Analysis of the Economic Value and Status of the Ecosystem Services Provided by the Ashtamudi Wetland Region, a Ramsar Site in Kerala

摘要

Wetlands provide critical services such as protection against flooding and wave action, water quality maintenance, habitat provision, food products, etc. Ashtamudi is the second-largest wetland ecosystem in Kerala state, and it provides numerous ecosystem services (ES). This study has analysed the economic value and current status of 11 important ES provided by this wetland. The considered services are fish production, clam production, shrimp/prawn larvae production, inland navigation, coir production, carbon sequestration and erosion prevention provided by mangroves, flood protection, cooling effect, tourism and future use-value. The total economic value of the wetland by considering the aforementioned services is 424 million US$ (in terms of 2017 International $ value), and every hundred square metres of the wetland provides an economic output of 820 US$ per year approximately. Even though the valuation of a few ES has been carried out in earlier studies, this particular study has incorporated more services in valuation and analysed the change in its value compared to previous years. This study also tried to analyse the status of 'wetland features' essential for the sustenance of ES, the spatial changes of the service providing habitats, and its impact on ES delivery. The study has been carried out in a GIS framework using inputs from various sources including remote sensing (RS) data. Landsat imageries and digital elevation model of the study area are used to understand the economic value and current status of certain services. Analysis, such as spatial change of service providing habitats, shoreline alterations, changes in NDVI of selected locations is carried out by utilizing the aforementioned RS data. Compared to the previous years, the value of supporting and regulating services is declining. At the same time, the value of certain provisioning and cultural services is improving. As the supporting and regulating services are the prerequisites for all other ES to sustain, the current trend indicates a collapse of the entire system shortly. While addressing this issue, more priority has to be given in restoring antecedent wetland condition, which will indeed lead to the improvement of supporting and regulating ES. Community-based institutional mechanisms have to be developed to ensure consistent monitoring and maintenance of the wetland.