July 23, 2004 The unique plant communities of the high Sierra Nevada appear to be under threat from rising temperatures. According to the Andalucian government, a rise of 1.2ºC has been detected in the province of Granada over the last 20 years, which although not much in itself has been enough to endanger 65 endemic plants, most of which are only to be found in the highest altitudes of the range. Like its African and Andean counterparts, the pseudo-alpine habitat, known cumbersomely as crioromediterraneo in Spanish, is extremely sensitive to changing temperatures, and gradually plants are being forced ever higher in search of cold enough conditions. Currently it is at some 2,600 metres. Sooner or later there may well be nowhere for them to go. Many of the plants here are relic species which were marooned after the end of the last ice age some 10,000 years ago. The reported presence of pine processionary caterpillars (*see below) at higher and higher altitudes is also a clear sign of habitat change.
The Sierra Nevada is one of the most important biodiversity hotspots in Europe. All five of Spain's bioclimatic zones are present here from Mediterranean up to crioromediterraneo, supporting up to 2,100 plant species of the total of 7,000 recorded for Spain. The fact that the whole of the British Isles only support some 1,900 plants will give you some idea of why botanists get so excited about the place. 10% of the total are Spanish endemics and 78 species are only found here. On the high slopes, the temperature range is surely one of the highest in Europe (in excess of 25ºC in July and probably as low as -35ºC in January). This is the continents's most southerly glacial landscape, and although the last remnants of the glaciers finally melted away at the end of the 20th century, snow is still the dominant form of precipitation (95%) on the high peaks and this stays on the ground for most of the year. Some 50 glacial tarns are scattered across the range and the higher areas are dotted with marshy grasslands and peatbogs known locally as borreguiles.
One of the great success stories of the range is the recovery of the Spanish ibex (cabra montés) population which mange and overhunting had reduced to 500 in the early 1960's. It is now home to by far the largest ibex population in Spain with 15,000 individuals.

Climate change or no climate change, on a purely anecdotal level, I remember the wonder at seeing the Sierra Nevada cloaked in snow the first time I went to Granada in a sweltering June in 1988. I've been back twice since at Easter, and all you could see from the city were a few patches on Veleta, the peak that frames La Alhambra. Incidentally, until 1805 no one was sure whether Veleta (3,396 m.) or Mulhacen (3,479 m) was the highest peak in Iberia. Locals, possibly ironically, know the gently sloping but immense Mulhacen as a 'cerro' or hill, while the more spectacular Veleta is accorded the status of a mountain.

* As every Spanish child knows, don't even think about handling the hairy caterpillars of the pine processionary moth ( procesionarias in Spanish). If they are touched, their hairs release an extremely nasty allergic skin reaction. Children have been known to go temporarily blind from rubbing their eyes after picking them up. They live in easily identifiable silvery nests in pine trees throughout Mediterranean Spain and get their name from their habit of forming head-to-tail trails as they move across land.