod (pelagic snail) Limacina helicina antarctica is an abundant zooplankton species in the Western Antarctic Peninsula (WAP) and is an important grazer of phytoplankton. However, their feeding ecology and microbiome have not been well investigated. We examined regional shifts in L. antarctica feeding and microbiome along the WAP by analyzing their gut contents with high-throughput sequencing of 16S and 18S rRNA genes. Dominant taxa present in L. antarctica guts was spatially variable and most distinct between the North and South regions, reflective of different prey microbial communities in these regions. This is the first study using a high-throughput sequencing technique to reveal L. antarctica feeding selectivity.

 

Tosa, Marie

B-F042: How does land use affect movement of western spotted skunks in the Pacific Northwest Forests?

Damon Lesmeister, Taal Levi

Andrews Forest LTER, Oregon State University

Tensions between biodiversity conservation and the demand for economic outputs are high in the Pacific Northwest where timber production dominates land use and numerous species, including small carnivores, have declined due to loss of old growth forest. To improve our understanding of the impacts of land use on small carnivores, we used baited trail cameras and very high frequency radio-collars to describe space use, movement patterns and rest site structures of the western spotted skunk (Spilogale gracilis) at the H. J. Andrews Experimental Forest in the Oregon Cascades during October 2017 – August 2018. Results suggest that spotted skunks occurred at lower elevations and primarily used underground burrows and live trees for rest sites.

 

Trinh, Rebecca

B-F055: 20 years of particle export in west Antarctic Peninsula coastal waters

Palmer Antarctic LTER, Columbia University

The west Antarctic Peninsula has experienced over 6°C increase in winter temperatures since 1950. This warming and decline in sea ice have been associated with changes to the phytoplankton and krill populations, resulting in changes in particulate organic carbon (POC) flux, as these components represent two major drivers to the biological carbon pump. Data from our sediment trap timeseries is unique in its longevity, allowing us to understand how POC flux has changed seasonally and annually over 21 years. Analysis from this study has found a high degree of inter-annual variability of POC flux, a significant decline in annual cumulative POC flux, and a shift in the timing of the peak POC flux to later in the summer/fall season.

 

Trusiak, Adrianna

A-F046: Role of iron and reactive oxygen in the production of CO2 in arctic soil waters

George Kling, Rose Cory

Arctic LTER, University of Michigan

Warming in the Arctic is causing permafrost soils to thaw, which could allow tremendous stores of organic carbon to be converted to CO2 on relatively short time scales. We discovered that carbon in the form of dissolved organic carbon (DOC) is susceptible to oxidation by a redox reaction involving iron and hydroxyl radical (•OH). Specifically, we found that •OH, a very reactive oxidant of carbon, is produced from oxidation of low O2, iron rich soil waters in the Alaskan Arctic. We determined that •OH produced from oxidation of arctic soil waters can oxidize DOC to CO2. Determining the rate of •OH oxidation of DOC to CO2 in the soil waters of the Alaskan Arctic is crucial in predicting how a warming Arctic may impact Earth’s climate.

 

Vadeboncoeur, Matthew

B-F033: “Teacomposition” in three global change experiments at Hubbard Brook Experimental Forest

Katie Jennings, Madison Morley, Lindsey Rustad, Cameron McIntire, Laurel Brigham, Ruth Yanai, Heidi Asbjornsen

Hubbard Brook LTER, University of New Hampshire

The ILTER “Teacomposition” initiative is a global study of decomposition rates that uses two types of tea (green and rooibos) in nylon teabags as uniform substrates. In 2016, we initiated this protocol in three experiments at HBR: a simulated ice storm (canopy disturbance), a simulated drought (throughfall exclusion), and a factorial fertilization experiment. As of the 12-month collection, we have not observed significant differences among treatments in the ice storm or drought experiments. However, at 3 months we observed that N fertilization significantly slowed the decomposition of rooibos tea, while fertilization with N+P together sped rooibos decomposition. Data from the 24-month collection (July 2018) will also be presented.

