O efeito de paisagens em mosaico sobre a comunidade de fauna do solo

Abstract

Habitat fragmentation is causing discontiguous landscapes with different uses on a global scale. Atlantic Forest is one of hotspots in Brazil, which makes priority area for biodiversity studies, and suggests actions for more sustainable management. The mountainous region of Rio de Janeiro shows up as a good model for the study because it has a strong history of fragmentation caused mainly by agricultural activities. For the study we selected soil fauna as an environmental indicator aiming to assess the existence of patterns of community composition of soil fauna under the effect of land cover or soil type. The study sites are the municipalities of Bom Jardim and Cachoeiras de Macacu, in Rio de Janeiro, where selected areas of pasture, annual crops (cassava, yams, eggplant, pumpkin, maize) and perennial crops (eucalyptus, banana and coffee), also forest ecosystems as control area. For the sampling we use three pitfall traps in each of the areas, with minimum distance of six meters. In redundancy analysis (RDA) for the land use factor obtained 21.69% and 33.05% of explanation realizing the partition of variance to Cachoeiras de Macacu and Bom Jardim, respectively, with significant values through a Monte Carlo test (p < 0.01) in both locations. The RDA performed for the factors soil type and altitude showed 12.65% and 22.5% contribution, however there were not significant (p > 0.05). In multidimensional scaling (MDS) obtained stress of 0.23 and 0.21 for the two factors evaluated. Similarity analysis showed differences between the groups formed in both locations for land use, highlighting the difference between forest areas and pastures, mostly. While, for soil type were not significant differences. We note the contribution of soil fauna groups by the analysys of similarity percentual, where pre-selected potential indicators in the landscape mosaic. The groups selected for use as indicators of soil were Auchenorrhyncha and Coleoptera to Bom Jardim, and Cachoeiras de Macacu selected Thysanoptera. For soil type factor, were not selected indicators in Bom Jardim, and groups Orthoptera, Hymenoptera, Sternorrhyncha, Symphyla, Poduromorpha, Heteroptera and Diplopoda were selected for Gleysol in Cachoeiras de Macacu. Also calculate the index V for the community of soil fauna, to try to understand the effect of different types of management on each component group. According to index V we noticed different levels of stimulation and inhibition to the groups of soil fauna in the different classes of land use, especially the phytophagous that were favored in general, and for mites and ants that were mostly inhibited . The community composition showed similarity to the various factors evaluated, ie, the community has been simplified and there is presence of non-specialized groups.