Long-term water balance dynamics in a Brazilian neotropical forest: Insights from seven years of continuous...

The Atlantic Forest ecosystems offer numerous ecosystem services. However, UNESCO regards it as one of the most fragile biosphere reserves globally due to anthropogenic pressures in Brazil that threaten its integrity and, consequently, its environmental management and quality. This study evaluated the water balance relationship in an Atlantic Forest fragment using hydrometeorological data collected over seven hydrological years (2014-2020) of continuous observation of the hydrometeorological elements and soil moisture. The focus was on analyzing evapotranspiration (ET), canopy rainfall interception (C), soil moisture, and deep percolation (DP) over time. On average, canopy rainfall interception accounted for 21.24 % of gross precipitation (GP), and evapotranspiration constituted an average of 86.36 % (±11.12) of GP. We observed that the severe droughts have severely impacted the water balance in the forest, with an ET/GP ratio of 98.81 % in 2013/2014 and 97.33 % in 2016/2017, which were the driest hydrological years observed in the region in the last 40 years. Deep percolation showed significant variation, ranging downward and upward during rainy and dry periods, respectively, driven by increased evapotranspiration and a marked reduction in GP and soil moisture. The water balance components highlighted that the Atlantic Forest is a crucial biome and a lifeline for providing ecological functions, particularly in water control and storage, even during dry periods.