Challenges for the conservation of Mediterranean vulnerable species under climate change. The case of Testudo graeca

General models predict an increased risk of extinction for various Mediterranean species, particularly those with fragmented populations or restricted distributions. Large-scale models offer an overview of the species that could be affected by climate change, but local or regional scale models are needed. These allow for higher spatial resolutions and the inclusion of local factors, which can significantly influence the actual effects of climate change, especially on populations located near the edges of a species' distribution.

For Testudo graeca, we present the results at different spatial scales (Mediterranean and Southeastern Spain) and using different levels of information. In southeastern Spain, GLM methods were applied to develop presence/absence and abundance models, which were then used to project distribution and abundance under high-resolution (10 km cell) climate scenarios.

The results highlight the need for local-regional models and suggest that more detailed information (abundance) could better represent species' responses during the transition to the future climate, particularly for long-lived species like T. graeca. Overall, the results point to a loss of potential habitat and abundance in the current area of ​​Southeastern Spain, posing a significant challenge for the conservation of a species with limited expansion capacity, like T. graeca.

The research has also revealed divergent results depending on the quality of information that is used. High quality information (high spatial resolution, inclusion of local factors, high quality species information as abundance) is basic to get robust and reliable results to identify priority areas for mid-term monitoring, assessment of extreme events impacts and active conservation measures for the species. High quality information is, therefore, essential for the management and conservation of species under climate change.