Levantamento de pequenos mamíferos em fragmentos de mata no Município de Cerro Largo - RS

Abstract

This research had the main goal to do a small mammal survey on small forest remnants in Cerro Largo, Rio Grande do Sul, Brazil. It also aimed (i) to describe the small mammal community richness, composition and species relative abundance; (ii) to verify the variation on vertical space use (ground x understory) and (iii) to analyze the relative efficiency of Sherman and Tomahawk traps. This small mammal research was realized on two small remnants of Atlantic forest on Cerro Largo, throw capture, mark, recapture, with Sherman and Tomahawk traps. With an effort of 1180 trap / night, 88 captures of 57 individuals were obtained. These individuals belong to four species, Akodon montensis, Oligoryzomys flavescens, Oryzomys sp. e Didelphis albiventris. The overall trap success was 7,5%. The trap success of the different methods were: 19,7% for Sherman traps displaced over the ground; 1,7% for Sherman traps displaced on the understory; 7,6% for Tomahawk traps displaced over the ground and 2,9% for Tomahawk traps displaced on the understory. The collected data indicate that the small fragments studied have a low species diversity and a high dominance, as A. montensis corresponds to 78% of all captures. The small mammal composition - presenting only species very common on anthropic areas - and the rareness of arboreal species - that use to be extinct on small forest fragments - also indicates that these communities present a high degree of anthropization. Regarding the different traps, the smaller ones - Sheman traps - had the best trap success, this is probable related with the small body size of the sampled animals.