Biological Importance 

The high biodiversity in the Atlantic Forest is a function of the extreme environmental variation in this biome. One of the most important factors in this variation is the 38º latitudinal span of the hotspot. The geographic distribution of lizards in the Atlantic Forest, for example, is significantly affected by latitude, with only one wide-ranging species in this area. The second major source of variation is elevation, as forests extend from sea level up to 1,800 meters, with corresponding gradients of biodiversity. Finally, inland forests differ considerably from coastal ones. These factors combine to generate a unique diversity of landscapes supporting extraordinary biodiversity.

The complexity of this biome can be illustrated by the definition and delimitation of Atlantic Forest vegetation in the Federal Decree 750/93, which regulates the use of natural resources and deforestation in the region: "The Atlantic Forest is to be considered as forest formations and associated ecosystems inserted in the Atlantic Forest domain, with the following delimitations established by the Brazilian Vegetation Map of IBGE (1988): ombrophilous dense atlantic forests; mixed ombrophlilous forests; open ombrophilous forests; semidecidual stational forests; decidual stational forests; the countryside swamps, the northeastern forest enclaves and the associated ecosystems - mangroves and restingas

Less than 8 percent of the original forest now remains, and it occurs mostly in isolated remnants scattered throughout a landscape dominated by agricultural uses. Deforestation is much more severe in the states of northeastern Brazil, where only 1-2 percent of the original cover remains, mostly in southern Bahia. In the states of the Central Corridor (Bahia and Espírito Santo) and Serra do Mar Corridor (Rio de Janeiro, part of Minas Gerais and São Paulo), the amount of remaining forest ranges from 2.8 percent in Minas Gerais to 21.6 percent in Rio de Janeiro, with intermediate values in São Paulo, Espírito Santo and Bahia.

Despite these disturbances, the Atlantic Forest and its associated ecosystems (restingas and mangroves) is still extremely rich in biodiversity, sheltering a significant proportion of the national total, with high levels of endemism. The Atlantic Forest contains an estimated 250 species of mammals (55 endemic), 340 amphibians (90 endemic), 1,023 birds (188 endemic), and approximately 20,000 trees, half of them endemic. For some higher taxa, like primates, more than two-thirds are endemic.

Centers of endemism have been recognized in the Atlantic Forest. Scientists believe that during the much drier conditions of the Pleistocene, there was a drastic reduction of the forest area in the Amazon and in the Atlantic Forest regions, resulting in "island" refuges in which only a few species could find favorable conditions. The long period of isolation led to species differentiation. When more favorable climatic conditions returned, thousands or millions of years later, vast areas of forest recovered, linking fragmented refuges. The extent and position of these centers is a matter of controversy, but most experts believe that at least four centers can be recognized in the Atlantic Forest, considering information for terrestrial vertebrates, forest butterflies, and plants: one in the northeast (Sergipe/Alagoas/Pernambuco), one in southern Bahia, one in northern Espírito Santo (Rio Doce center), and one in São Paulo (Paulista center). The region of the Central Corridor includes, therefore, one or two centers of endemism, and the Serra do Mar corridor is located in another center.

Prioritization of Corridors Within the Hotspot

Very recent analysis suggests that the distribution of wild birds, mammals, and butterflies - the most well-documented animal groups in the Atlantic Forest - indicates the existence of six bioregions: the Northeastern Swamps, Pernambuco, São Francisco, Diamantina, Bahia, and Serra do Mar. Bahia and Serra do Mar overlap with the Central and Serra do Mar corridors, respectively. The corridors are dominated by dense ombrophilous forest, including wet forests in flat, low-lying terrain in the Central Corridor (less than 200 meters above sea level) or in the slopes of Serra do Mar and Serra da Mantiqueira (200-2,000 meters above sea level), and small forest formations over recent marine sediments close to the sea, generally called restingas, as well as mangrove forests along estuaries.

