Efeito da exclusão de água sobre a composição e abundância dos diptera da macrofauna de solo em liteira de uma floresta de terra firme

Abstract

Diptera have an important role in the process of organic matter composition, being fundamental for soil structure and composition and plant development. Microclimatic changes can alter the distribution and abundance of these insects, both in the vertical and horizontal soil occupation direction. The present work aims to compare the composition and abundance patterns of Diptera present in litter in a dryland forest, in the periods before and after the experimental intervention Esecaflor (LBA Project), in the Scientific Station Ferreira Pena (ECFPn) -Municipality of Melgaço/PA, which consists of inducing an artificial drought with the exclusion of 80% of rainwater reaching the soil. The individuals were collected with the aid of Pitfall Traps and were taken to the laboratory kept in 70% alcohol for identification. It was found that in the pre-exclusion and water exclusion periods, the Diptera showed significant variation in their abundances, but both in the control and experimental plots. Among the most representative families, only Phoridae showed significant variation between collections. In the families Cecidomyiidae, Sciaridae and Drosophilidae the abundances did not differ between the plots, in both periods. Based on the results presented, it is not possible to infer on the influence of the treatment of the Esecaflor experiment on the abundance of the Diptera of the soil macrofauna. The significant variations between collections in the control plot point to additional effects influencing the variation of abundance in these groups, which cannot be detected with the established experimental design. To minimize this problem, it is intended, in the continuity of the work, to increase the sampling effort, establishing a greater number of control plots, distributed in other areas of the ECFPn, following a gradient of humidity between the sampling points, with a greater number of replications. A qualitative comparison of the fauna will also be sought, through specific identification of the collected material.