Factors that interfere with the estimation of bat richness in Atlantic Forest, southeastern Brazil

Abstract

Capture success of bats can be affected not only by local bat density, but also by several methodological aspects. Many factors interfere with the sampling completeness and capture success of bats. Considering the variety of sampling methods used for investigating, the objective of the present study is to analyze different factors that interfere with sampling completeness and species richness estimates of bats. To carry out the present study, we used data from the State of Rio de Janeiro from inventories carried out from 1989 to 2013 by the Laboratory of Bat Diversity and data from the literature until 2023. We analyzed the following parameters: number of sampling nights, period of nocturnal sampling, number of sites where the mist nets were opened, sampling in diurnal roosts, and moon phase. We observed that the localities with more than 30 species recorded had huge sampling efforts. For studies based on a small capture effort, the active search for roosts during the day increases the probability of recording species found mainly in high sampling effort studies. The most complete inventories are those with a sampling effort of at least 24 nights, including sampling in different habitats, such as trails, water bodies, and close to fruiting plants, as well those including search for day roosts and with fieldwork not restricted to a specific moon phase. Mist nets should be set up not only on trails and close to fruiting trees, but also over water bodies to increase the probability of recording insectivorous species.