Capture sequence and relative abundance of bats during surveys

ABSTRACT

It is expected that rare species will be gradually added to biodiversity surveys over time and that complete inventories will include rare species. The objective in the present work is to test whether the capture sequence of species during a bat survey is related to species abundance. Species with capture rates lower than 0.01x10-3 captures/hour-net were considered rare. At Ilha da Gipóia, rare species accounted for 22.22% of the total and, at Rio das Pedras Reserve, they represented 30.00%. The existence of a negative relationship between the relative abundance and the first night of capture of each species for the Ilha da Gipóia and the high significance level for the accumulation curve at both localities suggest that the documentation of a large number of rare species depends on a sustained capture effort. The common species were captured at the beginning of the field work and the remaining species were typically added to the collection according to their approximate relative abundance. However, rare or seldomly captured species were added at random.