Spatiotemporal changes in biodiversity by ecosystem engineers: how beavers structure the richness of large mammals

High levels of biodiversity may be needed to maintain ecosystem functioning. By creating niches for other species, ecosystem engineers have the potential to promote biodiversity, but it is unclear how this translates across spatiotemporal scales. We evaluated the long-term impact of ecosystem engineering by beavers ( Castor canadensis ) on the diversity of mobile species. We tested the hypothesis that the spatial distribution of engineered habitats in different states resulting from ecosystem engineering by beavers increases the biodiversity of large mammals across spatial scales. We tested a second hypothesis that engineered habitat in different states resulting from ecosystem engineering by beavers drive the diversity of large mammals. We compared the richness and composition of boreal mammals using camera traps between habitats with and without history of occurrence by beavers within a protected area, where trapping, hunting, and forest exploitation are prohibited. We found that unique species were mostly found in specific engineered habitats, with ponds and wet meadows showing more species than dry meadows. In addition to the increased diversity of dispersal-limited species, our results show that beavers promote the diversity of mobile species at both local and landscape scales, signaling the importance of niche creation in structuring animal communities across scales. ### Competing Interest Statement The authors have declared no competing interest.