Vegetation belts are projected to shift to higher elevation in the mountains, but also to move northward in the Scandes.
In particular, species of shrubs and trees are driving these shifts; leading to a loss of tundra in the Scandes and biodiversity-rich mountain vegetation in the southern study sites. The shift is at risk of proceeding more rapidly than the species can adapt to or follow spatially, leading to high risk of local extinction of species, or decreased vigour e.g. with implications for forests susceptibility to disturbances such as drought- and heat-related tree mortality and forest pests. This shift has implications for local management practices, e.g. for forestry from local to national level, and herding practices e.g. for reindeer management. It has implications for local climate feedbacks. In addition, it is also highly relevant for tourism, e.g. because of reduced snow cover and an altered flora in the landscape, and for nature conservation. Vegetation cover and composition can change profoundly, altering the characteristics of the landscape and representing a threat for a substantial number of red listed species.
Climate change leads to warming and changes in precipitation also at high altitude, and increased risk for e.g. fire events.
Scenarios show there is an increased prevalence of some types of extreme weather, e.g. heatwaves. The unprecedented, very high spatial and temporal resolution in climate models that has been used in BioDiv-Support permits an improved assessment of the frequency and intensity for extreme precipitation events and a wider range of climate change indicators including also in areas of complex terrain.
The total nitrogen deposition is projected to decrease in the Scandes, Pyrenees and Spanish Central System until the mid-21st century. However, additional policy action is needed, especially for the agricultural sector to reduce adverse impacts from nitrogen deposition.
Policy interventions have led to decreasing nitrogen deposition in Europe, but despite this the load will remain at levels far above the pre-industrial in most parts of Europe, even for remote high-altitude areas such as the Scandinavian Mountains. Reductions in nitrogen deposition to the Central Mountain System in Spain are expected to decrease impacts to sensitive habitats by 2050, with substantial decrease in the exceedances of critical loads in a majority of these (mainly shrub and pasture habitats). Critical loads for nitrogen will still be exceeded in mid-21st century in many parts of Europe.
We project that impacts on the mountain vegetation from near-surface ozone will be reduced by 2050 as a result of planned reductions in precursor emissions.
However, this is dependent on countries continuing their efforts to decrease emissions. As a result, the Spanish Central System is expected to meet the target value for impacts to vegetation set out in the current EU Air Quality Directive, but not the corresponding long-term objective. In Scandinavia, extreme weather events (heat-waves, wildfires) can promote elevated near-surface ozone also in the future. Additionally, an earlier and higher spring peak in near-surface ozone is partly a result of a prolonged growing season caused by climate change (as seen in our ecosystem simulations).