plains of New South Wales but is absent from coastal areas and the arid inland. Subspecies arida has the widest distribution of the subspecies and is found in all mainland states except Victoria. It grows in arid regions but only where there is sufficient subsoil moisture. Subspecies camaldulensis is the dominant eucalypt along the Murray-Darling river system and its tributaries. It also occurs on the Eyre and Yorke Peninsulas and Kangaroo Island in South Australia and in some locations along the Hunter River in New South Wales. It is the only subspecies in coastal Victoria. Subspecies minima is endemic to South Australia, where it grows in the northern Flinders Ranges and the northern Eyre Peninsula. Subspecies obtusa is endemic to tropical northern Australia, including parts of the Kimberley, the Top End and the Gulf of Carpentaria hinterland as far east as the Gilbert River, Queensland in Queensland. Subspecies refulgens is endemic to the Pilbara-Gascoyne-Carnarvon region, along rivers flowing westwards, including along some of the tributaries of the upper Murchison River. Subspecies simulata is mainly restricted to some rivers on Cape York Peninsula, but with some populations further south. Ecology The species can be found along the banks of watercourses, as well as the floodplains of those watercourses. Due to the proximity to these watercourses, river red gum is subject to regular flooding in its natural habitat. River red gum prefers soils with clay content. The trees not only rely on rainfall but also on regular flooding, since flooding recharges the sub-soil with water. The association of the river red gum with water makes the tree a natural habitat choice, indeed sometimes the only choice in drier areas, for other species. The trees provide a breeding habitat for fish during the flooding season, which also benefits aquatic bird life that depend on fish as a food source during their own breeding season. Wilson, who examined the management of river red gums in NSW, suggests shelter is provided for fish in rivers and streams by fallen branches from the river red gum. The "snags" formed when river red gums fall into rivers such as the Glenelg, are an important part of river ecosystems, and vital habitat and breeding sites for native fish like river blackfish. Unfortunately most snags have been removed from these rivers, beginning in the 1850s, due to river-improvement strategies designed to prevent hazards to navigation, reduce damage to in-stream