Beaver activity alters ecosystem function and macroinvertebrate communities in a degraded stream ecosystem

Beavers can shape freshwater ecosystems by creating dams which raise the water table, decrease stream velocity, and form ponds that widen the riparian zone. Even though their role as an ecosystem engineer is widely accepted, there are still major gaps in terms of how beavers affect ecosystem functions such as temperature, primary production, and decomposition, especially in various ecosystems. Furthermore, it is unclear how changes to these ecosystem functions influence macroinvertebrate community structure, which may have cascading ecological effects. Understanding how beaver activity affects ecosystem function and community structure is important to evaluate their effectiveness as agents of restoration. We hypothesized that beaver activity would increase primary production and decrease leaf litter decomposition, altering available energy sources and subsequently causing shifts in biomass and diversity of the macroinvertebrate community. We sampled Kimball Creek, a degraded stream in western Colorado, using paired samples in beaver ponds and riffle habitats, and using standard methods to sample water temperature and chemistry, algal production, decomposition, and macroinvertebrate abundance, diversity, biomass, and emergence. Although analyses are ongoing, thus far our results suggest that beaver ponds increase aquatic habitat and create areas of cold water refugia