Central Corridor

The Bahia Bioregion is an area of 120,954 square kilometers extending from Sergipe to Espírito Santo. Originally, 83 percent of this region was covered with dense ombrophilous forest, with small patches of mangroves, restingas, semideciduos forest, cerrados, and open ombrophilous forest. Currently, about 12 percent of the area remains covered by native forest. The region is known as an important area of endemism for several groups, including vertebrates, forest butterflies, and plants. For the purposes of CEPF, the Central Corridor is part of this bioregion, being limited in the north by the Jequiriçá River, the agrosystem division limit according to Ceplac for Southern Bahia. The Central Biodiversity Corridor of Atlantic Forest covers about 8.6 million hectares and represents about 75 percent of the Bahia Bioregion.

The Central Corridor is biologically diverse and supports many species of restricted distribution, including some threatened groups. For example, in a survey carried out in a privately owned reserve near Una, Bahia, 454 species of trees were found in a plot of one hectare, a world record for plant species richness. Another study conducted in a lower montane habitat (600-900 meters) in north-central Espírito Santo (Santa Lúcia Biological Station) revealed 443 tree species in an area of equivalent size.

Between Bahia and Espirito Santos States, the region is also unique because of the presence of several Amazonian taxa typically associated with the Atlantic coast, and by great species diversity. Spanning 44,000 hectares, central Espírito Santo is one of the main sections of dense ombrophilous forest, in the typology of Tabuleiros Forest, created by the connection of the Reserva Biológica de Sooretama with the Reserva Florestal de Linhares. When compared with other Neotropical forest formations, the Tabuleiros Forest is unusual in its high diversity of species and high density of lianas.

The Central Corridor presents a high number of endemic and threatened species of mammals and birds. The communities of primates in Southern Bahia and in the highlands of Espírito Santo are particularly interesting, because these are among the very few areas where all six Atlantic Forest genera of primates occur in sympatry. Twelve primate species occur in the region and represent 60 percent of the primates endemic to the Atlantic Forest.

Bahia is exceptionally high in bird diversity, with five new species and a new genus (Acrobatornis fonsecai) recently described in the mountainous and coastal cocoa-growing regions in the south and central parts of the state. The Central Corridor contains more than 50 percent of the birds endemic species of Atlantic Forest. The corridor is also particularly rich in amphibians and reptiles, with high level of endemism for these animals. At least 12 new species of anuran amphibians have been described recently in the Central Corridor.

The states of Bahia and Espírito Santo combined have 61 protected areas, 43 of which are strictly protected. In terms of area, state-owned protected areas cover 68% of the total protected land, and they have, in the average, 8,711 hectares. The federal government manages 11 protected areas, which cover 110,608 hectares.

Southern Bahia is the region where most Brazilian cocoa is produced, in a system known locally as cabruca. In this system, only 25-35 native species of trees are left per hectare to provide shade for the cacao tree, which dominates the undergrowth with 891 cacao trees per hectare. About 650,000 hectares of cocoa are cultivated in Bahia, 70% under the cabruca system. Although significantly disturbed, the cabruca forest supports a variety of native plants and animals, and helps to connect protected areas (such as Una Biological Reserve and Nova Esperança Ecological Station).

In extreme southern Bahia lies one of the most important blocks of forest in the Central Corridor, including four national parks - Descobrimento, Monte Pascoal, Pau-Brasil, and Abrolhos - protecting a total of nearly 50,000 hectares of forest and 90,000 hectares of marine areas. The small river basins protected by these national parks are extremely important not only to Atlantic Forest biodiversity, but to the coral reefs and other marine ecosystems in the Abrolhos Bank and the Abrolhos Marine National Park, the richest coral reef area in the South Atlantic.

The entire territory of Espírito Santo lies within the Atlantic Forest; proportionally, this is the state most devastated. Pastures, coffee, and Eucalyptus have replaced most of the forest. Only 8.4 percent of the original forest remains, and most of it is fragmented. Of the 372,862 hectares of native forest in the state, only 19.4 percent (72,263 hectares, or 3% of the state) are currently managed and officially protected with public access; the remaining 300,000 hectares are private property.

