Comparação de métodos para captura da cuíca-d’água, Chironectes minimus (Zimmerman,1780) (Mammalia, Didelphidae) no sul do Brasil

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A falta de conhecimento acerca da biologia de Chironectes minimus provavelmente está relacionada com as dificuldades de captura. Assim, dois métodos usando armadilhas do tipo Young, com dois tipos de iscas, foram comparados com o método usual de captura (controle). O estudo foi desenvolvido de fevereiro a junho de 2003 em dois córregos do Parque Municipal da Lagoa do Peri, na Ilha de Santa Catarina, sul do Brasil. Quatro indivíduos foram capturados duas vezes e aspectos da biologia da espécie foram registrados. Todas as capturas ocorreram através do método controle. Armadilhas instaladas em passagens estreitas dos rios, em locais com maior quantidade de rochas e raízes, foram mais efetivas para a captura de C. minimus. O sucesso de captura, considerando apenas o método controle, foi de 4%. Aspectos positivos e negativos de todos os métodos foram apresentados e discutidos.


Comparison of methods for capture of water-opossum Chironectes minimus (Zimmerman, 1780) (Mammalia, Didelphidae) in southern Brazil. The lack of knowledge about the biology of Chironectes minimus is probably due to difficulties in capturing specimens. Therefore, two methods using “Young” traps with two types of live baits were performed and compared with the standard method (control). The study was carried out from February to June 2003 in two streams in the Parque Municipal da Lagoa do Peri, Santa Catarina Island in southern Brazil. Four individuals were captured two times and aspects of the biology of the species were recorded. All captures were made with the control method. Traps set on narrow passages of the river, with rocks and roots, were more effective to capture C. minimus. The capture success was 4% when only this method was considered. Positive and negative aspects of each method are discussed.

Efficiency of four trap types in sampling small mammals in forest fragments, Mato Grosso, Brazil

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We sampled the small mammal community inhabiting semi-deciduous forest fragments in Mato Grosso, Brazil, using 4 different types of traps, Tomahawk, Sherman, snap,
and pitfall, in order to evaluate the efficiency of different trap types in sampling efforts. During our study, we captured a total of 984 individuals of 27 species over 33800 trap nights. Sherman traps captured a significantly greater abundance of individuals and higher species richness than the other 3 types of traps. The Tomahawk and snap traps exhibited similar capture rates, in both the number of individuals and species captured. Pitfall traps captured the fewest numbers of individuals and species and were the only trap type to have different, although not significant, capture rates between seasons. Pitfall traps captured four times more individuals during the wet season than during the dry season. Despite their relative inefficiency and the large effort it takes to install pitfall traps, we found that these types of traps can be useful in augmenting trapping efforts, as they often capture species that do not, or rarely, fall into other types of traps.


La eficiencia de cuatro tipos de trampas en un relevamiento de micromamíferos en fragmentos de bosques en Mato Grosso, Brasil. Una comunidad de pequeños mamíferos fue estudiada en fragmentos de bosques semideciduos en el estado de Mato Grosso (Brasil) usando 4 tipos de trampas, de captura viva (Tomahawk y Sherman), de captura muerta (trampa de golpe: snap) y trampa de caída (pitfall). Considerando todos los tipos de trampas tuvimos un esfuerzo total de 33800 trampas/noche, habiendo capturado 984 individuos de 27 especies. Las trampas Sherman demostraron ser significativamente más eficientes que los otros tipos utilizados tanto para abundancia, como para riqueza de especies. Las trampas Tomahawk y snap demostraron tener eficiencias similares en número de individuos y en número de especies capturadas entre las áreas estudiadas. Cuando se comparó la eficiencia entre las dos estaciones del año, verano e invierno, solamente las pitfall capturaron más individuos durante la estación de invierno en relación al verano; a pesar de haber tenido casi cuatro veces más de capturas durante este período, los resultados no fueron significativos. Pese al gran esfuerzo para el montaje de las pitfall, es fundamental su uso como complemento de los muestreos, por ser este método capaz de capturar especies que difícilmente, o raramente, logran ser colectadas usando otros tipos de trampas.