Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract Full Text

Economic tools ≠ Policy actions. Why benefit cost analyses are not a policy panacea for weedy but commercially valuable plant species.


Both governments and industry have highlighted the need to accurately identify and prioritise the positive and negative impacts of plants that are both weedy and commercially valuable. The introduction and subsequent naturalisation of such species results in conflict between members of the community: between those who derive benefits or positive impacts from the plant; and those who pay for the negative impacts that the plant may cause. Even when such impacts can be accurately identified, the prioritisation of conflicting impacts is mired by competing and conflicting values. A range of economic tools have been proposed as one panacea to this policy conundrum. Foremost among these are benefit cost analyses. This paper examines the reasons why this economic tool fundamentally fails to address this situation. While society is familiar with pricing economic benefits and loss, and increasingly the benefit of positive ecosystem services such as nitrogen fixation, it is often nearly impossible to identify and cost both direct negative environmental impacts such as the loss to biodiversity and indirect positive environmental impacts such as human well-being. While research can provide guidance as to what many of these values may be, it is both economically and temporally costly. Even if the positive and negative impacts are properly researched or intelligently assigned/assumed, what the outcome means in a policy (and political) context is far less clear, giving little real guidance about how best to manage these plants. It is proposed that a fundamentally different process or system of evaluation is needed, one that can deliver robust answers based on available evidence, that highlights information deficiencies and that is clearly linked to weed management policy tools. Post-border Weed Risk Management (WRM) systems already address these issues when they examine the negative impacts of weeds on economic, environmental and social values. This paper proposes combining elements of a system that assesses positive impacts or utility (Walton unpublished) with WRM systems resulting in a decision support model to guide policy and management of weedy but commercially valuable plant species.