Interception and surface runoff in different regeneration stages of Atlantic Forest, southern Brazil

In natural regeneration, vegetation goes through different stages over time, each of them with different conditions to drain the precipitated water to the soil surface. The aim of this study was to evaluate interception loss, throughfall, stemflow and surface runoff in early and advanced stages regeneration at evergreen rainforest subtype sites within the Atlantic Forest, located in the Serra do Itajai National Park, in southern Brazil. Rainfall was sampled by three rain gauges and throughfall was measured using "U" type gutters. The stemflow was measured in 24 trees per stage (i.e., 48 trees in total). The interception loss was calculated as the difference between rainfall and the sum of the throughfall plus stemflow. The surface runoff was evaluated using metal rails. Vegetation in the initial stage is a composition of 7 species with a basal area of 5.01 m2.ha-1 and advanced stage site consists of 28 species with a basal area of 34.7 m2.ha-1. Throughfall records were 81.7% in the initial and 74.1% in the advanced regeneration stages. The stemflows registered were 5.93% in the initial stage and 0.54% in the advanced stage while the interception losses were respectively 13.2% and 25.8%. Surface runoffs observations were 11.1% in the initial stage and 10.7% in the advanced stage. Statistically significant differences were found between the regeneration stages for the stemflow and for the interception loss parameters. The study showed that, for some hydrological processes, the behavior of the precipitated water differs for the stage of vegetation regeneration. The regeneration stage does not influence the surface runoff, demonstrating that after a few years of vegetation regeneration, this hydrological process is equivalent to vegetation in an advanced stage.