99 research outputs found

    Reclamation Outcomes on Energy Disturbances in Silver Sagebrush Communities

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    Bibliography: p. 255-272Some pages are in colour

    Annual migrations of female prairie rattlesnakes, Crotalus v. viridis, in Alberta.

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    Bibliography: p. 53-61Some pages are in colour

    A conceptual model of tuberculosis transmission risk in free-ranging bison herds of northern Canada

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    Tuberculosis transmission in free-ranging bison of northern Canada is of significant concern to wildlife managers because of its effects on condition and mortality in bison herds and the potential for transmission to local hunters and neighbouring cattle populations. The chronic nature of tuberculosis combined with the gregarious behaviours of bison permit its persistence in free-ranging herds even at low densities, which makes disease eradication difficult without whole herd depopulation. The protection of remaining non-infected free-ranging bison populations is thus of paramount importance to the conservation of specific disease-free wild bison in northern Canada and to the economic stability of cattle farms. Detection of movements and removal of dispersing animals between spatially separated free-ranging populations reduces the potential for contact between bison populations and minimizes the probability of tuberculosis transmission. In this thesis, a conceptual model was developed to assess the potential for tuberculosis transmission between two infected bison herds (Nyarling River and Garden River) in Wood Buffalo National Park and the spatially separated, Mackenzie Bison herd in the Northwest Territories. This conceptual model identifies gaps in knowledge and highlights areas where research is required to ensure accurate evaluation of tuberculosis transmission risk in freeranging bison. The main finding was that the bison cohort representing the highest risk for tuberculosis transmission between spatially separated free-ranging herds is mature males. The propensity of mature males to make long-distance movements is also not fully understood and research to predict these movements would make a significant contribution to risk assessment and management planning to reduce the probability of contact between infected and non-infected bison populations

    Wolf Depredation Trends and the Use of Fladry Barriers to Protect Livestock in Western North America

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    In Alberta, Canada (1982-2001), and in Idaho, Montana, and Wyoming, United States (1987-2001), wolves (Canis lupus) killed various domestic animals, among which the major prey were sheep in the United States (68%, n = 494) and cattle in Canada (95%; n = 1633). Under recovery programs, the wolf population increased in the United States, and depredation events increased proportionately. In both countries, the number of domestic animals killed each year was correlated with the number of wolves killed by government authorities for depredation management. We tested the ability of anti-wolf barriers made of flags hanging from ropes to impede wolf access to food and livestock. In 18 experiments, barriers prevented captive wolves (n = 9) from accessing food for up to 28 hours and allowed daily separation of wolves to administer contraceptive pills to a female wolf. Barriers prevented access by wild wolves to 100-m2 baited sites during two 60-day tests. We also set barriers around three cattle pastures. In Alberta during two 60-day trials on 25-ha pastures, wolves approached barriers on 23 occasions but did not cross them, and no cattle were killed. Wolves killed cattle on neighboring ranches during the trials and before and after the trials on the tested ranches. In Idaho four radio-collared wolves crossed barriers and killed cattle in a 400-ha ranch after 61 days of barrier exposure. Our results suggest that anti-wolf barriers are effective in deterring captive and wild wolves for \u3e1 and ≥60 days, respectively, and that wild wolves switch to alternative livestock when excluded from one herd of livestock. Our depredation data indicate that protecting livestock from wolves reduces the necessity for killing wolves. Barriers could play a role among the limited set of preventive measures available and offer a cost-effective mitigation tool for the problem of livestock depredation on a local scale

    Anthrax

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