ABSTRACT
What is the importance of open habitat in a predominantly closed forest to the dung beetle assemblage? The Atlantic Forest in Brazil is one of the most highly disturbed ecosystems and is mainly represented by fragmented areas. However, in places where human disturbances have ceased, certain areas are showing a natural regeneration pattern. The aim of the present study was to determine how the dung beetle assemblage responds to distinct habitat structures in a fragment of Atlantic Forest. For such, open and closed forest areas were sampled in a fragment of the Atlantic Forest in the northeastern region of Brazil. Pitfall traps baited with excrement and carrion were used to collect the beetles. A total of 7,267 individuals belonging to 35 species were captured. Canthon chalybaeus and C. mutabilis were restricted to open areas. Nearly 90% of the individuals of C. aff. simulans and Deltochilum aff. irroratum were identified in these areas. A higher percentage (> 50%) of Canthon staigi, Dichotomius aff. depressicolis and D. aff. sericeus occurred in closed areas. Abundance differed between areas, with higher values in closed areas. Richness was not influenced by the habitat structure. NMDS ordination exhibited the segregation of areas and ANOSIM confirmed that this variable explained the assemblage of dung beetle species. The findings of the present study validate that open areas are associated to more restrictive conditions, limiting a higher abundance of dung beetle. Although situated near preserved fragments, the studied open areas increase the heterogeneity of the general landscape.
ABSTRACT
First report of Oxysternon silenus Castelnau (Scarabaeidae, Scarabaeinae, Phanaeini) in the Brazilian Atlantic Forest. This is the first record of Oxysternon silenus in the Brazilian Atlantic Forest. Specimens were collected in the Serra Grande landscape, municipality of Ibateguara, in Alagoas State. The samples were done from August 17 to 19, 2007 with pitfall traps. Before the present study, Oxysternon silenus had been reported predominantly in Amazonian region. The finding of this species corroborates the hypothesis of the biogeographical relationships between the Amazon Rainforest and the Atlantic Forest.
Primeiro relato de Oxysternon silenus Castelnau (Scarabaeidae, Scarabaeinae, Phanaeini) na Mata Atlântica brasileira. Esse é o primeiro registro de Oxysternon silenus na Mata Atlântica brasileira. Os espécimes foram coletados em Serra Grande, município de Ibateguara, Alagoas. As coletas foram realizadas de 17 a 19 de agosto de 2007 com a utilização de armadilhas do tipo pitfall. Antes do presente estudo, Oxysternon silenus tinha sido reportada apenas na região Amazônica. O encontro dessa espécie reforça a hipótese das relações biogeográficas entre a Amazônia e a Mata Atlântica.
ABSTRACT
In this study, performed in a remnant of Brazilian Atlantic Forest, three types of dung from animals with distinct alimentary habits were utilized, in order to verify possible differences of attractivity of these dungs to the Scarabaeinae and the influence of seasonality in the attractivity. Three habitats were sampled: edge, clearing and forest core, each with 40 pitfall traps. A total of 2,137 beetles were collected from August 2005 to July 2006. Canthidium sp. 1 (43 percent) and Dichotomius sericeus (41 percent) were the most abundant species. From the total number of beetles collected, 80.5 percent were attracted to human dung, 11 percent to jaguar dung, 7.8 percent to waterbuck dung and 0.7 percent to the control. The species Canthidium sp.1, Canthidium sp. 2, Ateuchus sp., Canthon nigripenne, Canthonella sp. and D. sericeus came to all three bait types. Eight species were found in the baits with human dung, where Canthidium sp.1 (49 percent) and D. sericeus (39 percent) were the most common. A significant difference in attractiveness of the different baits was observed; the highest abundance found in traps baited with human dung (F = 36.59; g.l. = 3; p < 0.0001). A significant difference in richness was observed between rainy and dry seasons (F = 12.29; g.l. = 1; p < 0.001), the highest richness found in the dry season.
Nesse estudo, realizado em um remanescente de Floresta Atlântica Brasileira, três tipos de fezes de animais com distintos hábitos alimentares foram utilizados para verificar possíveis diferenças de atratividade dessas fezes por Scarabaeinae e a influência da sazonalidade nessa atratividade. Três habitats foram amostrados: borda, clareira e núcleo da floresta, cada um com 40 armadilhas de queda ("pitfall"). Um total de 2137 besouros foi coletado de agosto de 2005 a julho de 2006. Canthidium sp. 1 (43 por cento) e Dichotomius sericeus (41 por cento) foram as espécies mais abundantes. Do número total de besouros coletados, 80,5 por cento foram atraídos para fezes humanas, 11 por cento para fezes de jaguar, 7,8 por cento para fezes de cobo e 0,7 por cento para o controle. As espécies Canthidium sp.1, Canthidium sp. 2, Ateuchus sp., Canthon nigripenne, Canthonella sp. e D. sericeus foram aos três tipos de isca. Oito espécies foram encontradas nas iscas com fezes humanas, onde Canthidium sp.1 (49 por cento) e D. sericeus (39 por cento) foram as mais abundantes. Diferença significativa de atratividade por diferentes iscas foi observada; a maior abundância foi evidenciada em armadilhas iscadas com fezes humanas (F = 36.59; g.l. = 3; p < 0.0001). Diferença significativa foi observada na riqueza entre as estações chuvosa e seca (F = 12.29; g.l. = 1; p < 0.001) sendo a maior riqueza verificada na estação seca.