High Andean Plants

As you may know it, Chile is a country of very high mountains which rise up to 5000-6000 meters in the central and northern Chile and go a little down to about 2500-3000 meters in central-southern Chile and disappear almost completely in Patagonia, where only occasional peaks break the monotony of the flat landscape.

These mountains were always a formidable barrier for species dispersal and they are the main reason why Chile has such a high percentage of endemic plants: the Chilean species simply could not escape across the frontier, nor could new species come in.

There are two types of high Andean plants: extreme elevation plants which grow well beyond the tree-line (that is, above 3000 to 4000 meters) and high elevation plants, which grow at or close to the tree-line (in central Chile (around the capital, Santiago) that corresponds to about 2400 - 3000 m, and more to the south the tree-line descends to 1800 at the 37º parallel and to 1200 m at the 42º parallel).  The plants of the extreme elevation, although very interesting due to their hardiness and habitat conditions, can very often be found also in Argentina. So they are not endemic of Chile, but of the Southern Andes.  The Chilean plants which grow above, but not far from the tree-line are the most interesting ones: they cannot cross over the high mountain ranges, so they are confined to small niche areas on the western slopes of Chile and have very high endemic percentage. In fact, very often their altitude limitation confines them to very small areas within Chile, because they cannot cross deep transversal valleys and they cannot expand along the higher reaches. That means that very often a species is confined to an area as small as a few dozens of square kilometres, as is for instance the case with Alstroemeria pseudospatulata, Austrocactus philippii, Austrocactus spiniflorus and if this area extends in the north-south direction, it may quite often lead to great variability within the species or the species may present itself with clearly distinct subspecies.