Atlantic Forest

Gustavo A.B. da Fonseca^{1, 2, 13}, Anthony Rylands², Adriano Paglia⁵ and Russell A. Mittermeier¹

The Atlantic Forest, or Mata Atlântica, is a unique series of South American rainforest ecosystems quite distinct from the more extensive Amazonian Forests. It once extended almost continuously from the states of Rio Grande do Norte and Ceará in northeastern Brazil south to Rio Grande do Sul, and included the typical Atlantic coastal forest on the narrow, low-lying coastal plain, the forests on the foothills of the Serra do Mar and related mountain ranges that run roughly parallel to the coast, and the forests on the slopes of the Serra do Mar itself, reaching up to 1 800–2 000 m. In northeastern Brazil, these forests covered only a narrow coastal strip, rarely exceeding 50–100 km in width, and were replaced inland by drier Caatinga and Cerrado formations typical of the Brazilian interior. The Atlantic Forest also extends into eastern Paraguay, Misiones in extreme northern Argentina, and narrowly along the coast into Uruguay. Due to its widespread destruction, rampant even in the early sixteenth century, it is now difficult to know the region's original extent; however, as we define it here, it originally covered 1 233 875 km², including mangroves and restinga, or sandy coastal scrub, and those portions in Paraguay, Argentina, and Uruguay. We also include the offshore archipelago of Fernando de Noronha and its neighbor Atol das Rocas, which belong to the Fernando de Noronha Chain of submerged volcanic mountains in the equatorial Atlantic Ocean 350 km off the coast of northeastern Brazil.

Altitude determines at least three vegetation types in the Atlantic Forest: the woodlands of the coastal plain, the slope forests, and the high-altitude woodlands (Joly et al. 1991). This gradient influences, in turn, the pattern of richness and composition of the plant communities. Oliveira-Filho and Fontes (2000) found that increasing altitude affects the composition of woody plants, augmenting the relative abundance of species of the families Asteraceae, Melastomataceae, and Solanaceae, and reducing the legumes. In the most inland areas of this biome, the dominant vegetation is semideciduous, while mixed formations dominated by Araucaria angustifolia can be found in the coldest southern areas. Both in the coastal and high-plain areas, the family with the highest species diversity is the Myrtaceae (more than 300 species), while the most speciose genus is Eugenia (with more than 100 of the 3 500 woody species found in this biome). Overall, more than 8 000 of an estimated 20 000 species of plants (or 40%) are thought to be endemic. Endemism in trees is particularly high, with approximately 54% being restricted to the region, compared to about 30% for higher plants in general (Mori et al. 1981).

Vertebrate diversity and endemism in this hotspot are markedly high. There are 263 mammal species known to occur in the Atlantic Forest, of which 71 are endemic, including the thin-spined porcupine (Chaetomys subspinosus, VU) and painted tree rat or cocoa rat (Callistomys pictus), which are both representatives of monotypic endemic genera, and the maned sloth (Bradypus torquatus, EN), an unusual and larger relative of the widespread three-toed sloths (B. tridactylus and B. variegatus). One particularly notable endemic is the Brazilian arboreal mouse (Rhagomys rufescens, CR), the sole representative of an endemic genus, known only from two specimens collected from Rio de Janeiro, and very likely Extinct. In total, the Atlantic Forest has a remarkable 12 endemic genera, including also two endemic and threatened primate genera which represent the region's primary flagship species, the lion tamarins (Leontopithecus spp.), of which there are four species, and the muriquis (Brachyteles spp.), with two. Conservation efforts for the lion tamarins have demonstrated the importance of international cooperation between universities, zoos, national and international NGOs, and the Brazilian Government; this has resulted not only in their protection, but also the preservation of their remaining forests (Kleiman and Rylands 2002). The two Brachyteles species are the largest of the New World primates. As with the lion tamarins, conservation efforts and research focused on them have resulted in numerous initiatives protecting primate habitat and have also involved training of many Brazilian conservationists (Strier 1999).