 

Valipour, Mahnaz

A-F035: Modeling the integrated effects of forest harvesting and climate change scenarios on dynamics of vegetation, hydrology and nutrients using PnET-BGC model

Charles T. Driscoll, Chris E. Johnson, John J. Battles, John L. Campbell, Timothy Fahey

Hubbard Brook LTER, Syracuse University

The hydrochemical model, PnET-BGC was modified using field data from an experimentally whole-tree harvested northern hardwood watershed (W5) at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA to simulate the hydrology, biomass accumulation, and soil solution and stream water chemistry responses to clear-cutting. The confirmed model was used to investigate temporal changes in aboveground biomass accumulation and nutrient dynamics under three different harvesting intensities (40%, 60% and 80%) over three varied rotation lengths (30, 60 and 90 years) and coupled these scenarios with future climate change scenarios and compared the results.

 

Van Deynze, Braeden

B-F021 Technology and Trade-Offs in Managed Ecosystems: The Case of Glyphosate-Tolerant Soybeans

Kellogg Biological Station LTER, Michigan State University

Farmers use technologies to simultaneously manage several ecosystem services. While farmers mainly focus on managing provisioning services, they also target several regulating services. Using twenty years of weed control choice data from across the United States, this poster explores how the rapid adoption of glyphosate-tolerant (GT) soybean seed changed the relationships between two regulating services, soil health and weed control, and the technologies used to manage them. While GT seed first mitigated the trade-off between soil health and weed control by partially facilitating the adoption of conservation tillage, the rise of glyphosate-resistant weeds has induced a return to intensive tillage, strengthening this trade-off once again.

 

Vega Anguiano, Nico

B-K119: REU Poster: Dictating N2O Fluxes by Hydrometer Method in Differing Landscape Positions in Fertilized Fields

Kellogg Biological Station LTER, Humboldt State University

Landscape position influence Nitrous Oxide fluxes in fertilized agricultural fields through many properties including soil texture. As a result, soil and hydrological physical process contribute to emissions of N2O-a greenhouse gas-which has a radiating potential of almost 300 times that of Carbon Dioxide. Soil texture plays a pivotal role in how much N2O is emitted. Samples where subjected to the Hydrometer Analysis to analyze soil texture and proportion composition of sand, silt and clay. We had 13 sites located in the KBS LTER in Corn and Switchgrass systems. In a majority of the fields we found a significant positive correlation between fine-sized soil particles (silt and clay) and N2O fluxes when rainfall is consistent.

 

Viadero, Natasha

B-K102: Seasonal habitat use of Largemouth Bass in the Shark River of the Florida Coastal Everglades LTER

Jennifer S. Rehage, Rolando O. Santos, Jordan A. Massie

Florida Coastal Everglades LTER, Florida International University

Recreational angling for species such as Largemouth Bass (Micropterus salmoides) makes significant contributions to Florida’s economy, including areas of South Florida making up the Florida Coastal Everglades (FCE) LTER site. In this study, we make use of long-term data collected in the Shark River as part of the FCE LTER to examine the drivers and timing of habitat shifts as they relate to hydrology, namely the seasonal fluctuations of freshwater. We draw on telemetry data from a permanent array of acoustic receivers established in 2007 to track the immigration and emigration of bass within the mangrove river system. We then relate these movements with data on water levels, flow, and recession rates across multiple years.

 

Volaric, Martin

B-F064: Oyster reef activity measured using bioacoustic and aquatic eddy covariance techniques

Eli Stine, Peter Berg, Matthew Reidenbach

Virginia Coast Reserve LTER, University of Virginia

Oyster reefs are complex communities that exist against the backdrop of a dynamic physical environment. These ecosystems provide habitat to a wide variety of benthic organisms that both consume (oysters, fauna) and release (benthic algae) oxygen, resulting in complex oxygen flux dynamics over tidal and diurnal cycles. In this study we performed in situ bioacoustic sound recordings and aquatic eddy covariance oxygen flux measurements on intertidal oyster reefs, as well as laboratory particle image velocimetry (PIV) and sound measurements of various oyster reef fauna. Our goal is to determine how faunal activity varies over tidal and diurnal cycles, and how these changes impact the integrated reef metabolism.

