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25. Wildlife Damage to Crops and Livestock AUTHORS: SUMMARY The Risk of Wildlife Damage (RWD) Indicator is currently being developed to gain a better understanding of the biophysical and management factors that influence wildlife damage to agricultural products across D. Thompson, C. Callaghan, L. Liggins and T. Weins Canada. This tool will also help us assess whether the actual risk of wildlife damage is increasing, decreasing or remaining stable, in each province. Creation of the Risk of Wildlife Damage Indicator entails the development of predictive models of damage risk that harness crop-yield loss data and spatial information on key factors known to influence the severity of wildlife damage, such as weather events, cropping practices, mitigation efforts, proximity of wildlife habitat and wildlife population status. Risk models, INDICATOR NAME: Risk of Wildlife Damage Indicator historical data and small-scale farm surveys will be used to plot recent trends in wildlife damage and predict the changes that may occur in the trends following the adoption of damage prevention measures. STATUS: Currently under development THE ISSUE Canadians appreciate the aesthetic, recreational, subsistence, intrinsic and ecological values of wildlife, and maintaining wildlife populations is a major environmental priority in Canada (Federal-Provincial-Territorial Task Force on the Importance of Nature to Canadians 2000). At the same time, there is a growing realization that the creation of conservation areas such as parks, wildlife management areas and forest reserves does not provide sufficient habitat to maintain desired wildlife populations. Agricultural land has the most fertile soils with the most favourable microclimates in the country and historically has supported many of Canada’s wildlife species. Even today, many wildlife species continue to use farmland to meet their needs. Agricultural producers across Canada enjoy living in proximity to wildlife and natural areas and recognize the importance of wildlife as much as other Canadians. Many of them invest time and money to enhance wildlife habitat on their land (Environics Research Group 2000). However, interactions between wildlife and agricultural activities can at times result in severe damage to agricultural products. Most wildlife species have a benign or even beneficial effect on agriculture (e.g. songbirds and raptors help control pests), but the relatively few species that feed on crops, stored feed or livestock can cause yield losses, livestock losses and damage to farm property. For example, deer and elk damage field (e.g. corn, alfalfa, soybean) and horticultural crops, as well as haystacks; waterfowl damage various crops (e.g. wheat, barley, lentils); birds such as starlings and blackbirds damage fruit crops; and some carnivores kill livestock. Wildlife damage on agricultural land is most often caused by wildlife species that are not at risk and may actually be abundant (Conover 2002). Although most producers tolerate some risk of damage in their daily operations, the actual level, predictability, extent and cause of wildlife damage vary widely among the provinces, farming regions and individual farms, as well as from year to year. In a survey conducted in 2000, 57% of rural landowners interviewed across Canada said that they had at some point experienced this type of damage in their operations. Many believe that wildlife activity and damage are on the rise (Environics Research Group 2000). THE INDICATOR The Risk of Wildlife Damage Indicator will be a tool for identifying the biophysical and management factors that influence the risk of wildlife damage to agriculture, modelling their relationships and determining whether the risk of damage is increasing, decreasing or remaining static over time. This risk can be expressed as a functional relationship between biophysical factors (weather conditions, density and F. Biodiversity 165 importance of each variable to the overall risk of wildlife damage and to rank the expected frequency of damage for a prescribed geographic area. Independent damage occurrence data and/or expert opinions will be used to validate the provincial-scale results. distribution of problem species, availability of off-farm and on-farm habitat), management factors (damage reduction efforts, type of production and the use of beneficial management practices) and occurrence of damage (Figure 25-1). CALCULATION METHOD LIMITATIONS The biophysical factors influencing wildlife damage are likely too complex and regionally variable to be integrated into a single model that would accurately or precisely estimate the amount of wildlife damage expected to occur in every region of Canada. Therefore, a series of wildlife damage risk models will be developed using damage data for specific wildlife classes (e.g., waterfowl, ungulates [such as deer], and predators) in several regions across Canada. Spatial data on biophysical factors and data from existing wildlife damage records or smallscale surveys of producers will be gathered to build the