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

Abstract

Effectiveness of pitfall traps for sampling amphibians and reptiles in Brazil. The etfectiveness 01' pitt ll traps associated with drift fences to capture amphibians and reptiles in three field studies, in Rio Grande do Sul (extreme southern Brazil), S o Paulo (S o 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/pitt ll/month). At Itirapina, S o Paulo, 1262 amphibians and reptiles were obtained in 72 pitt lls (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 pitt lls (100- I 50 L, with drift fence) during three months (capture efticiencies ofca. 4.00 amphibians and reptiles/pitfall/month and 0.87 snake/pitt ll/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 Capture efficiencies of 1.25 to - 3.92 amphibians and reptiles/pitfall/month were obtained in four other unpublished studies made by other authors in Brazi l, ali ofthem using 20-35 L traps, either with or without drift fences.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 sall1ple 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 pitf lls during one 1l10nth, regardless ofthe size ofthe pitl lls and sall1pling design ofthe trap arrays. The main advantages and disadvantages ofthc method and detai led guidelines on how to design, install, and use the traps is discussed.