The guild of fruit-feeding butterflies in a fragmented landscape in the upper Paraiba River basin, São Paulo, Brazil

Author(s)

Danilo Bandini Ribeiro

• Document type: Master's Dissertation
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2006-06-09

Examining board members

Ronaldo Bastos Francini; Thomas Michael Lewinsohn

• Advisor: Keith S. Brown

Abstract

Most of the Atlantic Forest in the State of São Paulo occurs in fragments of various sizes. Previous studies indicate that forest fragmentation affects the butterfly community, changing its composition and diversity. In view of the importance of knowing the fauna of these forest remainders, the present work had the objective to characterize the assemblage of fruit-feeding butterflies of ten forest fragments (ranging from 11 to 83 hectares) in the Upper Paraíba River Basin - SP and verify if the diversity of this group is randomly distributed in time and space. The fragments are in a matrix composed of anthropogenic scrub, areas of extensive cattle pasture and areas of Eucalyptus plantation. The samplings were made monthly using "Van Someren-Rydon" traps. In each month the traps remained open in the field for eight consecutive days. A mixture of banana with sugar cane juice fermented for 48h was used as bait. The hypothesis that the fruit-feeding butterflies are randomly distributed in time and space was tested using additive partitioning of diversity. During 13 months 6488 individuals of 73 species and five subfamilies of fruit-feeding butterflies were sampled. According to the Chao 2 and Jacknife estimators the assemblage of fruit-feeding butterflies was almost totally sampled; the number of butterflies present in the community but not sampled is between two and 10 species (Chao 2 = 80.56 + 5.96; Jacknife = 83.89 + 3.46). These results are equivalent to those found in environments with similar characteristics but with less human disturbance and fragmentation, such as the Serra do Japi (SP) and the Reserva do Morro Grande (SP), showing that despite the extensive fragmentation of natural vegetation in the region of the Upper Paraíba River Basin - SP, the forest remants still retain much of the diversity expected in the region. Similarity analyses showed that the communities in the fragments are very similar to one another. Despite this great similarity, small differences in the composition of species assemblages can be verified in more sensible tests like the analysis of the surroundings and additive partitioning of diversity. Surroundings analysis showed that the composition and abundance of the assemblages are strongly determined by the vegetation of the immediate surroundings (radius of 100m around the sample unit). Additive partitioning of diversity showed that the butterflies species were more grouped than expected in space and time, principally at the small scales examined. Probably, the favorable resources and conditions for the occurrence of these insects are not randomly distributed in time and space, resulting in the aggregation of species and individuals. These results can guide the creation of more efficient protocols to help inventories of fruit-feeding butterflies, and reaffirm their potential as indicators. The patterns verified in this study show that the landscape scale is not the most important in determining the assemblage of fruit-feeding butterflies. Local factors give more consistent patterns, observed in the small scales in both analyses used. (AU)

• FAPESP's process: 03/11697-0 - Effects of anthropic activity and forest fragmentation on the lepidoptera guild
• Grantee: Danilo Bandini Ribeiro
• Support Opportunities: Scholarships in Brazil - Master