A quantitative approach for the design of robust and cost-effective conservation policies under uncertain climate change: The case of grasshopper conservation in Schleswig-Holstein, Germany.

Climate is a major determinant of the world's distribution of biodiversity and species ranges are expected to shift as the climate changes. For conservation policies to be cost-effective in the long run these changes need to be taken into account. To some extent, policies can be adapted over time, but transaction costs, lock-in effects and path dependence limit the extent to which such adaptation is possible. Thus it is desirable that conservation policies be designed so that they are cost-effective in the long run even without future adaptations. Given that the future climate change is highly uncertain, the policies need to be robust to climatic uncertainty. In this paper we present an approach for the robustness analysis with regard to the cost-effectiveness of conservation policies in the face of uncertain climate change. The approach is applied to the conservation of a grasshopper species in the German federal state of Schleswig-Holstein. For the assessment of the cost-effectiveness of considered policies we develop a climate-ecological-economic model. We show that in the near future all considered policies have a similar level of robustness, while in the more distant future the policies differ substantially in their robustness and a trade-off emerges between the expected performance and robustness of a policy.