Hydric ecosystem services in a non-disturbed rainforest of the Amazon, Amapá, Brazil

Abstract

Understanding the processes of the hydrological cycle of tropical forests reduces the uncertainties about water vapor estimates on a regional scale. Interception refers to water that does not participate directly in ecological processes. Thus, we investigated the interception process using 30 pluviometers, spaced one kilometer apart, within an area of 25 km² of the Amapá National Forest (FLONA Amapá). The total precipitation above the canopy was 2184.2 mm, and the internal precipitation was 1322.4 mm, representing a fraction of 60.5%. The estimated intercepted fraction was 828.3 mm, corresponding to 37.9% of the total precipitation above the canopy. As consequence of this water balance, approximately 828.3 L.m-2 of rainwater was temporarily retained by the forest and returned to the atmosphere as water vapor. We concluded that FLONA Amapá (4120 Km²) returns about 1.36 x 106 Olympic swimming pools to the atmosphere, annually. The moisture produced in this process, locally cools the air that is transported to other regions of Brazil. This process is a relevant ecosystem service to produce water vapor, confirming the hypothesis that tropical forests are effectively promoting the dynamic balance of the hydrological cycle in the Amazon basin.