Australian waterbirds—products of the continent's ecology

Some aspects of the ecology of 93 waterbird species, found predominantly on freshwater ecosystems, are reviewed. These species, belonging to six major orders—Anseriformes (ducks, geese and Black Swan), Podicipediformes (grebes), Pelecaniformes (Australian Pelican and cormorants), Ciconiiformes (herons, ibis, spoonbills and bitterns), Gruiformes (cranes, rails, crakes and gallinules), and Charadriiformes (waders and terns)—use a wide range of habitats and about half occur throughout the continent. Knowledge of their ecology remains poor for many waterbirds, particularly cryptic and rare species, and is moderate to good for hunted species. Life histories of Australian waterbirds differ from their counterparts elsewhere. Australia's highly variable climate and river-flooding patterns create wetland habitats, the spatial and temporal variability of which strongly influence the ecology of local waterbirds. Many waterbirds respond to newly generated habitats to feed and/or breed and then disperse or die as wetlands dry. Regular movements are not common in most Australian species although some, particularly waders, migrate between Northern Hemisphere breeding grounds and non-breeding habitat in Australia. Breeding of Australian waterbirds coincides with food abundance in the southern spring, the wet season in the tropics and following floods inland. Habitat loss through draining of wetlands, regulation of rivers, diversion of water for irrigation and floodplain development are currently the major threats to waterbirds. Other potentially threatening processes include exotic plants and animals, pollution, climate change and over-harvesting but evidence for the impact of these factors remains poor. Understanding of waterbird, particularly waterfowl, ecology has contributed significantly to the conservation management of wetlands in Australia. Research on single species, studies of movements using satellite technology, further investigation of the effects of hunting, long-term monitoring and large-scale analyses of the availability of wetland habitat should be future research priorities.