MOUNTAIN ECOSYSTEMS

Thou coveredst it with the deep as with a garment: the waters stood above the mountains. At thy rebuke they fled; at the voice of thy thunder they hasted away. They go up by the mountains; they go down by the valleys unto the place which thou hast founded for them. Thou hast set a bound that they may not pass over; that they turn not again to cover the earth. He sendeth the springs into the valleys, which run among the hills. They give drink to every beast of the field: the wild asses quench their thirst.By them shall the fowls of the heaven have their habitation, which sing among the branches. He watereth the hills from his chambers: the earth is satisfied with the fruit of thy works.He causeth the grass to grow for the cattle, and herb for the service of man: that he may bring forth food out of the earth;And wine that maketh glad the heart of man, and oil to make his face to shine, and bread which strengtheneth man's heart.[Psalms 104:6-15]

Mountain ecosystems are found throughout the world, from the equator almost to the poles, occupying approximately one-fifth of its land surface. Beyond their common characteristics of having high relative relief (or very marked topographic variation) and steep slopes, mountains are remarkably diverse (Ives. Messerli and Spiess, 1997). They are found on every continent, and at every altitude, from close to sea level to the highest place on the earth - the summit of Mount Everest (Sagarmatha or Qomolangma) on the border between Nepal and the Tibet Autonomous Region of China.

Half of the world's population depends on mountain water

An estimated one-tenth of the human population derive their life-support directly from mountains. Yet, mountains are important not only for their inhabitants, but for millions of people living in lowlands. At the global scale, mountains' greatest value may be as sources of all the world's major rivers, and many smaller ones (Mountain Agenda, 1998). Mountains play a critical role in the water cycle by capturing moisture from air masses; when this precipitation falls as snow, it is stored until it melts in the spring and summer, providing essential water for settlements, agriculture and industries downstream - often during the period of lowest rainfall. In semi-arid and arid regions, over 90 percent of river flow comes from the mountains. Even in temperate Europe, the Alps that occupy only 11 percent of the area of the Rhine river basin supply 31 percent of the annual flow - and in summer more than 50 percent.

Mountain water is also a source of hydroelectric power, most of which is used on the plains below. Historically, water wheels have provided energy in mountain regions, mainly for grinding grain. In rural Nepal there are an estimated 25 000 water wheels and over 900 micro-hydropower turbines - a more recent technology - that provide a critical source of energy, mainly for agroprocessing (Schweizer and Preiser, 1997). Such local renewable energy is a vital catalyst for economic development in areas that are at the far ends of the distribution networks for the fossil fuels on which most urban dwellers depend. In developing countries, wood fuel is the predominant energy source in mountain settlements, but it is also essential - whether as wood or charcoal - to many people living in urban centres in the lowlands and on the plains. For example, any visitor to Marrakech can observe the large piles of fuelwood stacked outside communal bakeries, to which every household brings its daily bread to be baked; the wood comes from the forests in the Atlas Mountains.

Mountain wood also has many other uses, including timber and wood products both for local use and, where road, rail or water networks permit, for export. It is significant to note, however, that, while deforestation of the tropical rain forests remains most visible in the global media, the highest rate of deforestation in any biome occurs in tropical upland forests -1.1 percent per year. Rates of clearing are particularly high in Central America, East and Central Africa, Southeast Asia and the Andes (FAO, 1993).

CENTRES OF BIODIVERSITY

Mountain ecosystems are globally important as centres of biological diversity. The greatest diversity of vascular plant species occurs in mountains: Costa Rica, the tropical eastern Andes, the Atlantic forest of Brazil, the eastern Himalaya-Yunnan region, northern Borneo and Papua New Guinea (Barthlott, Lauer and Placke, 1996). Other important centres are found in arid subtropical mountains. Many of these areas with the greatest biological diversity are designated as national parks or other types of protected area.

Mountains are important centres of biodiversity: mowing mountain meadows to maintain biodiversity, La Vanoise National Park, France

It is not only the diversity of natural mountain species that is of value to humankind, both intrinsically and as a source of "wild foods" such as mushrooms, game and birds, and many other non-timber forest products. Mountains are also important as centres of crop diversity. The maintenance and expansion of mountain populations in many parts of the world have been made possible by the introduction of potatoes and maize from Latin America. The original precursors of wheat came from the mountains of the Near East. These original varieties maintain their importance in the breeding of new varieties of major food crops. Equally, species that are not widely known but are adaptable and nutritious - such as many of the Latin American root and tuber crops which are the focus of research at the International Potato Center (CIP) in Peru - may be potential major sources of food.