LTER Science Update provides short, accessible articles describing recent news and publications from across the Network. We hope you will be informed and inspired. Subscribers can sign up online and manage their own subscription settings, so feel free to share with interested colleagues. Have a recent paper or project that may be of interest? Please send us a few basic details using our news submission form and we’ll follow up.

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Just How Does Nitrogen Drive Change in Plant Communities?

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Nitrogen enrichment can dramatically change the existing environment for plants and typically leads to increased productivity, decresed diversity, and shifts plant community composition. But what mechanisms are responsible for these changes? Researchers designed a multi-site experiment to find out, experimentally manipulating each of three possible drivers across mesocosms of three ecosystem types (tall grass prairie, alpine tundra, and desert grassland).

Chronic Nitrogen Deposition Restructures Soil Fungal Communities

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New analyses demonstrate that long-term nitrogen enrichment substantially changes the community composition of soil fungi in a temperate hardwood forest. The mix of fungal taxa that emerges appears to be better able to tolerate high nitrogen but less able to break down the lignin in organic matter, which contributes to an overall accumulation of soil carbon.

Art and Humanities LTER Programs Build Empathy for Nature

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Winged dancer leaps over a field of milkweed

Do arts and humanities programs at LTER sites further the Network’s mission? Recent research posits that art-humanities-science collaborations generate empathy – and associated emotions like inspiration, awe, and wonder – for the natural world. This empathy then drives society to engage with and care more broadly about nature.

Winter Conditions Vital to Year-Round Lake Dynamics

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This month’s Ecology Letters features the first global quantitative synthesis of under-ice lake ecology. In their analysis of 36 abiotic and biotic variables across 101 lakes, the authors issue a call to arms for more winter lake research—currently the focus of only 2% of freshwater publications. As the climate warms, they warn, temperate ecosystems are losing ice, and limnologists remain unsure what ecological processes are at stake. Though winter has long been understood as an inactive period, some data suggests that winter foodwebs and physical processes remain vigorous and that winter ecology can drive subsequent summer conditions.

Growing Grass: A Story of Nitrogen, Phosphorus, and Leaf Size

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Ecologists know that nitrogen, phosphorus and leaf area play key roles in the productivity of plant communities. But how tightly are they tied together? And are those relationships sustained over different types of landscapes? A recent study of tallgrass prairie communities, building on a previous study of arctic tundra, found leaf area index (LAI) to be strongly correlated to both total foliar nitrogen and total foliar phosphorus in several plant functional types (grass, forb, woody, and sedge) and grazing treatments (cattle, bison, and ungrazed).

Coastal Everglades in the Cold: Mapping Ecological Sensitivity

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How sensitive are coastal ecosystems to sharp changes in temperature? Using a detailed spatial analysis in the Florida Everglades, researchers found that cold snaps reduced ecosystem productivity most dramatically in areas with low water levels that were located away from the coast. With more extreme weather events predicted in the future, knowing the likely effects of low temperature events on subtropical wetlands systems can inform management of these important ecosystems.

Demystifying Governance for Ecologists

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There are certain events, such as severe storms or a crash in financial markets, that catalyze transitions in social-ecological systems, in a process that is akin to the way a hurricane or insect outbreak might catalyze an ecological transition. To understand the patterns that emerge in social-ecological systems, ecologists must understand governance, a process rooted in the key social science concepts of power and networks.

Finding the Hidden Phytoplankton Blooms

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In stratified lakes, a large portion of phytoplankton biomass is found—not at the surface, where sampling is easiest—but somewhere down the water column, in what is known as a subsurface chlorophyll maximum (SSCM). Researchers in Global Lake Ecological Observatory Network (GLEON) compared automated high-frequency chlorophyll fluorescence (ChlF) profiles with surface samples and discrete depth profiles. In 7 of the 11 lakes studied, automated sampling captured the presence of SSCM’s that would have been missed by conventional sampling.

What (and when) is the point-of-no-return?

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How-and when-do ecosystems change character? Are those shifts reversible? And what signs might precede them? Such questions are hard enough to answer in a single place. One might think that incorporating different kinds of ecosystems would only complicate the problem. But a group of scientists in the Long-Term Ecological Research Network is finding a remarkably consistent pattern by combining models and data across several long-term ecological experiments.

Climate variability predicted to affect outcome of exotic grass invasion

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Novel ecosystems can emerge through many kinds of changes, including changes in mean climate, species invasions, and increased or decreased variability. Researchers at Jordana Basin LTER have highlighted the role of interannual climate variability in changing the outcome when an exotic grass species invades dry shrubland. Using a process-based model, they predicted three outcomes, depending on the degree of variability and timing relative to invasion.

Arctic Communities See Access Challenges Ahead

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Climate-change is predicted to have a larger impact on Arctic regions than on temperate ecosystems. As a result, rural communities relying on local wild resources, or subsistence harvesting, are vulnerable to climate-change-induced environmental trends affecting the availability of fish, waterfowl, and other key resources.