Spatial distribution of insular cliff vegetation and future scenarios in a climate change perspective.

Cliff ecology has been studied for decades, providing good information about its high biodiversity values and their vulnerability to climate change. At the same time, literature shows how insular ecosystems are evolutionarily enhanced to present biodiversity hotspots with high endemicity rates, but they are also severely affected by anthropogenic effects. Together, insular cliff communities combine both biodiversity uniqueness and high vulnerability to global change, but few studies have evaluated these particular ecosystems. In this study, our aim was to provide novel information on the spatial distribution of insular cliff vegetation, taking the Balearic islands as a study case, assessing which environmental and climatic variables contribute to the definition of habitat conditions. Also, we used the predictions found in the WorldClim database to predict how the spatial distribution model vary. The map obtained showed that the mountains and coast were the most suitable habitats, especially the mountain ranges of the island of Mallorca. In particular, the high peaks of Serra de Tramuntana englobe the most fitted conditions for rupicolous species. Regarding the future climatic scenarios, in both the pessimistic and optimistic models, the spatial distribution of cliff vegetation remain intact in the mountain ranges where the habitat suitability was high, but disappear or reduce in other less favorable zones for the period 2021-2040. However, the extension of the distribution will be reduced in mid- and long-term periods, until 2081-2100, when the well-suited areas are only predicted to be in high-elevation mountains from the north of Mallorca island. These results emphasize the high vulnerability of these habitats to climate change due to their vulnerability to aridity and the strict requirements for habitat suitability (e.g., high slopes). From this, future studies should focus on single-species analysis to evaluate if any cliff specialist species can be at risk of extinction due to climate change.