 

Voter, Carolyn

A-F007: Climate- and development-driven heterogeneity in hydrologic fluxes from urban residential parcels

Steven P. Loheide

North Temperate Lakes LTER, University of Wisconsin-Madison

Since urbanization has well-documented negative impacts on nearby aquatic ecosystems, there is strong interest in improving our scientific understanding of where stormwater runoff is generated and how it interacts with other urban hydrologic fluxes so that we can design the most effective low-impact development practices. We use the process-based hydrologic model Parflow.CLM to explore how heterogeneity in development characteristics of residential parcels affects flow across impervious-pervious interfaces and thus parcel-scale hydrologic fluxes. Additionally, we use weather records from the 50 largest U.S. cities to explore how climate moderates the effects of development features on fluxes from residential parcels.

 

Wagner, Svenja

A-F092: Interactions between soil properties and precipitation explain production patterns across a diverse landscape

Osvaldo Sala

Jornada Basin LTER, Arizona State University

Aboveground net primary production (ANPP) is an important ecosystem process that, in drylands, is most frequently limited by water availability. Water availability for plants is in part controlled by the water holding capacity of soils. Two major determinants of water-holding capacity are soil texture and depth. How can we improve spatial models that predict ANPP based on precipitation? Can integrating soil texture and depth into existing explanatory models improve our predictive power? In this study, we tested soils from 5 different desert plant communities and 4 long-term precipitation experiments to explore the combined effect of water-holding capacity and precipitation on ANPP.

 

Waide, Robert

B-K106: New Perspectives on the Past, Present, and Future of LTER Science

Sharon E. Kingsland

Luquillo LTER, University of New Mexico

A broad spectrum of LTER scientists are contributing to a new volume that will explore, explain, and analyze different aspects of the history of the LTER program since the 1980s. Chapters will highlight, where appropriate, what the scientific achievements of LTER have been, and attempt to address the question: why has LTER mattered to ecology and why does it still matter? Our broad goal is to assess and explain how LTER developed in the way it did, how problems and challenges were addressed, and, where appropriate, to offer commentary on what might have been done differently and what lessons can be learned from the past (both from successes and failures). A complementary working group will provide a forum for feedback on the importance of the accomplishments of the LTER Network to the field of ecology.

 

Walsh, Jake

B-F010: Invasion ecology in the North Temperate Lakes

Mike Spear, Jake Vander Zanden

North Temperate Lakes LTER, University of Wisconsin – Madison Center for Limnology

LTER sites have been critical to understanding the long-term effects of nonnative species. Long-term study provides rare pre-invasion (or pre-management) ecological baselines as well as detailed understanding of post-invasion dynamics, which have included both natural and managed changes in nonnative populations. Here, we highlight key advances in invasion ecology via long-term study at the North Temperate Lakes (NTL) LTER, which include advancing our understanding of invasive species ecological and economic impacts, invasive population management, and invasion dynamics. We look forward to discussing more with the LTER researchers engaged in invasion ecology.

 

Warren, Dana

A-F039: Light as a fundamental driver of stream ecosystems in the HJ Andrews Experimental Forest, OR

Andrews Forest LTER, Oregon State University

Over the past six years, our research group has studied how riparian forest controls on stream light can affect stream biota and stream ecosystem function in headwaters at the HJ Andrews LTER. We began with correlative studies in which we found strong relationships between stream light availability and the biomass of periphyton, macroinvertebrates, fish and salamanders in HJA headwaters. We then experimentally assessed the role of light as a bottom-up driver of stream food webs. The application of a patchy shading in three replicate streams resulted in lower biomass of biota across multiple trophic levels. We are now explicitly linking our work on light to riparian forest structure with an experiment creating riparian forest canopy gaps.

