MOUNTAIN ECOSYSTEM

complex of living organisms in mountainous areas. Mountain lands provide a scattered but diverse array of habitats in which a large range of plants and animals can be found. At higher altitudes harsh environmental conditions generally prevail, and a treeless alpine vegetation, upon which the present account is focused, is supported. Lower slopes commonly are covered by montane forests. At even lower levels mountain lands grade into other types of landform and vegetatione.g., tropical or temperate forest, savanna, scrubland, desert, or tundra. Figure 1: Worldwide distribution of mountain lands. The largest and highest area of mountain lands occurs in the Himalaya-Tibet region; the longest nearly continuous mountain range is that along the west coast of the Americas from Alaska in the north to Chile in the south. Other particularly significant areas of mountain lands include those in Europe (Alps, Pyrenees), Asia (Caucasus, Urals), New Guinea, New Zealand, and East Africa. The worldwide distribution of mountain lands is shown in Figure 1. Additional reading Larry W. Price, Mountains & Man: A Study of Process and Environment (1981), provides a broad treatment of the mountain lands of the world. W. Tranquillini, Physiological Ecology of the Alpine Timberline: Tree Existence at High Altitudes with Special Reference to the European Alps (1979), details the Alpine tree line ecology using international examples, with particular reference to temperate-zone mountains. Franois Vuilleumier and Maximina Monasterio (eds.), High Altitude Tropical Biogeography (1986), discusses equatorial high mountain flora and fauna. Jeremy M.B. Smith