The Use of GIS in Sea Turtle Conservation

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1 Elissa Monahan NRS 509 Dec. 4 th, 2012 The Use of GIS in Sea Turtle Conservation There are seven sea turtle species found in waters throughout the world, and while these marine reptiles date back to prehistoric times, their populations today are at risk. The six species found in U.S. waters (green, hawksbill, Kemp s ridley, leatherback, loggerhead, and olive ridley) are all protected under the Endangered Species Act. The seventh species (flatback) is only found in Australia, but is protected under Australian law. Because they are slow maturing, migrate long distances, and use a variety of habitats throughout their life cycles, sea turtles can be challenging to study. However, the use of GIS technologies has advanced our ability to learn about these species and to collect and analyze data that can further conservation efforts. Studies of sea turtles through the use of GIS have looked at both their nesting and oceanic habitat. These studies can be classified into two broad categories, the first being range and habitat use and the second being threat assessments. Data on range and habitat use is largely obtained by attaching satellite transmitters to the carapaces of sea turtles, which allows researchers to track sea turtles movements. When entered into a GIS, the data collected from satellite transmitters can be used to map migration paths and range extent for different sea turtle species. Researchers have also overlaid GPS data collected from satellite transmitters with data showing ocean temperature gradients in order to identify important foraging habitats. GIS can be used to monitor sea turtle nesting habitat as well. Collecting GPS locations of sea turtle nests each nesting season allows monitoring programs on nesting beaches to develop databases that can show shifts and fluctuations in sea turtle nesting activity over time. In the conservation of any species, it is necessary to understand the ecology of the species under consideration. GIS technologies have made it feasible to collect data on sea turtle range and habitat use which is otherwise difficult to obtain and often limited to chance encounters. Using GIS to analyze this type of data can provide valuable insight into sea turtle population dynamics and critical habitat. This information about sea turtle ecology provides a strong foundation for sea turtle conservation. GIS has not only been useful in furthering our understanding of sea turtle range and habitat use, but has also become an important tool in assessing threats to sea turtle populations. The same aspects of sea turtle biology that make them difficult to study (slow maturation, long migrations, and use of various habitats) also make sea turtle populations particularly vulnerable to certain threats. For example, their long migrations and use of different habitats increases the likelihood that portions of their range will overlap with human activities that could be detrimental, and because they are slow to mature, populations are in turn slow to recover. For these reasons, it is important to understand the threats that are faced by sea turtle populations today and GIS can help to accomplish this.

2 One threat to sea turtle populations around the world is the compound effects of sea level rise and coastal development. This poses a significant threat to sea turtle nesting habitat. Sea turtles nest in the area of beach between the high tide line and the base of the dunes. If the land behind the dune system is developed, the dunes are not able to migrate back as sea level rises, resulting in the loss of the nesting beach. Various studies have used GIS to create models of particular nesting beaches and examine the loss of nesting habitat at those sites under different scenarios of sea level rise. A number of small islands also serve as important nesting grounds and it is possible that sea level rise could make these islands disappear. Loss of nesting habitat will have significant effects on certain sea turtle populations. In order to protect these populations, data from GIS studies of sea level rise and nesting habitat should be incorporated in to coastal management programs. GIS can also be used to conduct spatial analyses comparing sea turtle density with activities, such as shrimping, that have negative impacts on sea turtle populations. Bycatch by fishing industries is another significant threat to sea turtles throughout the world s oceans. When data is collected on sea turtle abundance and intensity of fishery activity within a particular region, GIS can then be used to assign a score to specific zones based on both factors. This type of analysis is helpful in predicting areas where fisheries are most likely to have the greatest impact on sea turtle populations. GIS technologies provide a practical way to collect and analyze data on species of sea turtle that are otherwise challenging to study on a global scale. These technologies have allowed researchers to gain valuable information on sea turtle ecology and to investigate the potential effects that various threats could have on sea turtle populations. As GIS technologies continue to evolve and become more accessible, the amount of data that can be collected on sea turtle populations will continue to grow. This data can be used to evaluate current management actions and conservation efforts and can help guide future decision making in areas that will greatly affect the survival of sea turtle populations worldwide.

3 Annotated Bibliography Eckert, S.A. High use oceanic areas for Atlantic leatherback sea turtles (Dermochelys coriacea) as identified using satellite telemetered location and dive information Marine Biology 149: Leatherbacks are the most endangered of the seven species of sea turtle, and documentation of habitat use by leatherbacks away from their nesting beaches is limited. In this study, Eckert used telemetry to track the post nesting migration movements of nine female leatherbacks. The turtles were tracked for up to 370 days and GIS software was then used to plot their movements and calculate high use areas. Eckert identified Galera Point as an important internesting area for female leatherbacks nesting in Trinidad. Identifying important areas such as Galera Point may be critical to the survival of this species. Eckert discusses plans to develop a port facility near Galera Point and uses his data to show that such development would have negative effects on leatherback populations. This study shows how GIS can be used to determine critical habitats for endangered species and how this data can be used to make future management decisions. Etnoyer, P., D. Canny, B.R. Mate, L.E. Morgan, J.G. Ortega Ortiz, and W.J. Nichols Seasurface temperature gradients across blue whale and sea turtle foraging trajectories off the Baja California Peninsula, Mexico. Deep Sea Research 53: Sea surface temperature fronts can be used to define different pelagic habitats, biological hotspots, and migration corridors, but information about what temperature gradients may be important to specific species is lacking. In this study, Etnoyer et al. used GIS technology and transmission coordinates from satellite tagged animals to analyze sea surface temperature gradients across sea turtle trajectories of the coast of Baja California. The aim of the study was to determine what temperate fronts are biologically relevant to sea turtles. Five species of sea turtle, all considered endangered, are found in the waters of Baja California and these same waters are also a hotspot for commercial fisheries. The authors found that the extended presence of sea turtles in regions with a high density of frontal features suggested that these areas represented important foraging grounds. While this paper includes a lengthy and technical methods section, the discussion demonstrates how GIS can be used to analyze how endangered species use different pelagic habitats, and how this type of information can help to set marine conservation priorities. Fish, M.R., I.M. Cote, J.A. Gill, A.P. Jones, S. Renshoff, and A.R. Watkinson Predicting the impact of sea level rise on Caribbean sea turtle nesting habitat. Conservation Biology 19:

