The Spanish Central System mountain range extends more than 450 km across the centre of the Iberian Peninsula, passing approximately 50 km north of Madrid. As well as having a large number of Mediterranean plant species, the mountains also act as a refuge for species more typical of the colder climates in central Europe, leading to a rich biodiversity.
Climate change is a threat to this biodiversity, since although low altitude species are able to move slowly up the mountain slopes, thus avoiding increasing temperatures and drought, those at high altitudes have no similar refuge.
Air pollution is another threat to these mountain ecosystems, which are exposed to high concentrations of tropospheric ozone and high rates of atmospheric nitrogen deposition, problems that are exacerbated due to the proximity to Madrid.
Downscaled climate simulations at a spatial resolution of 10 km (), using the as boundary conditions (CMIP5 RCP8.5 scenario), suggest that during the period 2000 to 2050, mean annual temperatures in the mountains are projected to increase more than 1.4 °C and annual precipitation to decrease by up to 20%, under this low ambition greenhouse gas emissions scenario.
Air quality modelling using the CHIMERE model shows that projected reductions in emissions (principally nitrogen oxides) during the same period are expected to reduce nitrogen deposition by more than 20%, as well as reduce maximum ozone concentrations, although the latter will be partly compensated by the increasing temperatures.
Initial results from a dynamic vegetation model (LPJ-GUESS) suggest that the projected changes in climate will indeed favour the movement of Mediterranean species to higher altitudes to the detriment of the endemic species, increasing the risk of local extinction.
In the next phase of the project we will use high-resolution climate and air quality simulations, coupled with the dynamic vegetation model to estimate the changes in the mountain biodiversity during the period 2000-2050.
These results will be used to develop tools that will enable stakeholders to explore the potential impacts of these changes and develop strategies to mitigate them, whilst considering the impact of other pressures such as tourism and grazing.