Proximate Climate Drivers of Beaver Pond Occupancy and Range Expansion in Arctic Alaska

North American beavers ( Castor canadensis ) are colonizing the Arctic tundra, introducing a disturbance regime that is thawing permafrost and expanding overwintering habitat for aquatic taxa. This range expansion is correlated with recent warming, but the mechanistic drivers facilitating colonization, including those promoting initial pond establishment and subsequent pond persistence, are unknown. Disentangling the potential environmental drivers is needed to predict the future distribution of this disturbance regime. Here, we use 9671 observations of beaver activity/inactivity from satellite imagery at 1437 beaver ponds between 2005–2020 in the tundra region of Arctic Alaska, alongside spatiotemporally linked climate and landscape attributes, to evaluate the proximate climate drivers of beaver pond establishment and persistence in this region. We find that beaver pond establishment is facilitated by milder winters, warmer June temperatures, higher photosynthetic activity, and higher springtime river discharge. Pond persistence is promoted by cooler June temperatures, lower springtime river discharge, and higher photosynthetic activity. Our results indicate that conditions in Arctic Northwest Alaska became roughly five times more suitable for beaver pond establishment between 2005 and 2020, coincident with a threefold increase in observed beaver activity in the region. This work shows that beaver range expansion into Arctic Alaska tundra regions has resulted from specific climate‐related drivers, and points to continued proliferation of this novel Arctic disturbance regime.