Degradation, Ecological Restoration and Adaptive Management of Estuarine Wetlands under Intensifying Global Changes, volume II

Book excerpt: Estuarine wetlands play important roles in providing various ecosystem services, such as providing habitat for living organisms, preventing seawater intrusion, conserving biodiversity, regulating microclimate, and promoting nutrient cycling and carbon sequestration. Estuaries are home to many mega-cities, such as New York, San Francisco, Shanghai, and Tokyo, accompanied by frequent human activities. These human-induced disturbances have rapidly altered the structure and function of estuarine ecosystems through land reclamation, pollution, overfishing, and altered flows. Moreover, estuarine wetlands have been greatly threatened by intensifying global climate changes, particularly more frequent tsunamis, sea-level rise, and large-scale biological invasions, which will not only affect primary and secondary productivity, community composition and distribution, and biodiversity, but also natural ecohydrological and biogeochemical processes, and will ultimately disrupt ecosystem services. To mitigate such negative impacts, a growing number of estuarine wetland restoration projects have been undertaken in recent years. These projects aim to re-establish a variety of ecological attributes, including community structure (species diversity and habitat) and ecological processes (energy flow and nutrient cycling), which implies increased resilience and resistance of estuarine ecosystems to abiotic and biotic stressors. However, ecological restoration practices are not always satisfactory in the face of uncertainties from intensifying global changes and socioeconomic variation. Ecologists, biologists, environmentalists have been working on finding more effective solutions to restore degraded estuarine wetland ecosystems on a global scale. The concepts of “nature-based solutions”, “adaptive management” or “ecological networks” seem to offer better prospects and are now being used to reframe estuarine restoration on critical uncertainties reduction, climate change adaptation, and mitigation strategies. As the world enters the United Nations Decade of Ecosystem Restoration (2021–2030), countries and organizations around the world will pay greater attention to the innovation of ecological restoration underpinnings to ensure that estuarine restoration achieves its full potential in delivering social and ecological coordination and, ultimately, sustainable development. Therefore, it is important to discuss how anthropogenic disturbances and climate change affect estuarine wetlands and how the latest restoration framework can guide future practices towards conserving and restoring the biodiversity of estuarine wetlands.