Amazon, Water stress, Drought, Plant Physiology, stomatal conductance

Tropical forests are essential for global ecosystem processes, such as carbon capture and the regulation of the hydrological cycle, contributing to climate stabilization. However, these ecosystems are threatened by the intensification of extreme events, such as prolonged droughts. The world’s longest precipitation exclusion experiment, ESECAFLOR, which for over two decades simulates severe drought conditions in the Caxiuanã National Forest in the Amazon, has been crucial for understanding how reduced rainfall affects tropical forests. However, we do not know how plants will respond after drought conditions. Therefore, this study aims to investigate the ecophysiological mechanisms related to variations in stomatal conductance and water potential in small trees (DBH less than 10 cm) after experimental drought. We will investigate leaf morphological characteristics, minimum conductance, daily stomatal conductance curves, and water potential at dawn and midday in 33 individuals from both control and experimental plots in the Caxiuanã National Forest, in the state of Pará. Data will be collected in October and November (during the drought period) and monthly from December to September 2025 (post-  drought, after the removal of the rainfall exclusion panels). These results will be essential to understand the resistance of the regenerating stratum to drought and its post-drought recovery capacity, providing valuable information about the resilience of tropical forests after extreme events.