: Snowpack persistence and its effects on Chugach Mountain Dall’s sheep populations

SCIENCE

Manuela Jay

Fluctuation in Dall’s sheep numbers are normal and occur in response to environmental factors (Murphie et al., 1976). The oscillation is primarily linked to weather events and has been observed since the 1940s throughout Alaska’s eight major ranges where Dall’s sheep are found: Kenai, Chugach, Talkeetna, Wrangell-Saint Elias, Alaska Range, Brooks Range, White Mountains, and the Yukon-Tanana uplands (Valdez et al., 1999). While population fluctuation is expected, scientists have observed a continual Dall’s sheep decline in Southcentral Alaska’s, Chugach Mountain Range since the early 1990s (Lohuis, 2014). Dall’s sheep population numbers decreased 50% from a count of 2,400 in 1996 to ~1,200 in 2019 (Smith et al., 2020). The Department of Fish and Game (ADFG) investigated body composition, predation, disease, and nutrition to identify limiting factors and causes of decline. Despite targeted research, a defined cause for continual Dall’s Sheep population decrease has not been identified and remains a concern. One of the remaining unexplored possible causes for population decline, is the impact of winter weather events on sheep. Recent scientific studies show that climate warming is altering the duration, amount, and timing of snowfall, snowpack, and snowmelt in mountainous regions across Alaska (Littell et al., 2018). These changes are thought to be pronounced at higher elevations and latitudes, that characterize Dall’s sheep habitat (Pan et al., 2018). The effects of warming events alter snow properties and increase snow density which may impact Dall’s sheep foraging behavior. This project aims to determine the impact of weather variability on Dall's sheep habitat use and behavior during winter months in the Chugach Mountain Range, Game Management Area 14C, utilizing field measurements, remote sensing methods, collar satellite data, and statistical modeling.

Profile

Name: Manuela Jay, Graduate Student

Institution: Alaska Pacific University

Mentor: Jason Geck, jsgeck@alaskapacific.edu

Award: Research Grant

Funding Period: 2021 to 2022