4 This article by Fish et al. details how GIS was used to evaluate the potential impacts of sea level rise on the nesting habitats of four endangered species of sea turtle on the Caribbean island of Bonaire. Nesting data, beach profile measurements, and land use data for land behind nesting beaches was collected. ArcView was then used to create models of 13 nesting beaches. Three different scenarios of sea level rise were used to investigate the potential of beaches to accommodate shifts in nesting range. The authors demonstrated how GIS can be used as a tool to predict the combined effects of development and sea level rise on the nesting habitats of sea turtles, and how this information can be used to incorporate the protection of endangered species into coastal management plans. Fuentes, M.M.P.B., C.J. Limpus, M. Hamann, and J. Dawson Potential impacts of projected sea level rise on sea turtle rookeries. Aquatic Conservation: Marine and Freshwater Ecosystems 20: In this study, Fuentes et al. analyze the potential impacts of sea level rise on key rookeries for the northern Great Barrier Reef green turtle population. Beach profiles were measured and the amount of nesting area that would be inundated under three different SLR scenarios (from the IPCC 2007) was analyzed using ArcGIS. This paper differed from other studies that looked at the effects of sea level rise on nesting areas, because the rather than looking at one rookery for a particular population, the authors looked at eight different locations representing 99% of the nesting activity for the northern Great Barrier Reef green turtle population. The authors discussed possible ways that this nesting population may respond to SLR, and showed how their data could assist managers in prioritizing management actions in order to mitigate the potential effects of SLR on an ecologically important species. Karavas, N., K. Georghiou, M. Arianoutsou, and D. Dimopoulos Vegetation and sand characteristics influencing nesting activity of Caretta caretta on Sekania beach. Biological Conservation 121: In this paper, Karavas et al. examine the relationship between sand and vegetation characteristics and nesting activity at Sekania beach on the island of Zakynthos. Sekania beach is the single most important nesting site for loggerhead sea turtles in the Mediterranean, and the aim of the study was to analyze the beach ecosystem to see what effects sand characteristics and vegetation structure may have on successful nesting. ArcView was used to map the spatial relationship between sand characteristics, vegetation, and nesting activity. While the results of this study did not add new information to the field of sea turtle studies, the authors entered all their data into a GIS database and discussed how this database could be used to establish an integrated monitoring system for Sekania beach. McDaniel, C.J., L.B. Crowder, and J.A. Priddy Spatial dynamics of sea turtle abundance and shrimping intensity in the U.S. Gulf of Mexico. Conservation Ecology 4:1 16.

5 In this article, McDaniels et al. use GIS to compare the distribution and abundance of sea turtles with shrimping activity in the Gulf of Mexico. Sea turtle observations were obtained through aerial surveys and shrimping effort data was collected from the National Marine Fisheries Service. Data was divided up according to the 12 statistical zones used by NMFS to monitor shrimping within the Gulf. Both sea turtle abundance and shrimping activity within each zone were categorized as high, medium, or low. ArcGIS was then used to analyze spatial patterns. Shrimp trawling has been identified as a large source of mortality for large juvenile and subadult sea turtles, and population models suggest that increased survival during these life stages would contribute most to population recoveries. The authors discussed possible strategies for managing interactions between shrimping activity and sea turtles in areas of high sea turtle abundance. They also clearly showed the limitations of their study and identified ways in which their study could be improved upon. Schofield, G., C.M. Bishop, G. MacLean, P. Brown, M. Baker, K.A. Katselidis, P. Dimopoulos, J.D. Pantis, and G.C. Hays Novel GPS tracking of sea turtles as a tool for conservation management. Journal of Experimental Marine Biology 347: In this paper, Schofield et al. describe how the use of GPS and GIS technologies can be used to evaluate management actions to protect loggerhead sea turtles at the Zakynthos rookery in Greece; the largest loggerhead rookery in the Mediterranean. Researchers used GPS loggers deployed on adult female loggerheads to track their movements during the nesting season. Using ArcView 3.1, they overlaid the GPS data on existing features such as sea depth parameters, Natura 2000 marine habitats, and the maritime zones of the National Marine Park of Zakynthos. Analysis of the data showed that the turtles inhabited a variety of shallow water habitats and spent a majority of their time outside of the no boating maritime protection zone, suggesting that the current protective measure may not be sufficient. The authors clearly demonstrated how the use of geospatial technologies can be used to make informed decisions about endangered species conservation and management.