Muskoxen are inexorably linked to climate stressors in the Arctic. Indeed, their ability to adapt to significant environmental change is poor, as evidenced by their complete loss from Asia and Europe; native populations persist only in tundra environments of Arctic North America. Although doing well in the Canadian Archipelago and a few mainland sites, muskoxen disappeared from Alaska 150 years ago.   Today’s persisting populations were re-introduced and they currently experience strong interacting effects of climate change, predation by wolves and by humans, and food limitation. Additionally, the expansion of brown bears northward adds the complexity associated with a new predator on muskoxen. This mosaic of climate and biological forces creates an interesting dynamic; some (but not all) herds in Western Alaska are increasing but those in Arctic National Wildlife Refuge have dropped to near extinction.   The causes of these differing trajectories are highly unclear; possibilities include changes in precipitation, freeze-thaw cycles, habitat quality, and predation. 

Goals

• Document historic population contraction, expansion, and persistence;
• Evaluate climate and vegetation as potential drivers of demographic change using retrospective analyses with GIS and Normalized Difference Vegetation Index (NDVI)  - a simple numerical indicator that can be used to analyze remote sensing measurements;
• Coordinate a field program to contrast birth, death, and other vital parameters among populations experiencing different environmental conditions while modeling future trends. 

Activities

Given the availability of existing 20-40 year data sets on population change in muskoxen, WCS has embarked on a three-pronged 5-year project to study muskox populations in Northwestern Alaska.