Climate change is rapidly driving global biodiversity declines. How wetland macroinvertebrate assemblages are responding is unclear, a concern given their vital function in these ecosystems. Using a data set from 769 minimally impacted depressional wetlands across the globe (467 temporary and 302 permanent), we evaluated how temperature and precipitation (average, range, variability) affects the richness and beta diversity of 144 macroinvertebrate families. To test the effects of climatic predictors on macroinvertebrate diversity, we fitted generalized additive mixed-effects models (GAMM) for family richness and generalized dissimilarity models (GDMs) for total beta diversity. We found non-linear relationships between family richness, beta diversity, and climate. Maximum temperature was the main climatic driver of wetland macroinvertebrate richness and beta diversity, but precipitation seasonality was also important. Assemblage responses to climatic variables also depended on wetland water permanency. Permanent wetlands from warmer regions had higher family richness than temporary wetlands. Interestingly, wetlands in cooler and dry-warm regions had the lowest taxonomic richness, but both kinds of wetlands supported unique assemblages. Our study suggests that climate change will have multiple effects on wetlands and their macroinvertebrate diversity, mostly via increases in maximum temperature, but also through changes in patterns of precipitation. The most vulnerable wetlands to climate change are likely those located in warm-dry regions, where entire macroinvertebrate assemblages would be extirpated. Montane and high-latitude wetlands (i.e., cooler regions) are also vulnerable to climate change, but we do not expect entire extirpations at the family level.

Luis B. Epele, Marta G. Grech, Emilio A. Williams-Subiza, Cristina Stenert, Kyle McLean, Hamish S. Greig, Leonardo Maltchik, Mateus Marques Pires, Matthew S. Bird, Aurelie Boissezon, Dani Boix, Eliane Demierre, Patricia E. García, Stephanie Gascón, Michael Jeffries, Jamie M. Kneitel, Olga Loskutova, Luz M. Manzo, Gabriela Mataloni, Musa C. Mlambo, Beat Oertli, Jordi Sala, Erica E. Scheibler, Haitao Wu, Scott A. Wissinger, Darold P. Batzer (2022) Perils of life on the edge: Climatic threats to global diversity patterns of wetland macroinvertebrates, Science of The Total Environment,
Volume 820

DOI: https://doi.org/10.1016/j.scitotenv.2022.153052

In metacommunity ecology, a major focus has been on combining observational and analytical approaches to identify the role of critical assembly processes, such as dispersal limitation and environmental filtering, but this work has largely ignored temporal community dynamics. Here, we develop a “virtual ecologist” approach to evaluate assembly processes by simulating metacommunities varying in three main processes: density-independent responses to abiotic conditions, density-dependent biotic interactions, and dispersal. We then calculate a number of commonly used summary statistics of community structure in space and time and use random forests to evaluate their utility for inferring the strength of these three processes. We find that (i) both spatial and temporal data are necessary to disentangle metacommunity processes based on the summary statistics we test, and including statistics that are measured through time increases the explanatory power of random forests by up to 59% compared to cases where only spatial variation is considered; (ii) the three studied processes can be distinguished with different descriptors; and (iii) each summary statistic is differently sensitive to temporal and spatial sampling effort. Including repeated observations of metacommunities over time was essential for inferring the metacommunity processes, particularly dispersal. Some of the most useful statistics include the coefficient of variation of species abundances through time and metrics that incorporate variation in the relative abundances (evenness) of species. We conclude that a combination of methods and summary statistics is probably necessary to understand the processes that underlie metacommunity assembly through space and time, but we recognize that these results will be modified when other processes or summary statistics are used.

Guzman, Laura Melissa, Thompson, Patrick L., Viana, Duarte S., Vanschoenwinkel, Bram, Horváth, Zsófia, Ptacnik, Robert, Jeliazkov, Alienor, Gascón, Stéphanie, et al. 2022. “ Accounting for Temporal Change in Multiple Biodiversity Patterns Improves the Inference of Metacommunity Processes.” Ecology 103( 6): e3683. https://doi.org/10.1002/ecy.3683