Studies of habitat selection and use by wildlife, especially large herbivores, are foundational for understanding their ecology and management, especially if predictors of use represent habitat requirements that can be related to demography or fitness. Many ungulate species serve societal needs as game animals or subsistence foods, and also can affect native vegetation and agricultural crops because of their large body size, diet choices, and widespread distributions. Understanding nutritional resources and habitat use of large herbivores like elk (Cervus canadensis) can benefit their management across different land ownerships and management regimes. Distributions of elk in much of the western United States have shifted from public to private lands, leading to reduced hunting and viewing opportunities on the former and increased crop damage and other undesired effects on the latter. These shifts may be caused by increasing human disturbance (e.g., roads and traffic) and declines of early-seral vegetation, which provides abundant forage for elk and other wildlife on public lands. Managers can benefit from tools that predict how nutritional resources, other environmental characteristics, elk productivity and performance, and elk distributions respond to management actions. We present a large-scale effort to develop regional elk nutrition and habitat-use models for summer ranges spanning 11 million ha in western Oregon and Washington, USA (hereafter Westside). We chose summer because nutritional limitations on elk condition (e.g., body fat levels) and reproduction in this season are evident across much of the western United States. Our overarching hypothesis was that elk habitat use during summer is driven by a suite of interacting covariates related to energy balance: acquisition (e.g., nutritional resources, juxtaposition of cover and foraging areas), and loss (e.g., proximity to open roads, topography). We predicted that female elk consistently select areas of higher summer nutrition, resulting in better animal performance in more nutritionally rich landscapes. We also predicted that factors of human disturbance, vegetation, and topography would affect elk use of landscapes and available nutrition during summer, and specifically predicted that elk would avoid open roads and areas far from cover-forage edges because of their preference for foraging sites with secure patches of cover nearby. Our work had 2 primary objectives: 1) to develop and evaluate a nutrition model that estimates regional nutritional conditions for elk on summer ranges, using predictors that reflect elk nutritional ecology; and 2) to develop a summer habitat-use model that integrates Deceased. Rowland et al. Elk Nutrition and Habitat-Use Models 1the nutrition model predictions with other covariates to estimate relative probability of use by elk, accounting for ecological processes that drive use. To meet our objectives, we used 25 previously collected data sets on elk nutrition, performance, and distributions from 12 study areas. We demonstra...
Recent declines in black‐tailed deer (Odocoileus hemionus columbianus) populations in Washington have been attributed partly to low recruitment. However, sparse information exists regarding fawn survival and factors affecting recruitment. During 2006–2009, we captured 228 fawns on the Olympic Peninsula, Washington, USA, to determine sources of fawn mortality, estimate survival rates, identify factors influencing survival rates, assess the influence of hair loss syndrome (HLS) on winter survival, and estimate population growth. We used known fate modeling in Program MARK to estimate survival rates to age 50 weeks and to 9 weeks by developing 2 candidate a priori model sets. We recorded 129 mortalities; predation was the leading cause (74%). Mountain lions (Puma concolor) and bobcats (Lynx rufus) were the most common predators. The survival rate to 50 weeks was 0.33 (95% CI = 0.24–0.43); survival differed between capture years and was age dependent, with fawns being most vulnerable to mortality during the first 9 weeks then again during the winter. The survival rate to 9 weeks was 0.65 (95% CI = 0.60–0.68), and our results suggested that an interaction between age and birth mass influenced survival. A posteriori modeling indicated that greater body mass and earlier birth date also influenced survival over the first 9 weeks of life. Fawns afflicted with HLS had lower survival rates than non‐afflicted fawns (P = 0.018) during winter. Poor body condition, based on femur marrow assessment, was a factor in 89% of fawns that died over winter. We estimated the growth of the population to be stationary at λ = 1.0. Estimates of lambda increased 3% when survival was modified to assume HLS was not a factor. We conclude that fawn mortality during the first 9 weeks followed by a significant increase in winter mortality, exacerbated by HLS, combine to limit black‐tailed deer population growth. Inherent nutritional limitations in summer forage may have influenced survival of many fawns, pre‐disposing them to mortality during the summer and winter. Wildlife managers can use this information to improve population modeling and management of black‐tailed deer populations afflicted with HLS. © 2014 The Wildlife Society.
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