Grand Rapids, MN, United States
Grand Rapids, MN, United States

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Jones M.D.,West Virginia University | Berl J.L.,West Virginia University | Berl J.L.,Purdue University | Tri A.N.,West Virginia University | And 3 more authors.
Ursus | Year: 2015

Recreational hunting is the tool most commonly used to manage American black bear (Ursus americanus) populations in North America. However, bear populations can be sensitive to overharvest, particularly of mature females that can directly affect population growth. Managers need a thorough understanding of the factors affecting harvest vulnerability when using hunting as a primary management strategy. Here, we coupled Global Positioning System spatial data from female black bears and human hunters in western Maryland, USA, from 2005 to 2007, in order to model bear harvest vulnerability. Specifically, we developed maximum entropy (Maxent) predictive occurrence models for bears and for bear hunters and evaluated the influence of 7 environmental variables on their distributions. We then assessed predicted distribution maps for probability of co-occurrence to identify areas of high and low harvest vulnerability. Slope and land ownership (i.e., private-public) were the 2 most important variables determining female bear distributions, whereas land ownership and cover type were the most important variables influencing hunter distributions. We classified roughly 12% and 16% of the study area as being of high relative use for bears and bear hunters, respectively. Only 5.4% of the study area was considered to have high harvest vulnerability (i.e., high probability of co-occurrence). Areas with high bear relative use but low hunter use (i.e., low harvest vulnerability) comprised 0.9% of the study area. We were most interested in areas of high and low harvest vulnerability to enable resource managers to adjust hunting regulations that meet harvest goals. © 2015 International Association for Bear Research and Management.

Reidy J.L.,University of Missouri | Thompson III F.R.,University of Missouri | Bailey J.W.,University of Missouri | Bailey J.W.,Forest Wildlife and Populations Research Group
Journal of Wildlife Management | Year: 2011

New analytical methods have been promoted for estimating the probability of detection and density of birds from count data but few studies have compared these methods using real data. We compared estimates of detection probability and density from distance and time-removal models and survey protocols based on 5- or 10-min counts and outer radii of 50 or 100m. We surveyed singing male Acadian flycatchers (Empidonax virescens), cerulean warblers (Dendroica cerulea), Kentucky warblers (Oporornis formosus), Louisiana waterthrushes (Parkesia motacilla), wood thrushes (Hylocichla mustelina), and worm-eating warblers (Helmitheros vermivorum) in bottomland and upland forest across 5 states in the Central Hardwoods Bird Conservation Region during the breeding season in 2007 and 2008. Detection probabilities differed between distance and time-removal models and species detectabilities were affected differently by year, forest type, and state. Density estimates from distance models were generally higher than from time-removal models, resulting from lower detection probabilities estimated by distance models. We found support for individual heterogeneity (modeled as a finite mixture model) in the time-removal models and that 50-m radius counts generated density estimates approximately twice as high as 100-m radius counts. Users should be aware that in addition to estimating different components of detectability, density estimates derived from distance and time-removal models can be affected by survey protocol because some count durations and plot radii may better meet model assumptions than others. The choice of a method may not affect the use of estimates for relative comparisons (e.g., when comparing habitats) but could affect conclusions when used to estimate population size. We recommend careful consideration of assumptions when deciding on point-count protocol and selection of analysis methods. © 2011 The Wildlife Society.

Jones M.D.,West Virginia University | Tri A.N.,West Virginia University | Tri A.N.,Forest Wildlife and Populations Research Group | Edwards J.W.,West Virginia University | Spiker H.,Mt. Nebo WMA
Northeastern Naturalist | Year: 2015

Western Maryland's population of Ursus americanus (American Black Bear; hereafter Black Bear) was nearly extirpated by the 1950s but recovered to 326 individuals by 2005. A knowledge gap currently exists regarding home-range dynamics of this recovering population. One of the most basic questions that managers wish to understand is how much space these Black Bears are using. To provide this information, we examined the home-range dynamics of 18 adult female Black Bears in western Maryland from 2006 to 2007 using GPS collars. We predicted that home-range estimates in our study population would be similar to that of surrounding states because Black Bear populations have been recovering for the past 50 years throughout Appalachia. Fixed-kernel estimates for spring, summer, and fall home ranges were 8.9 km2, 15.4 km2, and 20.7 km2, respectively. Fall and summer home ranges were similar, and both were larger (P < 0.10) than spring home ranges. Solitary females had spring home ranges 6.9 times larger than females with cubs, but ranges for all females were similar during other seasons. Home-range fidelity among seasons was high. As predicted, home-range sizes were comparable to those from other Appalachian states. With our results, managers can better understand space use of Black Bears in this recovering population. © 2015, BioOne. All rights reserved.

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