Spatial variations of interception loss components by Tamaulipan thornscrub in northeastern Mexico

Measurements of gross rainfall, throughfall and stemflow fluxes were conducted from April 1997 through April 1998 within a Tamaulipan thornscrub community in northeastern Mexico. Throughfall and stemflow fluxes represented 78.1% and 3.0% of gross rainfall, implying that interception loss from this community was 18.9%. Canopy water fluxes were often statistically different between study plots and these differences were largely explained by variations in plant dasometric characteristics. The revised Gash analytical model of rainfall interception loss was employed and simulated interception loss values were close to observed values. However, results from this study suggest that the parameters employed within the Gash analytical model are sensitive to spatially variable plant characteristics such as stem diameter, stem height and weighted leaf area index. This suggests that the transferability of the Gash model may be limited even within the same ecosystem unless the spatial variability of plant dasometric characteristics are taken into account.