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South America's floristic diversity is increased by its high mountains, especially the Andes Mountains, which extend from north to south along the western part of the continent for much of its length. South America has such diverse biomes as tropical rain forests, tropical savannas, extremely dry deserts, temperate forests, and alpine tundra. The largest of these biomes are deserts, savanna, and tropical forest. With the rapid rate of deforestation in places like the Amazon basin, some plants may become extinct before being cataloged, let alone studied.
The subtropical desert biome is the driest biome in South America and is considered the driest desert in the world, with an average annual precipitation of less than 0.25 inch (4 millimeters). The desert biome is restricted primarily to the west coast of South America from less than 10 degrees south of the equator to approximately 30 degrees south. Dry conditions prevail from the coast to relatively high elevations in the Andes. The Atacama Desert, in northern Chile, and the Patagonian desert, in central Chile, are the most notable South American deserts. Smaller desert regions also occur in the rain shadow portions of the Andes.
Next on the moisture scale are the savanna biomes. Savanna occurs in two distinctly different areas of South America. The largest savanna region includes three distinctive regions: the cerrado; the Pantanal; and farther south, in southern Brazil, Uruguay, and northern Argentina, the grassland called the Pampas. The other savanna region, the llanos, is found in lower-elevation areas of Venezuela and Colombia.
Although a few of the forests in South America are dry, most are rain forests, receiving annual precipitation from 79 inches to 118 inches (2,000-3,000 millimeters). The Amazon rain forest, the world's largest, accounts for more than three-fourths of the rain-forest area in South America. One of the most species-rich areas of the world, it is being rapidly destroyed by logging, ranching, and other human activities. Smaller rain forests are located along the southeastern coast of Brazil and in the northern part of Venezuela.
Covering much smaller areas are a small mediterranean region in central Chile characterized by cool, wet winters and warm, dry summers. In the far south of Chile and Argentina is a small area of temperate forest, becoming alpine tundra in the far south. Temperatures are relatively cool and mild year-round (except in the far south, where it can be extremely cold in the winter.
Plants of the Subtropical Desert
In the Atacama Desert, one of the world's driest, some moisture is available, but it is limited to certain zones.
Continue of the article: Plants of the Subtropical Desert
Plants of the Tropical Savanna Biome
The cerrado region of east central Brazil and southward is not only the largest savanna biome of South America but also one of the most romanticized of the world's savannas.
Continue of the article: Plants of the Tropical Savanna Biome
Plants of the Tropical Forest Biome
The Amazon rain forest is the largest contiguous rain forest in the world. It is so large and so lush with tree growth that its transpiration is actually responsible, in part, for the wet climate of the region.
Continue of the article: Plants of the Tropical Forest Biome
Plants of the Mediterranean and Temperate Forest Biomes
One of the world's five mediterranean climate regions is found in central Chile. This climate is characterized by warm, dry summers and cool, wet winters.
Continue of the article: Plants of the Mediterranean and Temperate Forest Biomes
See Also: South American Agriculture
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