Wood and other aquatic habitat

~ Riparian vegetation increases stream channel complexity and directly contributes to aquatic habitat through inputs of logs and branches. In turn, the provision of complex habitat has a major influence on aquatic biodiversity. ~ Logs and branches can enhance stream stability, regulate sediment transport and exert significant control on channel complexity in bedrock rivers and channel geomorphology in alluvial rivers. ~ Logs contribute to the formation of physical features in streams, such as scour pools and channel bars, which serve as habitat for in-stream biota. ~ Logs provide physical habitat for biota at all levels of the food chain, ranging from microscopic bacteria, fungi and algae, to macroinvertebrates, fish and turtles. ~ Logs also provide sites where bacteria, fungi and algae can process carbon and other nutrients such as nitrogen and phosphorus, thus contributing to ecosystem processes such as productivity and respiration. ~ In alluvial rivers, logs can modify surface water/ground water exchange and enhance nutrient processing. ~ Logs from Australian riparian zones are relatively immobile. Our streams tend to have a low average stream power, the wood has a high density and many riparian trees have a complex branching structure that ensures they are easily anchored in position. ~ Although vast amounts of wood have been removed from many Australian rivers, what does remain provides important habitat for microbes, invertebrates, fish and other animals. ~ Retention and reinstatement of logs should be a priority for river rehabilitation, instead of removal or even realignment.