Grizzly bear response to human development and activities in the Bow River Watershed, Alberta, Canada Michael L. Gibeau a, *, Anthony P. Clevenger b,c , Stephen Herrero d , Jack Wierzchowski e a Resources and the Environment Program, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4 b Faculty of Environmental Design, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4 c Department of Forestry, Wildlife and Fisheries, University of Tennessee, Knoxville, TN 37901, USA d Faculty of Environmental Design, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4 e Geomar Consulting Ltd., Box 1843, Grand Forks, British Columbia, Canada V0H 1H0 Received 4 February 2000; received in revised form 5 April 2001; accepted 17 May 2001 Abstract Few studies have reported the effects of multiple human activities on grizzly bears, Ursus arctos. We document the degree of grizzly bear response to various human developments as a function of multiple interacting variables based on observed median distances to roads, trails and development features in a landscape where human presence is widespread. Female grizzly bears remained further than males from paved roads regardless of habitat quality or time of day. Males were found closer to paved roads when within or adjacent to high quality habitat and during the period of least human activity. The combination of traffic volume and highway configuration, however, overrides a bear’s attraction to high quality habitats for high-speed, high-volume, highways. Avoidance of busy transportation corridors was strongest in the adult segment of the population. Bears were found closer to trails during the human inactive period when within high quality habitat and further from trails when distant to high quality habitat. Our data indicated an inverse relationship between the sexes in response to vehicles and traffic noise compared to the response to human settlement and encountering people. Female bears were found further away than males in relation to vehicles and traffic noise, yet found closer than males to human settlement and places where people may be encountered. Those males that were more willing to exploit high quality habitat near roads, did so at night and where hiding cover was present. Adult females were the most risk-averse cohort, choosing to avoid humans instead of seeking out high quality habitats. Adult female grizzly bears were influenced most by human activities and development. Management agencies must maintain access to high quality habitat, especially for adult females, and create new opportunities to support the reproductive potential of the population. # 2001 Elsevier Science Ltd. All rights reserved. Keywords: Development; Grizzly bear; Human impacts; Response; Roads 1. Introduction Many wildlife populations have been reduced to small fractions of their former size during modern times due to anthropogenic pressures such as habitat loss and overexploitation. This phenomenon is increasing in Canada. The Province of Alberta has an expanding economy based significantly on the development of natural resources such as agriculture, oil and gas, for- estry and nature-based tourism. Individual grizzly bears, having large home ranges, increasingly come into contact with all of these activities. Herrero (1994) showed that grizzly bear populations in Canadian national parks by themselves were probably all too small to have a high probability of long-term persis- tence, and therefore integrated management with sur- rounding provincial or territorial lands would be required. Within Banff, Yoho and Kootenay National Parks, Gibeau (1998) found that habitat effectiveness was significantly compromised by development. Whe- ther land is managed as parks, commercial forests or privately, management practices must respond to the grizzlies’ needs if these bears are to survive. There is an urgent need for scientific data to help land managers better understand the effects of human activities on grizzly bears. 0006-3207/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved. PII: S0006-3207(01)00131-8 Biological Conservation 103 (2002) 227–236 www.elsevier.com/locate/biocon * Corresponding author. Tel.: +1-403-220-8075; fax: +1-403-289- 6205. E-mail address: mike_gibeau@pch.gc.ca (M.L. Gibeau).