River damming has a remarkable impact on the hydrology of a river, modifying the probabilistic structure of the discharge time series. As riparian vegetation is closely connected to discharge stochasticity, it can experience remarkable changes after the construction of artificial reservoirs. A number of field studies have shown the consequences of river regulation on riparian vegetation, which often exhibits significant decreases and shifts along the transect. In this work, we have quantitatively explored the effects of dam-induced hydrological changes on the vegetation narrowing/widening process and on the total biomass along the transect. To this aim, we have used an eco-hydrological stochastic model to quantitatively study an exemplifying case. We have investigated the vegetation response to changes of the mean, the coefficient of variation and the autocorrelation time of the river discharges. The range of these changes has been deduced from the analysis of field data pertaining to pre- and post-dam conditions. The results have shown that the differences in vegetation between the pre- and post-dam conditions are nonnegligible and nonlinear behavior occurs: these results confirm the remarkable changes recorded in the field studies.