Diplopodas: ação no carbono e na água do solo em uma biotopossequência no semiárido da Paraíba.

Abstract

The regions called dry lands are present in almost all the continents on Earth, these regions have long dry periods and low availability of water resources. In Brazil, the Caatinga it is a region with a semi-arid climate that presents high biological and soil diversity. It has short periods where there is abundance of water and high biological activity, and long periods when water is the main limiting factor, however, the fauna and flora of this region it is adapted to the climate. Vegetation, it is the main source of organic matter for the soil. The organisms present in the soil are responsible for transforming the organic matter of the soil, consequently, it has a direct influence on several biogeochemical cycles and ecosystem services of the soil. Embuás, also known as gongolos or snake lice, arthropods of the Diplopoda class, are abundant in the humid period in the Caatinga, and their presence it is quite noticeable during this period. However, the action of these organisms on the dynamics of soil organic matter in the Caatinga it is still poorly known. In this research, we studied the action of embuás as an organism formation factor in the dynamics of carbon and water in soils and in soil ecosystem services of a biotopequence composed of rocky outcrops at the top, eutrophic eutrorthent in the shoulder, Eutrophic regosols in the middle third and Psamiticregosols in the lower third in the Private Reserve of Natural Heritage Fazenda Almas in Cariri, Paraíba Based on field observations and laboratory experiments, we evaluated the production of excrement by individuals of Spirobolida embuás from the consumption of plant material from horizon O of the soils of the four positions of the biotopequence. The physical and chemical attributes of the excreta were analyzed, such as density, maximum water retention capacity, organic matter contents and nutrients present in the plant material of each position. The droppings production was 10.0 mg/day at the top; 32.7mg/day, on the shoulder; 39.6 mg/day in the middle third and 36.0 mg/day in the lower third. Organic matter contents were 912.3 g/kg at the top; 779.0 g/kg on the shoulder; 762.4g/kg in the middle third and 823.7 g/kg in the lower third. The excrement density was 266kg/m3 at the top; 276kg/m3 on the shoulder; 300kg/m3 in the middle third and 273 kg/m3 in the lower third. While the maximum retention capacity of excreta was 3.93 g/g at the top; 4.92 g/g on the shoulder; 4.55 g/g in the middle third and 3.70 g/g in the lower third. The highest values of nitrogen, magnesium, iron, manganese, and zinc in the litter were in the shoulder position, precisely because in this position it receives the contribution from the top, being the position that most provides nutrients and water. The highest values of density and maximum retention capacity are of the excrements produced from the consumption of the litter of horizon O on the shoulder and the middle third. In these positions there is vegetation type Savannah-Estépica Forested “Dry forest” and are closer to the edge of the rocky outcrop. These droppings have a maximum holding capacity of up to 5 liters of water/kg. The action of embuás on soil organic matter has a direct influence on water dynamics, soil and ecosystem services linked to the carbon and water cycle in the Caatinga.