Natural
flow regimes are important for maintaining the ecological integrity of flowing
water systems. Likewise, altered flow regimes, often accompanied by other
environmental stressors, are a significant factor in the ecological degradation
and loss of biodiversity in freshwater systems globally. With many rivers and basins globally targeted
for some degree of flow restoration there is a need for measuring the success,
or otherwise, of environmental flow releases to inform long-term flow
management. What is missing from much of
the environmental flows literature, however, is a detailed discussion of
potential indicators that may be suitable for assessing the ecosystem responses
to environmental flows across a range of spatial and temporal scales. In this paper we present a conceptual model
of the ecosystem response to environmental watering and discuss a suite of
ecosystem-response indicators likely to be sensitive to flow-regime
restoration. This includes short-term changes in ecological responses resulting
from environmental flows delivered as individual pulse releases or ad hoc flow
releases, as well as, longer-term responses to more widespread systematic
restoration of the flow regime at the catchment scale, particularly in large floodplain
river systems.