| Autor: |
Silveiro, Antônio C.1,2 (AUTHOR) acsilveiro@gmail.com, Silvério, Divino V.1,3 (AUTHOR), Macedo, Marcia N.2,4 (AUTHOR), Coe, Michael T.2,4 (AUTHOR), Maracahipes, Leandro2,5,6 (AUTHOR), Uribe, Maria6 (AUTHOR), Maracahipes‐Santos, Leonardo2 (AUTHOR), Oliveira, Paulo Tarso S.7 (AUTHOR), Rattis, Ludmila2,4 (AUTHOR), Brando, Paulo M.1,2,4,6 (AUTHOR) |
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| Zdroj: |
Journal of Geophysical Research. Biogeosciences. Oct2024, Vol. 129 Issue 10, p1-15. 15p. |
| Abstrakt: |
Soil moisture is a crucial variable mediating soil‐vegetation‐atmosphere water exchange. As climate and land use change, the increased frequency and intensity of extreme weather events and disturbances will likely alter feedbacks between ecosystem functions and soil moisture. In this study, we evaluated how extreme drought (2015/2016) and postfire vegetation regrowth affected the seasonality of soil water content (0–8 m depth) in a transitional forest in southeastern Amazonia. The experiment included three treatment plots: an unburned Control, an area burned every three years (B3yr), and an area burned annually (B1yr) between 2004 and 2010. We hypothesized that (a) soil moisture at B1yr and B3yr would be higher than the Control in the first years postfire due to lower transpiration rates, but differences between burned plots would decrease as postfire vegetation regrew; (b) during drought years, the soil water deficit in the dry season would be significantly greater in all plots as plants responded to greater evaporative demand; and (c) postfire recovery in the burned plots would cause an increase in evapotranspiration over time, especially in the topsoil. Contrary to the first expectation, the burned plots had lower volumetric water content than the Control plot. However, we found that droughts significantly reduced soil moisture in all plots compared to non‐drought years (15.6%), and this effect was amplified in the burned plots (19%). Our results indicate that, while compounding disturbances such as wildfires and extreme droughts alter forest dynamics, deep soil moisture is an essential water source for vegetation recovery. Plain Language Summary: As extreme droughts and wildfires have become more common in southeastern Amazonia, they could alter soil moisture availability, but the intensity of these compounding effects still needs to be understood. This study investigates the impact of the extreme drought of 2015/2016, postfire vegetation recovery, the return of water to the atmosphere, and their interacting effects on water distribution across the soil profile in three treatment plots: an unburned Control, an area burned every three years, and an area burned annually from 2004 to 2010. Contrary to expectations, we found that soil moisture in the burned plots decreased in the years following the last experimental fire (2010), even as the vegetation recovered. Drought events significantly reduced soil moisture across all plots, but this effect was amplified in the burned plots. As land use changes increase and climate change intensifies, such drought‐induced soil drying may become more common, exacerbating the impacts of wildfires on ecosystem resilience and forest health across much of the region. Key Points: During the driest months of the year, burned forests showed significant reductions in soil moisture compared with unburned forestsThe drought event of 2015/2016 caused greater reductions in soil moisture in the burned forest than in the unburned forestBoth burned and unburned forests increased water use throughout the 8‐m soil column from 2011 to 2018 [ABSTRACT FROM AUTHOR] |
| Databáze: |
GreenFILE |
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