Search

Moose Alces alces are among the many species that are vulnerable to both direct and indirect effects of climate change. Habitat selection is one framework to assist investigators in disentangling the various factors (including weather) that ultimately dictate how animals respond to their environment. We investigated patterns of winter habitat selection by adult female moose in southwestern Montana, USA during 2007-2010, and how that selection was affected by snow (quantified by snow water equivalent) and winter temperatures. We used data from GPS collars and a suite of environmental covariates to quantify winter habitat selection at both study area (2nd order) and home range (3rd order) spatial scales using resource selection functions. Moose strongly selected for the willow (Salix spp.) cover type, and against grassland cover. Moose use of conifer cover at the home range scale increased when either amount of snow or ambient temperature was higher, although the latter only during periods of the day when conifer patches were likely to have been cooler than cover types lacking a canopy. Wildlife conservation and management naturally focuses on preferred habitats, particularly those that fulfill essentially all foraging requirements. However, habitats used preferentially under stressful weather conditions, even if used rarely overall, can also form a critical part of a species' overall needs. [ABSTRACT FROM AUTHOR]

Monitoring of browse utilization of plant communities is consistently recommended as an important component of monitoring moose (Alces alces) populations across regions. We monitored winter browse utilization by moose within a willow (Salix spp.) -dominated winter range of Montana in 2008-2010.We sought to improve our understanding of: 1) spatiotemporal heterogeneity of intensity of moose browsing across the winter range, 2) species-specific selection of willow by moose during winter, and 3) appropriate sample sizes, placement, and stratification of monitoring sites for estimating browse utilization. During 3 consecutive winters we monitored 108-111 transect segments, each 50 m in length, in a systematic distribution across willow communities and assessed the effects of covariates potentially predictive of variation in browsing. Mean annual estimated browse utilization across all segments was 11.5% of sampled twigs in 2008 (95% CI = 9.4 - 13.7%), 8.0% in 2009 (95% CI = 6.2 - 9.8%), and 8.3% in 2010 (95% CI = 6.5 - 10.1%). Modeling of variation in browse utilization revealed positive relationships with the proportion of preferred species (β = 0.44, P = 0.05) and previously browsed willow plants (β = 3.13, P < 0.001), and a negative relationship with willow patch width (β = -0.002, P < 0.001). We found that planeleaf (Salix planifolia), Wolf's (S. wolfii), and Booth's willow (S. boothii) were the most consistently preferred species, whereas Drummond's (S. drummondiana) and Geyer willow (S. geyeriana) willow were moderately preferred; Lemmon's willow (S. lemmonii) was used less than expected. Power analyses indicated that detecting a 10% increase in browse utilization with 95% confidence in consecutive years required measuring 38-41, 50-m segments. Because systems with low and heterogeneous browse utilization of willow present challenges for efficient monitoring, we encourage power analyses as a means of evaluating sampling protocols, in addition to consideration of covariates predictive of spatiotemporal heterogeneity. [ABSTRACT FROM AUTHOR]