Rates and Causes of Grizzly Bear Mortality in the Interior Mountains of British Columbia, Alberta, Montana, Washington, and Idaho

Abstract

Trends of grizzly bear (Ursus arctos) populations are most sensitive to female survival; thus, understanding rates and causes of grizzly bear mortality is critical for their conservation. Survival rates were estimated and causes of mortalities investigated for 388 grizzly bears radiocollared for research purposes in 13 study areas in the Rocky and Columbia mountains of Alberta, British Columbia, Montana, Idaho, and Washington between 1975 and 1997. People killed 77-85% of the 99 grizzly bears known or suspected to have died while they were radiocollared. In jurisdictions that permitted grizzly bear hunting, legal harvest accounted for 39-44% of the mortalities. Other major causes of mortality included control killing for being close to human habitation or property, self-defense, and malicious killings. The mortality rate due to hunting was higher (P = 0.006) for males than females, and subadult males had a higher probability (P = 0.007) of being killed as problem animals than did adult males or females. Adult females had a higher (P = 0.009) mortality rate from natural causes than males. Annual survival rates of subadult males (0.74-0.81) were less than other sex-age classes. Adult male survival rates varied between 0.84 and 0.89 in most areas. Survival of females appeared highest (0.95-0.96) in 2 areas dominated by multiple-use land and were lower (0.91) in an area dominated by parks, although few bears were killed within park boundaries. Without radiotelemetry, management agencies would have been unaware of about half (46-51%) of the deaths of radiocollared grizzly bears. The importance of well-managed multiple-use land to grizzly bear conservation should be recognized, and land-use plans for these areas should ensure no human settlement and low levels of recreational activity.

Faunal mortality on roads due to religious tourism across time and space in protected areas: A case study from south India

“…Much attention is given to understanding and mitigating the impact of roads through PAs on these animals as roads experience some form of traffic all through the year (e.g. Grosman et al, 2009;McLellan et al, 1999;Mech, 1989). Unlike in many developed countries, relatively large proportion of the traditional religious enclaves and scenic landscapes in Asia including India are located inside PAs.…”

Subadult brown bears (Ursus arctos) discriminate between unfamiliar adult male and female anal gland secretion

“…Subadult brown bears have a 15% chance of being killed by conspecifics in Scandinavia (Swenson et al 2001) and most of these killings occur during the mating/dispersal season. Thus, confrontations with adults have high risks for subadults, because adults could kill them (Mattson et al 1992;McLellan et al 1999;Swenson et al 2001). Moreover, adult males kill subadults more often than do adult females (McLellan 1994).…”

Grizzly bears and forestry

“…These activities also establish an often-permanent network of roads that can have lasting influences on forest ecosystems. In large carnivore studies throughout the world, roads have been implicated in reducing habitat quality due to noise, human avoidance, and fragmentation (McLellan and Shackleton, 1988;Clevenger et al, 1997;Dyer et al, 2001;Papouchis et al, 2001;Waller and Servheen, 2005;Nellemann et al, 2007), decreasing gene flow across major thoroughfares (Alexander and Waters, 2000;Kaczensky et al, 2003;Epps et al, 2005;Waller and Servheen, 2005), and increasing mortality due to both improved access for hunters and poachers (McLellan and Shackleton, 1988;McLellan, 1998;McLellan et al, 1999;Benn and Herrero, 2002;Nielsen et al, 2004a) and vehicle collisions (Clevenger et al, 2001;Kaczensky et al, 2003;Gunther et al, 2004). In Alberta, Canada, road densities are increasing rapidly due to industrial activity (Schneider, 2002), and grizzly bear (Ursus arctos) populations are at risk of declining (Banci et al, 1994;McLellan, 1998).…”