Shifting perceptions of risk and reward: Dynamic selection for human development by black bears in the western United States

Abstract

a b s t r a c tAs landscapes across the globe experience increasing human development, it is critical to identify the behavioral responses of wildlife to this change given associated shifts in resource availability and risk from human activity. This is particularly important for large carnivores as their interactions with people are often a source of conflict, which can impede conservation efforts and require extensive management. To examine the adaptations of a large carnivore to benefits and risks associated with human development we investigated black bear behavior in three systems in the western United States. Our objectives were to (1) identify temporal patterns of selection for development within a year and across years based on natural food conditions, (2) compare spatial patterns of selection for development across systems, and (3) examine individual characteristics associated with increased selection for development. Using mixed effects resource selection models we found that bear selection for development was highly dynamic, varying as a function of changing environmental and physiological conditions. Bears increased their use of development in years when natural foods were scarce, throughout the summer-fall, as they aged, and as a function of gender, with males exhibiting greater use of development. While patterns were similar across systems, bears at sites with poorer quality habitat selected development more consistently than bears at sites with higher quality habitat. Black bears appear to use development largely for food subsidy, suggesting that conflicts with bears, and potentially other large carnivores, will increase when the physiological demand for resources outweighs risks associated with human activity.Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

A conceptual model for the integration of social and ecological information to understand human-wildlife interactions

“…Unfortunately, these efforts are rarely successful as conflict rates do not necessarily reflect numerical changes in populations (Treves et al, 2010;Obbard et al, 2014), particularly when animals shift their behavior in response to changing environmental conditions (Wong and Candolin, 2015). For example, in our case study, bear foraging behavior has been found to be highly dynamic, as bears increase their use of anthropogenic foods in poor natural food years and decrease it in good natural food years, as a function of changing forage-risk trade-offs (Johnson et al, 2015). Baruch-Mordo et al (2013) suggested that managers may be able to reduce forage benefits around development by securing garbage and other attractants.…”

“…In addition to these external factors, several individual attributes are known to influence bear foraging behavior around human development, and thus, their probability of accessing human foods and interacting with people. For example, Johnson et al (2015) found that female bears that were older, had limited access to natural foods, and were experiencing hyperphagia (the period of increased foraging prior to hibernation) selected more strongly for human development.…”

“…Durango is surrounded by public lands popular for outdoor recreation, which attracts many new residents. The resulting development, aided by technological advancements in communications that allow people to live farther from traditional workplaces, has occurred within areas that were high-quality bear habitat (Johnson et al, 2015), increasing the availability of human foods on the landscape. Institutional factors include actions taken by local, state, and federal authorities to reduce conflicts and alter the distribution of bears.…”

“…This issue can be especially challenging for wide-ranging animals, such as large carnivores. For example, in our case study, researchers fit individual bears with GPS telemetry collars to understand habitat selection and space use with respect to human development (Johnson et al, 2015(Johnson et al, , 2017. Ideally, as a part of our experiment, we would have provided free bear-resistant garbage containers across the same area inhabited by our collared sample of bears to quantify the effects of bear-proofing on bear behavior and garbage-related conflicts.…”

“…The resulting ecological communities provide a diversity of plants and animals that produce natural foods for black bears, such as grasses, forbs, berries, acorns, and insects. Natural food abundance is highly variable across years due to annual variation in weather (e.g., drought conditions, late freezes), and scarcity in natural foods can cause bears to increase their use of human development (Johnson et al, 2015(Johnson et al, , 2017. For example, during a poor natural food year in 2012, bears around Durango increased their use of development and the population was estimated to have declined in association with high rates of humancaused mortality (e.g., vehicle collisions, harvest, lethal removals of conflict-involved individuals; Laufenberg et al, 2018).…”