Assessment of the potential for negative interaction between re-introduced elk (Cervus elaphus) and resident white-tailed deer (Odocoileus virginianus) in their wintering areas in Ontario, Canada

Attempts have been made to reintroduce elk (Cervus elaphus) in Ontario, Canada, since the early 1900's. These efforts are on-going and current plans are to establish viable elk populations in 6 pre-selected restoration sites in Ontario. Significant populations of white-tailed deer (Odocoileus virginianus) exist in close proximity to some of the proposed restoration sites. Therefore a decision was made to assess the potential impact of restoring elk in white-tailed deer wintering areas in Ontario, prior to the release of elk. The primary concerns regarding white-tailed deer/elk competition are transmission of the meningeal worm (Parelaphostrongylus tenuis) from white-tailed deer to elk and the winter carrying capacity of habitat where the restoration is to occur. A review of existing data revealed that significant winter concentrations of white-railed deer do exist in the vicinity of the Haliburton Highlands elk release site in Southern Ontario. However, that proposed release site is at least 10 km from white-tailed deer wintering areas and restrictive winters occur infrequently in that area. A review of the literature, as well as interviews with Provincial and State biologists and elk managers revealed that although there was anecdotal evidence of competition between elk and white-tailed deer in a few jurisdictions, there was neither quantitative nor qualitative data to support or refute those claims. However, as snow depths increase and elk switch to browse dominated diets, there is potential for white-tailed deer/elk competition for resources if sharing the same winter range, especially during severe winters. The chances that elk and white-tailed deer will share the same winter range will depend on where the released elk decide to settle for the winter, which may be influenced by availability of unused winter habitat and the quality of the available habitat. Therefore, elk will not be released directly into traditional white-tailed deer wintering areas in Ontario. A comprehensive research and monitoring program will be mandatory for future elk releases in Ontario.