Large carnivores need large areas of relatively wild habitat, which makes their conservation challenging. These species play important ecological roles and in some cases may qualify as keystone species. Although the ability of carnivores to control prey numbers varies according to many factors and often is effective only in the short term, the indirect effects of carnivores on community structure and diversity can be great. Perhaps just as important is the role of carnivores as umbrella species (i.e., species whose habitat area requirements encompass the habitats of many other species). Conservation areas large enough to support populations of large carnivores are likely to include many other species and natural communities, especially in regions such as the Rocky Mountains of Canada and the United States that have relatively low endemism. For example, a plan for recovery of grizzly bears (Ursus arctos) proposed by Shaffer (1992) covers, in part, 34% of the state of Idaho (compared to 8% covered by a U.S. Fish and Wildlife Service proposal) and would capture 10% or more of the statewide ranges of 71% of the mammal species, 67% of the birds, 61% of the amphibians but only 27% of the reptiles native to Idaho. Two-thirds (67%) of the vegetation types in Idaho would have 10% or more of their statewide area included in the Shaffer plan. The U.S. Fish and Wildlife Service recovery zones provide a much poorer umbrella. The umbrella functions of large carnivores are expected to be poorer in regions with high endemism. The application of metapopulation concepts to large carnivore conservation has led to proposals for regional reserve networks composed of wilderness core areas, multiple-use buffer zones, and some form of connectivity. The exceptional vagility of most large carnivores makes such networks feasible in a region with low human population density, such as the Rocky Mountains, but mortality risks still need to be addressed. Roads are a major threat to carnivore recovery because of barrier effects, vehicle collisions, and increased accessibility of wild areas to poachers. Development, especially for tourism, is also becoming a threat in many parts ofthe region.



Los carnivoros mayores requieren de extensas areas de habitat relativamente natural, lo cual hace de su conservacion un reto. Estas especies juegan un papel ecologico importante y pueden, en algunos casos, ser consideradas como especies clave. Aunque la capacidad de los carnivoros para controlar la abundancia de sus presas varia en funcion de numerosos factores y a menudo solo es a corto plazo, los efectos indirectos de los carnivoros sobre la estructura y diversidad de la comunidad pueden ser grandes. Posiblemente igual importancia tiene el papel de los carniivoros como especies sombrilla (i.e., especies cuyos requerimientos de extension del habitat comprenden los habitats de muchas otras especies). Es probable que areas de conservacion suficientemente grandes para mantener poblaciones de carnivoros mayores incluyan muchas otras especies y comunidades naturales, especialmente en regiones con endemismo relativamente bajo, tal como las Montanas Rocallosas. Por ejemplo, un plan de recuperacion de osos pardos (Ursus arctos) propuesto por Schaffer (1992) abarca, en parte, el 34% del estado de Idaho (comparado con el 8% del Servicio de Pesca y Vida Silvestre de los E.U.) abarcaria el 10% o mas de los rangos estatales de distribucion del 71% de las especies de mamiferos, 67% de aves y 61% de anfibios, pero solo el 21% de reptiles nativos de Idaho. Dos tercios (67%) de los tipos de vegetacion de Idaho tendrian 10% o mas de su extension en el estado incluida en la propuesta de Schaffer. Las zonas de recuperacion propuestas por el Servicio de Pesca y Vida Silvestre constituyen una sombrilla Mas pequena. Se espera que en regiones de alto endemismo la funcion cobertora de los carnivoros mayores es mas pobre. La aplicacion del concepto de metapoblacion en la conservacion de carnivoros mayores ha llevado a propuestas de redes regionales de reservas interconectadas de alguna manera y compuestas por zonas nucleo y zonas de amortiguamiento de usos multiples. La vagilidad excepcional de la mayoria de los carnivoros permite dichas redes en una region con baja densidad poblacional humana, tal como las Montanas Rocallosas, aunque los riesgos de mortalidad deberan ser considerados. Los caminos son una amenaza mayor para la recuperacion de carnivoros por fungir como barreras, propiciar colisiones con vehiculos y facilitar el acceso a cazadores furtivos. El desarrollo especialmente para el turismo tambien se esta convirtiendo en una amenaza en muchas partes de la region.

Conservation Biology and Carnivore Conservation in the Rocky Mountains

American black bears (Ursus americanus) and brown bears (U. arctos) can be important predators on neonatal ungulates. They prey less commonly on adult ungulates. Bear predation appears to be additive at low ungulate densities and may become compensatory as prey density approaches carrying capacity, K. As such, black and brown bear predation can limit, but generally does not regulate, ungulate populations. Maternal and neonatal physical condition, birth synchrony, and birth mass may predispose neonates to predation or other mortality factors. Though black and brown bear predation is an important proximate cause of ungulate neonatal mortality, habitat quality and quantity are important ultimate factors influencing this dynamic. Manipulating bear populations to enhance ungulate populations may be successful in the short-term if predation is additive, but long-term success has not been demonstrated.

