From North Brazil to Uruguay, the Brazilian Atlantic rainforest, also called Mata Atlantica, is a narrow “green” corridor along the coast. Highly threatened by deforestation, it is today one of the most endangered forests in the world, with only 7% of its original surface left. However, it is home to one of the most important biodiversity reservoirs on Earth: 40% of its 20,000 plant species and 30% of its 2,315 animal species are endemic.
Apart from its tremendous scientific importance, the Mata Atlântica is also vital to the fight against global warming. Additionally, Mata Atlântica represents a major social resource, as it provides the cities along the coast of Brazil with water (these cities make up 60% of the national population and 70% of the GDP) and sustains many rural communities whose livelihoods are directly linked to the conservation of forest resources.
William Wayt Thomas, PHD, is Elizabeth G. Britton Curator of Botany at the New York Botanical Garden. He has been studying the Atlantic Coastal Forest in Northeastern Brazil for 20 years.
He answered our three questions:
1) What is a Tropical Forest?
The “tropics” are the vast area between the Tropic of Cancer and the Tropic of Capricorn. Therefore, it includes Central America and the West indies, most of Mexico and South America, most of Africa, and most of Asia south of China. Any forest in that area, whether wet or dry, would, of course, be tropical forest. But, what most people think of as tropical forest are tall, green jungles dripping with orchids and lianas. These are the rain forests or moist forests – forests that never dry out completely. A rain forest averages nearly a centimeter (0.4 inches) of rain a day! They can be up to 150 feet (50 m) tall, and normally have many lianas (woody vines) and epiphytes (plants that live upon other plants) such as orchids, bromeliads, and aroids. Compared to temperate (non-tropical) forests, they have high biological diversity – that is, they contain many, many species of plants and animals, almost all of which occur nowhere else.
2) Today, what are the major threats to the Tropical Forests?
The primary threat to tropical forests is the pressure for land. This pressure results in deforestation, where the forests are cut down to harvest timber, to grow crops (such as rice, pulp wood, sugar cane, and many others) or create pastures. This can be done on a large scale, where forests are cleared to plant thousands of hectares or acres of a crop, such as a eucalyptus plantation for paper, or pastures for beef cattle. Near the coast or near cities, forests may be cleared to build houses or beach vacation resorts. On the other hand, often the clearing is done on a small scale where a single family clears enough land to plant the crops they need to subsist. In some cases, these families follow loggers, who open roads into previously inaccessible areas to cut timber. The farmers follow and clear more forest.
3) As a great specialist of the Brazilian Atlantic Rainforest, the Mata Atlântica, which represents today only 10% of its original size and is endangered, what are the concrete issues that the disappearance of the rainforest raises in Brazil? And in the world?
The Atlantic coastal forests of Brazil, a World biodiversity “hotspot,” once extended 3000 km from Rio Grande do Norte south to Rio Grande do Sul, forming a fringe of forest usually 100-200 km wide sandwiched between the ocean and the dry uplands of the Planalto. The forests are ecologically diverse depending on rainfall, elevation, and soil type. They range from the Araucaria forests in the south, to montane rain forests of the Serra do Mar of Rio de Janeiro and São Paulo, to the seasonal forests of the Northeast.
About 60% of Brazil’s population lives in the area that was the coastal forest, or Mata Atlântica. Consequently, most of it has been deforested, with less than 8% remaining, and even less in the states of northeastern Brazil. Approximately half (and more for some groups) of the animal and plant species found in the Atlantic forests are found ONLY there. Therefore, if the part of forest some of those species inhabit is cut down, they are extinct – gone forever.
Why is that important? Does it matter if those species disappear? Man is the steward for the environment. Therefore, it is up to us to protect what exists in the World. Ecologically, diversity is important and a loss of diversity, in the long run, will lower the environment’s efficiency in recycling nutrients. Also, on a more concrete level, we are just opening the door on a future in which genetic research can be coupled with biochemistry. Soon we will be able to truly use the genetic resources stored in the biological diversity of tropical forests – but only if we protect it now.