 

Weaver, Melinda

B-F085: Urban house finches are less responsive to novel sound but not other novel environmental stimuli

Central Arizona-Phoenix LTER, Arizona State University

Although many studies have tested animal responses to individual forms of novelty (e.g., human objects, food, urban noise), to our knowledge no study has comprehensively assessed behavioral reactions of urban and rural populations to numerous novel environmental stimuli. We tested exploratory behavior of urban, suburban, and rural house finches (Haemorhous mexicanus) in response to four different types of novelty (novel structural environment, novel object, novel noise, and novel food) in separate captive experiments and found compelling differences in how finches from different sites responded to novel noises, indicating that, in comparison with other types of novel stimuli, anthropogenic noise may be a key driver of urban adaptation.

 

Weber-Grullon, Luis

A-F083: Seedling establishment of Prosopis glandulosa on the Chihuahuan Desert

Osvaldo E. Sala, William A. Rutherford, Steven R. Archer

Jornada Basin LTER, Arizona State University

Woody-plant encroachment (WPE) has been occurring in US rangelands since early 1900s. Overgrazing has often been regarded as its primary cause, but there is also evidence that changes in precipitation may also play a major role. Even though WPE has been studied extensively, little is known about how woody-plant seedlings establish in grass-dominated landscapes. To better understand this process we asked: how do precipitation, grass-shrub competition, and herbivory interact to influence the probability of Honey mesquite (Prosopis glandulosa) establishment in grassland? We hypothesized that unique combinations of grazing, seed and seedling predation, grass-seedling competition and water availability are required for successful establishment.

 

Wedel, Emily

B-F008, Demography and Clonal Integration of Cornus drummondii in Tallgrass Prairie

David Hartnett and Jesse Nippert

Konza Prairie LTER, Kansas State University

Woody encroachment alters the community structure and ecosystem function of grasslands worldwide. In this study, we quantified the growth rate and demographic characteristics of the clonal shrub Cornus drummondii in response to fire frequency, grazing, and browsing. In addition, we conducted a N tracer study to assess nutrient retranslocation within shrub clones. Browsing lowered growth rates and reproductive effort while fire increased stem densities. These results highlight mechanisms of woody expansion in response to disturbance and may be used for the development of future management techniques to delay or reverse the process of woody encroachment.

 

Wells, Alex

B-K122: REU Poster: Gray Areas: Mapping Gray Vireo (Vireo vicinior) territories at Sevilleta National Wildlife Refuge

Kaija Gahm, Kathy Granillo

Sevilleta LTER, Middlebury College

The Gray Vireo (Vireo vicinior) is a small songbird listed as ‘Threatened’ by the state of New Mexico. Little is known of its breeding territories, which we investigated in the Sevilleta National Wildlife Refuge. Specifically, we sought to find 1) the average size of these territories and 2) the various factors influencing their size and placement. Utilizing two different methods of territory generation, our results not only suggest an average breeding territory size for Gray Vireos at Sevilleta, but also a significant negative correlation between territory size and coverage of Juniperus monosperma for one method of territory generation. Furthermore, breeding territories were most commonly located on northwest-facing slopes.

 

Welti, Ellen

A-F023: Sodium limitation in invertebrate food webs across 54 grassland sites

Konza Prairie LTER, The University of Oklahoma

Sodium has a unique role in food webs as a limiting nutrient primarily for plant consumers, but not for other trophic levels. We asked how the geography of sodium affects the abundance of invertebrates by sampling 54 grassland sites with variable sodium availability. Additionally, we conducted sodium addition experiments with the prediction that primary consumer attraction to sodium should increase in sites with low environmental sodium availability. Herbivore abundance increased by 50% with sodium addition. Our results demonstrate that invertebrate primary consumers are often sodium limited and increases in local sodium availability have the potential to increase invertebrate abundance and herbivory.

 

Whalen, Emily

B-F030: Manganese limitation as a mechanism for reduced decomposition in soils under nitrogen deposition

Harvard Forest LTER, University of New Hampshire

Long-term atmospheric nitrogen (N) deposition reduces leaf litter and lignin decomposition in forest soils, leading to an accumulation of soil carbon. Reduced decomposition has been accompanied by altered structure and function of fungal communities; however, a mechanistic understanding of fungal responses to chronic N enrichment is lacking. We evaluated manganese (Mn) limitation as a mechanism to explain these responses, as Mn is commonly reduced under N addition and is a cofactor of fungal lignin-decay enzymes. We found that Mn addition to chronically N-enriched soils increased lignin-decay enzyme activity and promoted fungal communities better adapted to decompose lignin, suggesting that Mn limitation contributes to reduced litter decay.

