Location and General Description
Caatinga is the largest dry forest region in South America and certainly one of the richest dry forests in the world. It encompasses the drier part of northeastern Brazil (Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Sergipe, Alagoas, Bahia, and northern Minas Gerais). Caatinga has very complex borders with Cerrado, Atlantic forest and Amazon, which have allowed a considerable biotic interchange among these regions during the evolutionary time. In general, Caatinga is located on crystalline or sedimentary depressions, whose continuity is broken by isolated plateaus distributed in mosaic fashion. Caatinga vegetation covers most of the ecoregion (Andrade-Lima, 1981). Botanists have recognized that the caatinga vegetation is so heterogeneous and diverse that one could correctly say that there is not one single caatinga vegetation, but several distinctive caatingas. That is the reason that some specialists termed this ecoregion as "caatingas region" rather than "caatinga region." Andrade-Lima (1981) recognized ten caatinga types that can be grouped into six large unities. Caatinga types range from low shrubby caatinga (up to 1 m tall) associated with shallow sandy soils and a level or gently undulating surface to tall caatinga forest (up to 25 to 30 m tall) associated with eutrophic soils derived from basic rocks. Climate is hot and dry with 6 to 11 dry months. The average annual rainfall varies between 250 and 1,000 mm, and the average annual temperature is between 24° and 26oC (Nimer, 1979). Caatinga harbors a unique biota, with thousands of endemic species. Every single biogeographic analysis in South America has pointed out Caatinga as an important area of endemism for different groups of organisms.
Although Caatinga’s biota is poorly known, studies so far have identified a very diverse and distinctive set of species. The biodiversity of Caatinga is made up of at least 1,200 species of vascular plants, at least 185 fish species, 44 lizards, 9 amphisbaenians, 47 snakes, 4 turtles, 3 crocodylia, 49 amphibians, 350 birds, and 80 mammals. The percentage of endemics is very high among vascular plants (around 30 percent), but somewhat lower among vertebrates (up to 10 percent). Invertebrates are poorly known, but it seems that most of them will turn out to be restricted to this ecoregion. Endemic species are not evenly distributed in the ecoregion, but concentrated in some special sites. For instance, among 41 species of lizards and amphisbaenians recorded from a system of paleodunes around Xique-Xique, Bahia, 40 percent are endemic to this small area (Rodrigues 2000). Caatinga endemics are also highly threatened. Among the ten most threatened birds in the world, two are Caatinga’s endemics: the indigo macaw (Anodorhynchus leari) and the little blue macaw (Cyanopsitta spixii).
Distinctive and endemic species include: plants, Godmania dardanoi, Cordia globosa, Billbergia fosteriana, Cereus jamacaru, Melocactus oreas, Pilosocereus gounellei, Copernicia prunifera, and Ziziphus joazeir; birds, Lear's macaw (Anodorhynchus leari), Spix macaw (Cyanopsitta spixii), and Moustached Woodcreeper (Xiphocolaptes falcirostris); mammals, a spiny rat (Proechimys yonenagae); and several lizards, Tropidurus amathites, Tropidurus divaricatus, and Tropidurus cocorobensis.
At least 50 percent of the Caatinga has been already been either completely converted from its native vegetation or modified in a major way (Casteleti et al. 2000). The severe overuse of caatinga for grazing and browsing for so many centuries has resulted in large-scale environmental modification of the region (Andrade-Lima, 1981). In addition, unsustainable timber extraction for fuel, extensive and uncontrolled fires and, more recently, cotton cultivation have all played critical roles in the nearly complete destruction of important regional ecosystems.
Types and Severity of Threats
As a result, a large area of the ecoregion is ranked today as highly threatened by desertification. In contrast with the huge proportion of the area under strong human pressure, less than 1 percent of the ecoregion is protected in parks or reserves. Several of these protected areas need to be implemented according to the best management guidelines. One of the best managed Brazilian National Parks is in the Caatinga: Parque Nacional da Serra da Capivara. This park combines two extraordinary features: an important set of Caatinga’s biota and one of the most important archeological sites in South America.
Justification of Ecoregion Delineation
The caatinga ecoregion comprises a large section of eastern Brazil. Delineation’s for the ecoregion follow IBGE (1993), and linework follows their classification of the following: "open shrubland caatinga", "dense shrubland caatinga", "park caatinga", and all enclosed "secondary vegetation and agricultural activities" under the greater caatinga classification. Linework was reviewed at an ecoregional workshop (. 10-14 August, 1999, Atibaia, Sao Paulo, Brazil). Information from this workshop is available in Conservation International do Brazil et al. (1999).
Andrade-Lima, D. 1981. The caatingas dominium. Revista Brasileira de Botânica 4: 149-153.
Conservation International do Brazil, Fundacao SOS Mata Atlantica, Fundacao Biodiversitas, Instituto de Pesquisas Ecologicas, Secretaria do Meio Ambiente do Estado de Sao Paulo, SEMAD/Instituto Estadual de Florestas-MG. Brasilia. 1999. Avaliacao e acoes prioritarias para a conservacao de biodiversidade de Mata Atlantica e Campos Sulinos, MMA/SBF, 2000. 40p.
Experts workshop for ecoregional priority setting. 10-14 August, 1999, Atibaia, Sao Paulo, Brazil
Nimer, E. 1979. Climatologia do Brasil. Rio de Janeiro: IBGE/SUPREN.
Casteleti, C.H., J.M.C. Silva, , A. Santos, y M. Tabarelli. 2000. Quanto ainda resta da Caatinga? Uma estimativa preliminar. Report presented to Workshop "Avaliação e Identificação de Ações Prioritárias para a Conservação, Utilização Sustentável e Repartição de Benefícios da Biodiversidade do Caatinga http://www.biodiversitas.org/caatinga.
Fundação Instituto Brasilero de Geografia Estatástica-IBGE. 1993. Mapa de vegetação do Brasil. Map 1:5,000,000. Rio de Janeiro, Brazil.
Rodrigues, M. T. 2000. A fauna de répteis e anfíbios da caatinga. Report presented to Report presented to Workshop "Avaliação e Identificação de Ações Prioritárias para a Conservação, Utilização Sustentável e Repartição de Benefícios da Biodiversidade do Caatinga http://www.biodiversitas.org/caatinga.
Prepared by: Jose Maria C. da Silva
Reviewed by: In process