Centres of biodiversity

Posted: 13 May 2008

Mountains are core areas of global biodiversity, providing many goods and services that sustain our lives - as recognised by the Parties to the Convention on Biological Diversity in 2004. Because of their isolation, mountains frequently contain species of plants and animals which are found nowhere else. In other words, they tend to have particularly high levels of endemism.

Short-toed eagle
Short-toed eagle
The rare Short-toed Eagle (Circaetus Gallicus), found in the Carpathian Mountains and the Vojvodina region of the Federal Republic of Yugoslavia. ©Milivoj Vuchanovich

Factors leading to high biodiversity include evolution and migration over geological time. In addition, mountains provide contrasting conditions at different altitudes, slopes facing different directions, and many microhabitats. Disturbances at all scales - from animals digging to avalanches - are common. Many mountains are what the ecologists call 'refugia', refuges for species that either have been exterminated by human action in adjacent lowlands, or were widespread during past climates, but now can only survive in the specific conditions offered by mountains.

At the same time, it should be recognised that most mountain ecosystems have been modified to some extent by people and/or their grazing animals. The continuation of such activities, particularly grazing, is often necessary to maintain populations of plants.

  • The alpine zone covers about 3 per cent of the Earth's land surface and is home to about 10,000 vascular plant species (with woody conducting elements), 4 per cent of the global total. One reason for this high biodiversity is the small size of most alpine plants. Within the alpine zone, the number of species decreases by about 40 for every 100 m of elevation.
  • Nearly half of the world's biodiversity hotspots are in mountains. Many of the major global centres of diversity for vascular plants, are in, or include mountains. Most notable are Costa Rica, the tropical eastern Andes, Brazil's Atlantic Forest, the eastern Himalaya and Yunnan, northern Borneo, and Papua-New Guinea. Many secondary centres are found in Mediterranean and arid mountains, the southern Rocky Mountains, the central Sahara, and Central Asia.
  • Although tropical rainforests are widely known for their high biodiversity, tropical mountain forests typically have more species in a smaller area than nearby rainforests. For instance, in Ecuador, 17,000 sq. km. of tropical cloud forest contain 3,411 vascular plant species: 300 more than in 70,000 sq. km. of lowland Amazon forests. The total moss diversity of the five Andean countries is estimated to be 7.5 times higher than for the entire Amazon basin.
  • Of the 20 plant species that supply 80 per cent of the world's food, seven originated in mountain areas: wheat, maize, potatoes, barley, sorghum, apples and tomatoes. Six others - rice, beans, oats, grapes, oranges and rye have been widely domesticated in mountain areas and distributed around the world.
  • In Peru, a high-diversity and mountainous country, 3,140 out of 25,000 vascular plant species are used by people, including 444 for wood and construction, 292 for agroforestry, 99 for fibre production, and others as cosmetics, narcotics, stimulants, dyes, and ornamentals.

    Mountain gorillaMountain gorillas, found only in and around the Virunga range of volcanoes on the borders of Zaire, Rwanda and Uganda, number about 620 individuals.© INCAFO

  • Mount Cameroon, the highest mountain in West Africa (4,095 m), hosts 210 bird species, 70 butterfly species, and over 2,300 species of plants in more than 800 genera and 210 families: 100 of the plant species are endemic.
  • Nepal's mountain ecosystems house at least 724 species of medicinal and aromatic plants. Only 100 species are being harvested for commercial use. Annual harvests, mainly exported to India, are estimated at 15-42,000 million tons a year, worth between US$ 8.6 and 26.7 million. However, the mountain farmers who collect the herbs see very little of the profits.
  • The Alps host about 4,500 vascular plant species: more than a third of the entire European flora. About 15 per cent of these may be endemic.
  • Nearly half of Italy's 275 butterfly species occur in and above the treeline ecotone in he Southeastern Alps and the Apennines.
  • Mount Kinabalu (4101 m) in Sabah is estimated to harbour over 4,000 vascular plant species, more than one-quarter of all the species in the United States.

Sources:

M.F. Price and N. Butt (editors) (2000) Forests in Sustainable Mountain Development, CABI, Wallingford.

Körner C. and E.M. Spehn (eds.) (2002) Mountain Biodiversity: A Global Assessment, Parthenon, New York and London.

Nagy, L., Grabherr, G., Körner C. and D.B.A. Thompson (eds.) (2003) Alpine Biodiversity in Europe. Springer, Berlin.

Spehn E.M, M. Liberman, and Körner C. (eds.) (2006) Land Use Change and Mountain Biodiversity. CRC Press, Boca Raton.

Links

Global Mountain Biodiversity Assessment.

Convention on Biological Diversity

Mountain Partnership.

Compiled by Dr Martin Price, Director of the Centre for Mountain Studies at Perth College, within Scotland's UHI Millennium Institute, 'creating the University of the Highlands and Islands'.