models. Then, statistical analyses will be performed to determine the relative With this indicator, damage risk assessment will be limited to wildlife such as ungulates, waterfowl, and predators, which are species that have historically been the focus of mitigation and compensation programs and a concern for producers and provincial wildlife managers. Initially, the Risk of Wildlife Damage Indicator will not address crop losses caused by invasive species or disease transmission between livestock and wildlife. It also will not cover crop damage caused by insects or rodents, although they may consume much more crop biomass than the waterfowl or ungulates. These components may be incorporated into a future version of the indicator. Figure 25-1: Conceptual model showing relationship among biophysical and management factors influencing the risk of wildlife damage On-Farm Habitat Quality & Quantity Beneficial Management Practices (BMPs) - Night penning livestock - Use of guarding animals - Border cropping - Lure cropping - Type of Production/ Cropping Systems - Farm Practices e.g. field/hedgerow management - Lands not in production e.g. woodlots, wetlands Risk of Wildlife Damage Weather Conditions - Late Spring/Early Fall - Time/Amount of Precipitation - Winter Severity Density/Distribution of Problem Species - Wildlife Management Practices - Population Demographics - Competition, Predation & Disease - Protected Species Off-Farm Habitat Quality & Quantity - Habitat Availability & Connectivity - Landscape Management - Habitat Enhancement - Protected Areas - Invasive Species 166 Environmental Sustainability of Canadian Agriculture: Agri-Environmental Indicator Report Series—Report #2 RESULTS This indicator is currently under development and results are not yet available. RESPONSE OPTIONS behavioural and life history characteristics, it is unlikely that any single method of damage prevention can guarantee success. Strategies employing several management techniques in an integrated approach are likely to be the most effective means of reducing damage (Ontario Soil & Crop Improvement Association 2000). Once this indicator comes on stream, it will aid in assessing the effectiveness of management strategies for reducing wildlife damage on agriculture and increase understanding of the factors that influence success. Socio-economic and political factors influence perceptions of damage and the approaches that are adopted to deal with wildlife damage. Consequently, strategies to reduce wildlife damage on farmland must reflect the diverse facets of the problem and they should be grounded in a broader economical, ecological and sociological context (Reed 1991). In the past, widespread REFERENCES lethal control programs (e.g. kill permits for Conover, M.R., 2002. Resolving Human-Wildlife ducks, poisoning of wolves) were commonly Conflicts: The Science of Wildlife Damage used to reduce wildlife damage to agriculture. Management. Lewis Publishers, Boca Raton However, this approach became increasingly (Florida). unpalatable to the public, and as societal values changed over Environics Research Group, time, lethal methods gradually 2000. Survey of Farmers, Ranchers gave way to non-destructive The Risk of Wildlife and Rural Landowners: Attitudes methods. Producers can now and Behaviours Regarding Land Damage Indicator will lessen the susceptibility of Stewardship. ERG, Toronto be a tool for identifying their farms to wildlife damage (Ont.). the biophysical and through a variety of beneficial Federal-Provincial-Territorial farm management practices management factors Task Force on the Importance such as production system that influence the risk of Nature to Canadians, 2000. decisions, habitat management, of wildlife damage The Importance of Nature to harvesting practices and Canadians: The Economic damage prevention measures, to agriculture. Significance of Nature-related including: Activities. Environment Canada, • fencing or border cropping with unpalatable Ottawa (Ont.). crops for large ungulates; Ontario Soil and Crop Improvement • visual and audio scare devices or lure crops Association, 2000. Wildlife Impact Assessment for waterfowl; for Ontario Agriculture. OSCIA, Guelph (Ont.). • the use of husbandry practices such as night penning, calving close to farm; • use of fencing, buildings and guardian animals to reduce livestock depredation by carnivores. Wildlife management agencies can also mitigate the susceptibility of farmland to wildlife damage through wildlife and habitat management efforts, targeted lethal control of carnivores and various prevention programs. Given the different damage-causing species and their diverse Reed, A., 1991. “Management of Greater Snow Geese in Relation to Crop Damage: the Need for a Diversified and Integrated Approach”. Pages 93-100 in M. Van Roomen and J. Madsen (eds), Waterfowl and Agriculture: Review and Future Perspective of the Crop Damage Conflict in Europe, proceedings of the ‘Farmers and Waterfowl: Conflict or Coexistence’ Workshop in Lelystad, Netherlands. Wetlands International, Publication No. 21, Slimbridge (U.K.). F. Biodiversity 167