Resposta de insetos herbívoros associados ao dossel em paisagem de matriz agrícola - floresta

• Ano de defesa: 2010
• Autor(a) principal: Soares, Luiz Gustavo Souto
• Orientador(a): Sperber, Carlos Frankl
• Banca de defesa: Neves, Frederico de Siqueira , Guerra Sobrinho, Tathiana
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso embargado
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Entomologia
• Departamento: Ciência entomológica; Tecnologia entomológica
• País: BR
• Palavras-chave em Português: Biodiversidade; Distribuição; Escala espacial; Interações ecológicas; Floresta tropical semidecídua; Mata Alântica; Conservação; Permeabilidade de hábitat
• Palavras-chave em Inglês: Biodiversity; Distribuition; Espatial scale; Ecological interactions; Semideciduous tropical forest; Mata Alântica; Conservation; Permeability of habitat
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::ECOLOGIA
• Link de acesso: http://locus.ufv.br/handle/123456789/3899

The original vegetation cover of the Zona da Mata Mineira were forests, but today these are restricted to secondary forest remnants, immersed in an agricultural matrix of pasturelands, coffee and Eucalyptus plantations. Even being regenerations, the canopies of these forests may harbor an important part of the original fauna, functioning as a source of biodiversity in these landscapes. Therefore, we supposed that the diversity of herbivorous insects associated to canopy should diminish from the forest interior to the matrix. The objective of this study was to test this assumption, as well as the following explanatory hypotheses for this pattern: insect diversity is determined by resource quantity and quality, environmental heterogeneity, conditions, and predation pressure. We sampled forest fragments immersed in a matrix of Eucalyptus (n = 3) and coffee (n = 3) plantations,along transect from 75m inside the forest up to 75m inside the matrix, in each site. We have chosen these two matrix types as they represent the most abundant agroecossystems with canopy in the region. Insects were classified into chewing and sap-sucking herbivores. In the landscapes with Eucalyptus, both chewing and sap-sucking insects presented an increase in species and individual numbers along the gradient matrix forest. In the landscapes with coffee plantations, there was no response of chewers to the gradient, while sap-sucking species and individual numbers diminished from the matrix to the forest. The habitat components that explained the distribution of chewers were: number of arboreal species, of arboreal strata and of spiders. For sap-suckers, these were leaf density and spider numbers. Therefore, we showed that matrix matrix composed of Eucalyptus and coffee plantations present different permeability for canopy herbivorous insects. Some of the environmental variables explained at least part of the observed patterns in these landscapes: for sap-suckers, leaf density may determine the patterns in both matrix types, because it represents feeding resource availability. For chewers, tree diversity (habitat heterogeneity) and crown volume (resource availability) explained part of the variation in theseorganisms, but were not sufficient to explain the differences between matrix types. We conclude that, at least for chewing herbivores, there are processes at the landscape scale, probably related to locomotion, that are not explained by local habitat variables. Furthermore, our results showed that the two feeding guilds respond at different spatial scales.