Land tenure shapes black bear density and abundance on a multi‐use landscape

Abstract

Global biodiversity is decreasing rapidly. Parks and protected lands, while designed to conserve wildlife, often cannot provide the habitat protection needed for wide‐ranging animals such as the American black bear (Ursus americanus). Conversely, private lands are often working landscapes (e.g., farming) that have high human footprints relative to protected lands. In southwestern Alberta, road densities are highest on private lands and black bears can be hunted year‐round. On protected lands, road densities are lowest, and hunting is prohibited. On public lands under the jurisdiction of the provincial government (Crown lands), seasonal hunting is permitted. Population estimates are needed to calculate sustainable harvest levels and to monitor population trends. In our study area, there has never been a robust estimate of black bear density and spatial drivers of black bear density are poorly understood. We used non‐invasive genetic sampling and indices of habitat productivity and human disturbance to estimate density and abundance for male and female black bears in 2013 and 2014 using two methods: spatially explicit capture–recapture (SECR) and resource‐selection functions (RSF). Land tenure best explained spatial variation in black bear density. Black bear densities for females and males were highest on parkland and lowest on Crown lands. Sex ratios were female‐biased on private lands, likely a result of lower harvests and movement of females out of areas with high male density. Synthesis and application: Both SECR and RSF methods clearly indicate spatial structuring of black bear density, with a strong influence based on how lands are managed. Land tenure influences the distribution of available foods and risk from humans. We emphasize the need for improved harvest reporting, particularly for non‐licensed hunting on private land, to estimate the extent of black bear harvest mortality.

Conservation implications of sex‐specific landscape suitability for a large generalist carnivore

“…Selecting the most suitable areas could result in mapping a more restricted predicted range; however, similar to our results, the modelled distribution range for reproductive female brown bears ( U. arctos ) in Poland was smaller than the range based on occurrence of both sexes (Fernández et al, ), suggesting a general pattern may occur that is independent of density. Sex‐specific behaviour has been observed in several ursid species, such as foraging behaviour in Asiatic black bears ( U. thibetanus ; Koike et al, ), road tolerance in black bears (Loosen, Morehouse, & Boyce, ) and brown bears (Mace et al, ), and spatial segregation in brown bears (Rode et al, ). Highlighting the importance of sex‐specific modelling, a habitat‐based conservation framework for brown bears in Canada was based on adult female habitat, as they are the most sensitive sex‐age class for population trajectories and their habitat use differed from males (Nielsen, Stenhouse, & Boyce, ).…”

Carnivores and Communities: A Case Study of Human-Carnivore Conflict Mitigation in Southwestern Alberta

“…People and large carnivores occupy the same landscape, and private agricultural lands used for livestock and crop production abut forested, mountainous public lands. Four native large carnivore species are present, including cougars (Puma concolor), black bears (U. americanus), wolves (C. lupus), and grizzly bears (U. arctos), and their home ranges substantially overlap private agricultural lands Loosen et al, 2018;Bassing et al, 2019). These large carnivore species are considered secure (i.e., not at risk) within Alberta except for grizzly bears, which have been listed as provincially threatened since 2010 (Alberta Government, 1991Government, , 2012Government, , 2016Alberta Environment Parks, 2016;Government of Alberta, 2017).…”

Response of female black bears to a high‐density road network and identification of long‐term road mitigation sites

“…Where bears currently range in the state, they experience road densities in their home ranges from 0.55 to 5.8 km/km 2 ( x = 2.23 km/km 2 , unpublished data). These road densities are some of the highest reported in studies on black bears in North America (Brody & Pelton, 1989;Beringer, Seibert & Pelton, 1990;Gold, 1997;Gantchoff & Belant, 2017;Loosen, Morehouse & Boyce, 2018). Across North America, black bears have been shown to use wildlife overpasses and underpasses (Allen, 2011;Sawaya et al, 2013;Healy & Gunson, 2014).…”