The Conservation of Brazilian Reptiles: Challenges for a Megadiverse Country
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The Conservation of Brazilian Reptiles: Challenges for a Megadiverse Country MIGUEL TREFAUT RODRIGUES Departamento de Zoologia, Instituto de Biociˆencias, Universidade de S˜ao Paulo, Caixa Postal 11.461, S˜ao Paulo 05422-970, Brasil, email [email protected] Abstract: About 650 species—330 snakes, 230 lizards, 50 amphisbaenids, 6 caimans, and 35 turtles— comprise the known reptile fauna of Brazil. Only 20 are considered threatened. Except for the marine and freshwater turtles, which suffer from overexploitation and habitat destruction, they are threatened because of their rarity and extremely restricted ranges. Despite its richness and diversity, research on Brazil’s reptile fauna is still largely restricted to alpha taxonomy. Surveys, an electronic database of all herpetological collections, and phylogeographic studies based on molecular genetic techniques are needed to improve our understanding of the biogeography of this group and to delineate effective conservation strategies to preserve the evolutionary potential of existing lineages. Autecological, population, and community studies that monitor effects of habitat degradation, fragmentation, and loss, pollution, and exploitation are needed for a better understanding of the effects of the widespread and ever-worsening degradation of Brazil’s natural ecosystems. La Conservaci´on de Reptiles Brasilenos:˜ Retos para un Pa´ıs Megadiverso Resumen: La fauna conocida de reptiles en Brasil comprende cerca de 650 especies—330 serpientes, 230 lagartijas, 50 anfisba´enidos, 6 caimanes y 35 tortugas. Solo 20 son consideradas amenazadas. Excepto por las tortugas marinas y dulcecu´ıcolas, estan´ amenazadas debido a su rareza y distribucion´ extremadamente restringida. A pesar de su riqueza y diversidad, la investigacion´ sobre la fauna reptiliana de Brasil esta restringida principalmente a la taxonom´ıa alfa. Se requieren prospecciones, una base de datos electronica´ de todas las colecciones herpetologicas´ y estudios filogeograficos´ basados en t´ecnicas de gen´etica molecular para delinear estrategias de conservacion´ efectivas para preservar el potencial evolutivo de los linajes existentes. Se requieren estudios de contaminacion,´ explotacion,´ autoecologicos,´ de poblaciones y comunidades para monitorear efectos de la degradacion,´ fragmentacio´nyp´erdida de habitat´ para un mejor entendimiento de los efectos de la extensiva y cada vez peor degradacion´ de los ecosistemas naturales de Brasil. Taxonomy and Conservation tile fauna. Although unfinished, the result was a slightly lower figure of 629 species. The full list will be available Brazil has the richest fauna and flora of all of South and on the society’s Web site in 2005 (SBH 2004). Central America, but most information on reptiles is still Amazonia has the most lizards and amphisbaenids (109 preliminary. Today about 650 reptile species are recog- species). The Cerrado and the Atlantic Forest have 70 and nized as occurring in Brazil: 610 Squamata (330 snakes, 67 recorded species, respectively. Numbers are lower in 230 lizards, 50 amphisbaenids), 6 caimans, and 35 tur- the Caatinga (45 species) and transitional areas such as tles. These numbers are from a personal checklist, but the Pantanal of Mato Grosso and high-elevation moor- the Brazilian Herpetological Society (SBH) is working on land or campo rupestre (each with 12 species). If humid a consensus list, following a workshop in 2004 that as- forest enclaves in the Caatinga (the brejos of northeast- sessed the taxonomy and geography of the Brazilian rep- ern Brazil) are included, its number of species jumps to Paper received December 1, 2004; revised manuscript accepted January 17, 2005. 659 Conservation Biology, Pages 659–664 Volume 19, No. 3, June 2005 660 Conservation of Brazilian Reptiles Rodrigues 73, comparable to the Cerrado and the Atlantic Forest. plex groups, numerous new species sit in laboratories Amazonia also has the highest diversity of snakes (138 awaiting description. A reptile fauna endemic to an area species), followed by the Atlantic Forest (with 134), the of sand dunes in the Caatinga, along the middle stretches Cerrado (117), and the Caatinga (45). Caatinga remains of the Rio S˜ao Francisco, was discovered as recently as the in last place even when the brejos are included (the num- 1990s (Rodrigues 1996, 2003). This discovery resulted in ber rises to 78). The numbers of snake species in the the description of five new genera, increased the number Amazon Forest, the Cerrado, and the Atlantic Forest are of Brazilian Squamata by 25 species, and revealed some similar if one includes savannas in the count of Amazo- extraordinary biological adaptations previously unknown nian