Article

Diverse landscape features helped buffer the effects of a winter storm for wildlife

A ledge creates a refuge in the snow. — The December 2021 storm left portions of the landscape encased in ice, while other windblown areas remained accessible to wildlife for forage.
NPS/Sarah Stehn

If you were in central Alaska during the winter of 2021-2022, you'll remember this storm! The December 2021 atmospheric river event brought record-breaking snowfall and rain to Interior Alaska created challenging conditions for people, but also for large mammals like caribou and wolves. Academic and park scientists who were working in the field at that time, independently studying weather, snow, and wildlife, came together to explore the impact of that singular weather event.

Researchers used various methods, including meteorological models and satellite data, on-site field evaluations, and long-term wildlife population data to assess the storm's effects on the season’s snowpack, wildlife movements, and survival. Key findings include:

The December 2021 storm was unprecedented, with snowfall and rainfall levels far exceeding historical records. This created a complex snowpack with varying ice thickness depending on vegetation type and topography.
After the storm, caribou shifted their range to higher elevations to avoid areas with thick ice that made foraging difficult. Wolf movement slowed during the storm, but increased afterward.
Topographically diverse landscapes like Denali that support various habitat types in a relatively small area can provide refuge to wildlife in adapting to increased frequency of dramatic weather events.

Overall, the research emphasizes the importance of landscape diversity in supporting wildlife resilience against climate change and highlights the need for further studies to gauge the broader ecological impacts of extreme weather events across multiple time scales.

Landscape heterogeneity buffers the impact of an extreme weather event on wildlife

Abstract

Extreme weather events are becoming more frequent, with poorly known consequences for wildlife. In December 2021, an atmospheric river brought record-shattering amounts of rain and snow to interior Alaska, creating conditions expected to cause mass mortality in grazing ungulate populations that need to access ground forage. We characterized snowpack conditions following the storm and used a 36-year monitoring dataset to quantify impacts on caribou (Rangifer tarandus) and their primary predator, wolves (Canis lupus). December precipitation was 7.3 SD above the 99-year mean and 2.5-fold higher than the prior record, with a return period of 333 years. However, ice thickness within the snowpack was highly variable across vegetation types, and caribou shifted to use higher elevations that can blow free of snow. Caribou and wolf mortality rates were 1.3–1.8 SD above normal and caribou population growth rates were low but similar to recent years, indicating a surprisingly weak demographic response. These findings indicate that landscape diversity may bolster resistance of wildlife populations to short-term, potentially devastating effects of extreme weather.

Prugh, L. R., J. D. Lundquist, B. K. Sullender, C. X. Cunningham, J. Dechow, B. L. Borg, P. J. Sousanes, S. Stehn, and M. T. Furand. 2024. Landscape heterogeneity buffers the impact of an extreme weather event on wildlife. Communications Biology 7(1515).