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

PIRES, M.M.; MALTCHIK, L.; BATZER, D.P.; EPELE, L.B.; MCLEAN, K.I.; EPELE, L.B.; MCLEAN, K.I.; STENERT, C.; GRECH, M.G.; MUSHET, D.M.; STENERT, C.; GRECH, M.G.; MUSHET, D.M.; PIRES, M.M.; MALTCHIK, L.; BATZER, D.P.

GLOBAL CHANGE BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2020 vol. 26 p. 6895 - 6903

1354-1013

Climate change that affects biota in lower latitudes may presage biotic assemblages of 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 macroinvertebrates 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 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.