Leaf litter decomposition aiming the monitoring of areas in ecological restoration process in Mato Grosso do Sul state

Abstract

The decomposition process helps in the balance and functioning of forest ecosystems by providing essential nutrients for the sustenance of plants. The objective was to evaluate the leaf decomposition as an indicator of functionality in three areas of environmental restoration by the planting of seedlings over ten years old in Mato Grosso do Sul state. The study was conducted in 2017 in the municipalities of Ivinhema, 13 years after planting (IV-13), Jateí at the age of 14 (JA-14) and Caarapó, 17 years old after planting (CA-17).  Leaves of the forest floor surface were collected, oven dried at 65°C and weighed in 10-gram portions to be placed in the litterbags, randomly distributed on the forest floor surface. To evaluate the loss of dry biomass, 10 litterbags were removed at 30, 60, 90, 120, 150 and 180 days after installation. The percentage of the remaining mass, decomposition rates (k), the half-life (t ½) and Pearson’s correlation (r) between the remaining mass and precipitation and temperature were estimated. The (k) in the 180-day period for CA-17 was 0.004 g g^-1 day ^-1 and 0.003 g g^-1 day ^-1 for IV-13 and JA-14, to the (t ½) was 269,49 days for IV-13, 218,29 for JA-14 and 194,89 days for CA-17. The (r) was weak for all areas and variables, except IV-13, which obtained moderate (r) for precipitation. The age of the plantations is not decisive, the decomposition is mainly governed by the internal and external characteristics of the areas. The indicator was efficient in understanding the decomposition rates, confirming a more accelerated foliar mass for CA-17 and JA-14, which can result in the faster release of nutrients to the soiland return to vegetation. It is recommended to use complementary indicators for a holistic understanding of the dynamics of ecosystems in restoration.