Biology Reference
In-Depth Information
Figure 6.3:
An artificial groyne build into the Tharwa River (ACT) to slow stream flow and create deep pools
needed by the endangered Trout Cod. (Photo by Mark Lintermans)
the persistence of some species of frogs. It is also essential for an array of species of
native freshwater fish, as well as mammals like the Platypus.
Threats and their management
A range of factors threatens the integrity of streams and natural drainage lines on
farms. Two key ones are the extensive removal of riparian vegetation, and
overgrazing and vegetation trampling by domestic livestock. These can result in
highly elevated levels of nutrients in waterways with corresponding negative
impacts on water quality.
Removal of native vegetation and overgrazing can have other negative impacts,
such as increased erosion with subsequent sedimentation and silting of waterways
in some parts of streams, whereas in others it can result
in streambank incision, leading to faster rates of water
flow and loss of chain-of-ponds systems (see Figure 6.5).
Linking formerly disconnected chains of ponds can have
devastating effects on frogs because: (1) the increased
speed of water flow can sweep away their eggs; and (2)
they become more susceptible to introduced predators
like the Mosquito Fish.
8
Halting vegetation removal
and controlling grazing
pressure are the two most
important ways to protect
the quality of habitats
associated with creeks,
streams and farm dams
