Tropical and Subtropical Landscapes of the Andes

Abstract

The Andes represent Earth’s longest mountain system and include some of the world’s highest peaks. The rugged relief found above 1,000 m elevation produces strong environmental gradients tied to dramatic changes in temperature, moisture, and atmospheric pressure. These physical factors provide the background to understanding Andean landforms and land cover. In this chapter, we review these factors and patterns, and the complicating influences of geology and human land use, for the tropical and subtropical portions of the Andes, above 1,000 m and from 11°N to 24°S, in Venezuela, Colombia, Ecuador, Perú, Bolivia, and northernmost Argentina and Chile. The tropical Andes are recognized as one of the most important regions in the world from the viewpoint of biodiversity conservation (Myers et al., 2000; Brooks et al., 2002). They are home to ancient human settlements and early civilizations (Burger, 1992; Bruhns, 1994; Dillehay, 1999), and large indigenous populations (Maybury-Lewis, 2002) living in some of the highest permanent settlements in the world. As a result, a better understanding of the physical geography of this complex region is important for sustainable development initiatives and other global environmental concerns. Historically important overviews have been written for this region by von Humboldt (1807), Troll (1931), and Ellenberg (1958). Country-level studies include those for Venezuela (Monasterio, 1980), Colombia (Cuatrecasas, 1958; Rangel, 2000), Ecuador (Whymper, 1896; Acosta Solís, 1968; Jørgensen and León-Yánez, 1999), Perú (Weberbauer, 1945; Young and León, 2001), and Bolivia (Navarro and Maldonado, 2002). Luteyn (1999) has assembled information on the plants of the high elevations of the northern Andes, Luteyn and Churchill (2000) have examined the plant communities of the tropical Andes, and Kappelle and Brown (2001) have provided descriptive accounts of the montane forests. Inspiring chronicles can be found in Steele (1964) and Botting (1973). In this chapter, we first describe the relationships among the physical environments and natural landscapes of the tropical and subtropical Andes. We then discuss the natural vegetation types to be found, as typified by the forests, shrublands, grasslands, high Andean types, and wetlands. Finally, we summarize key aspects of the role of historical biogeography and human influences on and within those landscapes.