Overview on Mangrove Forest Disaster Prevention and Mitigation Functions

This paper provides a comprehensive overview on coastal protection and hazard mitigation by mangroves.Previous stud-ies have made great strides to understand the mechanisms and influencing factors of mangroves’protection function,including wave energy dissipation,storm surge damping,tsunami mitigation,adjustment to sea level rise and wind speed reduction,which are sys-tematically summarized in this study.Moreover,the study analyzes the extensive physical models,based on indoor flume experi-ments and numerical models,that consider the interaction between mangroves and hydrodynamics,to help our understanding of mangrove-hydrodynamic interactions.Additionally,quantitative approaches for valuing coastal protection services provided by man-groves,including index-based and process-resolving approaches,are introduced in detail.Finally,we point out the limitations of previous studies,indicating that efforts are still required for obtaining more long-term field observations during extreme weather events,to create more real mangrove models for physical experiments,and to develop numerical models that consider the flexible properties of mangroves to better predict wave propagation in mangroves having complex morphology and structures.

Adaptation Decision Support: An Application of System Dynamics Modeling in Coastal Communities

This research develops and applies a system dynamics(SD) model for the strategic evaluation of environmental adaptation options for coastal communities. The article defines and estimates asset-based measures for community vulnerability, resilience, and adaptive capacity with respect to the environmental, economic, social, and cultural pillars of the coastal community under threat. The SD model simulates the annual multidimensional dynamic impacts of severe coastal storms and storm surges on the community pillars under alternative adaptation strategies.The calculation of the quantitative measures provides valuable information for decision makers for evaluating the alternative strategies. The adaptation strategies are designed model results illustrated for the specific context of the coastal community of Charlottetown, Prince Edward Island, Canada. The dynamic trend of the measures and model sensitivity analyses for Charlottetown—facing increased frequency of severe storms, storm surges, and sea-level rise—provide impetus for enhanced community strategic planning for the changing coastal environment.This research is presented as part of the International Community-University Research Alliance C-Change project ‘‘Managing Adaptation to Environmental Change in Coastal Communities: Canada and the Caribbean'' sponsored by the Social Science and Humanities Research Council of Canada and the International Development Resource Centre.

Identifying ecological risk and cost-benefit value for supporting habitat restoration:a case study from Sansha Bay,southeast China

Background Coastal wetlands with high biodiversity and productivity provide essential ecosystem services that have a significant positive socio-economic impact.However,coastal reclamation,pollution,and climate change are threatening coastal wetlands.Thus,it is critical to identify priority areas for restoration and improve habitat resilience to adapt to environmental changes.Here,we propose a general analysis framework integrating nature-based solutions(NbS)into habitat restoration to increase coastal resilience to multiple stressors in Sansha Bay,southeast China.Results The total loss of value in ecosystem services due to reclamation in Sansha Bay was US$162.18 million from 2000 to 2015.The coastal habitats were at medium risk of degradation,with some high-risk areas concentrated in the northwest and along the west coasts,which were prioritized for restoration.Conclusions Our proposed framework,which integrates hard and soft engineering such as mudflat renovation,mangrove afforestation,and an ecological seawall,can aid in the improvement of coastal resilience.The project cost was US$12.71 million and was estimated to generate US$36.75 million in environmental services.We recommend evaluating and monitoring shoreline changes,environmental factors,and marine biological resources using longterm sampling surveys and remote sensing methods.Our findings can serve as a guide for government decisionmaking in coastal restoration planning and management.

Marsh persistence under sea-level rise is controlled by multiple,geologically variable stressors

Introduction:Marshes contribute to habitat and water quality in estuaries and coastal bays.Their importance to continued ecosystem functioning has led to concerns about their persistence.Outcomes:Concurrent with sea-level rise,marshes are eroding and appear to be disappearing through ponding in their interior;in addition,in many places,they are being replaced with shoreline stabilization structures.We examined the changes in marsh extent over the past 40 years within a subestuary of Chesapeake Bay,the largest estuary in the United States,to better understand the effects of sea-level rise and human pressure on marsh coverage.Discussion:Approximately 30 years ago,an inventory of York River estuary marshes documented the historic extent of marshes.Marshes were resurveyed in 2010 to examine shifts in tidal marsh extent and distribution.Marsh change varied spatially along the estuary,with watershed changes between a 32%loss and an 11%gain in marsh area.Loss of marsh was apparent in high energy sections of the estuary while there was marsh gain in the upper/riverine section of the estuary and where forested hummocks on marsh islands have become inundated.Marshes showed little change in the small tributary creeks,except in the creeks dominated by fringing marshes and high shoreline development.Conclusions:Differential resilience to sea-level rise and spatial variations in erosion,sediment supply,and human development have resulted in spatially variable changes in specific marsh extents and are predicted to lead to a redistribution of marshes along the estuarine gradient,with consequences for their unique communities.