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Project Title: Patterns of Biodiversity and Climate Change Impacts in the Bahamas: Data to Support the Planning of Marine Reserves Description: This project will support the Bahamian government’s decision making process to select new areas for marine reserves in their territorial waters. It will involve in-depth analysis of data previously collected in and around the Bahamas Islands on biodiversity, fisheries habitat, and the impacts of hurricanes and climate change. Outcomes of the project are expected to have a significant impact on the marine reserve site selection process and will result in a more sustainable network of marine reserves in the Bahamas. Deliverable outcomes, implications and methods: The Bahamas Archipelago is a massive system covering thousands of kilometers. A national habitat map underpins many conservation activities including setting a base map for a GIS, demarcating management zones and marine reserves, providing a general map of biodiversity, and forming a basis for a sophisticated conservation model. Upon completion of this project, the Living Oceans Foundation’s online Geographic Information System (GIS) will have a new Bahamas interactive portal built around the national-scale habitat map. Reefs with prolific mangrove access have a greater supply of several commercially-important fishes and increased levels of grazing that are thought to improve the reef’s recovery from hurricanes and bleaching events. Examples of outputs from this project that will serve to inform management activities and the design of a national network of marine reserves are: a) Areas of reef that have greatest fisheries and grazing productivity. Such areas should be prioritized within a reserve design as they have maximum chances of being sustainable even if the reserves are small. b) Critical mangrove habitats that offer nursery habitat functions. These areas should be conserved (rather than developed for tourism) as they are exceptionally important to coral reefs. c) Priority sites for mangrove reforestation. Restoration activities that occur after major hurricanes or in response to coastal development should prioritize where mangroves are planted. The algorithm will identify those sites which – if restored – would offer the greatest value to the reef ecosystem as a whole. 3) Ranking of marine habitats for biodiversity conservation Currently, managers aim to represent 20% of each habitat in a reserve which implicitly assigns equal importance to each habitat. However, using our data on the composition of species in each habitat, we can provide a more appropriate weighting, identifying the minimal set of habitats needed to represent all species. Firstly, a report will be prepared ranking the relative importance of each habitat for protecting species in the Bahamas. Such information is useful when providing a case against a particular activity that may damage specific habitats. Secondly, the species lists’ are available for inclusion in reserve selection algorithms. Adding a detailed species list to The Nature Conservancy’s reserve selection algorithm places greater priority on key reef habitats and increases the chance that the reserve network will meet its aim of protecting biodiversity. 4) Location of biodiversity hotspots Two previous grants from the Living Oceans Foundation have enabled the University of Exeter to develop the World’s first method for mapping hotspots of beta diversity in 2-dimensions. A desirable aspect of the method is that it combines both the field knowledge of species in each habitat with the larger-scale information on habitat distribution available from remote sensing. Moreover, it allows beta diversity – which is an important level of biodiversity – to be mapped and monitored at meaningful scales for conservation and marine reserve design. Maps of beta diversity will help conservation efforts by identifying some of the richest areas of the Archipelago for priority conservation. Such information will be particularly useful to local communities that are actively engaged in locating local marine reserves. 5) Risk of hurricane impacts on the reserve network Any form of conservation plan must consider catastrophic events and how to spread the risk of losing several key elements at once. There are two key large-scale threats to coral reefs of the Bahamas – hurricanes and mass coral bleaching. Essentially, the conservation planner must try to spread reserves so that not all reserve areas within a region (e.g. major Bahamian island) are in a damaged state at once. This requires some new and innovative research that fuses GIS analysis with ecological modeling. The aim of this research is to identify the minimal spacing among reserves that ensures that only one reserve in a region is in a depleted state (defined as having less than 10% coral cover) at any given time. First of all, the project needs a realistic model of hurricane tracks for the Bahamas and this is most accurately accomplished using the entire record for the past 150 years. A GIS of Bahamian hurricane tracks dating back to 1851 will be created from the archive held online by the National Hurricane Center. The result will be a map of hurricane impact for every year between 1851 and 2004. Following that activity, a program will be written to simulate the position and sizes of potential marine reserves in the Bahamas. Coral cover tends to increase in years without hurricanes and be set back when hurricane activity is great. The program can then track the number of ‘healthy’ versus ‘unhealthy’ reserves over time and look for designs that prevent multiple reserves being unhealthy in the same region. 6) Risk of coral bleaching due to global warming The second – and perhaps greater – threat to coral reefs of the Bahamas is coral bleaching. Bleaching occurs when sea temperatures become unusually warm during summer months and can cause massive coral mortality. However, some regions rarely experience very high sea temperatures because strong coastal currents rapidly disperse the warming waters. Knowing the location of such areas is useful in helping to spread the risk of multiple reserves being impacted simultaneously. Therefore the first aspect of this project component is to map patterns of Sea Surface Temperature (SST) throughout the Bahamas. This will be carried out in collaboration with NOAA’s Coral Reef Watch team. We anticipate producing 10 maps, one for each decade until 2100. Each map will display the number of bleaching episodes per decade, revealing firstly how these patterns vary in space and secondly how the frequency of bleaching changes over time. Lastly, the impacts of bleaching will be added to the coral reef simulation model and used to predict the future state of Bahamian reefs over the next century. The model simulations will identify the degree to which potential reserves are likely to withstand climate change and the degree to which protection of parrotfish in reserves is able to contribute to the sustainability of coral reefs. NOTE: No country has ever incorporated the effects of climate change into their planning of marine reserves and this project will set a global precedent. Summary of Anticipated Benefits to the Bahamas The Government of the Bahamas, in association with the Bahamas National Trust and The Nature Conservancy, has embarked on a plan to form a national network of marine reserves. A key aim of the plan is to ensure the sustainable protection of Bahamian biodiversity for future generations. However, without the expected outcomes of this project, it is not clear whether the planning process can meet its objectives. The planning process does not currently have a continuous map of biodiversity resources, it is unable to objectively prioritize protection to the most important habitats (from a biodiversity perspective), it cannot identify those areas that are richest in biodiversity, or those areas that are most productive. Moreover, there is no explicit plan to spread risks from hurricanes and global warming which will accelerate the incidence of coral bleaching events. This is not meant to criticize the agencies involved as these gaps in data require extensive resources and specialist expertise to fill. However, the proposed collaboration between Exeter and the Living Oceans Foundation should fill these gaps by providing the necessary GIS data and ancillary information (e.g habitat rankings, optimal reserve spacing to spread risk) to make the on-going planning process in the Bahamas much more effective. The Bahamas will become the first country to incorporate climate change into its planning for a sustainable network of marine reserves.
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