Influência da caprinocultura sobre a assembleia de escorpiões (Arachnida: Scorpiones) da Caatinga

Abstract

Exploration of natural vegetation has a direct effect on environmental quality in several regions, especially those included I the Brazilian semi-arid region. In the Caatinga, the largest range of Seasonally Dry Tropical Forest in South America, anthropic activities are one of the main conservation issues of the biome. Among the anthropic activities carried out in the Caatinga, the goat breeding is the most harmful to the natural vegetation quality. This is mainly due to the management of pasture goat farming in the region. Free grazing compromises the structure of the habitat where goats occur, and consequently leads to the imbalance of other animals, especially habitat-dependent species, such as scorpions. Therefore, this work evaluated the potential effects caused by goat-free grazing on the Caatinga scorpion assemblage. Specifically, the goat-effects farming on the diversity (richness, abundance, and composition) of the scorpion assemblage as well as the body condition of the animals were measured. Sampling took place in three municipalities located in the state of Pernambuco, Brazil. In each municipality, 24 transects were installed (6 in areas with influence by goats and 6 without the goat influence) with 10mx30m, apart by 20m each. Active searches were carried out at night (19:00-22:00h) with the aid of UV flashlights. Each transect was covered for one hour by a pair of collectors. In total, 396 scorpions distributed in six species were collected. Our results showed that scorpion’s diversity was significantly affected by goat farming, with richness and abundance being reduced in areas influenced by goats. Species composition was also affected, favoring habitat-generalist species over habitat-specialist species. Finally, the body condition of scorpions was negatively affected by the presence of goats, with scorpions having smaller body size and mass. The free grazing of goats in areas of Caatinga natural vegetation resulted in a simplification of the environment structure, negatively impacting the assemblage of scorpions.