Forests Mitigate Drought in an Agricultural Region of the Brazilian Amazon: Atmospheric Moisture Tracking to Identify Critical Source Areas

Tropical rainforests provide essential ecosystem services to agricultural areas, including moisture recycling. In the Amazon basin, drought frequency has increased in the late 20th and early 21st centuries, but the role of forests, ocean, and nonforested areas in causing or mitigating drought has not been determined. Using a precipitationshed moisture tracking framework, we quantify the contribution sources of evaporation to rainfall in Rondonia in the Brazilian Amazon. Forests account for similar to 48% of annual rainfall on average, and more than half of the forest source is from protected areas (PAs). During droughts in 2005 and 2010, moisture supply decreased from oceans and nonforested areas, while supply from forests was stable and compensated for the decrease. Remote sensing and land surface models corroborate the relative insensitivity of forest evapotranspiration to droughts. Forests mitigate drought in the agricultural study region, providing an important ecosystem service that could be disrupted with further deforestation.

Automated summary

Tropical rainforests play a crucial role in providing essential ecosystem services to agricultural areas, including mitigating drought through moisture recycling. Studies in the Brazilian Amazon have shown that forests contribute significantly to annual rainfall, with protected areas contributing more than half of the forest source. During droughts, forests remain stable in their moisture supply, offsetting the decrease in supply from oceans and nonforested areas.