Characterization of Throughfall Heterogeneity in a Tropical Pre-Montane Could Forest in Costa Rica

Abstract

Understanding the water budget in tropical forests is essential because of its role in ecosystem health, drinking water supply, land, and resource management. Throughfall, the amount of precipitation reaching the forest floor, plays an important role in the balance between precipitation, runoff, and other components of the water budget. Previous research has indicated that vegetation and precipitation variables are the main drivers of throughfall variability. During the data collection stage of this study, rain gauge networks were deployed in a 2.2-hectare watershed within a tropical pre-montane transitional cloud forest in Costa Rica. Throughfall data were collected daily for a total of 39 events from 28 June–17 July 2012 and 12 June–16 July 2013. To quantify vegetation cover, leaf area index was estimated above each gauge using hemispheric photography. Precipitation and its intensity were also recorded for each event based on portable weather stations. The purpose of this thesis is to use these observational datasets to provide a comprehensive quantitative assessment of the spatial and temporal throughfall variability, and determine its main drivers. This study demonstrates that rainfall intensity and canopy density significantly affect throughfall patterns. However, throughfall variability is also driven by complex interactions between coupled factors.