Maximizing benefits for biodiversity: the potential of enhancement strategies in impact assessment

Our demands on natural systems outweigh the capacity of those systems to support us. This paper calls for an approach to development that consistently delivers 'net benefit' for biodiversity or 'ecological enhancement'. Examples of enhancement are presented through four case studies in India undertaken between 2005 and 2010. Actions focus on improving the overall ecological structure, composition and functions of sites; strengthening ecological networks by creating new habitats and buffer areas; and improving the services provided by the ecosystems, without jeopardizing biodiversity. While recognizing the importance of quantitative metrics of impacts and mitigation measures to determine outcomes, such measures were not available in these cases; enhancement is evaluated primarily in relation to pre-project conditions. The paper emphasizes the importance of considering alternatives that satisfy the mitigation hierarchy, and proposes a number of criteria for evaluating ecological enhancement.