Araneofauna (Arachnida: Araneae) do parque ecológico Jatobá Centenário, Morrinhos – GO: estrutura, composição e influência de fatores climáticos

Abstract

Spiders are a megadiverse group, the seventh most richness, surpassed only by five insect orders and Acari. They are considered good bioindicators due to their great sensibility to biotic and abiotic variations. As generalist predators they have an important whole in regulation of arthropod populations. Despite these facts the Araneae order is few known being expected more than ten thousand species in the world. The tropical and subtropical regions are bad sampled, main due to the lack of taxonomists. Due to temporal and spatial stratification, this group presents a great variety in prey capture strategies. The separation of the spider community in guilds can help to understand the ecosystem dynamic, being an important tool to ecological studies. Thus, due to the importance of soil spider community, this dissertation intended to establish a characterization of ground araneofauna, to analyse the present guilds and species dominance, studying the influence of climatic factors acting on this fauna in a semidecidual forest in the tropical savanna Cerrado. The study site was Parque Ecológico Jatobá Centenário, a fragment of 90 hectares, placed in the municipality of Morrinhos, Goiás state. The climate in the area is AW according to Koppen, presenting two typical seasons, one hot and moist and another dry and cold. Spiders were sampled four times through the year using pitfall traps, each one remained in the field for seven days. Were collected 4139 spiders, of 35 families and 118 species. In the rainy season was observed the higher abundance, richness and diversity. Temperature, humidity and rainfall presented differences between seasons. Dominance analysis showed the presence of one self-dominant and three dominant species, that represented 40% of the total sample. The presence of few dominant species and several rare is typical of tropical communities. The families were grouped in eight guilds, the more representative belonging to “ground and vegetation active hunters” and “ground and vegetation weavers”. The intra guild abundance of individuals was different between seasons, the rainy season presented higher abundance. The present data have significant importance considering that few others presented more species or individuals. The absence of relation between biotic and abiotic variables may be influenced by microclimate and structural differences in the environment, as for example the amount of litter, shadows and prey diversity. The sampled guilds were influenced by the xiii methods, directed to ground dwelling spiders, the species of shrub communities were accidentally sampled, probably captured when moving between plants or dispersing.