Line of action:

Terrestrial ecosystems

Status:

Finalizado

Execution date:

2021

End date:

2022

Total budget:

112.539,28€

Amount of aid from the Biodiversity Foundation:

44.891,91€

The olive ridley turtle(Testudo graeca) is included as a vulnerable species in the Spanish Catalog of Threatened Species, mainly due to the loss and fragmentation of its habitat. Response models suggest that in southeastern Spain climate change will displace the ideal area for the species. The lack of connectivity between the main current population centers and with future suitable areas will lead to significant local extinctions without the possibility of occupying new areas.

In this context, this project has contributed to quantifying the effects of habitat loss over the last 20 years, evaluating current corridors and proposing others that would mitigate the effects of climate change on the species.

The objective of this initiative was to analyze the decline of Testudo graeca due to habitat loss and fragmentation in southeastern Spain over the last 20 years, project its effects in climate change scenarios and propose mitigation measures.

As specific goals it has pursued with:

• Disseminate and communicate project results.
• Analyze habitat loss over the last 20 years.
• Study connectivity between subpopulations.
• Model the distribution of the species for 2050, considering climate change scenarios.
• Study connectivity between subpopulations by 2050, considering climate change scenarios.
• Evaluate the functionality of current and future corridors.
• Characterize the conservation status of representative subpopulations of the population as a whole and of the corridor areas: density, demographic dynamics, connectivity and habitat quality.
• Propose corridor areas that guarantee the conservation of Testudo graeca in southeastern Spain in the face of climate change scenarios.

• Dissemination and communication of project results.
• Modeling of the historical and current distribution of the species and generation of basic GIS mapping.
• GIS identification of the main corridor areas.
• Projection to 2050 of models of species response to climate.
• GIS identification of future corridor areas.
• Analysis of the functionality of current and future corridors based on the study of the landscape structure.
• Selection of monitoring subpopulations.
• Review of previous information on population density and dynamics in populations in the corridor areas.
• Carrying out censuses in identified populations to determine population density and dynamics.
• Study of the effect of changes in habitat quality on nutritional intake.
• Prioritized proposal for the creation and/or conservation of key corridors for the conservation of Testudo graeca subpopulations under climate change scenarios.

• It has been quantified how the availability of habitat for the species and its connectivity have decreased in the southeastern Iberian Peninsula, specifically in Murcia and Almeria, since historical times.
• As a result, a net loss of 171 ^km2 of turtle habitat has been found over the last 20 years, as well as an increase in population fragmentation. Connectivity deficits occur in low-medium slope areas, coinciding with areas that historically have had low-intensity agricultural uses, and are now undergoing major modifications in the form of linear infrastructures, agricultural intensification or increased urban and industrial uses.
• Despite being listed in Annexes II and IV of the Habitats Directive, the Natura 2000 Network only guarantees the conservation of 30.9% of the suitable habitat of the olive ridley turtle in Murcia and Almeria.
• A projection has been made of how the potential distribution of the species will change under climate change scenarios.
• Climate change projections point to a drastic reduction of current optimal habitats and a northwestward shift of future potential habitats. The analyses have made it possible to identify key corridors for the species, both in the present and in the future.
• Eleven actions are proposed to mitigate conservation problems derived from fragmentation and climate change. These proposals have been shared with the administrations directly responsible for the conservation of the species.