Efeitos da complexidade estrutural da paisagem sobre os térmitas de solo em ecossistemas inseridos na região semiárida do Nordeste do Brasil

Abstract

Although they are best known for their potential as a pest, termites have only about 10% of their species with this potential, being organisms that influence the physical structure, chemical composition and nutrient cycling in soils tropical ecosystems, in addition to being sensitive to changes in the environment in which they live, representing good environmental indicators. Thus, this study identified the assemblages of soil termites associated with cowpea and sweet sorghum crops and also in the remaining vegetation (VR) of Caatinga, evaluating the influence of environmental factors on its assemblages, in areas of Caatinga located in the state of Paraíba and that present a difference in the structural complexity of the landscape. The samples were collected between the years 2018 and 2019, following the method proposed by the Tropical Soil Biology and Fertility Program (TSBF), with modifications. In each treatment (crops and VR in each area), blocks of soil (20 × 20 × 30 cm) were extracted, divided into three layers: A (0-10 cm), B (10-20 cm) and C (20 -30 cm). Ten species of termites were found belonging to the family Termitidae (nine species) and Rhinotermitidae (one species). The highly complex area showed the greatest abundance of termites, including soil feeders (a group that can be an environmental indicator), both in crops and in VR. Considering only the crops, this area also presented the greatest species richness and when considering only the VR, it shared the same richness with the area of intermediate complexity. In relation to the low complexity area, there was a low species richness both in the crops and in the VR. Most of the species found in crops in the high complexity area do not have the potential as a pest, as they act in the processes of decomposition and nutrient cycling, which can contribute to increasing the productivity of the agricultural system. Species richness, abundance and biomass did not differ significantly between the three soil strata, considering all types of treatment of the areas. Regarding only the VR of the areas, the cation exchange capacity was a significant predictor for species richness, which may reflect a positive impact of termites on the chemical properties of the soil. Thus, our results highlight the importance that these insects can exercise in semiarid ecosystems, reinforce the importance of maintaining natural areas surrounding cultivation and can support studies in the Caatinga that aim at sustainable development.