Distribuição espacial da fauna edáfica em topossequência sobre um remanescente de floresta ombrófila densa em Pernambuco

Abstract

Soil is considered a fundamental component as it induces the dynamic processes that shape the growth and development of the biological heritage of different terrestrial ecosystems. This biotic structure is represented by plants, animals, microorganisms, and soil fauna. In the specific case of soil fauna, there is significant morphological and functional diversity among these organisms, which are classified according to their respective sizes or body diameters and the ecological roles they play in the soil. Therefore, the objective of this work was to diagnose and evaluate the spatial distribution of soil fauna over a remnant of Dense Ombrophilous Forest, according to its toposequential exposure. The studies were conducted at Dois Irmãos State Park (Pedi), Recife-PE, at two moments: the rainy season (August) and the dry season (January). To carry out the activities, the vegetational cover was divided into three thirds (lower, middle, and upper), where simple samples of leaf litter and soil were collected to a depth of 5 cm. These materials were sent to the Forest Defense Laboratory at the Federal Rural University of Pernambuco (UFRPE) for manual sorting, initially of the macrofauna and then of the mesofauna, using Berlese-Tüllgren funnels to evaluate ecological structural characteristics. For data analysis, the ecological indices of Shannon-Weaver, Pielou, and Simpson were applied, with results showing a higher abundance of individuals in the lower third and in the leaf litter layer during the rainy season, with a predominance of the order Hymenoptera, but greater species richness in the upper third, indicating higher diversity in the leaf litter of this section. The dry season had more individuals than the rainy season, suggesting that the action of rain influences density in the different thirds of the toposequence, with greater accumulation in the lower third due to its lower altitude. The ecological indices indicated that the highest diversity is concentrated in the leaf litter of the upper third, as observed in the rainy season. Microclimatic data showed higher temperatures in the upper third, providing further support for the greater diversity present there. Hymenoptera was the taxonomic group with the highest presence in both periods, followed by Blattodea, Araneae, Chilopoda, and Coleoptera. The cluster analysis demonstrated that the dry season had greater similarity among the thirds, considering leaf litter and soil, than the rainy season.