The importance of sampling methods and landscape variation on explaining small mammal communities in a Neotropical ecotone region

Understanding the main patterns that affect biodiversity in local and biogeographic scale is central in ecological and conservation studies. Here, we investigated the trappability of small mammals by different methodologies in a fragmented landscape on Atlantic Forest-Cerrado ecotone, and compared the estimated richness and composition of this study community with small mammals surveyed in central Brazil phytogeographic domains. We compared the number of captures between trap type, trap position and the interaction between these variables using a generalized linear mixed model, and compare our findings with those from published data in a radius of 1000 km, using rarefaction and extrapolation methods. Pitfall traps were essential in capturing Monodelphis kunsi, Calomys tener and Oligoryzomys fornesi, whereas wire-cage traps were more efficient on capturing Didelphis albiventris. Calomys expulsus and D. albiventris were significantly more captured in traps on the ground, and Gracilinanus agilis, Marmosa murina, Oecomys bicolor, O. catherinae and Rhipidomys macrurus had more captures in traps on understory. The use of different trap types, mainly pitfall traps, as sampling the vertical strata of habitat, is a good strategy for achieving the completeness sampling of small mammals in the Neotropics. The relative lower small mammal richness in Atlantic Forest-Cerrado ecotone compared to other domains could be explained by the historical higher habitat loss reported for this ecotone zone; thus, we highlight the need of conservation efforts for the preservation of small mammals and else biota that inhabit such type of environment.

Automated summary

This study found that different trap types had varying efficiency in capturing different small mammal species, with pitfall traps being more important for certain species, while ground traps also had unique advantages. The lower small mammal richness in the Atlantic Forest-Cerrado ecotone compared to other regions may be attributed to the historically higher habitat loss in this area.