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The Kimberley Rivers and Streams ecoregion is characterized by a number of streams that flow year-round and by many intermittent streams and ephemeral swamps. The ecoregion is home to a large number of endemic species of many types. The Kimberley plateau, reaching an elevation of about 3,280 feet (1,000 m), stretches from the coast of the Indian Ocean through one corner of northwest Australia. This area is rugged, with a diverse landscape of mountains, moist forests, rocky coastline, and sand dunes.
Two rivers outline the Kimberley ecoregion: the Fitzroy River, at 325 miles (525 km) long, forms the southern border of the area, while the just slightly shorter Ord River runs along its eastern edge. Both rivers start in mountain ranges and are fed by many tributaries as they make their way through rocky gorges and valleys to the Timor Sea. Other rivers and streams drain the Kimberley Plateau, many of which experience a torrential influx of water during the short wet season and then dry out during a prolonged dry season. Many swamps in this region also contain water only during the wet season. Two important areas for freshwater biodiversity are found within the protected areas of Drysdale River National Park and Prince Regent Nature Reserve. Several families of fish in this ecoregion are noted for their large numbers of endemic species, including gudgeons (Eleotridae), grunters (Terapontidae), hardyheads (Atherinidae), and rainbowfish (Melanotaeniidae). Freshwater fish include several species of venomous eel-tail catfishes, the Kimberley grunter, the Greenway’s grunter, and the pygmy rainbowfish. Endemic fish in the Eleotridae family include the slender gudgeon, Barnett River gudgeon, and the only two members of the endemic genus Kimberleyeleotris -- the Mitchell gudgeon and Drysdale gudgeon. In addition to a number of aquatic snakes, fresh waters in this ecoregion also support populations of several aquatic lizards, including Mitchell’s and Mertens’ water monitors. Other reptiles in this ecoregion include the northern snake-necked turtle, northern snapping turtle, and Victoria short-necked turtle. Both freshwater crocodiles and saltwater crocodiles occur here as well.
There is one large dam on the Ord River, but most waterways still retain their natural patterns of flow. Grazing by livestock destroys vegetation and causes soil erosion, while the mining of minerals causes water pollution. Non-native fish, which have been introduced to the rivers, compete with native species for habitat and food and sometimes prey upon them.
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