About 936 birds have been recorded from this hotspot, 148 of them endemic. There are also 22 endemic genera. No fewer than four Endemic Bird Areas (EBAs) have been identified in the region (Stattersfield et al. 1998), the Atlantic Forest Lowlands being one of the most important in South America, with a total of 52 species and 10 genera confined to this single EBA. More recent work has also identified 161 Important Bird Areas in the hotspot (Bencke and Maurício 2002). There are several outstanding avian flagships, including the Alagoas curassow (Mitu mitu, EW), a large cracid of the lowland Atlantic Forest of northeastern Brazil that was last seen in the wild in 1987 and is now held only in captivity (Stattersfield et al. 1998), and the related red-billed curassow (Crax blumenbachii, EN), found further south in the Atlantic Forest Lowlands, especially in the State of Espírito Santo in the large Sooretama Biological Reserve. The Brazilian merganser (Mergus octosetaceus, CR) is an important flagship for the southern Atlantic Forest in Brazil and Misiones. Finally, one of the most spectacularly colored of all birds is the sevencolored tanager (Tangara fastuosa, EN), also from northeastern Brazil; it has declined mainly due to habitat destruction and live capture for the pet trade.

Reptile species in the hotspot number 306, of which 94 species and eight genera (four of them monotypic) are endemic. The wormlike subterranean reptiles of the genus Amphisbaena are particularly well represented, with 20 species, although endemism is low with only two species endemic, one of them, A. ridleyi, endemic to Fernando de Noronha. Endemism is perhaps most marked in the genus Bothrops, with nine endemics of the 17 species present. Amphibian diversity is very high, with 483 species having been recorded from the Atlantic Forest, of which a remarkable 286 are largely endemic. There are also 23 endemic genera; the most speciose are Cycloramphus with 25 species and Hylodes with 20, while seven genera are represented by single species. There is also a single endemic family, the Brachycephalidae, represented by six species of the genus Brachycephalus.

Among the remaining vertebrates, there are at least 350 fish species known to occur in the hotspot, of which 133 are endemic; in addition, 10 of the 68 genera represented are endemic. Invertebrates are not well known, although 63 of 88 tiger beetle species recorded from the hotspot are endemic (D. Pearson, pers. comm.), as are 948 of 2 120 butterfly species (Brown and Freitas 2000).

Prince Maximilian zu Wied-Neuwied of Germany was one of the first scientists to travel through the Atlantic Forest. When he carried out his expedition in the early nineteenth century, he found some of the richest, tallest, and most impressive forests on Earth. But even then some regions had already been colonized for more than two centuries, and were showing the effects of widespread habitat destruction. Indeed, the Atlantic Forest was the first region of Brazil to be colonized. It has always been the most heavily populated part of Brazil (108 million or 60% of the population of Brazil), and is the agricultural (particularly sugar cane, coffee, cacao, and livestock) and industrial center of the country. Two of the three largest cities in all of South America, São Paulo and Rio de Janeiro, are only about 400 km apart in the central portion of the Atlantic Forest.

Dean (1995) and Coimbra-Filho and Câmara (1996) reviewed the history of the destruction of these remarkable forests, which has been especially severe in the low-lying coastal regions and the long-exploited northeast (Sergipe, Alagoas, and Paraíba), where less than 1% remains. In the Brazilian portion of the Atlantic Forest, only about 78 348 km² of forest remain, mostly represented by second-growth forests in advanced stages of regeneration (INPE and SOS Mata Atlântica 1997). The best-preserved areas are along the steep slopes of the coastal mountains of the states of Rio de Janeiro, São Paulo, and Paraná. In Paraguay, Barboza et al. (1997) estimated that only 11 618 km² (13.2%) of the original 88 050 km² of forest was still intact (see Cartes 2003). Considerable deforestation has been taking place since then. Only about 10 000 km² of the socalled Paraná Forest (once covering approximately 22 350 km²) remains in Misiones, Argentina (Chebez and Hilgert 2003). Combining these figures, we arrive at a total of 99 966 km², or about 8.1%, of the Atlantic Forest left in intact condition. This habitat loss has left large numbers of the region's endemic species severely threatened with extinction (Brooks et al. 1999).

