ENSO impacts on litter stocks and water holding capacity in secondary forests in eastern Amazonia

Among the impacts of climate change, there is the intensification of phenomena such as the El Nino Southern Oscillation (ENSO) responsible for El Nino and La Nina. However, understanding their effects on the functional processes of forests is limited. Therefore, this study evaluated the effects of ENSO on litter stock and water holding capacity (WHC) in a successional forest in eastern Amazonia. Evaluations occurred in periods with the most rainfall in El Nino (2019) and least in La Nina (2021) years. Twelve permanent plots were used to sample litter. ENSO effects were evident for WHC, higher during El Nino. However, this influence was not clear for litter, as only in the rainy season effects were found. There was a positive correlation of WHC with precipitation and humidity, while litter stocks were negatively correlated with temperature and wind speed. Although the subject of this study requires long-term assessments, preliminary results suggests that, depending on the intensity of ENSO, forest functional processes can be strongly impacted and altered. The conclusion reinforces warnings by the scientific community about the impacts of climate change on the maintenance of litter stocks, decomposition and, consequently, the biogeochemical cycle and essential ecosystem services for the maintenance of Amazonia biodiversity. The need to develop long-term research to understand the effects of climatic change on litter stocks and water holding capacity is highlighted, especially in Amazonia.