Wetland microhabitats support distinct communities of aquatic macroinvertebrates

The drivers of aquatic macroinvertebrate distribution in Prairie Pothole Region wetlands are not as well understood as in other aquatic ecosystems (e.g. rivers or lakes). We collected aquatic macroinvertebrates from 35 fishless prairie pothole wetlands in Alberta, including two habitat zones: the emergent zone and the open-water zone. Within each zone, we collected a vegetation sample and a water column sample, thus capturing four distinct microhabitats. We tested for community differences among these microhabitats with nested ANOVAs, looking at macroinvertebrate abundance, taxa richness, and evenness. We also visualized trends in community composition among the microhabitats with nonmetric multidimensional scaling ordination. Interestingly, we observed no difference in macroinvertebrate communities between the open-water and the emergent habitat zones. However, we found significant differences in richness and evenness between water column and vegetation sample types nested within habitat zones. Additionally, we observed high taxonomic turnover between sample types. Our results emphasize the importance of within-zone microhabitats in structuring aquatic macroinvertebrate communities in prairie pothole wetlands, and the relative insignificance of emergent and open-water habitat zone distinctions. Future analyses of macroinvertebrates in wetlands should sample both the vegetation and the water column, regardless of habitat zone, to prevent biased surveys of macroinvertebrate communities.