Riverine habitat heterogeneity: the role of slackwaters in providing hydrologic buffers for benthic microfauna

Murray-Darling Freshwater Research Centre

MDFRC item.

Slackwater habitats within lowland rivers support abundant biotic communities and provide these communities with a refuge from increases in discharge. These refuges allow biota to persist as discharges, vary and provide a source of colonists for slackwaters further downstream. In order to investigate the response of slackwater benthic microfaunal communities to changes in discharge, artificial slackwaters were created within the main channel of a lowland river and benthic microfaunal communities were sampled over a 60-day period. Benthic microfauna within the artificial and reference slackwaters were recorded in higher richness and abundance than in the main river channel. Within days the communities in the artificial slackwaters were similar to those in the reference slackwaters. The rapid speed of colonisation suggests that initial colonisation of slackwaters is likely to occur via active or passive dispersal of biota and that these systems and communities are resilient to changes in discharge.