Managing basin-wide ecosystem services using the bankruptcy theory

Bankrupt ecosystems are those that cannot appropriately provide all their ecosystem services. In this paper, a novel bankruptcy-based methodology is developed to manage ecosystem services. To test the applicability of the developed methodology, it is used in the Zarrinehrud river basin in Iran. First, an integrated framework is used to assess regulating, supporting, provisioning, and cultural ecosystem services of the study area under three climate change scenarios of Representative Concentration Pathway (RCP) 4.5, 6.0, and 8.5. Then, for each ecosystem service, an aggregated utility is calculated that takes into account the stakeholders' different opinions toward ecosystem services. The utilities of the ecosystem services show that the Zarrinehrud river basin is bankrupt. To manage this ecosystem, six bankruptcy methods of Adjusted Proportional, Constrained Equal Loss, Constrained Equal Award, Piniles, Talmud, and Hybrid are developed and used in the study area. In this study, the summation of ecosystem services' aggregated utilities under each management scenario is considered as an asset, and all mentioned bankruptcy methods are used to redistribute these assets to different ecosystem services. Considering aggregated utilities, redistributed utilities, and each ecosystem service's claim, two different Root Mean Square Error-based approaches are developed to find the most applicable management scenario in a bankruptcy condition. Using the mentioned approaches, management scenario 128, which is comprised of all management packages, is chosen as the best option under all climate change scenarios. This scenario includes projects such as improving cropping patterns, allocating water to the lake from new water resources, and rehabilitating irrigation and draining systems. Moreover, analyzing the results derived from different bankruptcy methods shows that the Talmud, Hybrid, and Constrained Equal Loss methods have the best performance.