Much of what remains of the Brazilian Atlantic Forest is under various forms of protection. According to the World Database on Protected Areas, only 4.1% of the Atlantic Forest Hotspot is under some form of legal protection, although this drops to 1.8% when one considers only those in IUCN categories I to IV. A recent study looking at the state of protected areas in Brazil revealed that, as of December 2003, there were 100 national and state parks (19 717 km²), 28 federal and state biological reserves (1 848 km²), and 77 federal and state ecological stations and reserves (1 598 km²) in the Brazilian Atlantic Forest, totaling 205 strictly protected areas covering 23 163 km² (Rylands et al. 2004). If one includes the various areas officially reserved for sustainable use (mainly Environmental Protection Areas), this protected area coverage is increased somewhat, although levels of protection vary. In neighboring countries, eight protected areas totaling 1 392 km² exist in the Atlantic Forest portion of eastern Paraguay, and cover 1.6% of its original extent (Cartes 2003), while in Misiones, there are 60 protected areas of various categories, totaling about 4 598 km², or 21% of the original extent of Atlantic Forest in that Argentinian province (Chebez and Hilgert 2003). In addition to lands protected by the government, there is also an important legal mechanism for private protection in Brazil known as the Private Natural Heritage Reserve Program (Reserva Particular do Patrimônio Natural- RPPN). Since 1990, more than 500 areas of this kind (covering about 4 500 km²) have been created, mostly in the Atlantic Forest and the Cerrado.

In 1997, a groundbreaking study, commissioned by the World Bank and carried out by the Wildlife Conservation Society and Conservation International, proposed a major project to establish extensive forest corridors in the Atlantic Forest and Brazilian Amazonia (Ayres et al. 1997). Some will have over 8 million ha of continuous habitat, with the existing protected area system as the backbone. Seven such areas have been identified using biological indicators such as species richness and levels of endemism. These corridors, covering only 15%–20% of the total area of these two major regions, are estimated to contain over 75% of the rainforest diversity in the country. With some $44 million coming from the Pilot Program to Conserve Brazilian Rain Forests (PP-G7; administered by the World Bank), two corridors —one in the Atlantic Forest and one in the Amazon— will be established during the next four years to test this innovative approach. The first Atlantic Forest corridor focuses on southern Bahia and Espírito Santo. This is only one of a host of important conservation initiatives being carried out in the Atlantic Forest.

Although a retrospective of what has happened in the Atlantic Forest may look rather grim, new conservation instruments and funding mechanisms —most of them using up-to-date scientific information to orient investments—, combined with the largest body of well-trained conservation professionals in the whole of South America, greatly increase the likelihood that a significant portion of what remains of the Atlantic Forest's biodiversity will be maintained. In one major development, the Alliance for the Conservation of the Atlantic Forest launched a four-year small grants program in 2003 to help local organizations work directly with private landowners in managing existing RPPNs and to create new ones —a move that will substantially increase the number of private reserves in the two conservation corridors within this hotspot. The alliance of Conservation International-Brazil and SOS Mata Atlântica is implementing the program as a core part of the $8-million Critical Ecosystem Partnership Fund investment strategy for the Brazilian part of this hotspot.

The Atlantic Forest region was also the cradle of the Brazilian environmental movement, with the growth of NGO capacity there over the past 30 years being among the most impressive in the tropical world. The most recent survey indicated that there were approximately 700 environmental NGOs active in Brazil; about 30 of these have annual budgets of over $300 000 and about 20 are national in scope (Fonseca and Pinto 1996). Indeed, although it clearly rates as one of the highest-priority hotspots on Earth and has already lost over 90% of what once existed, it is fair to say that of those hotspots found within developing countries, the outlook for the Atlantic Forest region is undoubtedly one of the brightest.

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