title: Climate extremes are associated with invertebrate taxonomic and functional composition in mountain lakes.
abstract: Climate change is expected to increase climate variability and the occurrence of extreme climatic events, with potentially devastating effects on aquatic ecosystems. However, little is known about the role of climate extremes in structuring aquatic communities or the interplay between climate and local abiotic and biotic factors. Here, we examine the relative influence of climate and local abiotic and biotic conditions on biodiversity and community structure in lake invertebrates. We sampled aquatic invertebrates and measured environmental variables in 19 lakes throughout California, USA, to test hypotheses of the relationship between climate, local biotic and environmental conditions, and the taxonomic and functional structure of aquatic invertebrate communities. We found that, while local biotic and abiotic factors such as habitat availability and conductivity were the most consistent predictors of alpha diversity, extreme climate conditions such as maximum summer temperature and dry-season precipitation were most often associated with multivariate taxonomic and functional composition. Specifically, sites with high maximum temperatures and low dry-season precipitation housed communities containing high abundances of large predatory taxa. Furthermore, both climate dissimilarity and abiotic dissimilarity determined taxonomic turnover among sites (beta diversity). These findings suggest that while local-scale environmental variables may predict alpha diversity, climatic variability is important to consider when projecting broad-scale aquatic community responses to the extreme temperature and precipitation events that are expected for much of the world during the next century.
authors.affiliation: Department of Biology University of San Diego San Diego CA USA.
authors.forename: Kate S
authors.initials: KS
authors.lastname: Boersma
authors.affiliation: Department of Biology University of San Diego San Diego CA USA.
authors.forename: Avery
authors.initials: A
authors.lastname: Nickerson
authors.affiliation: Department of Biological Sciences California Polytechnic State University San Luis Obispo CA USA.
authors.forename: Clinton D
authors.initials: CD
authors.lastname: Francis
authors.affiliation: Department of Biological Sciences University of Arkansas Fayetteville AR USA.
authors.forename: Adam M
authors.initials: AM
authors.lastname: Siepielski
keywords: aquatic ecology; aquatic invertebrate; biodiversity; climate variability; community structure; extreme events; functional diversity; global change; lentic; macrophyte