Climate‐ versus geographic‐dependent patterns in the spatial distribution of macroinvertebrate assemblages in New World depressional wetlands

Abstract

Analyses of biota at lower latitudes may presage impacts of climate change on biota at higher latitudes. Macroinvertebrate assemblages in depressional wetlands may be especially sensitive to climate change because weather-related precipitation and evapotranspiration are dominant ecological controls on habitats, and organisms of depressional wetlands are temperature-sensitive ectotherms. We aimed to better understand how wetland macroinvertebrate assemblages were structured according to geography and climate. To do so, we contrasted aquatic-macroinvertebrate assemblage structure (family level) between subtropical and temperate depressional wetlands of North and South America using presence-absence data from 264 of these habitats across the continents and more-detailed relative-abundance data from 56 depressional wetlands from four case-study locations (North Dakota and Georgia in North America; southern Brazil and Argentinian Patagonia in South America). Both data sets roughly partitioned wetland numbers equally between the two climatic zones and between the continents. We used ordination methods (PCA and NMDS) and tests of multivariate dispersion (PERMDISP) to assess the distribution and the homogeneity in variation in the composition of macroinvertebrate assemblages across climates and continents, respectively. We found that macroinvertebrate assemblage structures in the subtropical depressional wetlands of North and South America were similar to each other (at the family level), while assemblages in the North and South American temperate wetlands were unique from the subtropics, and from each other. Tests of homogeneity of multivariate dispersion indicated that family-level assemblage structures were more homogeneous in wetlands from the subtropical than the temperate zones. Our study suggests that ongoing climate change may result in the homogenization of macroinvertebrate assemblage structures in temperate zones of North and South America, with those assemblages becoming enveloped by assemblages from the subtropics. Biotic homogenization, more typically associated with other kinds of anthropogenic factors, may also be affected by climate change.

Perils of life on the edge: Climatic threats to global diversity patterns of wetland macroinvertebrates

“…Across wetlands under cool or mild temperature summers, we detected a positive relationship between maximum temperature and diversity metrics, suggesting that diversity in these habitats is constrained by low temperatures (e.g. Stenert et al 2020). However, in temporary wetlands where summers were hot, richness declined (although beta diversity turnover increased because they hosted some macroinvertebrate specialists; e.g., anostracan crustaceans).…”

“…Ruhí et al (2013) assessed a longitudinal gradient (spanning the Palearctic of Europe and Nearctic of North America) and found that invertebrate assemblages differed based on broad ranges in temperature and aridity. Stenert et al (2020) analyzed a latitudinal gradient (spanning North and South America) and found that climate zones (temperate vs subtropical) controlled family-level composition and beta diversity. However, the simultaneous influences of temperature and precipitation on wetland invertebrate assemblages has never been directly assessed.…”

Spatiotemporal assembly patterns of macroinvertebrate metacommunity structure in subtropical wetlands with different hydroperiods

“…In addition, field tests on this topic in subtropical climates of the neotropical region are especially rare. One recent study suggested that macroinvertebrates from subtropical regions may exhibit different patterns of variation in their composition compared to temperate regions (Stenert et al, 2020), suggesting that metacommunity dynamics may differ regionally.…”

Environmental context mediates the interaction between fine sediment and hyporheic macroinvertebrate

“…[Eh], total phosphorus, total nitrogen, water depth, river width, and altitude). All statistical procedures were conducted in the R environment for statistical computing v. 3.5-3 implemented using RStudio software (Cristina Stenert, 2020;Pavoine & Goslee, 2020). We performed the analysis available in the 'vegan' v. 2.5-6 package (Oksanen et al, 2019).…”