The Cost-Effectiveness of Biodiversity Conservation in Agricultural Landscapes

Abstract

The worsening global biodiversity crisis combined with limited resources for conservation makes the prioritisation of cost-effective actions critical, particularly in agricultural landscapes where multiple conservation actions are available that vary widely in their effectiveness and cost. In such situations, understanding the complexities and drivers of the cost-effectiveness can improve the efficiency and effectiveness of future conservation investments. In this thesis I present the results of a multidisciplinary investigation of cost-effectiveness in the conservation of biodiversity in agricultural landscapes, focussing on two key themes. The first involved the cost-effectiveness of agri-environment schemes, where farmers receive financial incentives for biodiversity outcomes, a major policy mechanism that accounts for billions of dollars in public conservation expenditure globally. I include three chapters (Papers I-III) from a book I cowrote and edited on the lessons learned from agri-environment schemes in Australia, in which I discuss the various environmental and economic factors that influence cost-effectiveness. I applied the principles and practices identified through this research in an evaluation of the costeffectiveness of an Australian agri-environment scheme (Paper IV). I found that the total cost per hectare of habitat restored through the scheme was less than half that achieved using conventional designs such as windbreak plantings. Despite such clear benefits of considering cost-effectiveness, through a review of the global agri-environmental literature I show that the integration of economic factors in evaluations of biodiversity outcomes is still lacking and shows little evidence of improving; fewer than 15% of the 239 studies reviewed include any measure of cost-effectiveness (Paper V). The second key theme emphasized the equal importance of combining appropriate measures of effectiveness with detailed financial costs, and focused on two specific actions commonly employed in the conservation of birds in agricultural landscapes: revegetation of cleared land, and the passive restoration of remnant vegetation. Through field evaluations of 84 habitat restoration sites in southeastern New South Wales, I found significantly higher gains in bird species richness, including woodland birds, following revegetation than those from protection of remnant vegetation (Paper VI). Despite the higher cost of revegetation, I show the superior cost-effectiveness of this approach where remnant vegetation is unlikely to cleared under the counterfactual (Paper VII) and the strong influence of site design factors such as geometry in determining cost-effectiveness. In another study (Paper VIII), I demonstrate improved cost-effectiveness of habitat restoration through the integration of economic data in a systematic conservation planning approach that accounted for the temporal dynamics of threatened birds. The third theme explored the potential environmental and social benefits of the adoption of broader economic principles and techniques in the planning of ecological restoration (Paper IX). Combined, this research reveals the many factors that influence the financial costs of conservation on agricultural land and the complex interactions with ecological factors that influence the overall cost-effectiveness. It also highlights the relative simplicity of the economic evaluation techniques available, and showcases the conservation benefits that can be achieved through the improved collection and integration of financial costs and biodiversity benefits in the planning of conservation expenditure.