Southwest Australia Rivers and Streams - A Global Ecoregion
All of the exotic species far outsize the native freshwater fauna found here
Snapshot: Ecoregion 168
Size:
325,000 sq. km (125,000 sq. miles)
325,000 sq. km (125,000 sq. miles)
Habitat type:
Small Rivers
Geographic Location:
Southwestern Australia
Conservation Status:
Critical/Endangered
Quiz Time!
Where does the salamaderfish go when the temporary pools dry up?
Answer:
It burrows underground until it reaches damp sand. This fish is able to breath by absorbing oxygen through its moist skin, like the lungless salamanders of North America. Salamanderfish have been found as deep as 2 feet below ground! And when the pools fill again with water, the fish emerge from underground.
About the Area
Comprised of short coastal rivers, this region exhibits lower species richness than Eastern Australia, but displays high levels of endemism due to long periods of isolation.
The pools and marshes that form among granite outcrops come and go with the seasons and support unusual species of plants and insects that have adapted to the changing availability of water. Local Species
Nine of fourteen fish species found in this ecoregion are endemic, as are twelve of nineteen fairy shrimp (Anostraca) species.
Among the endemics are Freshwater cobbler (Tandanus bostocki), Nightfish (Bostockia porosa), Western pygmy perch (Edelia vittata), Long-headed goby (Afurcagobius suppositus), and King River perchlet (Nannatherina balstoni).
In addition, the anadromous and monotypic-pouched lamprey (Geotria australis) inhabits this ecoregion. Salamanderfish (Lepidogalaxias salamandroides) - the only species in the family Lepidogalaxiidae, is one of the distinctive species found here.
The salamanderfish may be related to galaxiids, of which there are three endemic species in this ecoregion as well: Western minnow (Galaxia occidentalis), Black-stripe minnow (Galaxiella nigrostriata), and Western mud minnow (G. munda).
Threats
A number of introduced species, including Rainbow trout (Onchorhynchus mykiss) and Brown trout (Salmo trutta) have proliferated in streams and rivers of the region. With the exception of one endemic species, all of the exotic species far outsize the native freshwater fauna found here.
Habitat loss (particularly of important ephemeral pools), alteration of the natural flow regime, and negative impacts from agricultural practices, all pose threats to the native biota.
Resources
• NationalGeographic.com
