Bat diversity of Ilha da Marambaia, Southern Rio de Janeiro State, Brazil (Chiroptera, Mammalia)

Patterns and drivers determining phyllostomid bat diversity in land-bridge islands off the south-east coast of Brazil

Few studies that apply the theory of island biogeography have considered the functional and phylogenetic dimensions of diversity. However, the joint use of the three diversity dimensions, i.e. taxonomic, functional and phylogenetic, can help us to gain a better understanding of the mechanisms underlying ecological and evolutionary processes. Here, we compare phyllostomid bat assemblages between five land-bridge islands off the south-east coast of Brazil and compare these islands with three sites on the mainland. For this, we have estimated the three dimensions of α- and β-diversity, nestedness and community indexes based on mean trait values for the islands and the mainland. The mainland showed higher species richness and taxonomic, functional and phylogenetic diversity. In addition, only species richness and phylogenetic diversity were positively related to island area. Taxonomically and functionally, the poorest assemblages (minor islands) were subgroups of the richer assemblages (mainland and larger islands). Taken together, our results show that bat assemblages of smaller islands tend to be more sensitive to changes in species richness than those of larger islands, with the larger islands working as a ‘source’ of species for small islands. These results demonstrate the high conservation value of the larger islands, which has direct consequences for local population dynamics of phyllostomid bats.

Bat assemblages of protected areas in the state of Rio de Janeiro, Brazil

ABSTRACT We analyzed the bat assemblages found in protected areas in the state of Rio de Janeiro, Brazil, which is the best-sampled region of the Atlantic Forest. We selected 24 strict nature reserves and nine sustainable-use protected areas. We used data from inventories and complemented with data from the literature. We compared strict and sustainable-use protected areas, and tested whether the bat assemblages varied between habitat types. We tested the effect of geographic distance on the dissimilarity between bat assemblages, as well as the relationship between species composition and the size, mean altitude of the protected area, and capture effort. We compiled a total of 34,443 capture records, involving 67 species. Three species were captured only once, which raises cause for concern. Bat assemblages did not vary between protected area categories, but did vary among habitats with less than 1,000 captures. Assemblages were more similar to one another in geographically proximate areas. The size of the protected area and capture effort did not affect the composition of the bat assemblages, but altitude did influence this parameter. The Atlantic Forest is a priority biome for research and conservation, and reliable data on species distributions are essential for the development of conservation strategies.

Comparison between Winkler's extractor and pitfall traps to estimate leaf litter ants richness (Formicidae) at a rainforest site in southest Brazil

The aim of this study was to compare in the same site the efficiency of the two most used techniques for sampling ant diversity, Winkler's extractors and pitfalls. We studied communities of leaf litter ants from the Brazilian Atlantic Forest, compared richness estimates for genera and species, and built species accumulation curves. These two methods resulted in a satisfactory sampling of richness; 21.3% of the genera and 47.6% of the species were collected exclusively with Winkler's extractors, whereas 6.4% of the genera and 9.5% of the species were collected exclusively with pitfalls. Winkler's extractor had proven to be the most efficient single sampling technique to estimate richness. However, pitfalls also recorded a significant portion of the total richness. Despite differences in efficiency, species accumulation curves for both techniques were similar, as well as the curve obtained with both methods combined. We noticed that Winkler's extractors were c. 74.0% more efficient than pitfalls in the Atlantic Forest. Therefore, sampling techniques must be used with a well-structured sampling design in order to advance knowledge on the ant fauna of Brazilian biomes, especially in the leaf litter, allowing more complete environmental analyses.

Morcegos (Mammalia, Chiroptera) da Reserva Rio das Pedras, Rio de Janeiro, Sudeste do Brasil

Uma lista das espécies de morcegos da Reserva Rio das Pedras, Município de Mangaratiba, foi elaborada através de capturas com redes de neblina, desde setembro de 1995 até junho de 2008, totalizando 242424 h.rede de esforço de captura. O total de 30 espécies de morcegos foi registrado em 1321 capturas e recapturas. As espécies predominantes foram Carollia perspicillata e Artibeus lituratus. Seis famílias foram registradas: Emballonuridae, Noctilionidae, Phyllostomidae, Thyropteridae, Vespertilionidae e Molossidae. Comparando com seis listas de espécies disponíveis de locais distantes até 100 km, a Reserva Rio das Pedras apresentou alta riqueza, diversidade e abundância de Phyllostominae, comprovando a relevância do local para a conservação dos morcegos.

Foraging activity of the free-tailed bat Molossus molossus (Chiroptera; Molossidae) in southeastern Brazil

Sunset and sunrise regulate the activities of most studied bat species. To verify patterns of foraging activity, 29 bat sampling nights were carried out over a dam in Rio de Janeiro city, which resulted in 363 hours with 730 captures, representing 13 species of insectivorous bats. Molossus molossus constituted the bulk of the captures (79.9%) and was present in 82.8% of the sampling nights. This bat species exhibited crepuscular and nocturnal activity (from -6 minutes to 900 minutes after the time of sunset). A bimodal activity pattern was observed, and two non-overlapping capture peaks. The first peak lasted from 6 minutes before sunset to 420 minutes after sunset. The second peak began at 564 minutes after sunset and ended just after sunrise. The first capture peak was observed in 75.9% of the nights, and the second peak in 62.1% of the nights. The time of the first capture exhibited a positive linear relationship with sunset and the time of the last capture, a positive linear relationship with sunrise. The existence of a relationship between night length and the difference between first and last captures of each night shows that M. molossus has longer activity the longer the night, showing a seasonal variation in the activity period.