Cost-effective policy instruments for biodiversity conservation under climate change – The need for flexibility

Climate change is one of the main threats for biodiversity. As it affects the ecological and economic system, conservation costs and impacts may change in a heterogeneous manner. This implies that cost-effective conservation sites and measures may no longer be so in the future. We investigate spatial flexibility (to adapt the location of conservation sites) and management flexibility (to adapt the conservation measures on those sites) as novel criteria for analysing the cost-effectiveness of policy instruments to conserve biodiversity under climate change. We develop a generic climate-ecological-economic modelling approach that captures the role of spatial and management flexibility to assess the cost-effectiveness of policy instruments. We apply the modelling approach to the conservation of an indicator species in agricultural grasslands in a case study area in Northern Germany, and compare the cost-effectiveness of the policy instruments of land purchase (low spatial flexibility, high management flexibility) and long-term individual conservation contracts (medium spatial and management flexibility) considering a period from 2020 to 2079. We find that both spatial and management flexibility matter in the case study and discuss their broader relevance for conservation in a changing climate.