Eficiência de armadilhas de queda (pitfall traps) em amostragens de anfíbios e répteis no Brasil

Revista Brasileira De Zoologia - REV BRAS ZOOL 01/2000; 17(3). DOI: 10.1590/S0101-81752000000300017

ABSTRACT Effectiveness of pitfall traps for sampling amphibians and reptiles in Brazil. The etfectiveness 01' pittàll traps associated with drift fences to capture amphibians and reptiles in three field studies, in Rio Grande do Sul (extreme southern Brazil), São Paulo (São Paulo, southeastern Brazil), and Amazonas (Amazonas, northern Brazil) is described. At Santa Maria, a total of 2040 amphibians and reptiles were caught in 30 pitfalls (200 L, with drift fence) during 18 months ofstudy (capture efficiencies of 3.78 amphibians and reptiles/pitfall /month and 0.14 snake/pi-ttà ll/month). At Itirapina, São Paulo , 1262 amphibians and reptiles were obtained in 72 pittà ll s (100 L, with drift fence) during six l110nths (capture efficiencies of I 1,9 amphibians and reptiles/pitfall/month and 0,38 snake/pitfall/month). At Rio Pitinga, Amazonas, over 600 amphibians and reptiles were caught in 50 pittàlls (100-I 50 L, with drift fence) during three months (capture efticiencies ofca. 4.00 amphi bians and reptiles/pitfall/month and 0.87 snake/pittàll/month). Capture efficiencies of 1.25 to -3.92 amphibians and reptiles/pitfall/month were obtained in four other unpublished studies made by other authors in Brazi l, ali ofthem using 20-35 L traps, either with or without drift fences. Higher capture efficiencies for snakes were obtained in those studies in which larger containers (100-200 L) were used. The resuJts presented here indicate that pitfall traps are extremely useful to sall1 ple all1phibians and reptiles in Brazil, especially anurans and lizards. From these results, it is possible to preview the capture of 125 to 1200 all1phibians and reptiles with 100 pitfàlls during one 1l10nth, regardless ofthe size ofthe pitlàlls and sall1pling design ofthe trap arrays. The main advantages and disadvantages ofthc method and detai led guide lines on how to design, install , and use the traps is disc ussed. Armadilhas de interceptação e queda consistem de recipientes enterrados no solo (pitfalls) e interligados por cercas-guia (driftlences; CORN 1994). Quando um pequeno animal se depara com a cerca, geralmente a acompanha, até eventualmente cair no recipiente mais próximo. Estas armadilhas são amp lamente utilizadas para a amostragem de anfíbios, répteis e pequenos mamíferos (e.g. SEMLITSCH et aI. 1981; MENGAK & GUYNN 1987; WILLIAMS & BRAUN 1983). Uma das vantagens do método é a captu ra de animais que raramente são amostrados através dos métodos tradicionais que envo lvem procura visual (CAMPBELL & CHRISTMAN 1982).

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