(Andropogon gayanus)
Gamba grass, Townsville, Q'ld,© Btcpg (Wikimedia).
Legal status of gamba grass in Tasmania
- Gamba grass is a
declared weed under the
Tasmanian Biosecurity Act 2019 and associated Regulations. The importation, sale and distribution of gamba grass are prohibited in Tasmania.
- Gamba grass is also a
Weed of National Significance (WONS).
- The legal responsibilities of landholders and other stakeholders in dealing with gamba grass are laid out in the Statutory Weed Management Plan for Gamba Grass.
- Gamba grass does not occur in Tasmania.
What does gamba grass look like?
The many cultivars of gamba grass have the following key features:
mature plants grow up to 4 m tall, with tussocks up to 70 cm in diameter;
leaves are 30–60 cm long and up to 3 cm wide with a distinctive white midrib and covered with soft hairs;
stems are robust and also covered in soft hairs;
the root system spreads up to 1 m from the tussock, close to the soil surface;
reproduce from seed contained in a fluffy V-shaped seed head consisting of up to six groups of branches, each containing 2-18 primary branches.
Gamba grass roadside infestation, Q'ld, © Queensland Gov't.
Gamba grass
Impacts of gamba grass
In tropical savannas gamba grass can become the dominant grass species, but it will also invade woodlands, forests and vine forest edges. Competing strongly with native pasture, it can significantly alter soil-nutrient cycles and water cycles, replacing a range of native plants, (including native pastures), resulting in a decline in the diversity and abundance of native fauna and flora directly through competition, and indirectly through increased fire intensity and fire frequency.
When not intensively managed, fire risk from gamba grass also poses a major threat to infrastructure and culturally important sites. Altered fire regimes associated with the high biomass of gamba grass invasions has resulted in significant increases in fire management costs in the Northern Territory.
Where does gamba grass occur?
Gamba grass is a large, perennial tussock grass native to tropical and subtropical savannas of Africa.
Gamba grass grows best in the seasonally dry tropical savannas. While it can persist in areas with 400-3000mm annual rainfall, it prefers 750-1500mm rainfall per annum and a distinct 3-7 month dry season. Active growth usually occurs over a 4 to 8 month period, sometimes longer if adequate soil moisture exists.
Varieties of gamba grass were first introduced into northern Australia for pasture production benefits in the 1930’s, but the challenge to contain existing plantings and the movement of seed from these sites has resulted in it spreading extensively throughout various landscapes.
Major infestations now occur in the Northern Territory ‘Top End’, Queensland’s Cape York and Atherton Tablelands, and limited occurrences in the Kimberley region of Western Australia.
Gamba grass is considered to be a low climate match for Tasmania.
For further information or help in identifying gamba grass, refer to the Commonwealth of Australia website,
Weeds of National Significance - Gamba grass.
What you need to do
See also
Statutory Management Plan for Gamba Grass
Other useful links
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