 

Wheeler, Megan

A-F084: Using mobile apps for easy, consistent long-term or cross-site data collection

Stevan Earl, Sharon J. Hall

Central Arizona-Phoenix LTER, Arizona State University

Uniformity and consistency are often difficult to achieve when collecting ecological data yet are critical to producing publishable, reusable data, particularly for long-term, cross-site projects. Mobile data collection apps allow enforcement of data formatting at the point of collection and can integrate multiple types of data. These features can help investigators streamline the process of adding new data to long-term datasets or compiling data across sites. We will share our experiences using form-based mobile apps, which are powerful yet require little to no programming expertise, for data collection in a single-site study and in a multi-investigator national study, and will demonstrate the use of this tool on a phone and laptop.

 

Whitney, Christopher

B-F029: Effect of small dam removals on nitrogen exports

Wilfred Wollheim

Plum Island Ecosystems LTER, University of New Hampshire

There are currently more than 2 million small dams in the United States with advocacy for their removal increasing for reasons such as the restoration of migratory fish passage, reestablishment of a more natural flow and sediment regime, and reducing threats to human safety from aging infrastructure. What is unknown however is the effect these dam removals will have on biogeochemical processes and in turn, how these processes will alter reach-scale nitrogen (N) exports. Here, we take advantage of a planned small dam removal on the Ipswich River in MA to understand the effects on reach-scale N exports. Similar work taking place in other impoundments will help to understand how these effects scale with impoundment size, discharge, and other factors.

 

Wigmore, Oliver

A-F003: Improving understanding of high resolution spatiotemporal variability in snow depth and vegetation productivity with multispectral UAS.

Noah Molotch

Niwot Ridge LTER, University of Colorado

Spatiotemporal variability in snow depth influences numerous ecohydrologic processes, including water availability and length of the growing season. This variability often occurs at sub 10m distances, thus these interrelationships are difficult to resolve with satellite observations. Similarly, point measurements may poorly capture local variations that are critical for determining ecosystem response to snow depth. We deployed a multispectral UAS at weekly interval to map surface features and quantify ecohydrologic variables including snow depth and vegetation productivity at 5-50cm resolution across 80ha at the Niwot Ridge LTER. Key questions to be addressed are: 1) how does spatial variability in snow depth impact vegetation productivity, 2) how can UAS help us to identify ecohydrologic ‘hotspots’ and ‘hot moments’ across heterogeneous landscapes.

 

Winslow, Erin

B-K111: Coral Community Dynamics: A Mystery in Moorea, French Polynesia

Mo’orea Coral Reef LTER, UCSB

Coral reefs around the world are threatened by anthropogenic stressors like increasing frequency and magnitude of storms, increasing temperatures, and decreasing pH. Corals are an integral part of reef systems in tropical locations, and protect island communities while providing habitat for commercial and subsistence fisheries. Understanding what future coral communities might look like if conditions remain the same is important to improve upon management strategies. Studying coral demographics through time and modelling future reefs based on growth, death, and recruitment rates of different genuses of coral can give us an idea of what the status of our future reefs may be.

 

Wilcox, Kevin

B-F023: How do we better incorporate plant community dynamics into process-based models?

Kimberly La Pierre; Meghan Avolio

Konza Prairie LTER, University of Wyoming

Process-based models are powerful tools to predict ecosystem functioning under a range of environmental conditions. However, capability within these models to represent shifts in plant community structure is limited. We challenged seven state-of-the-art models to match observed plant community change through time under experimental resource manipulation and the corresponding impacts on ecosystem functioning. Overall, models were unable to match observations due to imperfect representation of inter-specific competition for resources. We present avenues forward for empiricists and modelers to improve vegetation dynamics in process-based models.

