Invasive species on British Columbia's grasslands: Estimating the benefits of control policies

Invasive species are among the most important drivers of biodiversity loss and changes in ecosystem services leading to substantial worldwide economic and ecological damages. The invasion of grasslands by non-native plant species imposes a wide range of costs on society; these costs are associated with a reduction in biodiversity, wildlife habitat loss, and impacts on recreational opportunities, amongst other ecosystem services. Damage reductions need to be examined when establishing control programs and public policy. Inadequate information on invasive plants’ economic impacts and the extent to which they affect human welfare has created a significant barrier to implementing comprehensive national invasive species management programs. This study examines people’s attitudes and perceptions of the problem of invasive plant species on grasslands in British Columbia (B.C.) using a choice experiment. The results of the choice experiment indicate how much respondents are willing to pay for various attributes of a control policy, such as location, method of control, and degree of control for invasive plant species in B.C. It also determines how much respondents are willing to pay for different policy packages(combinations of the control attributes) to control invasive plant species. Results from 1,000 respondents across B.C. indicate serious concern and a willingness to pay to control the problem. Preference is given to control everywhere in the interior of B.C. (where most grasslands are located) relative to only control in sub-regions of the interior. Biological and targeted grazing are preferred to chemical spraying and moderate or major eradication relative to minor eradication. Estimates indicate that, at the minimum, British Columbians are willing to pay around CDN$200 million per year in extra taxes to control invasive plant species everywhere in the interior of B.C. with a moderate or major eradication over the next decade using chemical spraying. Using biological or targeted grazing, the valuation doubles to around CDN$400 million annually. These values are estimates of the aggregate benefits of controlling invasive species in B.C.’s grasslands, but not the costs of controlling nor the productivity of the control measures, which would be needed to conduct a cost-benefit analysis. Furthermore, to bridge the gap between public preferences and experts’ opinions regarding priorities in invasive species control programs, the survey was circulated to a group of experts and stakeholders and the results were contrasted with the results of the public survey. Lastly, the thesis provides a coherent framework for the sustainable prevention and management of non-native invasive plants in B.C