Trap efficiency evaluation for small mammals in the southern Amazon

Abstract

The effectiveness of ecological researches on small mammals strongly depends on trapping techniques to survey communities and populations accurately. The main goal of this study was to assess the efficiency of three types of traps (Sherman, Tomahawk and Pitfall) to capture non-volant small mammals. We installed traps in 22 forest fragments in the southern Brazilian Amazonia. We captured 873 individuals belonging to 21 species; most of the individuals (N = 369) and species (N = 19) were trapped using Pitfalls, followed by Shermans (N = 271 individuals; N = 15 species) and Tomahawks (N = 233 individuals; N = 15 species). Pitfalls trapped a richer community subset of small mammals than the two other types of traps, and a more abundant community subset than Tomahawks. Proechimys sp. was the most abundant species trapped (N = 125) and Tomahawk was the most efficient type of trap to capture this species (N = 97 individuals). Neacomys spinosus and Marmosops bishopi were more trapped in Pitfalls (N = 92 and 100 individuals, respectively) than Shermans and Tomahawks. Monodelphis glirina was more trapped in Shermans and Pitfalls than Tomahawks. Species composition trapped using the three types of traps were distinct. Pitfalls captured a more distinct subset of the small mammal community than the two other live traps. We recommend the association of the three types of traps to reach a more comprehensive sampling of the community of small mammals. Thus, as stated by previous studies, we also recommend the complementary use of Shermans, Tomahawks and Pitfalls to account for a thorough sampling of the whole small mammal community in researches conducted in the tropical forests of Amazonia. KEYWORDS: Fragments, sampling techniques, abundance, community ecology Avaliação da eficiência de armadilhas para pequenos mamíferos no sul da Amazônia RESUMO A eficácia das pesquisas ecológicas de comunidade de pequenos mamíferos depende fortemente do uso de técnicas adequadas nas capturas durante as amostragens. O principal objetivos deste estudo foi avaliar a eficiências de três tipos de armadilhas (Sherman, Tomahawk e Pitfall) para capturas de pequenos mamíferos não-voadores. Nós instalamos armadilhas em 22 fragmentos de floresta no sul da Amazonia Brasileira. Nós capturamos 873 indivíduos de 21 espécies, a maior parte dos indivíduos (N=369) e espécies (N=19) foram capturados usando pitfalls, seguidos de Shermans (N=271 indivíduos, N=15 espécies) e Tomahawks (N=233 indivíduos, N= 15 espécies). Pitfalls capturou a maior riqueza da comunidade de pequenos mamíferos quando comparada aos outros dois tipos de armadilhas, e uma maior abundancia que Tomahawk. Proechimys sp. foi a espécies mais abundante capturada (N=125) e Tomahawk foi o tipo de armadilha mais eficiente para a captura desta espécie (N=97 indivíduos).Neacomys spinosus e Marmosops bishopi foram mais capturados em Pitfalls (N = 92 e 100 indivíduos, respectivamente) que Shermans e Tomahawks. Monodelphis glirina foram mais capturados em Shermans e Pitfalls que Tomahawks. A c...

Optimising sampling methods for small mammal communities in Neotropical rainforests

“…and abundance Rodent = Plus accepted as the best for sampling small mammals (Slade et al 1993, O'Farrell et al 1994, Santos-Filho et al 2006). More recently, researchers have found that the use of pitfall traps may increase their ability to sample small mammal communities and individuals (Gotelli & Colwell 2001, Umetsu et al 2006, Caceres et al 2011, Ribeiro-Júnior et al 2011, Santos-Filho et al 2015. Researchers also need to determine how much sampling effort to employ, and there has been enormous variation in the sampling effort used to estimate species richness and abundance (Steele et al 1984, Thompson et al 2007).…”

“…, Santos‐Filho et al. ). Researchers also need to determine how much sampling effort to employ, and there has been enormous variation in the sampling effort used to estimate species richness and abundance (Steele et al.…”

First record of Tweedy’s Crab-eating Rat, Ichthyomys tweedii Anthony, 1921 (Rodentia, Cricetidae, Sigmodontinae), for Costa Rica

“…Many researchers have demonstrated that combining different kinds of trapping methods or adding some variations to the classic techniques (e.g., Risch and Brady 1996;Santos-Filho et al 2015) can enhance trapping efficiency on small mammal communities and increase the reliability of the recorded diversity. Given that Ichthyomys tweedii is listed as Data Deficient by the IUCN and as Critically Endangered by Panama environmental authorities (Boada et al 2019), a detailed survey designed with the appropriate methods to capture this species in very specific localities could generate valuable ecological information with important implications on its local and global current conservation status.…”

A New and Simple Method to Capture Small Arboreal Mammals: The Suspended Pitfall

“…Ground pitfalls were also more effective than Sherman and Tomahawk traps in the southern Amazon. Most of the individuals and species were trapped using pitfalls (Santos-Filho et al, 2015). Despite the great effort to install ground pitfalls, its use has been increasing in recent years.…”