American Pika (Ochotona princeps) Population Survival in Winters with Low or No Snowpack

Abstract

A prediction that has gained considerable traction in the American pika (Ochotona princeps) literature is that because of climate change, high mortality is likely to occur in winters of low or early snowmelt and cause extirpation of local populations. The basis for this prediction is the perception that the absence of an insulative layer of snow to protect pikas from severe winter cold temperatures may cause animals to utilize metabolic reserves through excessive thermoregulation before the spring emergence of fresh vegetation, or die directly from exposure to extreme winter temperatures. The Sierra Nevada of east central California experienced its lowest snowfall in recorded history during the winter of 2014/2015. We observed patch occupancy as a proxy for overwinter survivorship of American pikas in the Sierra Nevada during summer 2015 in comparison to baseline populations at the same sites during summer 2014. In summer 2015, pika presence was documented at 36 of 37 sites where pikas had been observed in summer 2014. Contrary to the low snowfall-high mortality prediction, there was no evidence that the nearly total lack of snow caused unusual overwinter mortality in Sierra Nevada pikas.