Gully erosion and climate induced chemical weathering for vulnerability assessment in sub-tropical environment

Abstract

Land degradation significantly impacts habitats, agriculture and economy, particularly in regions with high population density. Gully erosion poses one of the major challenges for land degradation despite several conservation measures. Here we present a novel technique of gully erosion susceptibility mapping by employing EBO (Eco-geography based optimization) with its ensembles: Bagging, Dagging, and Decorate. The EBO and its ensembles model were evaluated by various statistical approaches such as SST (sensitivity), PPV (positive predictive values), NPV (negative predictive values), SPF (specificity), ACC (accuracy), RMSE (root mean square error) and Cohen's Kappa model. We measured the morphological characteristics and chemical weathering in addition to gully head cut that is responsible for surface soil erosion where chemical weathering indirectly increases gullying process. The AUC values of EBO (Eco-biogeography-based optimization), EBO-Bagging, EBO-Dagging and EBO-Decorate for training datasets are 0.969, 0.915, 0.954 and 0.920 respectively. The AUC values of EBO, EBO-Bagging, EBO-Dagging and EBO-Decorate for validation datasets are 0.934, 0.901, 0.912 and 0.842 respectively. We apply this technique in the Kangsabati catchment area where we found that the upper part is more vulnerable to gullying leading to land degradation. Truer novel technique would aid in identifying land degradation-prone areas, and in formulating better strategies for better land use.