Efeitos contrastantes da qualidade do habitat sobre distintas guildas alimentares de insetos herbívoros em sistemas agroflorestais cacaueiros

• Ano de defesa: 2017
• Autor(a) principal: Samuel Matos Antunes de Novais
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Uso da terra; Cabruca; Conservação; Biodiversidade; Theobroma cacao; Manejo; Insetos; Cacau; Manejo Ecologia
• Link de acesso: http://hdl.handle.net/1843/BUBD-9VDFNB

The intense modification of natural habitats increases the importance of agroforestry for biodiversity conservation in the tropics. Traditional agroforestry systems with native shade trees may maintain a significant portion of biodiversity when compared to systems with more intense management. The main objective of this study was to evaluate the role of traditional agroforestry cocoa, the cabrucas, in relation to agroforestry rubber monodominant, for the conservation of herbivorous insects (folivorous, sap-sucking and xylophagous). Herbivorous insects were sampled in three distinct habitats, native forest and cabruca and rubber agroforestry in southeastern Bahia, Brazil. In each habitat were determined 18 plots of 10m2 where measures of habitat structure were performed and sampled herbivorous insects with the aid of a malaise/window trap. The folivorous species composition did not differ between habitats, but the reduction of the diversity of shade trees and canopy cover had a negative effect on the abundance and diversity of these insects. The composition of sap-suckers insects was similar between native forest and cabruca agroforestry, and differed from rubber agroforestry. The abundance and richness of sucking insects were similar between habitats. The composition of xylophagous insects differs between rubber agroforestry and other habitats. However, abundance of xylophagous is higher in rubber agroforestry, while the richness of this guild was higher in cabruca agroforestry. Besides the structural simplification of the habitat in rubber agroforestry, the intrinsic characteristics of this habitat with rubber tree presence, known as the rubber tree, determined the patterns found in this study. The folivorous guild has become extremely sensitive to changes in habitat quality, where only a few species remain at low densities with the simplification of habitat. Differently, for the sap-sucking guild, we observed a substitution and a dominant of species in rubber agroforestry, while the sap-sucking community remained similar between cabruca agroforestry and native forest. This pattern was also observed for xylophagous insects, in which the simplification of habitat with a single species of shade in rubber agroforestry maintains low species richness, but with higher abundances. We conclude that cabrucas agroforestry maintain the community structure of herbivorous insects very similar to that found in native forests of the region, being a good strategy for land use and biodiversity conservation. We also highlight the potential risk of emergence of local pests in rubber agroforestry for both tree species shade, rubber tree, and for the associated cacao.