The Atlantic Forest (Portuguese: Mata Atlântica) is a region of tropical and subtropical moist forest, tropical dry forest, tropical savanna, semi-deciduous forest and mangrove forests which extends along the Atlantic coast of Brazil from Rio Grande do Norte state in the north to Rio Grande do Sul state in the south, and inland as far as Paraguay and the Misiones Province of Argentina. The Atlantic Forest is characterized by a high species diversity and endemism.
It was the first environment that the Portuguese conquerors encountered over 500 years ago when it was thought to have had an area of 1,000,000 to 1,500,000 sq km (390,000 to 580,000 sq mi) and stretching an unknown distance inland. Currently, the Atlantic Forest spans over 4,000 sq km (1,500 sq mi) along the coast of Brazil and in a small part of Paraguay and Argentina. In Argentina, it is known as Selva Atlántica. The Atlantic Forest is now designated a World Biosphere Reserve, which contains a large number of highly endangered species.
The enormous biodiversity of the Atlantic Forest results in part from the wide range of latitude it covers, its variations in altitude, its diverse climatic regimes as well as the geological and climatic history of the whole region. The Atlantic Forest is isolated from is neighboring large South American forests: The Amazon Region and the Andean Forest. The open vegetation of the Caatinga and the Cerrado separate it from the Amazon, and the dry vegetation of the central depressions of the Chaco separate it from the Andean Forest. This isolation has resulted in an evolution of numerous endemic species, such as lion tamarins, woolly spider monkey, and marmosets.
During glacial periods in the Pleistocene, the Atlantic Forest is known to have shrunk to extremely small fragmented refugias in highly sheltered gullies, being separated by areas of dry forest or semi-deserts known as caatingas. Some maps even suggest the forest actually survived in moist pockets well away from the coastline, where its endemic rainforest species mixed with much cooler-climate species. Unlike refugia for equatorial rainforests, the refuges for the Atlantic Forest have never been the product of detailed identification.
Despite so little forest remaining, the Atlantic Forest remains extraordinarily lush in biodiversity and endemic species, many of which are threatened with extinction. Approximately 40 percent of its vascular plants and up 60 percent of its vertebrates are endemic species, meaning they are found nowhere else in the world. The official threatened species list of Brazil contains over 140 terrestrial mammal species found in Atlantic Forest. In Paraguay there are 35 species listed as threatened, and 22 species are listed as threatened in the interior portion of the Atlantic Forest of Argentina. Nearly 250 species of amphibians, birds, and mammals have become extinct due to the result of human activity in the past 400 years. Over 11,000 species of plants and animals are considered threatened today in the Atlantic Forest.
Unfortunately, the Atlantic Forest has been facing human-induced threats for decades. Around 70% of Brazil’s 190 million people live along the Atlantic coastline. The incorporation of modern human societies and their needs for forest resources has greatly reduced the size of the Atlantic Forest, which has resulted in species impoverishment. Almost 88% of the original forest habitat has been lost and replaced by human-modified landscapes including pastures, croplands, and urban areas. This deforestation continues at an annual rate of .5% and up to 2.9% in urban areas.
Results of Human Activity
Habitat fragmentation leads to a cascade of alterations of the original forest landscape. For example, the extent of human disturbances, including habitat destruction, in the Atlantic Forest has led to an extinction crisis. The endemic species in this region are especially vulnerable to extinction due to fragmentation because of their small geographic rages and low occurrence. In a study of the Atlantic Forest fragments, community level biomass was reduced to 60% in plots less than 25 hectares. Key ecological processes such as seed dispersal, gene flow, colonization and other processes are disturbed by fragmentation.
Conservation and Nongovernmental Organizations
Due to the Atlantic Forest’s vast diversity of endemic plants and animals as well as the fragmentation affecting these species, many groups and organizations are working towards the restoration of this unique ecosystem. Non-governmental Organizations (NGO) are huge benefactors in Brazil, providing funding as well as professional help to the Atlantic Forest due to the Brazilian Environmental Movement. One organization, called BirdLife International, is using their research to preserve bird biodiversity of the area by primarily working with people towards sustainability in the use of natural resources. Some organizations are receiving grants from the Critical Ecosystem Partnership Fund (CEPF) if they abide by their directions.
- Species protection program
- The Program for Supporting Private Natural Heritage Reserves
- The Institutional Strengthening Program