Fatores moderadores de efeitos dos cupins no solo

Abstract

The influence of termites on soils has been widely discussed in the scientific literature. Recognized as ecosystem engineers, these insects promote significant modifications in the physical, chemical, and biological properties of the environments they inhabit. Understanding whether there are general patterns in termite influence, or which factors drive variation at smaller spatial scales, is essential for assessing their true ecological importance. However, the literature reveals conflicting findings. While some studies report positive effects of termites on various soil properties, others document opposite outcomes. In light of these discrepancies, this thesis investigates the factors responsible for such differences. The thesis is structured into three chapters. The first chapter presents a systematic review that examines how termite influence on soil properties varies according to soil class and termite subfamily. The second chapter present field data comparing termite effects in areas with distinct soil types. Furthermore, the third chapter evaluates the potential of termite constructions as carbon reservoirs in semiarid environments. The results suggest that termites adopt different strategies depending on the soil class. In general, termite activity reduces the sand fraction while increasing the proportions of silt and clay. However, in clay-rich soils, this influence is not significant. Similar patterns are observed across different termite subfamilies, which construct diverse nest types and consequently have varying impacts on soil properties. A notable example is the Macrotermitinae subfamily. Their nests, which harbor symbiotic fungi, increase soil pH—an effect not observed in other subfamilies. Studies that identify termite species and soil classes, and that include comparisons across multiple regions, are essential for establishing more consistent patterns regarding the ecological impacts of these insects. The analysis of Constrictotermes cyphergaster hypogeal constructions, conducted in this thesis, revealed that termite-induced changes in soil properties vary depending on the study area. Moreover, this species was found to contribute to carbon storage in nutrient-poor soils, particularly in Caatinga environments.