Compound-specific δ13C isotopes and Bayesian inference for erosion estimates under different land use in Vietnam
Recent studies have pointed out the potential of the compound specific stable isotope (CSSI) technique based on long-chain fatty acids methylester (FAME) to identify hot spots of soil erosion by means of land use types. We tested the applicability of the CSSI technique on the basis of soil and sediment samples derived from a small agriculturally used catchment in Vietnam which is exemplary for many mountainous areas in Southeast Asia. Following CSSI analysis we set up a statistical decision sequence to identify hot spots of soil erosion by i) testing for significant differences between δ13C values of fatty acids (FA) of different contributing land use types and thereafter ii) examining the data using a Monte Carlo simulation of mixing polygons to provide a quantitative basis for model rejection and exclusion for sediment samples which violate the point-in-polygon assumption and iii) applying a Bayesian model with a Markov chain Monte Carlo (MCMC) model fitting using ...