Ecosystem stability is related to animal community dynamics at a continental scale

Marta A. Jarzyna, Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH, Kari EA Norman, Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, Jalene LaMontagne, Department of Biological Sciences, DePaul University, Chicago, IL, Matthew R. Helmus, Biology, Temple University, Philadelphia, PA, Daijiang Li, Louisiana State University, Baton Rouge, LA, Stephanie Parker, National Ecological Observatory Network (NEON), Battelle, Boulder, CO, Sydne Record, Biology, Bryn Mawr College, Bryn Mawr, PA, Eric R. Sokol, Batelle, National Ecological Observatory Network (NEON), Boulder, CO, Phoebe Zarnetske, Department of Integrative Biology, Michigan State University, East Lansing, MI and Thilina Surasinghe, Department of Biological Sciences, Bridgewater State University, Bridgewater, MA

Background/Question/Methods
Biodiversity is known to promote ecosystem stability but finding generalities that hold across taxonomic groups and spatial and temporal scales remains challenging. We use organismal data collected from the National Ecological Observatory Network (NEON) to evaluate the drivers of ecosystem stability for four taxonomic groups: small mammals, ground beetles, fish, and aquatic macroinvertebrates. Specifically, we evaluate the roles of asynchronous species population dynamics and maintenance of dominant species in promoting ecosystem stability. We define ecosystem stability as mean species abundance divided by its temporal standard deviation, and measure it across two temporal scales: intra- and inter-annual. To understand the contributions of both mechanisms to ecosystem stability, we quantify intra- and inter-annual change in biodiversity in two ways: as (i) temporal dissimilarity in community composition and its species replacement and richness components and (ii) change in species’ abundance distributions as captured by change in species rank, richness, and evenness. We explore the relationships of intra- and inter-annual ecosystem stability with each metric of biodiversity change using linear and quadratic models in a Bayesian framework with INLA statistical software.
Results/Conclusions
We find that ecosystem stability increased with species replacement and its contribution to overall dissimilarity for all taxonomic groups, suggesting asynchronous population patterns as the primary mechanism promoting ecosystem stability at the continental scale. We also find, however, that ecosystem stability declined slightly at highest levels of species replacement or change in species rank, suggesting that stability is promoted by population asynchrony but not a complete turnover in community composition or reshuffling of species abundances. Our study provides an initial assessment of the relationship between ecosystem stability and biodiversity change at a continental scale and illustrates the utility of fine temporal resolution data collected across ecosystems and biomes to understand the general mechanisms underlying biodiversity-stability relationships.