Systematic planning for river rehabilitation: integrating multiple ecological and economic objectives in complex decisions

Abstract

1. Owing to intensive human use, freshwaters are among the most seriously threatened and modified environments on the planet. Their poor condition and the risk to services that humans need from these ecosystems make their rehabilitation a priority. However, many previous studies have reported the poor performance of many rehabilitation activities. 2. Here, we analyse reasons for this poor performance, focussing on the planning of rehabilitation activities, and propose a new approach. We argue that the failure to include driving factors at a scale adequate to capture the ecological processes involved, together with an insufficient incorporation of socio-economic aspects, is a key factor leading the poor performance of many rehabilitation activities. 3. We propose a new approach, 'systematic rehabilitation planning', that brings together advances made in conservation planning (cost-effectiveness analysis) and ecosystem science (understanding the complexity of ecosystem processes). This enables planning to be done at the catchment scale, and the trade-offs between various rehabilitation actions to be integrated and prioritised. 4. Finally, it is important, given the constraints imposed by a lack of knowledge, that the planning process is part of an adaptive cycle where it can benefit from and consolidate the experience gained during the implementation and monitoring stages.