Modelling Critical Coastal Ecosystems
A study on the marine turtles nesting habitat in the Mediterranean

Nima Moin, Ian May

Geo-information Science and Earth Observation Institute, (NL)
UNEP-WCMC, Cambridge, (UK)

Mediterranean coastline is under intensive pressure and degradation due to both development and exploitation impacts as well as natural processes. In this respect, loss of sandy beaches is one of the most serious consequences that trigger a substantial threat to biodiversity. Sandy coastlines serve as the habitat for numerous species that are dependent on such ecosystems. One of the species that are affected most is marine turtle that come to certain Mediterranean coasts for nesting. Sea turtles' current situation as an endangered species has reached an alarming state (refer to IUCN Red Data Book). Reports to the EU call for immediate action. Even initiatives to declare some of sea turtle nesting areas as NATURA 2000 sites have not achieved the goals as expected.

The very common causes of degradation of sandy beaches are wind and wave erosion as well as the anthropogenic factors such as exploitation and tourism-related development activities. Temporal variability and complexity of the natural and anthropogenic actors in these ecosystems bring up the need for tools that could effectively assist management systems both in spatial planning and monitoring. Geo-information systems could serve as efficient tools in this respect. However the degree to which GI could fall practical remains questionable and requires deep professional study.

Sea turtles are migratory as well as solitary species. Of the thousands of kilometres of beaches in the Eastern Mediterranean, the Caretta caretta sea turtles only nest in very few of them. To date, the selection of nesting site by sea turtles has remained as a mystery. One important question, which could be addressed in a GI model, is to integrate the various variables and possibly find an explanation to the high density of sea turtle nesting in certain beaches of Greece, and to some extent Turkey and Cyprus. Interestingly, significant variations have been observed in nesting density between two adjacent and apparently similar beaches. To this date no study has been able to explain the reason for this preference.

In the realm of CZM, management of sandy beaches is a complex issue. These "tiny" coastal fronts - which sometimes hardly reach 10m in width, hence require super fine spatial resolution representation- are subject to various known and unknown processes. The immense level of uncertainty due to natural and anthropogenic impacts makes the management task more demanding. Better understanding of the interactions between the various factors is needed to tackle the rising problems. Spatial information and GIS as a decision support tool are anticipated to facilitate achievement of management objectives. However numerous challenges are involved in fulfilling the goal, including data acquisition, processing and presenting.