摘要: Wetlands have been defined as areas of marsh, fen, peat, land or water whether natural or artificial, permanent or temporary, in which water is static or flowing, fresh, brackish or saline, including marine areas, and the depth of which at low tide does not exceed six metres (IUCN, 1996). This broad definition includes lakes, estuaries, mangroves, sea-grass beds, coral reefs and flowing waters such as rivers, streams and creeks. For the purposes of this chapter, wetlands include shallow-water habitats such as swamps, mires, bogs, inland'lagoons' and shallow, vegetated lakes, as well as artificial wetlands such as farm dams, rice paddies and those constructed for water treatment. Wetlands can be considered distinct from lakes and flowing waters in that they are generally shallow, have imperceptible or random mass water movement, and contain emergent vegetation at least around their margins. For algae, wetland habitats include the substratum (sand, mud, peat or rock), any free water, and the surface of animals and living and dead vegetation. These habitats overlap with those found in larger lakes and slow-moving rivers. Lakes can be bordered by wetlands, and even the largest rivers in Australia are at times and in places shallow and still. Australian wetlands can be categorised in relation to water chemistry (acidic, basic, calcium carbonate-rich, saline, brackish or fresh; Bailey & Williams, 1973), location (upland, lowland, coastal, riparian, etc.; McComb & Lake, 1990), or water regime (permanent, seasonal, intermittent, episodic or ephemeral; Paijmans et al., 1985). Given the relative dryness of most parts of Australia, water regime can be of …