Determining mussel restoration success: An Australasian case study

Abstract

Restoration is becoming an increasingly common management tool to aid in recovering degraded, damaged, or destroyed ecosystems. Developing and adopting best practices are valuable for maximising restoration efficiency. This frequently includes using natural reference sites to guide restoration goals and target setting, as well as assessing restoration success. Natural reference sites are representative of an ecosystem that has not experienced intense degradation and provides a basis for the conditions that restoration is aspiring to achieve. However, in the instance of mussel reefs, historical overharvesting and habitat degradation have led to a widespread decline in natural reefs, with few natural sites remaining. While mussel restoration is receiving increased efforts, the absence of reference conditions has resulted in many projects lacking clearly defined and achievable restoration goals. This study aims to improve the efficiency of mussel restoration by developing example restoration goals and a theoretical reference system. A broad range of restoration goals are proposed in line with associated ecosystem services, which restoration practitioners can adapt and apply depending on specific project objectives. A dynamic theoretical reference system for mussel restoration is also developed using knowledge of past reefs, observations from remaining reefs, and anticipated future conditions. Two case studies of the application of restoration goals and the theoretical reference system are provided for mussel restoration projects within New Zealand and Australia. This research provides guidance for restoration practitioners to effectively plan and assess progress of restoration, in line with project goals and targets.