@article{Burkholder_DeCesare_Garrott_Boccadori_2017, title={HETEROGENEITY AND POWER TO DETECT TRENDS IN MOOSE BROWSE UTILIZATION OF WILLOW COMMUNITIES}, volume={53}, url={https://alcesjournal.org/index.php/alces/article/view/178}, abstractNote={Monitoring of browse utilization of plant communities is consistently recommended as an important component of monitoring moose (<em>Alces alces</em>) populations across regions. We monitored winter browse utilization by moose within a willow (<em>Salix </em>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,<em>P </em>= 0.05) and previously browsed willow plants (β = 3.13, <em>P </em>< 0.001), and a negative relationship with willow patch width (β = 0.002, <em>P</em> < 0.001). We found that planeleaf (<em>Salix planifolia</em>), Wolf ʼs (<em>S. wolfii</em>), and Boothʼs willow (<em>S. boothii</em>) were the most consistently preferred species, whereas Drummondʼs (<em>S. drummondiana</em>) and Geyer willow (<em>S. geyeriana</em>) willow were moderately preferred; Lemmonʼs willow (<em>S. lemmonii</em>) 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.}, journal={Alces: A Journal Devoted to the Biology and Management of Moose}, author={Burkholder, Braden O. and DeCesare, Nicholas J. and Garrott, Robert A. and Boccadori, Sylvanna J.}, year={2017}, month={Jun.}, pages={23–39} }