TRaCK: Tropical Rivers and Coastal Knowledge

Science and knowledge that governments, communities, industries for sustainable use of Australia's tropical rivers and estuaries

Dynamics of Aggregated River Wood and Importance as Fish Habitat in a Tropical Australian River

TitleDynamics of Aggregated River Wood and Importance as Fish Habitat in a Tropical Australian River
Publication TypeConference Participation
Year of Publication2010
AuthorsPettit, NE, Warfe, DM, Pusey, BJ, Kennard, MJ, Douglas, MM, Davies, PM, Bunn, S
Keywords5: Foodwebs and biodiversity

The input of wood into the Daly River in tropical northern Australia provides habitat complexity that is likely to have a major influence on aquatic biodiversity and river geomorphology. Wood recruitment to the river from the riparian forests occurs sporadically during flood events in the wet season. Surveys in 2008 and 2009 of the aggregated river wood formations (AWR) found densities of 37 - 78 pieces km-1 with five distinct types of ARW identified. After large wet season flows in 2008/2009 between 46 – 51% of ARW had moved. Distribution of wood age classes indicated continual recruitment and slow turnover of wood within the river. Fish species richness was higher in river reaches with a high proportion of wood, but there was no significant effect of wood on the total abundance of fish. The importance of wood as habitat appeared to vary for different species and ages of fish. Wood was also a significant habitat feature that influenced fish community composition. This study demonstrates the dynamic nature and complex characteristics of in-stream wood and its importance as fish habitat. This highlights the need to consider in-stream wood in the development of relevant flow-habitat-ecology relationships.