Do Whales and Penguins Compete?

Palmer Antarctica LTER
Humpback whale populations are growing at their biological maximum as they recover from intense  commercial whaling. New cetacean research at PAL LTER shows that humpbacks forage in close proximity to the penguins near Palmer Station, and in similar portions of the water column used by Adélie penguins during critical chick rearing periods. Palmer LTER researchers... Read more »

Climate Forcing of the West Antarctic Peninsula

Palmer Antarctica LTER
Over the past five decades, the West Antarctic Peninsula (WAP) has experienced changes related to rapidly warming winter atmospheric temperatures, dramatic sea ice declines, and accelerated glacial melting. Interactions between ocean and atmospheric climate cycles (El Niño, Southern Annual Mode) influence shoreward heat delivery associated with deep warm ocean waters and alter the upper mixed... Read more »

Restoration Returns ‘Blue Carbon’ Stores

Virginia Coast Reserve LTER
A 20-year landscape-scale experiment at VCR LTER was the first to show the role of restoration in reestablishing carbon burial in seagrass meadows, which matches natural systems after a decade. Virginia Coast Reserve scientists authored the international protocol through Verified Carbon Standards for issuing seagrass restoration carbon offset credits on the voluntary market. Carbon stored... Read more »

Climate Change Shifts Grasslands to Shrublands

Virginia Coast Reserve LTER
Over the last 30 years, nearly half of the upland area on the barrier islands has changed from grassland to shrub thickets, similar to transitions observed in other drylands. For coastal systems, this transition is driven by regional climate (higher winter temperatures, lower precipitation) and shrub feedbacks on microclimate (warmer winter and cooler summer temperatures).... Read more »

Coastal Change is Accelerating

Virginia Coast Reserve LTER
Historically, this undeveloped landscape has been a shifting mosaic; a new 30-year retrospective now shows directional change and accelerating ecosystem loss. Barrier island upland area has declined by a third, and island marsh loss due to storm overwash has increased, especially in the last decade. Feedbacks between vegetation and sediment transport determine barrier island dune... Read more »

Environmental Management can Mitigate Greenhouse Gas Emissions

Kellogg Biological Station LTER
A research technician samples greenhouse gases on the KBS LTER Main Cropping Systems Experiment Agriculture emits quantities of greenhouse gases equivalent to those from the transportation sector, and long term LTER research has revealed how farmers can better manage intensive row crop systems to mitigate climate change. Plant-microbe-soil interactions can enhance soil carbon sequestration, reduce... Read more »

Evolutionary Responses of Soil Microbes

Kellogg Biological Station LTER
A KBS LTER graduate student collects soil cores in a prairie strip on the Main Cropping Systems Experiment. Twenty-plus years of nitrogen fertilization have caused rhizobia in soybeans to evolve toward reduced nitrogen fixation. These evolutionary changes have ecological consequences, as the evolution of reduced cooperation alters soil nitrogen availability. Directed changes to the microbial... Read more »
A prairie strip growing in wheat at the KBS LTER Main Cropping Systems Experiment.

Landscape Diversity Enhances Pest Suppression

Kellogg Biological Station LTER
A prairie strip growing in wheat at the KBS LTER Main Cropping Systems Experiment. Simplification of agricultural landscapes reduces abundance of predatory insects, at substantial cost to farmers and society. Diverse landscapes harbor generalist predators such as ladybird beetles, which control crop pests such as soybean aphids, limiting the need for insecticide use. Given global... Read more »

Carbon Storage Responds to Forest Growth, Mortality, and Climate

Andrews Forest LTER
Old-growth forest-stream ecosystems store enormous amounts of carbon. Andrews LTER researchers found that forest biomass accumulated at relatively linear rates over a century – counter to theoretical predictions that biomass accumulation would slow during forest succession. They also found that climate change related mortality at Andrews is low compared to other forests in the western... Read more »

Newly Recognized Stream Responses to Warming Trends

Andrews Forest LTER
Cross-site comparisons reveal varying long term trends in nitrogen exports, and varying responses to warming trends. Although theory predicts that streamflow should recover quickly after disturbance, paired watershed comparisons found decreases in summer flow (relative to undisturbed watersheds) in regenerating post-harvest forests 25 to 45 years old.  