 

Wood, Lauren

A-F069: Biotic controls over carbon dynamics in barrier islands

Leigh McCallister, Julie Zinnert

Virginia Coast Reserve LTER, Virginia Commonwealth University

Woody encroachment occurs across the globe, decreasing grassland area and increasing habitat productivity. At the Virginia Coast Reserve, this change is non-linear and driven by increased temperatures and microclimate modification. Productivity is > 1000 g m2 in young shrubs, declining with age. Despite the high input of leaf litter, soil C stocks remain low in the sandy soils. We show that soil C leaches into groundwater, with DOC ranging from ~8 to > 100 ppm and highest below the oldest shrub thickets. The ultimate fate of this carbon is unknown.

 

Woods, Natasha

B-F065: Community disassembly and reassembly in maritime forests

Philip Austin Tuley, Julie C. Zinnert

Virginia Coast Reserve LTER, Virginia Commonwealth University

Global climate change contributes to community disassembly in coastal ecosystems. Maritime forests represent a climax community increasing diversity and structure across the landscape. With rising sea-level and range expansion of native and invasive species, maritime forests have been declining along the Atlantic Coast. Community reassembly after a disturbance can be impacted by biotic (e.g. bird dispersed seed) and abiotic (e.g. salinity gradients) factors. Salinity has been a major driver of change in VCR barrier island forests. We examined community disassembly after multiple disturbance events and potential for community reassembly through bird dispersal and the sensitivity of tree species to salinity in maritime forest at the VCR.

 

Yanai, Ruth

A-F036: Quantifying Uncertainty in Ecosystem Studies (QUEST)

Hubbard Brook LTER, SUNY-ESF

Ecosystem scientists have rarely included error estimates when reporting nutrient pools and fluxes, in spite of the importance of uncertainty to interpretation and extrapolation of the results. The nitrogen budget at Hubbard Brook illustrates some of the challenges in quantifying uncertainty in hydrologic inputs and outputs, propagating model error in forest biomass, and accounting for spatial variability in sampling soils. Uncertainty analysis has many benefits, such as evaluating monitoring approaches to avoid wasting effort and identifying where resources should be directed to best improve understanding. QUEST is an NSF RCN devoted to promoting the development and application of uncertainty analysis (www.quantifyinguncertainty.org).

 

Yang, Yi

A-F024: Pocket gopher bioturbation effects on old field carbon and nitrogen dynamics

Johannes Knops

Cedar Creek LTER, University of Nebraska-Lincoln

Abandoned agricultural fields (old fields) are considered as net C sinks. However, relative importance of factors controlling C accumulation is unclear. Besides edaphic and microbial factors, bioturbation has strong impact on biogeochemistry yet was rarely examined. We investigated how pocket gophers (Geomys bursarius) affect C and N dynamics in old fields at Cedar Creek LTER. Gophers create soil disturbance by digging up soil and form mounds. We found it requires 5 years for plant biomass to recover on the gaps mounds create. Although N mineralization rates were elevated in mounds, the net effect of gopher bioturbation is lowering C and N loss from soil, as the soil under mounds have decreased mineralization and much larger soil volumes.

 

Yang, Yang

B-F035: Monitoring Mercury in Adirondack Loons: How Much is Enough?

Ruth Yanai, Kara Phelps, Nina Schoch, Gregory Lampman, and David Evers

Hubbard Brook LTER, State University of New York College of Environmental Science and Forestry

Mercury, an airborne neurotoxic pollutant, is transported by wind and deposited in remote areas, where it can enter the food chain and threaten wildlife as well as humans. The common loon is a top-trophic predator in the freshwater food web and an important bioindicator of surface water Hg pollution. Designing long-term monitoring of Hg concentrations in loon blood and eggs requires understanding the relationship between sampling intensity and detectable changes. We conducted a power analysis and found that increasing effort in the number of lakes per year or the number of years could decrease the intensity required in another parameters. We also found that more acidic lakes required greater sampling intensity than less acidic lakes.

