Immediate facilitation and engineering legacy of beavers: 54 years of patch dynamics in a boreal landscape.

Beavers are powerful ecosystem engineers that transform terrestrial areas into aquatic systems. Beaver-induced disturbances create a dynamic mosaic of wet and dry successional habitats across the landscape, yet the long-term impacts of beavers on biodiversity remain poorly understood. We used unique long-term data on beaver floods to study how the return of the beaver-induced patch disturbances affects habitat suitability and connectivity, which serve as proxies for biodiversity, in a boreal landscape over a 54-year period. We demonstrate landscape-level changes by analyzing three taxa that respond differently to flood and post-flood phases. The nearly tenfold increase in the overall suitability index highlights a significant improvement in the conditions supporting biodiversity. Increasing habitat connectivity between valuable patches reflects better dispersal for organisms. Beaver facilitation shapes ecosystems and resource availability over both short and long periods. Since different species may require immediate effects or lasting legacies, it is crucial that beavers remain continuously in the landscape for maintaining biodiversity.