An infestation of gamba grass near Darwin
In northern Australia, concern has been raised about the impacts
of introduced grass species, in particular Andropogon
gayanus (gamba grass). Gamba grass is a perennial species of
African grass that was introduced in the Northern Territory as a
replacement for native pastures.
Gamba grass is a useful pasture species and can be managed if it
is grazed by cattle. However gamba grass is now invading savanna
ecosystems throughout the Top End of the Northern Territory and
when it is not grazed it grows vigorously in tall stands that
provide fuel for intense fires (Howard 2002) . These fires in turn
appear to be helping the spread of gamba grass which is adept at
invading burnt areas.
This invasion could have significant consequences for native
communities, as well as ecosystem function and stability,
comparable to the dramatic effects of invasion documented in other
ecosystems (D'Antonio & Vitousek 1992, Vitousek et al. 1996).
This is of particular concern as gamba grass invasion has the
potential to alter all three determinants of savanna functioning:
nutrient and water availability and fire regimes.