Spatiotemporal habitat use by a multitrophic Alaska alpine mammal community

Abstract

Evaluating sympatric habitat use of a mammal community can help determine intra- and inter-guild interactions and identify important habitats, potentially improving the management of these communities with a changing climate. Increasingly variable climatic patterns in Alaska, USA, are raising concerns of mismatched phenologies and altered ecosystem structures. We studied the occupancy of 10 mammal species over 15 months, via camera traps, occupying alpine areas of the Alaska Range in interior Alaska, from 2013 to 2014. We tested hypotheses about how habitat use of these species within and between groups varied by spatial and temporal covariates. Furthermore, we modeled two-species occupancy of brown bears (Ursus arctos Linnaeus, 1758) and gray wolves (Canis lupus Linnaeus, 1758) against different potential prey species. Our results suggest that medium-sized and large herbivore use was positively correlated with fine-scale covariates including rock, forb, and graminoid coverage. Large herbivore habitat use was also correlated with abiotic landscape covariates. Detection probabilities of predators and Dall’s sheep (Ovis dalli dalli Nelson, 1884) was improved by camera traps on wildlife trails. Two-species models suggested co-occurrence of habitat use between brown bear – caribou (Rangifer tarandus (Linnaeus, 1758)) and gray wolf – caribou. Results demonstrate the sympatric habitat use by multiple groups of mammals within Alaskan alpine ecosystems and the importance of incorporating multiple groups and spatial scales when making management decisions.

Daily abundance of Dall’s sheep peaks during late summer in a seasonal habitat of high‐management interest

“…Our study provides the type of results that are useful for filling existing information gaps about wild mountain sheep in the face of increasing human encroachment on their habitats and new disease threats (Jex et al 2016, Cotten 2018. Increasing daily abundance of ewes in July and decreasing ewe abundance in September around a mid-August peak of 90 ewes per day is consistent with results from occupancy modeling of Dall's sheep habitat use within a portion of our survey area (Dertien et al 2017(Dertien et al , 2019. The pronounced peak in ewe abundance was matched by a relatively stable average lamb-to-ewe ratio from 1 July to 1 October (≈0.20-0.25).…”

“…The survey area is bisected by Alaska Game Management Units 20D and 13B and falls within the boundary of the Delta Controlled Use Area (Schmidt 2019). The United States Army Garrison Alaska operates the 11 km 2 Black Rapids Training Area in the central portion of the survey area and the 4 km 2 Whistler Creek Training Area in the eastern portion of the survey area (Dertien et al 2017(Dertien et al , 2019.…”