CAREER:Functional diversity and ecosystem function provisioning by a guild of macrofaunal consumers in riverine ecosystems

Freshwater ecosystems harbor incredible diversity and are experiencing more rapid biodiversity losses than any other ecosystem type. Despite this, little is known of the ecosystem services provided by these diverse ecological communities. Freshwater mussels are a highly imperiled, species-rich group of long-lived animals that play critical roles in maintaining water quality, and strongly impact freshwater ecosystems.

While the ecological value of freshwater mussels is widely appreciated, their life history and role in the cycling of important nutrients is often overlooked. The density of these organisms is quite variable and can be very high. Variation in both mussel densities and characteristics make them ideal for studies of the impacts of animals on the cycling of limiting nutrients (i.e., nitrogen and phosphorus) in rivers.

The proposed research will integrate the study of communities of freshwater mussels with investigations of critical ecosystem services. Research results will also be used to introduce ideas on the role of biodiversity in ecosystem function into the instruction of undergraduate courses, K-12 day camps, and after school programs.

Using a combination of measurements across organismal, community, and ecosystem scales, this project will examine the interactive role of species traits and community composition in altering the fluxes and stores of energy and nutrients in river ecosystems. There has been great interest in recent years in ascertaining the direct roles of animals in creating biogeochemical hotspots, but their indirect role in microbially-mediated nutrient transformations and the trait-specific context-dependency of this has been overlooked.

This research will examine how freshwater mussels influence nutrient transformations in streams by linking species traits, system-wide observations, and experimental manipulations to ask: 1) Do species traits (e.g. stoichiometry, body size) influence the role animals play in nutrient cycling and does this vary with environmental context? 2) Do animal aggregations significantly alter nutrient cycling and transformations via the active transfer of nutrients from the sediments to the water column? 3) Do species traits and population fluctuations influence nutrient cycling and transformations across space and time? This research will advance scientific understanding by investigating how community composition and coincidental trait diversity influences biogeochemical cycling over time and space while also informing conservation of a highly imperiled group.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.