Orville Dyer. 1998. Mammals in Smith, I.M., and G.G.E. Scudder, eds. Assessment of species diversity in the Montane Cordillera Ecozone. Burlington: Ecological Monitoring and Assessment Network, 1998.

MAMMALS

Orville Dyer
British Columbia Ministry of Environment, Lands & Parks
Penticton, B.C.

ACKNOWLEDGEMENTS

I would like to thank David Nagorsen, Mammal Curator at the Royal BC Museum, for providing A Checklist of the Mammals of the Montane Cordillera Ecozone (Appendix 1) and for comments and suggestions on the text. His assistance and encouragement were invaluable. Any errors however, are solely my responsibility. I also would like to thank Sydney Cannings of the BC Conservation Data Centre for current conservation status information and Dr. Geoff Scudder of the University of British Columbia (UBC) for prompting me to complete this project and for comments on draft material. I appreciated cheerful assistance from Dr. David Shackleton of UBC, Steven Brechtel of Alberta Natural Resources Service, Les Gyug of OK Wildlife Consulting and Kathy Paige, Matt Austin, Tony Hamilton, Laura Friis, Dave Fraser, Ian Hatter, Bob Lincoln and Tom Ethier of the BC Ministry of Environment, Lands and Parks. Finally, thanks go to Carl MacNaughton for drafting species distribution information and Leigh Dyer for editorial comments.

Special thanks go to Ian McTaggart Cowan, Charles Guiget, David Nagorsen and the Royal BC Museum for their efforts to summarize mammal research in British Columbia and provide that information to the public. This contribution is very important. Without public awareness and support, our natural heritage of mammals and other species is threatened.

ABSTRACT

The Montane Cordillera Ecozone is currently home to 94 native terrestrial mammal species. Three introduced species also occur in the Ecozone. The tremendous diversity of species reflects the great variety of habitats present in this large area.

The majority of native species (73) are doing well. Their numbers and distribution are currently expanding, stable or slightly decreasing. However, at least 21 species are at risk, based on British Columbia Conservation Data Centre (CDC) rankings (Appendix 2). Five (5) species are Red Listed (under consideration for Threatened or Endangered status) and another 16 species are Blue Listed (considered Sensitive or Vulnerable). Species at risk fall into several categories based on habitat preferences and threats to populations and habitats.

Thirteen species (57% of species at risk, Table 1) depend on dry grassland, shrub-steppe and open forest. The majority of these species are , or were, found in the southern interior of British Columbia, in the Thompson, Fraser, Okanagan, Similkameen and Columbia drainages. Within this area, 4 species are restricted to the south Okanagan and Similkameen valleys, considered one of the 3 ecosystems, most at risk in Canada (Federal-Provincial-Territorial Biodiversity Working Group 1994).

Habitat loss and fragmentation, related primarily to urban and agricultural development, are the main reasons that most of these species are at risk. Habitat degradation due to forestry and range practices, noxious weed invasion, road development and killing or disturbance by humans also are concerns. Very few, small, poorly connected conservation areas have been established for protection of the shrub-steppe and low elevation forest required by these species.

TABLE 1

Red List

White-tailed Jackrabbit
Pallid Bat
Western Red Bat
Badger

Blue List

Great Basin Pocket Mouse
Spotted Bat
Western Small-footed Myotis
Fringed Myotis
Nuttall's Cottontail
Western Harvest Mouse
Townsend's Big-eared Bat
Bighorn Sheep
Bison (Extirpated)

Four Blue Listed species (Grizzly Bear, Caribou, Wolverine and Fisher) depend on large areas of boreal forest to support their large home ranges. They were once distributed throughout most of the Ecozone but have experienced significant population declines, especially in the south. Habitat loss and fragmentation, along with human caused mortality and disturbance related to wilderness access, are the main concerns for this group. Habitat loss has been attributed to forestry practices and urban, agricultural, road, mine and hydroelectric developments. Existing conservation areas generally are not large enough to maintain viable populations of these species in perpetuity.

Four other Blue Listed species do not fit well into the above categories. They are forest dwelling species with limited distributions in the Ecozone. The Mountain Beaver depends on humid forests in the southern Cascade Mountains; critical burrow sites are affected by forestry practices. The Cascade Mantled Ground Squirrel uses rock outcrops and open forest in the Cascade Mountains and is potentially threatened by human activities that enhance competitive species. Keen's Long-eared Myotis is a coastal forest species on the periphery of the Ecozone. Disturbance by humans and forestry practices that affect tree cavity roosts are the main conservation concerns for this species. The Northern Long-eared Myotis inhabits northern boreal forests. Limited information is available on this species in the Ecozone and research is required to address conservation concerns..

In addition, 14 subspecies are of conservation concern due to small and isolated populations. Seven are Red Listed and 7 are Blue Listed (Appendix 3). Threats are similar to those listed above, for species. Loss of genetic variation within small, isolated populations has become an important conservation concern in recent years. Subspecies distribution, population numbers and trends are not well documented for many species and require research.

 

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