Biogeochemical variations along hillslope catenas within the Bisley Research Watersheds, Luquillo Mountains, Puerto Rico

Paper summarized the spatial variation in biogeochemical storages and processes within the 13 ha subtropical steepland landscape of the Bisley Research Watersheds in NE Puerto Rico.  Within the watersheds variations in micro-climate, throughfall, soil properties, above-ground biomass, tree species composition, and disturbance frequency have been significantly related to hillslope position. In contrast, mass weighted concentrations of above ground nutrients, the density of seedlings, and other processes are poorly explained by topographic variables.  While a simple topographic based hillslope-catena model can explain general patterns; spatial auto-correlations of most variables occur over distances less than 10 m and the topographic variables alone typically explain less than 50 percent of the variance in most biogeochemical variables.  This paper explores the mechanisms that contribute to these spatial patterns with a special emphasis on determining sample sizes needed to quantify watershed scale storages and biogeochemical processes.