Efficiency of small mammal trapping in an Atlantic Forest fragmented landscape: the effects of trap type and position, seasonality and habitat.

Trapping methods can strongly influence the sampling of mammal communities. This study compared the efficiency of the capture of small mammals in Sherman traps in two positions (at ground level and in trees) and pitfall traps in a fragmented landscape. Trapping sessions were carried out between October 2008 and October 2009 at two fragments (8 and 17 ha), an agroforest corridor between them, and the adjacent pasture. A total effort of 4622 trap-nights resulted in 155 captures of 137 individuals from six species. Pitfalls had greater success (4.03%), followed by Shermans on the ground (2.98%) and on trees (2.37%; χ2 = 6.50, p = 0.04). Five species were caught in Sherman ground traps, four in pitfalls and just two on trees. There was no difference among trap types for marsupials (χ2 = 4.75; p = 0.09), while for rodents, pitfalls were more efficient than Shermans on the ground (Fisher's exact test, p = 0.02). As a result, the efficiency of each trap type differed among habitats, due to differences in their species composition. Pitfalls were more efficient in the rainy season (Fisher's exact test, p <0.0001) while Shermans on trees were more efficient in the dry season (Fisher's exact test, p = 0.009). There was no difference between seasons for Shermans on the ground (Fisher's exact test, p = 0.76). Considering the results found, we recommend that future studies of forest mammal communities, particularly those designed to test the effects of forest fragmentation, include combinations of different trap types.

Species composition of Bromeliaceae and their distribution at the Massambaba restinga in Arraial do Cabo, Rio de Janeiro, Brazil.

We studied some ecological parameters such as richness, abundance, density, biomass and variation in species composition in four vegetation zones and in a zone with anthropic disturbance in the Massambaba Restinga in Arraial do Cabo, Rio de Janeiro State. We sampled 100 plots of 100 m(2) (10 x 10 m) recording the bromeliad species and their abundance. We found a total of seven bromeliad species, with Vriesea neoglutinosa (5647 ramets) and Tillandsia stricta (1277 ramets) being the most abundant. The vegetation zone called Clusia shrubs had the highest richness (S = 5) and density (6360 ramets.ha(-1)) of bromeliads. The differences found in abundance and variation in species composition among vegetation zones seems to be related to the vegetation structure of each zone.

Species composition of Bromeliaceae and their distribution at the Massambaba restinga in Arraial do Cabo, Rio de Janeiro, Brazil / Composição de espécies de Bromeliaceae e sua distribuição na restinga de Massambaba, Arraial do Cabo, RJ, Brasil

We studied some ecological parameters such as richness, abundance, density, biomass and variation in species composition in four vegetation zones and in a zone with anthropic disturbance in the Massambaba Restinga in Arraial do Cabo, Rio de Janeiro State. We sampled 100 plots of 100 m² (10 x 10 m) recording the bromeliad species and their abundance. We found a total of seven bromeliad species, with Vriesea neoglutinosa (5647 ramets) and Tillandsia stricta (1277 ramets) being the most abundant. The vegetation zone called Clusia shrubs had the highest richness (S = 5) and density (6360 ramets.ha-1) of bromeliads. The differences found in abundance and variation in species composition among vegetation zones seems to be related to the vegetation structure of each zone.

Estudamos a riqueza, a abundância, a densidade, a biomassa e a variação na composição de espécies de bromélias em quatro zonas de vegetação e em uma área com distúrbio antrópico da restinga de Massambaba, Arraial do Cabo, RJ. Estes parâmetros foram avaliados através do registro das espécies e de suas abundâncias em 100 parcelas, proporcionalmente distribuídas entre as zonas. Encontramos sete espécies de bromélias, sendo Vriesea neoglutinosa e Tillandsia stricta as mais abundantes. A arbustiva aberta de Clusia foi a zona de vegetação com maior riqueza (S = 5) e abundância total (6360 rosetas) de bromélias. As diferenças encontradas na composição e na abundância de espécies de bromélias entre as zonas parecem estar relacionadas com a estrutura da vegetação de cada zona.

Spatial distribution by Canistropsis microps (E. Morren ex Mez) Leme (Bromeliaceae: Bromelioideae) in the Atlantic rain forest in Ilha Grande, Southeastern Brazil.