The role of American black bears and brown bears as predators on ungulates in North America

We studied moose (Alces alces) survival, physical condition, and abundance in a 3-predator system in western Interior Alaska, USA, during 2001-2007. Our objective was to quantify the effects of predator treatments on moose population dynamics by investigating changes in survival while evaluating the contribution of potentially confounding covariates. In May 2003 and 2004, we reduced black bear (Ursus americanus) and brown bear (U. arctos) numbers by translocating bears � 240 km from the study area. Aircraft-assisted take reduced wolf (Canis lupus) numbers markedly in the study area during 2004-2007. We estimated black bears were reduced by approximately 96% by June 2004 and recovered to within 27% of untreated numbers by May 2007. Brown bears were reduced approximately 50% by June 2004. Late-winter wolf numbers were reduced by 75% by 2005 and likely remained at these levels through 2007. In addition to predator treatments, moose hunting closures during 2004-2007 reduced harvests of male moose by 60% in the study area. Predator treatments resulted in increased calf survival rates during summer (primarily from reduced black bear predation) and autumn (primarily from reduced wolf predation). Predator treatments had little influence on survival of moose calves during winter; instead, calf survival was influenced by snow depth and possibly temperature. Increased survival of moose calves during summer and autumn combined with relatively constant winter survival in most years led to a corresponding increase in annual survival of calves following predator treatments. Nonpredation mortalities of calves increased following predator treatments; however, this increase provided little compensation to the decrease in predation mortalities resulting from treatments. Thus, predator-induced calf mortality was primarily additive. Summer survival of moose calves was positively related to calf mass (b > 0.07, SE ¼ 0.073) during treated years and lower (b ¼� 0.82, SE ¼ 0.247) for twins than singletons during all years. Following predator treatments, survival of yearling moose increased 8.7% for females and 21.4% for males during summer and 2.2% for females and 15.6% for males during autumn. Annual survival of adult (� 2 yr old) female moose also increased in treated years and was negatively (b ¼� 0.21, SE ¼ 0.078) related to age. Moose density increased 45%, from 0.38 moose/ km 2 in 2001 to 0.55 moose/km 2 in 2007, which resulted from annual increases in overall survival of moose, not increases in reproductive rates. Indices of nutritional status remained constant throughout our study despite increased moose density. This information can be used by wildlife managers and policymakers to better understand the outcomes of predator treatments in Alaska and similar environments. 2011 The Wildlife Society.

https://www.adfg.alaska.gov/static/home/library/pdfs/wildlife/propubs/keech_2011_journal_wildlife_management_75_effects_predator_treatments_moose.pdf

Effects of predator treatments, individual traits, and environment on moose survival in Alaska

Distribution theory predicts that for two species living in sympatry, the subordinate species would be constrained from using the most suitable resources (e.g., habitat), resulting in its use of less suitable habitat and spatial segregation between species. We used negative binomial generalized linear mixed models with fixed effects to estimate seasonal population-level resource selection at two spatial resolutions for female brown bears (Ursus arctos) and female American black bears (U. americanus) in southcentral Alaska during May–September 2000. Black bears selected areas occupied by brown bears during spring which may be related to spatially restricted (i.e., restricted to low elevations) but dispersed or patchy availability of food. In contrast, black bears avoided areas occupied by brown bears during summer. Brown bears selected areas near salmon streams during summer, presumably to access spawning salmon. Use of areas with high berry production by black bears during summer appeared in response to avoidance of areas containing brown bears. Berries likely provided black bears a less nutritious, but adequate food source. We suggest that during summer, black bears were displaced by brown bears, which supports distribution theory in that black bears appeared to be partially constrained from areas containing salmon, resulting in their use of areas containing less nutritious forage. Spatial segregation of brown and American black bears apparently occurs when high-quality resources are spatially restricted and alternate resources are available to the subordinate species. This and previous work suggest that individual interactions between species can result in seasonal population-level responses.

Population-level resource selection by sympatric brown and American black bears in Alaska

The acquisition of behavior in animals is a function of both inheritance and learning, where learning can occur asocially (independent of other animals), socially (by observing other animals), or both. For species that have a prolonged parent–offspring relationship and that live solitary adult lives, social learning between parents and offspring may be a dominant form of learning. If parent–offspring learning is a dominant avenue for acquiring behavior or if behavior is inherited, then behaviors that confer significant fitness advantages should lead to subpopulations of genetically related individuals with similar behavioral patterns. We investigated whether foodconditioning behavior in black bears (Ursus americanus) is inherited or learned via parent–offspring social learning. We combined genetic data with behavioral data for 116 black bears from Lake Tahoe Basin, Nevada, and Yosemite National Park, California. We categorized individual bears as food-conditioned or non–foodconditioned based on their behavior over a several-year period of intensive study at each site. We compared levels of relatedness, based on microsatellite DNA genotyping, within and between these groups and compared behavior between 9 mother–offspring pairs determined through genetic analysis of maternity. Based on 4 separate analyses of the data there was little evidence that food-conditioning behavior in black bears partitioned along related lineages, indicating that the acquisition of food conditioning behavior was not solely a function of social learning or inheritance.

http://www.ndow.org/uploadedFiles/ndoworg/Content/public_documents/Wildlife_Education/Publications/black_bear_conflict_behavior.pdf

J. Beecham

Papers

A shadow in the forest : Idaho's black bear