 

Yepa, Felix

B-K116: Soil food web analysis of trophic interactions and nutrient dynamics under Arctic shrub and tussock Tundra ecosystems

Yamina Pressler, Rodney Simpson, Morgan Salter, Amanda Morrison, and John C. Moore

Arctic LTER, Colorado State University

 

Yorke, Christie

B-F073: Sea urchins are a detritus channel to kelp forest food webs

Santa Barbara Coastal LTER, University of California, Santa Barbara

An overwhelming amount of macroalgal net primary production (NPP) ends up in the detrital pool, but little is known about the fate of this NPP. Kelp detritus, in particular, may be recycled into kelp forest food webs. The purple sea urchin is an important herbivore and detritivore in southern California giant kelp forests. We assembled artificial communities of small kelp forest consumers, including detritivores, and provided isotopically labeled kelp litter to them with and without purple urchins present. We predicted that the urchins would act as shredders, making the kelp detritus available to more species. This study is the first to examine the role of a shredder as a potential detrital channel in a marine food web.

 

Young, Alexander

A-F030: Using hyperspectral imagery to detect foliar nutrition of trees from the sky

Marissa Gabriel, Ruth D. Yanai

Hubbard Brook LTER, SUNY-ESF

NEON’s Airborne Observation Platform collects spectra from tree canopies, but the resulting data are strictly empirical and require calibration with field measurements. We analyzed spectra collected from three stands at Bartlett Experimental Forest, where N and P have been added annually since 2011 in a full factorial design, and matched photochemical reflectance index (PRI) to individual tree canopies of known species. PRI was increased by N addition but was not consistently affected by P addition. Future analyses will assess 426 spectral bands with 1-m resolution to identify hyperspectral properties affected by foliar N and P and test whether tree species and their foliar nutrition can be identified from the air.

 

Zaricor, Marissa

B-F017: Can we predict drought tolerance in Poaceae using plant traits?

Seton Bachle and Jesse Nippert

Konza Prairie LTER, Kansas State University

The potential of increased drought due to global climate change elevates the need for research on the limitations and resiliency of plants from endangered ecosystems, such as mesic grasslands. Our study aims to investigate the different physiological and morphological effects of drought on C3 and C4 grass species, to identify predictable traits that indicate drought tolerance. Our study includes grasses that differ in phylogeny which allows us to analyze if drought tolerance differs between photosynthetic pathways or if it varies due to evolutionary divergence. We will examine traits that may reflect advantages in a drought, such as fine root length, and use photosynthetic rate and chlorophyll fluorescence to monitor tolerance and recovery

 

Zatkos, Lauren

A-F042: Effects of varying densities at higher trophic levels on food web structures

Ivan Arismendi, Brooke Penaluna, & Alba Argerich

Andrews Forest LTER, Oregon State University

Understanding the structure and functionality of food webs is a key component of effective ecosystem management. Conceptualizing and quantifying changes made to food webs as species compositions shift is vital to managing these environments as climate change progresses. Headwater streams play a direct role in the health of downstream systems, affecting nutrient transport, primary production, and fisheries. Using long-term data collected from headwater streams at the H.J. Andrews as part of the SCALER project, we will construct food webs using the Cheddar package in R. This tool will allow us to quantify web attributes such as connectance, linkage density, and generality, and identify differences between food webs from stream reaches that have remain unaltered (control) and those that have manipulated low and high vertebrate predator abundances.

 

Zeglin, Lydia

B-F016: Summary of belowground responses to a 30-year grassland fertilization and fire cessation experiment

Konza Prairie LTER, Kansas State University

Native tallgrass prairie is characterized by nitrogen (N) limitation and maintained by fire disturbance. We measured changes in soil processes and microbial communities that drive N availability and loss after 30 years of experimental fire and N fertilization. We learned that fire cessation can change N availability, root N pools, and denitrification as much or more than direct fertilization. Fertilization causes a predictable microbial community shift, and a loss of enzyme activity, and these responses are stronger with fire suppression. Plant and soil fungal heterogeneity was correlated, but long-term fire and fertilization had stronger effects on soil process and community change than monthly, event-based, or plot-scale heterogeneity.

 

Zimmerman, Jess

A-K126: Site Poster

Luquillo LTER