Seasonal influence of snow conditions on Dall’s sheep productivity in Wrangell-St Elias National Park and Preserve

Deep snow conditions and colder fall temperatures significantly reduce lamb production in Dall's sheep, with challenging snow conditions early in the season having a more pronounced negative impact on recruitment dynamics. This study used a 37-year dataset from Wrangell-St Elias National Park and Preserve to analyze the relationship between seasonal snow characteristics—such as depth and density—and summer lamb-to-ewe ratios. Researchers employed a spatially-explicit snow evolution model, calibrated with ground-based surveys and validated by remote camera data, to assess how fall snow depth and air temperature influence sheep productivity. The findings suggest that early establishment of harsh snow conditions is more detrimental than late-season snow cover, providing critical insights for wildlife managers to anticipate population dynamics in this iconic Arctic ungulate species.

Cosgrove, C. L., Wells, J., Nolin, A. W., Putera, J., & Prugh, L. R. (2021). Seasonal influence of snow conditions on Dall’s sheep productivity in Wrangell-St Elias National Park and Preserve. Plos One, 16(2), e0244787. https://doi.org/10.1371/journal.pone.0244787