A Global Assessment of Mountain Biodiversity and its Function

Abstract

The montane and alpine regions of the world cover about 10% of the terrestrial area, a life zone ca. 1000 m above and below the climatic treelines in temperate and tropical latitudes, including some of the biologically richest ecosystems. The alpine life zone above the climatic treeline hosts a vast biological richness, exceeding that of many low elevation biota and covers 3% of the global terrestrial land area (Koerner 1995). The overall global vascular plant species richness of the alpine life zone alone was estimated to be around 10,000 species, 4% of the global number of higher plant species. No such estimates exist for animals but based on flowering plants, high elevation biota area, as a general rules, richer in species than might be expected from the land area they cover. Within the alpine zone, the total plant species diversity of a given region commonly declines by about 40 species of vascular plants per 100 m of elevation (Fig. 1). The upper montane forest, its substitute pastureland, and the often fragmented treeline ecotone also host a wealth of organismic diversity, often exceeding that in the alpine life zone.