Macroinvertebrate Community Composition and Diversity in Mnomen (Zizania spp.; Wild Rice) Beds in Michigan

Zizania spp. (Mnomen [wild rice]) are annual aquatic plants found in rivers and lakes in Michigan, forming emergent beds that are home to many macroinvertebrates. Macroinvertebrates are key components of aquatic food webs and indicators of river quality. We compared macroinvertebrate community composition and diversity inside and outside of Mnomen beds in the Kalamazoo River (Michigan). Our study locations outside of Mnomen beds generally lacked any aquatic vegetation. We used leaf-pack collectors deployed in the river in 3 seasons. We identified animals collected using morphology and calculated taxon diversity and richness with Simpson's and Margalefs indices, respectively. Season and Mnomen presence both impacted community composition in our study area. When looking at macroinvertebrate diversity and richness, seasonal patterns were stronger than differences between habitat with and without Mnomen. Taxon richness was marginally higher, though not significantly so, in areas with Mnomen, but diversity was not related to Mnomen presence. Many invertebrates were more abundant in and some taxa were found to be strongly associated with sites with Mnomen. In this respect, our results are consistent with the idea that Mnomen facilitates the presence of invertebrates, and demonstrate the importance of further research to understand the community-level relationships in this system.