Central America: Climate, Vegetation, and Animal Life
The three chief climatic influences on Central America are low latitudinal location extending from about 8° to 18°N, contrasting windward-leeward exposure to the northeast trade winds, and elevation ranging from sea level to over 13,000 feet (4,000 meters). Seasonal differences are based more on precipitation than temperature. In general, the heaviest rainfall occurs between May and November. Because of frontal exposure to the moisture-laden trade winds that sweep in from the Atlantic, the Caribbean coast and eastern slopes get twice as much rain as the Pacific side, which lies in the rainshadow of the mountains. Total rainfall varies widely, from as little as 20 inches (500 mm) in the driest leeward locations to more than 200 inches (5,000 mm) on exposed eastern headlands.
Climate changes with elevation. The zone between sea level and 2,500 feet (750 meters) has an unmodified tropical climate and accounts for the production of most of Central America's commercial banana and cacao crops. A more temperate climate extends from 2,500 to 6,000 feet (1,800 meters). This is the zone that produces most of the coffee, tobacco, maize, and other food crops and that has the highest population in all the countries except Nicaragua. Above 6,000 feet agriculture is based on middle-latitude crops, such as wheat and apples, and on livestock.
Drainage is affected by both climate and slope conditions. The highlands are better drained than the lowlands, and the Pacific coast is better drained than the Caribbean. Of the numerous streams that originate in the highlands, those that descend to the Pacific are short and swift, and virtually none is navigable even for small vessels. The streams that flow to the Caribbean are longer and eventually merge into coastal marshes. Some of these, such as the San Juan between Costa Rica and Nicaragua and the Coco (Segovia) between Nicaragua and Honduras, are navigable for small craft. Numerous lagoons line the coast, and large lakes, such as Managua in Nicaragua and Atitlán in Guatemala, lie in the interior.
Vegetation and Animal Life
In prehistoric times the Central American land bridge served as a roadway over which plants and animals migrated between North and South America. Natural vegetation in the region is varied. Mangrove swamps occur on both coasts. The hot, wet Caribbean highland slopes and coastal lowlands are characterized by a tropical evergreen forest that includes mahogany, balsa, rosewood, palm, and other tropical tree species. On the drier Pacific slope is a mixture of evergreen and deciduous forest alongside savanna grass, while cactus and desert shrubs grow in the driest locales. Inland, at higher elevations, is a mixed forest of deciduous oaks and pines.
Hundreds of species of birds, ranging from large eagles to tiny hummingbirds, are native to the forests and swamps of Central America. In addition there are numerous varieties of insects. Amphibians, such as crocodiles, turtles, frogs, and lizards, are found in the forests or in warm waters. Among the mammals are monkeys, deer, jaguars, and small rodents.
Central Americans have to cope with a variety of natural hazards. Mosquitoes and parasites abound. Destructive hurricanes frequently strike the coastal margins, especially on the Caribbean side, destroying crops and causing floods and landslides that may take thousands of lives. No part of Central America is free from earthquakes, which have devastated the capitals of Guatemala, El Salvador, and Nicaragua more than once and with appalling death tolls. Also on record are violent volcanic eruptions that, besides killing thousands of people and cattle, may cause catastrophic crop damage from falling ash. All of Central America's volcanoes are on the Pacific side of the highlands.