Impacto do fipronil sobre a comunidade de cupins (Insecta: Isoptera) em áreas cultivadas com eucalipto no cerrado

Abstract

The establishment of forest with exotic species of Eucalyptus has been growing markedly in the latest years. Nevertheless, the use of that plantation provokes impacts upon environment, altering the natural habitats with effects on the richness and composition of species. On the silvicultural practices commonly used in planting is the previous treatment of the seedlings with fipronil (fenilpirasol, 0.4%). This procedure warrants the protection of these seedlings against subterranean termites (Isoptera: Termitidae) for a period of up to six months. Nevertheless, it is not known the effects of this management practice on the local diversity of termites, which caused the forest certifiers to restrict the use of this chemical in that plantation. Thus, the objectives of this study were: to compare the diversity of termites between the cultivated and uncultivated areas with eucalyptus; to verify the possible effects of the previous treatment of eucalyptus seedlings with fipronil on the composition, structure and richness of termite species in time, as well as to evaluate the resilience time of that termite community in a savanna region of Minas Gerais. The work was conducted in the municipality of João Pinheiro, MG in the period of nine months. The treatments studied were composed of areas where eucalyptus seedlings previously treated and untreated with fipronil and of recovering native vegetation and reservation areas with “stricto sensu” native savanna vegetation. The sampling methodology utilized was through of the collecting transect arrangement in the areas by following adapted protocol, with evaluations at 90 days before and at 90 and 180 days after the planting of the seedlings. The collected material was separated and later identified. Fifty-three termite species belonging to the families Termitidae (96%) and Rhinotermitidae (4%) were found. The species composition was quite similar between the areas with and without previous treatment of the seedlings with fipronil. High similarity occurred among the species present in those areas, differing from the uncultivated areas. The species richness within the functional groups ranged in time, but it was not affected by the fipronil treatment at the dosage utilized. The richness of termite species differed between the cultivated and non-cultivated areas. There was no significant difference between the areas treated and untreated with fipronil and neither among the uncultivated areas, but there was variation of richness in time within each treatment. One can conclude that the chemical tested does not affect negatively the termite community in the savanna region in Minas Gerais, and therefore, it was not possible to determine the resilience time of this community as related to the application of that chemical.