species, remnant patches of Amazonian forests in the for South America (Rodrigues & Junc´a 2002). Although count of Cerrado species, and open formations (savannas the reptile fauna of the Caatinga was considered well re- and campo rupestre) in the count for the Atlantic Forest. searched (Vanzolini et al. 1980), such unexpected dis- This similarity is explicable by the changes in the location coveries suggest how little we know of the patterns and and extent of forests and savanna in the Pleistocene and processes responsible for the evolution and differentia- early Holocene (Haffer 2001; Wang et al. 2004). Patterns tion of our fauna. We are still in the exploratory phase in of endemism among these biomes can best be assessed terms of our understanding of Brazil’s biological diversity, with lizards because many snakes and all amphisbaenids and no area should be regarded as having low biological are secretive, fossorial, and little known. Amazonia has importance without exhaustive inventories and field sur- 81 endemic lizards, the Atlantic Forest 40, the Caatinga veys. 25, and the Cerrado 16. A further 16 lizards are en- Phylogenetic studies using molecular techniques have demic to other formations, including sand dunes, restinga contributed greatly to our understanding of lineages (sandy coastal scrub and forest), campo rupestre, and dry within species or species groups. They have allowed for forests. revisions of taxonomically complex groups, frequently re- Although these numbers give an idea of the faunistic vealing unrecognized taxa and facilitating the reconstruc- differences between these major biomes, they are not di- tion of historic affiliations, contacts, and isolation events rectly comparable because some complex groups tend to among populations and between species: important for be more prevalent in one or another ecosystem, and some the recognition of isolated or distinct lineages. They have have received modern and thorough (if not exhaustive) also been key in developing conservation strategies, es- taxonomic revisions. A revision of the genus Tropidurus, pecially in patchy or isolated environments such as open forexample, increased the diversity of species typical of habitats in Amazonia (e.g., savannas and white sand scrub open areas (Rodrigues 1987; Frost et al. 2001). The same or campina), isolated forest patches in the Caatinga, and will happen when other genera, such as Cnemidopho- high-altitude moorland in the Atlantic Forest. Studies of rus,are revised, further increasing open-formation num- agekkonid, Gymnodactylus darwinii,ofthe coastal At- bers and endemism. Likewise, differences in the extent lantic Forest between Rio Grande do Norte and S˜ao Paulo, to which different regions and biomes have been inven- forexample, have demonstrated an accentuated genetic toried are still large enough to bias the numbers. variation resulting in a split into two species and the Except for possibly the Crocodylia, the size of the recognition that larger rivers are separating genetically Brazilian reptile fauna is still underestimated because of differentiated populations (Pellegrino et al. 2005). insufficient inventories and too few taxonomists. The Molecular systematics provides information on the ge- five largest reptile collections in the country—the Mu- netics of wide-ranging species or species groups in con- seum of Zoology (University of S˜ao Paulo); the Em´ılio tinuous habitat. Comparisons of the divergence patterns Goeldi Museum, Bel´em; the National Museum, Rio de of populations currently isolated in, for example, forest Janeiro; the snake collection of the Instituto Butantan, S˜ao patches in the Cerrado, with those of populations that Paulo; and the herpetological collection of the University were restricted and isolated in the past but are widespread of Bras´ılia—have yet to be fully entered into electronic today (i.e., those that differentiated in Tertiary or Quater- databases. Even when combined, they fail to represent nary forest refuges in the Amazon and the Atlantic Forest) many key areas and ecosystems: gaps that persist when are of great interest for setting priorities for protected ar- all of the country’s zoological collections are considered. eas. When supplemented with more refined autecological The geographical representation needed for exhaustive and metapopulation studies, these tools are indispensable systematic revisions for most genera is lacking, and, there- forabetter understanding of the dynamics of highly frag- fore,any certainty that current taxonomic arrangements mented landscapes. provide a true picture of the diversity. The Squamata, in general, are quite resistant to habitat Inventories in new areas frequently reveal new species. fragmentation. For a time, recently isolated forest frag- Irecently described two genera of gymnophthalmid ments