Estudos integrados para interpretação da dinâmica hídrica em ambientes florestais amazônicos

Abstract

The forest acts directly in the interception and redistribution of rainwater, influencing the conduction of rain to the surface of the soil, helping to maintain moisture within the forest, regulating water flows and contributing to the maintenance of water quality and availability. Even though water is an essential resource for maintaining life on our planet, care for water maintenance in many regions does’t reflect its importance and essentiality. In the Amazon Rainforest region, the exuberant forest suffers from predatory exploration, which causes changes in its functionality, influencing the maintenance of environmental services and ecohydrological processes. Understanding and quantifying the influence of the forest on the water dynamics in Amazonian forest environments are fundamental for proposing alternatives that contribute to the maintenance and functionality of this biome. This thesis aimed to develop an integrated study to interpret the water dynamics and understand the effects of the exploratory activity of a Sustainable Forest Management Plan on the hydrological processes in Amazonian forest environments in an area of public native forest under forest concession in the Jamari National Forest (Flona do Jamari), state of Rondonia, Brazil. The study was carried out in the Jamari National Forest (Flona do Jamari), Rondônia, Western Brazilian Amazon where the predominant vegetation is of the Open Ombrophilous Forest type, and the climate is of the Aw-Tropical Wet type, hot and humid with two distinct periods: wet (October to April) and dry (May to September). Two areas were selected: one with preserved forest (AN) and the other logged (AE). In the selected areas, 3 plots (P1, P2 and P3) measuring 20 m x 20 m were installed and monitored monthly between October/2019 and October/2020 to obtain the necessary information to characterize the structure of the vegetation, the distribution of rainwater, the accumulated burlap stock, and interpret the behavior of the main soil physical attributes. The results of this study point out that the dynamics of rainwater distribution behavior over the monitoring period was similar among the areas, reflecting the high temporal and spatial variability, as well as the seasonality of the region. The internal precipitation (Pi) was the variable that most influenced the effective precipitation (Pe) presenting higher average than the open precipitation (Pa) in most months of monitoring for the natural area (AN). The hydrological variable Et was the only one that showed statistically significant difference between the areas, which may be related to the difference in the density of individuals observed. The dynamics of accumulation of burlap and its fractions was similar between the areas, and the accumulation was strongly related to the seasonality of the region. The water retention capacity (CRH) of the burlap fractions contributed effectively to the CRH of the total burlap stock, which showed higher rates than the effective water retention capacity of the burlap (ERH). The hydrological behavior of the soils of the evaluated areas was influenced by the characteristics of the vegetation structure, hydrological variables, and variations in soil physical properties over the monitoring period. The research helped to understand the hydrological process of the understory in the forest areas, and according to the data from this study, it’s possible to conclude that the forest exploration activities made by the Sustainable Forest Management Plan affected the hydrological behavior in the explored area.