ABSTRACT
Global warming will reduce available land area for cold-adapted organisms and therefore it will be a threat to mountain plant species richness, especially in front ranges where alpine plants are restricted to small and isolated summits. At very high elevations, biodiversity diminishes gradually but so does land area, leading to very high biodiversity/land area ratios which often exceed those of lower elevations. The Rocky Mountains have higher community and landscape diversity than surrounding lowlands. Natural timberline elevation in the Bolivian Andes is at 3800–4200 m, but human activities have lowered it to 3300–3600 m, destroying over 95% of the original forest cover above 3500 m. The Caucasus seems to be richer in species than the mountains of central Asia, when related to surface area. Alpine vascular plant species richness across 43 European mountain areas decreases from south to north. Of all global change impacts on mountain biodiversity, land use is the most important factor.
