Cross site investigation using LTER Data.

Identifying environmental drivers of plant reproduction across LTER sites

Reproduction is a key component of plant life cycles and is crucial for dispersal, however it has a surprisingly poorly understood relationship to environmental drivers. This is particularly true for plant species with highly variable reproduction over time, known as ‘mast seeding’. While mast-seeding patterns have been linked to weather (temperature, precipitation), describing past patterns… Read more »

Ecosystem transitions: increased variability and regime shifts

several large rainfall exclusion shelters on an open grassland

Human impacts on ecosystems can result in persistent compositional shifts that are difficult to reverse even after relaxation from perturbations. Considerable debate remains on whether these observed shifts in ecosystems are due to the existence of tipping points and systems with alternative attractors, or whether observed shifts in ecosystems represent communities in alternative trajectories that… Read more »

Synthesizing population and community synchrony to understand drivers of ecological stability across LTER sites

Gammarid amphipod.

Project Summary: Understanding factors that influence ecological stability is a key question in ecology. Population ecology has highlighted that synchrony within a species over space is an important indicator of species stability. Community ecology, in contrast, has highlighted that asynchrony between species within space may enhance the stability of aggregate properties (such as total productivity)…. Read more »

Scaling-Up Productivity Responses to Changes in Biodiversity

experimental plots with a variety of old field species

Project summary: Although hundreds of short-term local experiments indicate that random changes in biodiversity can cause substantial changes in primary productivity, considerable debate remains regarding whether these influences of biodiversity are weaker or stronger at larger spatial and temporal scales in natural ecosystems. Given this knowledge gap, current models often implicitly assume no influence of biodiversity… Read more »

Advancing soil organic matter research: Synthesizing multi-scale observations, manipulations & models

deep soil profile, rich in organic matter, with grain growing on top

Soil organic matter is a massive storehouse for carbon, as well as a key regulator of nutrient cycling and soil quality in terrestrial ecosystems, yet ecology lacks a full understanding of the controls on stabilization and breakdown of soil organic matter. Two sets of competing theories underlie models that adequately predict site-specific dynamics, but result… Read more »

Integrating plant community and ecosystem responses to chronic global change drivers

Three individuals collecting samples in desert brush.

Project Summary: Many global change drivers (GCDs) lead to chronic alterations in resource availability. As communities change through time in response to these GCDs, the magnitude and direction of ecosystem responses is also predicted to change in a non-linear fashion. We propose to examine whether plant community dynamics are predictive of shifts in ecosystem function… Read more »

Global Patterns in Stream Energy and Nutrient Cycling

stream running through wetland

Project summary: Dissolved organic matter (DOM) provides a significant source of energy and nutrients to ecosystems and its biogeochemical cycling is inextricably linked to dissolved inorganic nitrogen (DIN). In stream ecosystems in particular, there is considerable spatial and temporal variation in the relationships between the different fractions of DOM (dissolved organic carbon and nitrogen) and DIN…. Read more »

A synthesis to identify how metacommunity dynamics mediate community responses to disturbance across the ecosystems represented in the LTER network

Aerial of Cedar Creek

Metacommunity ecology considers both the local- and regional-scale factors that influence community assembly. Previous work has identified dispersal, niche differentiation, and habitat heterogeneity as crucial parameters that determine metacommunity dynamics and stability in response to disturbance. However, it remains unclear whether the parameter combinations that are predicted to confer stability do so over long time… Read more »

Synthesis of stream ecosystem responses to nutrient enrichment at multiple trophic levels

The goals of this proposed LTER Synthesis Working Group are (1) to initiate and coordinate the integration of data from multiple sites on stream ecosystem responses to nutrient amendment, (2) to synthesize these data with a quantitative evaluation of functional responses at the microbial, primary producer, consumer and whole-stream levels, (3) to produce an NSF Research Coordination Network proposal that will expand data integration and synthesis efforts to members of the broader national and international stream ecology communities and (4) to promote interaction between LTER and the NEON expe

The Influence of Precipitation Variability on Diversity and Composition of North American Grasslands

Overview:

We propose to organize a working group that will analyze and synthesize long-term data on the relationship between precipitation variability and the structure of North American (NA) grassland plant communities.

This project will build on prior LTER-related synthetic efforts that have evaluated the response of aboveground net primary productivity (ANPP) to precipitation variability [1-2] and the relationships among ANPP, plant community composition and resource availability [3-7] in NA grasslands.