Diversity of the Arthropod edaphic fauna in preserved and managed with pasture areas in Teresina-Piauí-Brazil.

The soil fauna plays an important function over the processes of organic matter decomposition, nutrient cycling, ground aeration and fertility. Thus, studies on the composition and structure of such communities are important, considering moreover the lack of information in different regions of Brazil and mainly related to the state of Piauí. This study aimed to evaluate the density and diversity of the soil arthropod fauna in a Cerrado area in preservation conditions and in a pasture area. Both are situated in the city of Teresina, capital of the state of Piauí. Pitfall traps were used for sampling. Five stations with four traps were placed in each area. The traps were constituted by a 500 mL plastic cup containing a preserving solution made with 70% alcohol and 40% formalin. The traps were weekly changed by occasion of the collections. Eight samples were performed in the period between March and April 2007. The results were evaluated using the following variables: number of orders, number of families, total of species and total number of individuals. Evaluation of the Diversity Index and Similarity Coefficient were also performed. As result, the variables and diversity indices were slightly higher in the preserved area. However, the similarity coefficient showed only 10% similarity between both areas.