Project Funding: 2015 - 2019

NRA: 2014 NASA: Terrestrial Ecology   

Funded by NASA

Abstract:
Dall sheep are an emblem of the North. The global distribution of this iconic species is contained entirely within the Arctic and boreal region of northwestern North America, and the rapid changes associated with a warming climate throughout the ABoVE domain therefore have profound implications for this species and the ecosystem services it provides. Dall sheep are critical to the functioning of alpine ecosystems, provide valued subsistence harvest opportunities for residents, and draw tourists and trophy hunters from around the world. Alpine ecosystems are important reservoirs of biological diversity in the ABoVE domain, and high-elevation snowpack is a vital source of water for residents and wildlife throughout the region. Declines in Dall sheep populations throughout their range have led to emergency harvest closures and made sheep harvest by far the most contentious wildlife management issue in Alaska. Dall sheep likely function as bellwethers of alpine ecosystem health, and signs are pointing towards increasing ailment. Lack of knowledge about climate change impacts in alpine ecosystems represents a critical gap in our understanding of resilience and vulnerability to environmental change in the Arctic and boreal region of western North America. Our proposed project addresses this gap through a powerful combination of fieldwork, remote sensing, modeling, and synthesis at both region-wide and localized scales. The overarching goal of our study is to address the question: How are vegetation and snow conditions changing in alpine ecosystems throughout the ABoVE domain, and how do these changes impact iconic northern wildlife and critical ecosystem services? We hypothesize that shrub expansion is reducing alpine habitat area and connectivity among sheep populations, but the productivity of alpine vegetation may be increasing. The extent of snow cover during the lambing season and snowpack characteristics over winter are expected to strongly impact Dall sheep recruitment and survival. To evaluate these and other hypotheses, we propose to: (1) produce time series of snow extent, NDVI, and shrub encroachment throughout alpine areas of the ABoVE domain, (2) evaluate how these factors affect Dall sheep movements, habitat selection, and population viability using empirical models that couple remote sensing products and geospatial data from radio-collared Dall sheep (>350,000 locations from at least 451 sheep in 7 populations from 1997- present), (3) improve a spatially-explicit snowpack evolution model to characterize snowpack (depth, hardness, icing) at a spatial resolution relevant to wildlife management (100-m), and (4) relate our improved understanding of alpine ecosystem dynamics to the societal implications of altered sheep harvest by developing harvest models and participating in a newly-formed Dall sheep working group. Our interdisciplinary team has expertise in wildlife population dynamics and movements, remote sensing, northern social-ecological research, snow processes in mountainous regions, and land surface hydrology modeling. In addition, collaborations with an extensive network of biologists from government agencies and tribal councils throughout the range of Dall sheep, including several major costsharing partnerships, make this ambitious project feasible. Findings from our study will provide insight into the resilience and vulnerability of Dall sheep, indicators of alpine ecosystem functioning, across this iconic species' global range. In addition, our work will substantially improve the remote sensing of snowpack characteristics and may inform future NASA missions by identifying key sensor data needed to further improve models. These advances will improve the ability of scientists to both (1) understand how changes in snow characteristics affect wildlife, and (2) measure and predict changes in hydrological systems and freshwater dynamics in the ABoVE domain and beyond.

Publications:

Aycrigg, J. L., Wells, A. G., Garton, E. O., Magipane, B., Liston, G. E., Prugh, L. R., Rachlow, J. L. 2021. Habitat selection by Dall's sheep is influenced by multiple factors including direct and indirect climate effects. PLOS ONE. 16(3), e0248763. DOI: 10.1371/journal.pone.0248763

Boelman, N. T., Liston, G. E., Gurarie, E., Meddens, A. J. H., Mahoney, P. J., Kirchner, P. B., Bohrer, G., Brinkman, T. J., Cosgrove, C. L., Eitel, J. U. H., Hebblewhite, M., Kimball, J. S., LaPoint, S., Nolin, A. W., Pedersen, S. H., Prugh, L. R., Reinking, A. K., Vierling, L. A. 2019. Integrating snow science and wildlife ecology in Arctic-boreal North America. Environmental Research Letters. 14(1), 010401. DOI: 10.1088/1748-9326/aaeec1

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. DOI: 10.1371/journal.pone.0244787

Leorna, S., Brinkman, T., McIntyre, J., Wendling, B., Prugh, L. 2020. Association between weather and Dall's sheep Ovis dalli dalli harvest success in Alaska. Wildlife Biology. 2020(2). DOI: 10.2981/wlb.00660

Mahoney, P. J., Liston, G. E., LaPoint, S., Gurarie, E., Mangipane, B., Wells, A. G., Brinkman, T. J., Eitel, J. U. H., Hebblewhite, M., Nolin, A. W., Boelman, N., Prugh, L. R. 2018. Navigating snowscapes: scale-dependent responses of mountain sheep to snowpack properties. Ecological Applications. 28(7), 1715-1729. DOI: 10.1002/eap.1773

Prugh, L. R., Sivy, K. J., Mahoney, P. J., Ganz, T. R., Ditmer, M. A., van de Kerk, M., Gilbert, S. L., Montgomery, R. A. 2019. Designing studies of predation risk for improved inference in carnivore-ungulate systems. Biological Conservation. 232, 194-207. DOI: 10.1016/j.biocon.2019.02.011

Sivy, K. J., Nolin, A. W., Cosgrove, C. L., Prugh, L. R. 2018. Critical snow density threshold for Dall's sheep (Ovis dalli dalli). Canadian Journal of Zoology. 96(10), 1170-1177. DOI: 10.1139/cjz-2017-0259

Van de Kerk, M., Arthur, S., Bertram, M., Borg, B., Herriges, J., Lawler, J., Mangipane, B., Lambert Koizumi, C., Wendling, B., Prugh, L. 2020. Environmental Influences on Dall's Sheep Survival. The Journal of Wildlife Management. 84(6), 1127-1138. DOI: 10.1002/jwmg.21873

van de Kerk, M., Verbyla, D., Nolin, A. W., Sivy, K. J., Prugh, L. R. 2018. Range-wide variation in the effect of spring snow phenology on Dall sheep population dynamics. Environmental Research Letters. 13(7), 075008. DOI: 10.1088/1748-9326/aace64

Verbyla, D., Hegel, T., Nolin, A., van de Kerk, M., Kurkowski, T., Prugh, L. 2017. Remote Sensing of 2000-2016 Alpine Spring Snowline Elevation in Dall Sheep Mountain Ranges of Alaska and Western Canada. Remote Sensing. 9(11), 1157. DOI: 10.3390/rs9111157

Verbyla, D., Kurkowski, T. A. 2019. NDVI-Climate relationships in high-latitude mountains of Alaska and Yukon Territory. Arctic, Antarctic, and Alpine Research. 51(1), 397-411. DOI: 10.1080/15230430.2019.1650542

Zhou, J., Tape, K. D., Prugh, L., Kofinas, G., Carroll, G., Kielland, K. 2020. Enhanced shrub growth in the Arctic increases habitat connectivity for browsing herbivores. Global Change Biology. 26(7), 3809-3820. DOI: 10.1111/gcb.15104

More details may be found in the following project profile(s):

• NASA Terrestrial Ecology (TE) Project Profile
• NASA Arctic-Boreal Vulnerability Experiment (ABoVE) Project Profile