Habitat selection by Dall’s sheep is influenced by multiple factors including direct and indirect climate effects

Abstract

Arctic and boreal environments are changing rapidly, which could decouple behavioral and demographic traits of animals from the resource pulses that have shaped their evolution. Dall’s sheep (Ovis dalli dalli) in northwestern regions of the USA and Canada, survive long, severe winters and reproduce during summers with short growing seasons. We sought to understand the vulnerability of Dall’s sheep to a changing climate in Lake Clark National Park and Preserve, Alaska, USA. We developed ecological hypotheses about nutritional needs, security from predators, energetic costs of movement, and thermal shelter to describe habitat selection during winter, spring, and summer and evaluated habitat and climate variables that reflected these hypotheses. We used the synoptic model of animal space use to estimate parameters of habitat selection by individual females and calculated likelihoods for ecological hypotheses within seasonal models. Our results showed that seasonal habitat selection was influenced by multiple ecological requirements simultaneously. Across all seasons, sheep selected steep rugged areas near escape terrain for security from predators. During winter and spring, sheep selected habitats with increased forage and security, moderated thermal conditions, and lowered energetic costs of movement. During summer, nutritional needs and security influenced habitat selection. Climate directly influenced habitat selection during the spring lambing period when sheep selected areas with lower snow depths, less snow cover, and higher air temperatures. Indirectly, climate is linked to the expansion of shrub/scrub vegetation, which was significantly avoided in all seasons. Dall’s sheep balance resource selection to meet multiple needs across seasons and such behaviors are finely tuned to patterns of phenology and climate. Direct and indirect effects of a changing climate may reduce their ability to balance their needs and lead to continued population declines. However, several management approaches could promote resiliency of alpine habitats that support Dall’s sheep populations.

Winter habitat selection by female moose in southwestern Montana and effects of snow and temperature

“…Our results mirror those of other studies showing that habitat selection is dynamic, and particularly subject to variation in abiotic conditions such as temperature and snowpack (Resano‐Mayor et al 2019, Aycrigg et al 2021, Teitelbaum et al 2021). However, the effects of these factors themselves were further dependent on conditions such as spatial scale and particular vegetation types, adding nuance to our interpretation of climate‐mediated selection patterns.…”

“…Wildlife-habitat relationships are an important component of species ecology with temperature-or snow-mediated effects on wildlife habitat selection are important for understanding and predicting wildlife-habitat relationships into the future (Marchand et al 2015, Mayer et al 2019, Resano-Mayor et al 2019, Aycrigg et al 2021, Teitelbaum et al 2021.…”

“…However, landscapes subject to management are changing in response to warming climates (Wang et al 2012), and habitat selection patterns themselves are dynamic as a function of abiotic conditions (Nielsen et al 2010, Freitas et al 2016). In the context of climate change, temperature‐ or snow‐mediated effects on wildlife habitat selection are important for understanding and predicting wildlife–habitat relationships into the future (Marchand et al 2015, Mayer et al 2019, Resano‐Mayor et al 2019, Aycrigg et al 2021, Teitelbaum et al 2021).…”

I Spy Through a Camera’s Eye: Divii in the Gwich’in Settlement Area

“…Straddling the northern Yukon-NWT border in Canada, the Northern Richardson Mountains feature rugged terrain dominated by alpine tundra and exposed rock and underlaid by continuous permafrost (Danks and Downes, 1997). Dall sheep typically occupy high elevations that offer both predator escape terrain and foraging opportunity (Rachlow and Bowyer, 1998;Van de Kerk et al, 2020;Aycrigg et al, 2021). My MSc research focuses on the central-eastern portion of the Northern Richardsons near Mount Goodenough.…”

“…Dall sheep (Ovis dalli dalli), a species of cultural, ecological, and economical significance, is an example of one species facing the current and looming threats of climate change. Uncertainty about the effects of ecological change on Dall sheep population demographics and mortality factors highlights the critical need for additional research to support effective stewardship decision making (Aycrigg et al, 2021).…”