The late-denning activities of the American black bear in Utah

Abstract

EXECUTIVE SUMMARYDuring the early part of the 20 th Century, predators were subjected to high levels of take because of real or perceived threats to human health or safety and conflicts with agriculture/livestock. Many of our native predators have reestablished and are now very common in Oregon. The Oregon Department of Fish and Wildlife (ODFW or department) recognizes the high value of our native wildlife, including predators, and manages for a balance between sustainable populations and acceptable levels of conflicts, which is challenging at times. Public attitude toward black bears (and other wildlife species) has changed during the past several decades, and increasing black bear populations have increased the complexity of certain management issues. State wildlife agencies have been, "…caught in the middle and try to maintain a balance with their management strategies," (Pelton 2000:390) as they shift from goals related to population recovery to goals related to regulation of abundance. The mission of the department is to protect and enhance Oregon's fish and wildlife populations and their habitats for use and enjoyment by present and future generations. This plan is the strategy of the department to meet its mission for management of black bears in Oregon.The 2012 Oregon Black Bear Management Plan updates the 1993-1998 Oregon Black Bear Management Plan. During the planning and revision process, stakeholder groups were invited and provided input for the plan. A public comment period also was utilized during the revision process to inform the public of the intent of the plan, how black bears are managed in Oregon, and for the department to consider public input on bear management.The plan includes information on biology and ecology of bears, with a focus on Oregon; historical and current management approaches; and biological data collection. The plan also establishes a set of four objectives designed to balance ecological, social, and economic considerations for informed decision making when managing populations of black bears. These objectives are not considered mutually exclusive; therefore, some level of trade-off is to be expected under certain situations. As with the previous bear management plans, the department continues to develop efficient and effective bear management strategies to meet objectives within its personnel and fiscal resource limitations.Objective 1 is to maintain healthy and optimum bear populations while providing optimum recreational opportunities, and considering objectives related to other wildlife species and the level of human-bear conflicts. Management of individual species should include considerations related to an ecosystem-based management approach. Management of other wildlife species, such as deer and elk, may affect management of bears, including those related to population abundance. Decisions related to management of harvested species include providing recreational opportunities for hunters. Therefore, objectives should be balanced and trade-offs should be acknowledged. ...

The role of spring temperatures in the den exit of female brown bears with cubs in southwestern Europe

“…The inverse relationship between maximum temperature and den exit in brown bears was also reported by Miller (1990), McLoughlin et al (2002, Manchi and Swenson (2005), and Delgado et al (2018), as well as for American black bears by Miller et al (2017) and Johnson et al (2017). In particular, Pigeon et al (2016) reported that for each increase of 4°C in spring temperature, den exit occurs 10 days earlier.…”

“…These fluctuations may be caused by both interannual variations in climatic variables resulting from climate change and extreme climatic events and temperature anomalies, which have been predicted for southwestern Europe (Giorgi et al 2004, Castro et al 2005, Pendergrass et al 2017. These year-to-year changes in hibernation length have already been reported in American black bears (U. americanus; Miller et al 2017) and even in brown bears, where these changes depend on temperatures or precipitation during winter and spring (Miller 1990, Mcloughlin et al 2002, Friebe et al 2014, Evans et al 2016, Pigeon et al 2016, Johnson et al 2017, Delgado et al 2018. Therefore, identifying the triggers of den exit of FCOYs and its adjustment to climatic factors is of great importance and would allow for better predicting the effect of climate change on this vulnerable brown bear population.…”

Life history consequences of climate change in hibernating mammals: a review

“…Warmer temperatures and shorter winters had reliably negative effects on hibernation emergence phenology, but studies of drier conditions were few (Table 1). A longer growing season, measured as last date of spring frost, had no effect on hibernation emergence in the one study where it was investigated (Miller et al 2017). Among the few positive effects on phenology were warmer fall temperatures delaying hibernation immergence in black bears Ursus americanus (Johnson et al 2018) and brown bears Ursus arctos (Evans et al 2016, Delgado et al 2018).…”

Denning in brown bears

“…Moreover, the increased climatic variability could make the weather patterns that govern the seasonality of animal life cycles to some extent more unpredictable for many organisms, including bears (Weiskopf et al, 2020). Actually, these interannual fluctuations in hibernation chronology due to climatic conditions have already been reported in both American black bears (Miller, Smith, Auger, Black, & Allphin, 2017) and brown bears (Delgado et al, 2018;Evans et al, 2016;Friebe et al, 2014;McLoughlin, Case, et al, 2002;. reported that for each 4°C increase in spring temperature brown bear den exit occurs 10 days earlier.…”