THE AMAZON BIOME
Formation of the Amazon
200 million years ago the world was very different. Theories have suggested that there was only one ancient super continent called Pangaea – a huge land mass surrounded by a super ocean called Panthalassa. Around 150 million years ago this giant land mass began to crack and break apart into smaller fragments. Over millions of years, these smaller land masses moved across the ocean to become today’s continents.
THE GEOGRAPHY OF THE AMAZON BASIN
Today the Amazon River Basin holds the largest tropical rainforest in the world, ranging from the eastern slope of the Andes mountains to the Atlantic Ocean and covering an area of 2,400,000 square miles (6,300,000 km). The highest point in the watershed of the Amazon is the peak of Yerupaja at 6,635 metres (21,768 ft). The basin is about the size of the continental Unites States, contains over half of the planet’s remaining rainforests, and spans over nine countries that include Brazil, Bolivia, Peru, Ecuador, Columbia, Venezuela, Guyana, French Guiana, and Suriname, with Brazil holding about 60 percent of the Amazon’s forests.
Ecosystems of the Amazon
The Amazon basin is made up of a mosaic of ecosystems and vegetation types that include rainforests, seasonal forests, deciduous forests, flooded forests, bamboo stands, palm forests, savannas, dry forests, and cloud forests. The basin is curved like a cup that starts high up in the Andes (average elevation 13,000 feet) and descends the steep slope to unfold into the flat alluvial plain of the Amazonia lowlands (average elevation 100 meters-328 feet).
The Amazon basin is divided into three basic zones:
- The lowlands of the Amazon-This region lies within 9 countries, is the largest geographical area of the Amazon with mostly flat plains, boundless areas of trees and species, a vast river system, and elevations around sea level.
- The transition zone-where the lowlands of the Amazon meets the slope of the Andes Mountains in(500-1,500 meters). Species from both the highlands and lowlands of the Amazon Basin intersect to create an unique area teaming with life and abundance.
- The tropical Andes-covers 1.5%. of the basin and runs mainly through five Amazonia countries that include Venezuela, Ecuador Columbia, Bolivia, and Peru. The slopes of Andes house an abundance of gradients, diverse landscapes, habitats and types of vegetation and forests, that are comprised of tropical rain forests that include cloud forests, and landscapes of the highest altitudes of the Andes Mountains, with grasslands and craggy, steep stone mountains covered with snow and glaciers.
Photo by Adrian Tejador
BIODIVERSITY OF THE AMAZON BASIN
The Amazon basin contains a huge abundance of biological diversity. There are millions of animals, some known, and some not yet discovered, living in the Amazonia Basin. One in ten species lives in the Amazon Basin, with a new species discovered every 3 days. Many of the larger animals spend there time moving from tree to tree across the canopy, sometimes jumping, sometimes crawling, sometimes flying in search of food or shelter. The smaller animals, may live their entire lives in one tree, in a small crevice, in the cup of a flower, or a tiny nest sheltered in a hidden place.
In the lowlands of the Amazon approximately 1,300 birds, 40,000 plant, 427 mammals, 400 amphibians, 1378 reptiles, and 3,000 freshwater fishes have found to date. The highest numbers of species in the lowlands belong to the insect populations with approximately 2.5 million species thought to live in the basin with ants contributing to 30% of all animal biomass in the Amazon.
In comparison, the Tropical Andes has more species than the Amazonia lowlands and is unequalled by any other spot in the world for its richness in biodiversity and endemic species (organisms belonging exclusively or confined to a particular place). The Tropical Andes contains about 45,000 plant species of which 20,000 are endemic, 3,000 vertebrate species with about 1,500 endemic, 1,666 bird species, 479 reptile species, 830 amphibian species and 570 species of mammals. Areas with an abundance of biodiversity bring energy, reproduction, are healthier and more resilience against severe weather, pests, and disease.
TREES OF THE AMAZON BASIN
There are approximately 390 billion trees in the Amazon creating differing habitats for the worlds highest numbers of biodiversity. Because the Amazon is in the tropics near the equator, the sunlight strikes these forests directly and straight on keeping temperatures hot and moist, with an average humidity of between 77% and 88%. The humid air helps produce extreme and frequent rainfall of about (80-400 inches) per year through evaporation and transpiration.
There are so many trees in the Amazon that they make as much as 75% their own rainfall. On an average sunny day the trees of the Amazon release 20 billion tons of moisture into the atmosphere seeding the clouds with rains.
THE RIVERS OF THE AMAZON BASIN
The Amazon River begins from a small stream called Apacheta Creek in the Peruvian Andes, and winds its way east over the northern half of South America, growing and fanning out to carry approximately 20% of the planets fresh water to sea . The distance from Apacheta Creek in Peru to the mouth of Marajó Bay in Brazil where the Amazon river meets the ocean is about 4,345 miles (6,992 km). The Amazon River has 1,100 tributaries and is the second longest river after the Nile. It discharges the largest volume of water with twenty eight billion gallons of water released into the Atlantic every minute, decreasing the oceans salinity for more than 100 miles offshore. The water discharged daily from the Amazon rivers into the Atlantic is enough to supply 9 years of fresh water for New York City. Amazonia receives about 9 feet of rain every year. Fifty percent of this returns to the atmosphere through the foliage of the Amazonia trees. The Rivers of the Amazon carry an abundance of aquatic life that include 3,000 freshwater fish species, and more than 370 types of reptiles. Many species are unique and endemic only to these rivers. Fish are a critical component of the Amazonia food web and are a major source of food for people and other carnivorous species. The rivers of the Amazon also serve as a major means of transportation for the peoples, who use a variety of crafts that range from basic balsa rafts and dug out canoes to modern steel hulled boats.
Photo by Dano Grayson
PEOPLES OF THE AMAZON BASIN
The Amazon Basin has a long history of human settlement, with varied tribes, customs and cultures. Some estimates put the first pre-historic human settlements in the Amazon between 10,000 to 30,000 years ago, with evidence indicating that populations may have been very large, even in the millions. Unfortunately, in the early 1500’s the indigenous populations were affected by the European’s conquest of South America and the Amazon Basin in search of gold and other natural resources. The Europeans brought with them diseases and death in their quest to control the region. In the first century of the European’s presence, the Indigenous populations of South America and the Amazon were reduced by 90 percent.
Today it is estimated that 20 million indigenous people live in the 9 Amazon countries. These populations remain diverse with differing cultures, languages, and beliefs. Groups of people range from the tribes of uncontacted Indians, to the colorful peoples of the highland Andes, to nontraditional peoples who have given up the indigenous ways to adopt today’s western culture. The most widely spoken language in the Amazon is Portuguese followed closely by Spanish.There are still hundreds of native languages spoken in the Amazon, but with the rise in globalization many of these languages and cultures are becoming critically threatened.
The wisdom and knowledge of the Indigenous peoples to care for the lands of the Amazon Basin is today being recognized by policy makers and organizations around the world as being a critical component in the protection and conservation of forests. Evidence has shown that many indigenous territories have lower deforestation rates and incidence of encroachment than conventional protected areas.
Photo by Adrian Tejador
Why the Amazon? With Q’uorionka Kilcher
“Those who contemplate the beauty of the earth find reserves of strength that will endure as long as life lasts. There is something infinitely healing in the repeated refrains of nature — the assurance that dawn comes after night, and spring after winter.”
– Rachel Carson