The Applica tion of the D istr ibuted Eco-hydrolog ica lModel TOPOGin a Mounta inous Sma llWa tershed of Tempera te Zone:A Ca se Study in the Sma llWa tershed of Pa ilugou in Qilian Mounta ins Research progress on the mechanisms and influence factors of nitrogen retention and transformation in  riparian ecosystems. Simulation of water resources evolution driven by vegetation construction and control of eco-hydrological processes in Erdos Larus Relictus Nature Reserve Large scale eco-hydrological model and its integration with GIS