Interacciones entre índice de área foliar, densidad del dosel y precipitación efectiva de un bosque de Polylepis reticulata ubicado en un ecosistema de páramo

Abstract

The measurement of vegetation cover is fundamental to quantify the percentage of precipitation intercepted by it. The most widely techniques used to measure the cover in situ are: the leaf area index (LAI) and the canopy density (CD). However, no attention has been paid to the differences recorded in the use of the two techniques or how these variables influence the hydrological balance particularly on the throughfall (TF). For this reason, the objective of the study is to evaluate the relationship between vegetation cover measurements realized by the LAI and CD methods and to identify how they relate with the TF, important for hydrological applications. The study was developed in a Polylepis reticulata forest of 15633 m2 , located at the Zhurucay Ecohydrological Observatory, south of Ecuador, in an altitudinal range of 3765 to 3809 m a.s.l. The LAI was measured with the CI-110 Plant Canopy Imager equipment and CD with a spherical densiometer, covering a wide range of canopy cover values. The study site was instrumented with 9 tippingbucket rain gauges to measure TF. The results indicate that LAI and CD averages are 2.43 m2 m-2 y 88% respectively; whose relationship is significant (R2= 0.913; p<0.05). Mean annual TF is 773.2 mm, which tends to decrease with the increase of the LAI and CD; although, their relationship is not statistically significant (pvalue>0.05). Our study shows the importance of characterizing the vegetation cover, to understand the interaction with TF.