The devastation of the Atlantic Forest in Espírito Santo and Bahia makes the enforcement of protected areas, as well as the creation of new ones, a top priority. Suitable new protected areas have already been identified; however, there are not enough human and financial resources to manage the existing ones. Central problems include lack of financial resources to implement management plans; insufficient technical personnel and equipment to direct and guard the units; poaching of forest products; and intentional fires.

Serra do Mar Corridor

The Serra do Mar Bioregion is an area of 111,580 square kilometers extending from Rio de Janeiro to northern Rio Grande do Sul. Currently, about 30.5 percent of the area remains covered by native forest. Originally, 95 percent of this region was covered with dense ombrophilous forest, including patches of mangroves and restingas. For the purposes of CEPF, this corridor is defined in the south by the Paraíba do Sul watershed and in the north by the Paraíba do Sul river. The Serra do Mar Biodiversity Corridor covers about 7.5 million hectares and represents about 35 percent of this bioregion. The area proposed to be treated by the CEPF does not include northern Paraná and southern São Paulo, because those areas have many NGOs, academic institutions (some with the greatest technical capacity in Brazil), and state governments with strong environmental programs. Furthermore, compared with other regions in Atlantic Forest, the excluded areas have access to considerable funding for conservation projects.

The Serra do Mar Corridor is one of the richest biodiversity areas in the Atlantic Forest. It encompasses several distinct ecosystems, such as submontane forests, montane forest, restingas, and mangroves. The northern Serra do Mar, especially in Rio de Janeiro state, is the subregion of the Atlantic Forest with the greatest concentration of endemic species for many groups and the greatest concentration of threatened species of birds.

The coastal streams in the state of Rio de Janeiro have the highest level of fish endemism in the Atlantic Forest. An example is the São João river basin, a priority area identified in the Conservation Priority-setting Workshop for the Atlantic Forest, where the lowland rivers and hillside streams are of extreme biological importance owing to their high diversity, high level of endemism and the presence of unique fish communities. Twelve areas in the Serra do Mar Corridor were assigned the highest priority for conservation within the Atlantic Forest, based on biodiversity and endemism. The Serra dos Órgãos, for example, stands out as a continuous forest of the montane and high montane type, showing impressive levels of endemism, richness of invertebrates, and numbers of threatened species of mammals, amphibians, and reptiles. In this region, many forest fragments are now part of protected areas, making them suitable for long-term conservation action and investment - particularly the implementation of corridors to increase connections. The Itatiaia region, between Rio de Janeiro and Minas Gerais, also features high levels of endemism.

The Serra da Mantiqueira Mountains in the Serra do Mar were also considered a conservation priority for the state of Minas Gerais. This region also has high diversity of plants and animals, including many endemic species of amphibians and reptiles and the greatest diversity of small mammals in the Atlantic Forest.

The restingas also support important endemics. The Restinga of Jurubatiba, on the north coast in Rio de Janeiro State, is one of the best-preserved restingas of Brazil. Jurubatiba Park shows a great mosaic of well-defined ecosystems, with many rare, endemic, or Threatened species. This area can be considered a refuge for species already extinct in other regions of Rio de Janeiro, where the restingas are degraded or have already disappeared.

The Serra do Mar region includes the largest remaining block of Atlantic Forest sensu stricto (dense ombrophilous forest), formed by the slopes and tops of Serra do Mar and Serra da Mantiqueira, and adjacent flat lowlands. Although these forests are near the two largest metropolitan areas in Brazil (the cities of São Paulo and Rio de Janeiro), they remain well-preserved, thanks to steep slopes that are not suitable for agriculture. Here the federal government owns 38 percent of the existing protected areas, and the average size of the protected areas in the Serra do Mar Corridor is over 35,000 hectares - 40,000 hectares for the federal reserves. The region presents one the most important protected areas of the Atlantic Forest (e.g. Serra dos Órgãos National Park, Serra da Bocaina National Park, and Itatiaia National Park) that harbor an extremely high concentration of endemic and Endangered species. This presents a more favorable prospect for long-term survival of native species in this part of the Atlantic Forest than in other regions.

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