Mountainous areas, characterised by steep environmental gradients, are some of the most sensitive and vulnerable areas to climate change.  Mountainous areas are to be found in all the country’s biogeographic regions - Mediterranean, Alpine, Atlantic and Macaronesian – and are home to areas of immense biodiversity and endemic wealth, managed using traditional techniques in the various sectors that contribute to conserving their high natural and cultural value and to shaping the resulting landscape (forests and pastureland, agriculture and livestock breeding, hunting and fishing, water and land, etc.), together with more intensive uses (winter sports tourism, extractive activities) which all face major impacts due to climate change. 
 
On the other hand, the fact that mountain systems are so sensitive to climate change makes them ideal testing grounds in which to monitor its impacts.