Significance of mountain biodiversity
Mountain regions cover 13-25% of the terrestrial land surface and support exceptionally high biodiversity. The factors explaining this diversity are manifold and include natural gradients of altitude and geology; rapid altitudinal changes in climatic conditions across very short distances that give rise to a range of bioclimatically defined vegetation types in close proximity; micro-topography, which adds considerable variation in the temperatures organisms experience in mountain habitats; and anthropogenic gradients of historical and current land use and of disturbance. Additionally, because of the biogeographic isolation under which they have evolved, mountain biomes also harbor high numbers of endemic species that further add to the uniqueness of mountain biodiversity.
Mountain ecosystems are as fragile as they are rich and both natural and anthropogenic drivers of change contribute to putting them and many of the global mountain biodiversity hotspots at risk. Major threats include the loss of vegetation and soils due to inappropriate agricultural and forestry practices and extractive industries, and global climate change.
Ecological integrity of mountain ecosystems and intact biodiversity are key to the provision of numerous ecosystem services that are contributing largely to human well-being, including tourism and recreation; climate, air quality, and water flow regulation; carbon storage; protection against natural hazards and the impact of extreme events; the production of diversified and healthy food; and the provision of clean water to half of humankind.
The conservation and sustainable use of mountain ecosystems in general and of mountain biodiversity in particular is thus of prime importance for ecological and socio-economic reasons. The natural challenges to maintaining mountain biodiversity and the severe land-use pressure and other environmental stresses make mountain ecosystems among the most endangered landscapes in the world (Chapter 13, Agenda 21, The Rio Protocol).