Ecological effects of perturbation by drought in flowing waters

SUMMARY Knowledge of the ecology of droughts in flowing waters is scattered and fragmentary, with much of the available information being gathered opportunistically. Studies on intermittent and arid‐zone streams have provided most of the information. Drought in streams may be viewed as a disturbance in which water inflow, river flow and water availability fall to extremely low levels for extended periods of time. As an ecological perturbation, there is the disturbance of drought and the responses of the biota to the drought. Droughts can either be periodic, seasonal or supra‐seasonal events. The types of disturbance for seasonal droughts are presses and for supra‐seasonal droughts, ramps. In droughts,…