Spatial cost-benefit analysis of blue restoration and factors driving net benefits globally.

Abstract

Marine coastal ecosystems, commonly referred to as blue ecosystems, provide valuable services to society but are under increasing threat worldwide due to a variety of drivers, including eutrophication, development, land use change, land reclamation, and climate change. Ecological restoration is sometimes necessary to facilitate recovery in coastal ecosystems. Blue restoration (i.e. in marine coastal systems) is a developing field, and projects to date have been small scale and expensive, leading to the perception that restoration may not be economically viable. Here, a global cost-benefit analysis was conducted to determine the net benefits of restoring coral reef, mangrove, saltmarsh, and seagrass ecosystems, where the benefit is defined as the monetary value of ecosystem services. We found that benefits outweigh costs (i.e. there are positive net benefits) for restoration of all blue ecosystems. Mean benefit: cost ratios for ecosystem restoration were higher than prior studies, most likely due to more recent lower cost estimates used. Among ecosystems, saltmarsh had the highest net benefits followed by mangrove, with lower net benefits for coral reef and seagrass ecosystems. In general, restoration in nations with lower incomes had higher net benefits than those with higher incomes. Within an ecosystem type, net benefit varied with restoration technique (coral reef and saltmarsh), ecosystem service produced (mangrove and saltmarsh), and project duration (seagrass). These results challenge the perceptions of the low economic viability of blue restoration and should encourage further targeted investment in this field. This article is protected by copyright. All rights reserved.