Social Vulnerability of Coastal Communities to Impacts of Climate Change on Coral Reef Ecosystems

Coral reefs play a central role in the economies of many coastal communities. Whether through fisheries or tourism, reefs contribute to the incomes and livelihoods of millions of people. For this reason, the impact of climate change on coral reef ecosystems consitutes a critical concern for governments and scientists alike. In this study, Cinner et al. examine the social vulnerability of fisheries dependent communities to changes to coral reef ecosystems. They focus on three dimensions of vulnerability, exposure, sensitivity, and adaptive capacity, in order to better gauge the source of vulnerability. They found that key sources of vulnerability differ considerably within and between the five countries studied. Additionally, this study illustrates how these differences differ from site to site, enabling the authors provide a framework of site-specific policy actions aimed at reducing different aspects of vulnerability.–Cecilia Ledesema
Cinner, J. E., T. R. McClanahan, N. A. J. Graham, T. M. Daw, J. Maina, S. M. Stead, A. Wamukota, K. Brown, and Ö. Bodin. 2012. Vulnerability of coastal communities to key impacts of climate change on coral reef fisheries. Global Environmental Change, 12−20.

            Josh Cinner from the ARC Centre of Excellence for Coral Reef Studies collaborated with various scientists to produce this study. Research was done between 2005 and 2006 at 29 sites located throughout Kenya, Tanzania, Seychelles, Mauritius, and Madagascar. Diverse sites were selected in order to provide a spectrum of social and environmental conditions. The data obtained for each site included: exposure, sensitivity, and adaptive capacity. Exposure was measured based on remote sensing data from an Indian Ocean scale stress model. Additionally, a predictive model of coral susceptibility to thermal stress and coral bleaching was used to determine exposure. The predictive model was based on past coral bleaching data and oceanographic conditions throughout the western Indian Ocean region. A systematic sampling design of 1564 households located in the 29 sites measured the level of dependence on fisheries, a metric of sensitivity. In addition, the data gathered from these household surveys were used to develop a social adaptive capacity index, specifying eight indicators of adaptive capacity. Two techniques were employed to examine vulnerability: an equation provided a quantitative vulnerability score; the three indices of vulnerability were plotted on a bubble plot, where sensitivity is plotted against adaptive capacity and the size of the points indicates exposure levels.
            The results from this study suggest that there is considerable spread of vulnerability both within and among the five countries. With a mean country level of exposure at 0.26, Mauritius had the lowest exposure. Meanwhile, Kenya and Seychelles experienced the highest exposure, at 0.58 and 0.57, respectively. Environmental conditions that contribute to high reef exposure include low temperature variability, high ultraviolet and photosynthetic radiation, high sea water temperature and low wind velocity. National-scale averages of sensitivity varied from a low of 0.10 in Seychelles to a high of 0.22 in Tanzania. Overall, the ten sites with the highest sensitivity were located in Tanzania, Kenya, and Madagascar. Seychelles and Mauritius were the countries with the highest adaptive capacity sites as well as highest overall national-level averages of adaptive capacity. At the national scale, Kenya had the highest overall vulnerability, followed by Tanzania, Madagascar, Seychelles, and Mauritius. The results for national-scale averages of local-scale vulnerability were largely consistent with national-scale studies of the vulnerability of national economies to the impacts of climate change on fishing.
            The authors used the abovementioned data to develop a policy framework at the local and national levels. Thus, they recommend specific policy tools to address different dimensions of vulnerability, accounting for varying temporal scales. Cinner et al. suggest that governments emphasize reducing the impacts on the most vulnerable in the short term, enhance adaptive capacity and reduce sensitivity in the medium term, and reduce exposure by mitigating climate change in the long term. At the local scale, efforts can include improved information about weather, evacuations from highly vulnerable areas, and diversification within the fishery. Additionally, strengthening community groups responsible for managing coastal resources would serve to decrease vulnerability. Meanwhile, national scale efforts to increase adaptive capacity include adaptation planning, improvement of coastal infrastructure, and investments in alternative energy and new industries. Cinner et al. stress that differing levels of exposure may have different implications for natural resource management. For example, high exposure areas where reefs will be damaged by climate regardless of resource management constitute poor targets for protected areas. The policy framework highlights specific measures to reduce vulnerability to the impacts of coral bleaching on fisheries.

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