Changing snows affect wildlife monitoring and management

This week, scientists from the University of Alaska Fairbanks are presenting their work alongside thousands of colleagues from around the world at the 2023 American Geophysical Union fall meeting. Some of their discoveries are featured here. You can also find out more about UAF at AGU by searching for #UAFxAGU on social media platforms.

The effectiveness of aerial surveys to estimate Alaska’s moose populations is at risk.

The surveys rely on adequate snow cover during the survey windows, because moose can be seen more easily against the white background.

But snowfall is arriving, on average, later each year, according to an analysis by UAF Department of Biology and Wildlife professor Todd Brinkman and his collaborators. They evaluated 33 years of fall moose aerial survey data from across Alaska to explore how changing snow conditions may affect the long-term feasibility of these methods.

Wildlife managers use aerial surveys to estimate moose population size and sex ratios. The resulting information helps to set hunting regulations for the following year.

Brinkman’s team found that later snowfall arrival pushes the survey window later in the season, when less daylight limits the time spent counting moose from aircraft. Bull moose also begin to shed their antlers, making accurate assessments of sex ratios difficult.

Using forward modeling of expected snow conditions based on the current trend, the team estimates that the current method for surveying the moose populations will not be feasible across much of Alaska in another three to four decades.

“While we can’t undo this trend,” Brinkman said, “with enough forward thinking, wildlife managers can develop new monitoring strategies, in advance, to maintain consistent population counts and regulations that optimize harvest opportunities.”

This research was funded by the Arctic-Boreal Vulnerability Experiment, a NASA Terrestrial Ecology Program field campaign conducted in Alaska and western Canada. ABoVE is a large-scale study of environmental change and its implications for social-ecological systems.