Geographic analysis of beaver pond locations in Western Arctic Alaska

Abstract:

Beavers have extended their range into the arctic tundra of Alaska in recent decades, and the cause of this is presumed to be some combination of climate change ameliorating habitat and a rebound from historic trapping. Our goal is to determine the geographic attributes of tundra beaver ponds, and to examine whether other suitable habitat exists elsewhere in the Alaska Arctic. Using our new dataset of over 7000 beaver pond locations in western Alaska, we evaluated geographic attributes of beaver pond locations related to topography, hydrology, and climate. Beaver ponds occur in a variety of landscape settings, from floodplains of large rivers (14%, 6th order) to small tundra streams (64%, 1st order), drained lake basins (3%), and lakes (19%). Beaver ponds occupy relatively low gradient streams (< 6%) at elevations below 380 masl with mean annual air temperatures ranging from -8 °C to 0 °C. Beavers are constructing ponds preferentially in low shrub (43%) and tall shrub (25%) vegetation. Areas with similar geographic attributes to current pond locations exist beyond the current beaver pond extent, leading us to believe that uncolonized parts of western and northern AK are suitable beaver habitat, and that beavers will continue to increase their numbers and extend their range into the Alaska Arctic.