Canistropsis microps (Bromeliaceae: Bromelioideae) is an endemic species of Atlantic rain forest areas in Rio de Janeiro State, which are very abundant in not very disturbed forests in Ilha Grande, on the southern coast of the State. In this study, we analyzed the vertical and horizontal distribution patterns of the species in an area of rain forest with little evidence of disturbance at Vila Dois Rios, Ilha Grande, relating the patterns to sunlight in the microhabitat. We also identified the types of substrate used by the species and the rate of asexual reproduction. Canistropsis microps had high densities (estimated at 84,425 rosettes/ha), and has an aggregated distribution (Id = 2.86). About 80% of the rosettes were generated by clonal growth, whereas less than 20% were produced from seedlings. Most of the rosettes were found on straight tree trunks (DBH > 50 cm). There was a significant inverse correlation between the incidence of sunlight in the habitat and the abundance of individuals. Rosettes were found up to a maximum height of 9.5 m, but most occured between 1.5 and 5.5 m, where light varied from 25 to 50 micromol x s(-1) x m(-2). We conclude that vertical and horizontal distribution patterns in C. microps may be partially explained by the occurrence of appropriate substrate, an intensity of sunlight favorable to the development of the species and to a high rate of vegetative reproduction.

Spatial distribution by Canistropsis microps (E. Morren ex Mez) Leme (Bromeliaceae: Bromelioideae) in the Atlantic rain forest in Ilha Grande, Southeastern Brazil

Canistropsis microps (Bromeliaceae: Bromelioideae) is an endemic species of Atlantic rain forest areas in Rio de Janeiro State, which are very abundant in not very disturbed forests in Ilha Grande, on the southern coast of the State. In this study, we analyzed the vertical and horizontal distribution patterns of the species in an area of rain forest with little evidence of disturbance at Vila Dois Rios, Ilha Grande, relating the patterns to sunlight in the microhabitat. We also identified the types of substrate used by the species and the rate of asexual reproduction. Canistropsis microps had high densities (estimated at 84,425 rosettes/ha), and has an aggregated distribution (Id = 2.86). About 80 percent of the rosettes were generated by clonal growth, whereas less than 20 percent were produced from seedlings. Most of the rosettes were found on straight tree trunks (DBH > 50 cm). There was a significant inverse correlation between the incidence of sunlight in the habitat and the abundance of individuals. Rosettes were found up to a maximum height of 9.5 m, but most occured between 1.5 and 5.5 m, where light varied from 25 to 50 µmol.s-1.m-2. We conclude that vertical and horizontal distribution patterns in C. microps may be partially explained by the occurrence of appropriate substrate, an intensity of sunlight favorable to the development of the species and to a high rate of vegetative reproduction.

Canistropsis microps (Bromeliaceae: Bromelioideae) é uma espécie endêmica das áreas de Mata Atlântica do Estado do Rio de Janeiro, sendo muito abundantes em florestas pouco perturbadas da Ilha Grande, na costa sudeste do Estado. Nesse estudo, nós analisamos o padrão de distribuição vertical e horizontal da espécie em uma área de floresta com pouca evidência de distúrbio na Vila Dois Rios, Ilha Grande, relacionando os padrões à incidência de luz no microhabitat. Nós também identificamos os tipos de substratos usados pela espécie e a taxa de reprodução assexuada. Canistropsis microps possui elevadas densidades (estimada em 84.425 rosetas/ha), e uma distribuição agregada (Id = 2,86). Cerca de 80 por cento das rosetas são geradas pelo crescimento clonal, enquanto menos que 20 por cento são produzidos a partir de sementes. Muitas das rosetas foram encontradas em troncos retos de árvores (DAP > 50 cm). Houve uma correlação significativa inversa entre a incidência da luz solar no habitat e abundância de de indivíduos. As rosetas foram encontradas até uma altura máxima de 9,5 m, mas a maioria ocorreu entre 1,5 e 5,5 m, onde a luz variou de 25 a 50 µmol.s-1.m-2. Nós concluímos que o padrão de distribuição vertical e horizontal em C. microps pode ser parcialmente explicada pela ocorrência de um substrato apropriado, uma intensidade de luz solar favorável para o desenvolvimento da espécie e a alta taxa de reprodução vegetativa.