Mangrove forests in South Asia provide essential ecosystem services to the regions dense coastal population, and they support important functions of the biosphere. They are under threat, however, from natural and anthropogenic forces. Scientific understanding of rates, patterns, and causes of mangrove cover change and resulting impacts on ecosystem services is limited for the region. To help fill this gap, we propose a three-year project to examine mangrove cover change from 1985 to the present in Bangladesh, India, Myanmar, Pakistan, and Sri Lanka, and to assess the consequences for two globally important ecosystem services, carbon sequestration and biodiversity conservation. We will:
Objective 1: develop an operational methodology for annual monitoring of mangrove cover changes;
Objective 2: create a comprehensive database of annual mangrove cover changes from 1985 to the present at 30 m resolution;
Objective 3: quantify the impacts of mangrove cover changes on carbon stock changes and species extinction risks on an annual basis from 1985 to the present; and
Objective 4: analyze the effectiveness of existing mangrove protection programs, and prospective cost-effective expansions of them, in reducing carbon emissions and species extinctions.
The project will integrate research in remote sensing, conservation biology, and environmental economics. Research to achieve the first two objectives will emphasize analysis of Landsat data. We will preprocess Landsat data using a new automated algorithm, and we will evaluate three approaches for classifying the annual mosaic. We will compare the approaches using interpreted high resolution satellite data and field survey data from four sites and select the most accurate ones for the annual change analysis.
For the third objective, we will estimate carbon stock changes by combining area data from the mangrove cover change database with carbon densities per unit area. We will use meta-analysis to estimate the latter, and we will value carbon stocks changes using published estimates of the social cost of carbon. We will investigate mangroves role in biodiversity conservation by using data from the mangrove cover change database to assess how much original forest remains and how fragmented it is, and down-scaled species range maps to determine which areas have the most endemic species facing the greatest extinction risks as a result of habitat loss and fragmentation.
For the fourth objective, we will build on the other research and conduct three types of economic studies: conventional retrospective evaluations of the impacts of protection programs on avoided mangrove deforestation and degradation in all five countries; and, for Bangladesh and India, novel retrospective evaluations of the impacts of protection on carbon sequestration and biodiversity conservation, and prospective analyses of new mangrove areas to protect in order to cost-effectively enhance carbon sequestration and biodiversity conservation.
Duke University and the United States Environmental Protection Agency will implement the project in collaboration with researchers at South Asian institutions. The project team is well-positioned to implement the project successfully given the team members prior collaborations and complementary expertise. We will disseminate results to the research community in the usual ways (publications, seminars, conferences), generating at least six peer-reviewed publications in high-impact journals. We will use policy briefs and newsletters to reach national authorities responsible for mangrove protection decisions and national and international authorities working on financial mechanisms for conservation (e.g., carbon payments). We will build capacity in research and applications by involving junior researchers in the project, integrating findings into courses we and our collaborators teach, and linking the project to a nascent South Asia Regional LCLUC Initiative.