COSEWIC Assessment and Status Report on the Plains Bison Bison bison bison in Canada THREATENED 2004 COSEWIC COSEPAC COMMITTEE ON THE STATUS OF COMITÉ SUR LA SITUATION ENDANGERED WILDLIFE DES ESPÈCES EN PÉRIL IN CANADA AU CANADA COSEWIC status reports are working documents used in assigning the status of wildlife species suspected of being at risk. This report may be cited as follows: COSEWIC 2004. COSEWIC assessment and status report on the plains bison Bison bison bison in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 71 pp. (www.sararegistry.gc.ca/status/status_e.cfm). Production note: COSEWIC would like to acknowledge Greg Wilson and Keri Zittlau for writing the status report on the plains bison Bison bison bison in Canada prepared under contract with Environment Canada. The report was overseen and edited by Marco Festa-Bianchet, the COSEWIC Terrestrial Mammals Species Specialist Co-chair. COSEWIC would like to acknowledge Parks Canada for providing partial funding for the preparation of this report. For additional copies contact: COSEWIC Secretariat c/o Canadian Wildlife Service Environment Canada Ottawa, ON K1A 0H3 Tel.: (819) 997-4991 / (819) 953-3215 Fax: (819) 994-3684 E-mail: COSEWIC/[email protected] http://www.cosewic.gc.ca Ếgalement disponible en français sous le titre Ếvaluation et Rapport de situation du COSEPAC sur le bison des prairies (Bison bison bison) au Canada. Cover illustration: Plains bison — Illustration by Wes Olson. Her Majesty the Queen in Right of Canada 2004 Catalogue No. CW69-14/379-2004E-PDF ISBN 0-662-37298-0 HTML: CW69-14/379-2004E-HTML 0-662-37299-9 Recycled paper COSEWIC Assessment Summary Assessment Summary – May 2004 Common name Plains bison Scientific name Bison bison bison Status Threatened Reason for designation There are currently about 700 mature bison of this subspecies in three free-ranging herds and about 250 semi- captive mature bison in Elk Island National Park. The largest free-ranging herd, in the Pink Mountain area of BC, is outside the historical range of this subspecies. The population in Prince Albert National Park is increasing by about 10% a year. The greatest problem facing these bison in Canada is the lack of habitat, due to conversion to agriculture and urbanization. Additional threats include domestic cattle disease and the risk of genetic pollution from escaped ranched bison, including some that may carry cattle genes. The total number of free-ranging and semi- captive mature bison of this subspecies is just under 1000, and there are fewer than five populations. Occurrence British Columbia, Alberta, Saskatchewan, Manitoba Status history Designated Threatened in May 2004. Assessment based on a new status report. iii COSEWIC Executive Summary Plains Bison Bison bison bison Species information Plains bison, Bison bison bison Linnaeus 1758, are one of two subspecies of Bison bison, along with Bison bison athabascae Rhoads 1897, the wood bison. Distribution Plains bison were once widespread across North America, but now only occur in fragmented populations throughout their historic range. Wild populations occur in British Columbia and Saskatchewan. Alberta, Saskatchewan, and Manitoba contain semi-wild or captive herds. Habitat The Canadian range of plains bison once extended over the prairies, including grasslands, shrublands and some woodland areas. However, plains bison will only exist in regions containing suitable grasslands and meadows. Much of the original plains bison habitat has changed drastically during the last century due to agricultural conversion and urbanization. A large amount of the current Canadian bison range is under government protection, and no changes are expected in habitat availability. Although little remains of the original traditional prairie habitat for plains bison, some reintroduction opportunities do exist. Biology Plains bison are polygynous mammals. They are gregarious and herd size and structure vary throughout the year. Males establish a fluid dominance hierarchy, where dominance rankings often change within a breeding season, and many males breed each year. Bison are well adapted to exist in native grasslands and meadow regions. They primarily consume sedges and grasses. Population sizes and trends The Canadian population of plains bison includes 670-740 mature animals in three free-ranging herds and 250-270 mature animals in one semi-wild herd. An additional iv 63-83 mature bison occur in four small, captive populations. All populations, except for Pink Mountain, are stable or increasing in size. Elk Island National Park, the semi-wild herd, is either the direct or indirect source for all plains bison herds in Canada. Limiting factors and threats The largest impediment to plains bison conservation is a lack of habitat. Most of its original range has been lost to agriculture and urban development. There are, however, a few areas where reintroductions may still be possible. A number of plains bison populations in the United States have hybridized with cattle. To date, Elk Island National Park and Pink Mountain, the only Canadian plains bison surveyed for cattle genes, have shown no evidence of hybridization. Only three free-ranging herds of plains bison are subject to natural selective factors. Two of these populations are small, with 100 and 320 bison. Most Canadian plains bison populations were founded with between 10 and 50 individuals from Elk Island National Park, raising concerns as to their levels of genetic diversity. Efforts to conserve plains bison in Canada are hampered by the lack of a consensus for protection between provincial and federal legislation. Hybridization with wood bison may also be a threat to the conservation of plains bison in Canada. Game ranching poses a threat to plains bison; there is a risk of hybridization between wild plains bison populations and ranched herds of wood and plains bison when ranched animals escape. At present, no Canadian plains bison population is infected with any disease that jeopardizes its existence. However, domestic cattle can act as disease reservoirs for bison, and their proximity could put the health of some bison herds at risk. Special significance of the species Millions of plains bison once roamed the prairies of North America, where they were the dominant herbivore. As such, they greatly affected the Great Plains ecosystem. The histories of plains bison and Aboriginal Peoples in North America are inextricably linked. Existing protection or other status designations Bison have a global heritage status rank of G4, meaning they are globally common but rare in parts of their range. The General Status of Species in Canada classifies bison as Sensitive. In British Columbia and Manitoba, plains bison are listed as Vulnerable. In Saskatchewan, plains bison are listed as At Risk. In Alberta, plains bison are considered extirpated from provincial land. Plains bison are classified as domestic animals in Alberta and Manitoba. The Pink Mountain herd in British Columbia is on land that is not protected by a government agency, but is protected from unregulated hunting under the B.C. Wildlife Act. v COSEWIC HISTORY The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process. COSEWIC MANDATE The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species and include the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens. COSEWIC MEMBERSHIP COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal organizations (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biosystematic Partnership, chaired by the Canadian Museum of Nature), three nonjurisdictional members and the co-chairs of the species specialist and the Aboriginal Traditional Knowledge subcommittees. The committee meets to consider status reports on candidate species. DEFINITIONS (after May 2004) Species Any indigenous species, subspecies, variety, or geographically or genetically distinct population of wild fauna and flora. Extinct (X) A species that no longer exists. Extirpated (XT) A species no longer existing in the wild in Canada, but occurring elsewhere. Endangered (E) A species facing imminent extirpation or extinction. Threatened (T) A species likely to become endangered if limiting factors are not reversed. Special Concern (SC)* A species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats. Not at Risk (NAR)** A species that has been evaluated and found to be not at risk. Data Deficient (DD)*** A species for which there is insufficient scientific information to support status designation. * Formerly described