Biodiversity Losses and Gains

Andrews Forest LTER
The northern spotted owl, an iconic species in federal lands policy, continues to decline. Over 4,000 invertebrate species have been recorded at AND LTER since 1991. Native climate-sensitive bird species appear to be persisting, despite multi-decade warming, likely because old forests buffer micro-climate.  

Pioneering Urban System Science

Baltimore Ecosystem Study
Researchers at BES LTER developed new theory and methods for characterizing the multidimensional, multidisciplinary nature of urban ecosystems. This work sparked the development of a new “urban systems science” which has become a key component of sustainability science across the globe.  

Understanding Urban Watersheds

Baltimore Ecosystem Study
Baltimore LTER research showed that nutrient cycling and retention in urban watersheds are driven by complex dynamics, with surprisingly high nitrogen retention, climate sensitivity, and surface water-groundwater interactions. These studies have been a foundation for novel analyses of how ecosystems are affected by contaminants of emerging concern.  

Recognizing Social Feedbacks

Baltimore Ecosystem Study
The BES LTER Household Telephone Survey provided information on environmental knowledge, perceptions, values, and behaviors of residents, their influence on ecosystem structure and function, and the ways that ecosystem structure and function may affect residents’ physical activity, social cohesion, perception of neighborhood desirability, and willingness to relocate.  

Unexpected Urban Biodiversity

Baltimore Ecosystem Study
Baltimore LTER research has helped challenge the assumption that urban biodiversity is low by showing that biological communities in urban environments are diverse and dynamic. This diversity ultimately affects human well-being, and fluxes of water, energy, carbon, and nutrients.  

Spring Melt Matters

Beaufort Lagoon Ecosystems LTER
Over half of the fresh water and water-borne nutrients flowing from land to the Alaska Beaufort Sea each year are delivered during a two-week period in the spring — earlier than most seasonal Arctic research begins. These inputs are dominated by three large rivers that flow into the central Alaska Beaufort Sea. The composition of... Read more »

Diverse Carbon Sources Fuel Food Webs

Beaufort Lagoon Ecosystems LTER
Most consumers in Beaufort Sea lagoons exhibit omnivorous (generalist) feeding strategies. Food web structure shifts with the seasons as food sources change from ice cover to open water. Multiple food sources provide sustenance to consumers including allochthonous (marine and terrestrial/ riverine organic matter) and autochthonous (microphytobenthic and phytoplankton) organic matter.  

Coastal Erosion is Increasing

Beaufort Lagoon Ecosystems LTER
Two Inupiat BLE LTER students stand at the base of an eroding shoreline on Barter Island Consistent with reports from other regions of the Arctic and the Beaufort Sea Coast, coastal erosion rates appear to have increased along the shores of Elson Lagoon near Utqiaġvik (formerly Barrow) over the last half century. Areas with historically... Read more »

Extreme Variability in Physio-Hydrological Conditions

Beaufort Lagoon Ecosystems LTER
Researcher James McClelland sampling water during ice break-up in Kaktovik Lagoon, Alaska. Beaufort Sea lagoons experience large seasonal variations in temperature and salinity related to the Arctic freeze-thaw cycle. In the most extreme cases, lagoons swing from completely freshwater conditions during the spring to hypersaline conditions during the winter. Variations in salinity regimes among lagoons... Read more »

Ecosystem Enrichment in Terrestrial and Aquatic Systems

Arctic LTER
The thermokarst failure at Lake NE-14. Warming will increase nutrient cycling in soils, increasing its fertility and nutrient supplies to streams and lakes. Data from long term fertilization studies at ARC LTER are used to model tundra responses to climate change and disturbance. Long term phosphate fertilization has altered the Kuparuk River’s structure and function,... Read more »

Diversity of Species Interactions in a Changing Arctic

Arctic LTER
Species must deal with the rapidly melting snow. Microbial communities decreased from soil, to streams, to lakes. About half of the common lake bacteria detected were rare species in soils and headwater streams. Initial inoculation from soils was followed by species sorting downslope. With warming, microbial trophic structure has become more homogenous across soil horizons,... Read more »