Can environmental flow pulses help to restore river-floodplain ecosystems

Environmental Flows are now a prominent restoration tool for Australian Rivers. Flow pulses represent one type of environmental flow release often used by managers as they have been affected by water resource development, are associated with environmental benefits and they are feasible, given existing constraints. Flow pulses can be characterised as an increase in flow
from base flow anywhere up to bank full which can mean inundation of riparian areas and adjacent wetlands. The challenge in using flow pulses as part of a restoration program is that they are a short term and, in some cases, localised action that seeks to contribute to achievement of long-term, large scale changes in condition. This presentation will summarise what is known of the influence of single flow pulses on river-floodplain systems within the context of their longer term influences as a step in identifying their potential value as a restoration tool. Broadly, flow pulses can influence ecosystem condition in the medium to long term through their effects on habitat availability and subsequent species’ survival and recruitment. Flow pulses also change patterns of connectivity either delivering subsidies that promote productivity or creating opportunities for dispersal that may influence resilience. Finally, flow pulses may influence processes such as primary production and decomposition that influence food availability. The evidence for the short-term effects of flow pulses is accumulating, however, evidence for their longer term significance
is scant and this will need to be addressed if flow pluses are to contribute to restoration.