Shift in location of pygmy rabbit ( Brachylagus idahoensis) habitat in response to changing environments

Abstract

We show how land use and potential climate changes occurring in sagebrush communities in the Great Basin of North America are affecting the pygmy rabbit, a sagebrush obligate species. We revisited 105 sites where pygmy rabbits were collected before 1950 and determined the current presence of the species using infrared-triggered camera surveys. Pygmy rabbits were present at 36% of the sites. Fourteen percent of the sites showed signs of pinyon–juniper woodland encroachment, with only one of these sites still harboring pygmy rabbits. Sites also showed current evidence of fires (16%), urbanization (13%), and agricultural conversion (6%). At a local scale, fire frequency reduction due to livestock grazing and fire suppression have shifted pygmy rabbit habitat to lower elevations. However, overall there was more extirpation at lower elevation sites, and the increase in mean elevation of 157 m closely corresponded to the predicted elevation increase with the rise in average global temperature seen over the last century. Warming temperatures may continue to raise lower elevation boundaries of habitable sites, while higher elevation sites are being increasingly impacted by pinyon–juniper encroachment. Predicted warming temperatures also may engender greater wildfire frequencies exacerbating habitat loss, the greatest threat to pygmy rabbit persistence.