SYMPOSIUM PRESENTER TITLE: Beavers at work: Boosting biodiversity through habitat engineering here, there, and everywhere ABSTRACT: Biodiversity increases from beaver activity result from their physical modification of ecosystems—both terrestrial and aquatic. Beaver construction of dams and ponds, as well as in-stream excavation activity, create lentic habitats within lotic systems, increase aquatic habitat complexity, enhance groundwater connectivity, and increase the extent of hydric soils. Beaver tree harvesting serves as a form of ecological disturbance by opening forest canopies, increasing the availability of snag trees, promoting early successional species, and enhancing edge habitat. Each of these beaver-mediated changes boost gamma diversity across trophic levels within affected biomes. This synthesis of local research in northwestern Wisconsin and research from the US and Europe highlights the mechanics and magnitude of beaver impacts to biodiversity as well as the specific species and life cycles that are supported by beavers. Documented impacts include increases in zooplankton and insect diversity and biomass, increased prevalence of wetland obligate plants and animals, increased bat foraging activity, and the establishment of thermal refugia during extreme weather. Beaver-modified habitats also play critical roles for specific species, with evidence of waterfowl use of beaver ponds as preferred nesting and brooding habitat. Beaver dams serve as travel corridors for terrestrial species; provide early successional habitats for migratory game birds, support bats through pre-hibernation and migration, and provide juvenile trout nursery habitat. Understanding how and when to leverage beavers as conservation and habitat management tools can benefit both game species and species of conservation concern in Wisconsin. BIO: Cortney Dean is a conservation biologist and independent researcher focusing on the large-scale ecosystem impacts of beaver impounded streams in northwestern Wisconsin. Her work focuses on beaver impacts to biodiversity, specifically bats, breeding & migratory birds, and insect communities, as well as how water quality is impacted by beaver dams.