Esforço amostral e ecologia de formigas de liteira, com ênfase em Gnamptogenys e Pachycondyla (Hymenoptera: Formicidae) em uma floresta de terra firme na Amazônia Oriental

Abstract

The increasing use of ants (Hymenoptera: Formicidae) for monitoring and in inventory programs results in a greater amount of sampling material, with financial limitations and lack of experts to make the taxonomy of this group. I looked forward to overcoming these problems through the analysis of the effort of the TEAM Project protocol, using the concepts of taxonomic sufficiency, rarefaction and sample dilution, applied to the randomization test of Mantel, to verify the autocorrelation among groups of samples. The ants were identified to genus and the individuals of Pachycondyla and Gnamptogenys to species. The aim of the study was to determine the minimum effort necessary to obtain an appropriate inventory of these taxa, evaluating the minimum number of samples and the maximum dilution to detect them without reducing the viability of the data, and also, to determine the effect of the environmental variables over the taxocenoses. In a continuous primary forest area, during October 26th and November 3rd, 2003, during the dry season, I sampled ants and other invertebrates in 6 plots distributed in 33,000 ha. Each plot was 1 km2 and in each one, 4 transects of 100 m were surveyed. Using Winkler and pitfall traps 10 sub-samples were collected in each transect, separated 10 m from each other. The environmental variables (volume of litter, percentage of sand, temperature and pH of the soil) utilized were not enough to explain the distribution of the species studied. Apparently the number of species in a group of samples is not the only determinant condition to proceed in the dilution of the samples. It is desirable that the analyses proceeded in this study can be repeated with a greater number of samples of this same protocol. Protocols oriented to a group that encompasses a larger number of species can have amostral mistakes because of the distinct ecological requirements of the species involved. Isolated ecological studies encompassing Gnamptogenys and Pachycondyla are necessary to establish those factors that are related to the distribution of these species.