Cooperative Fish and Wildlife Research Units Program: Alaska
Education, Research and Technical Assistance for Managing Our Natural Resources

Alaska Project

Effects of Large Scale Climate Patterns (PDO, ENSO, AO) on Calving Ground Location, Forage Availability, and Calf Survival of the Porcupine Caribou Herd

June 2016 - October 2019


Participating Agencies

  • Science Support Program (SSP) FWS

Our goal is to develop a mechanistic understanding of why Concentrated Calving Areas (CCAs) of the Porcupine Caribou Herd (PCH) were located predominantly in the Yukon Territory, 2000-2013, after a 17 year period (1983-1999) of being located predominantly in Alaska and the 1002 Area (Fig. 1 a,b). This goal addresses whether or not the eastward shift in concentrated calving, 2000-2013 is “permanent” or may be one phase of a cyclic phenomenon. The working hypothesis is that PCH caribou shifted calving eastward, 2000-2013, because the Pacific Decadal Oscillation (PDO) shifted to a negative phase and affected the location of high quality/high quantity forage in relation to predation risk (i.e., cows continued to find the best place to calve in a variable and cyclic climate). When the PDO shifts back to a predominantly positive phase, we expect calving to shift back to the Alaska Coastal Plain.