Grader grass
Themeda quadrivalvis
family
Poaceae
origin
Exotic
declaration
NIL
For information only
Common names
Grader grass, Habana grass, , Oatgrass, Kangaroo grass.
An upright and short-lived grass growing 50-200 cm tall. Its stems, leaves and seed-heads turn reddish-brown or golden-brown in colour as they mature. Its seed-heads consist of many drooping, fan-shaped flower clusters interspersed with short 'leaves'. The mature seeds (4.5-5.5 mm long) have a cluster of hairs at the base and are topped with a large twisted awn (10-45 mm long).
Impact
Impact
rangelands, particularly in areas that are overgrazed or disturbed. It replaces native plants and forms tall thickets that can cover large tracts of land. Due to its greater biomass than the native plants it replaces, and hence its higher fuel loads, grader grass (Themeda quadrivalvis ) alters the fire regime. It does this by carrying more wildfires that are of a much greater intensity than the native plants are used to. Each of these hot fires, during the late dry season, cause a thinning of the native woodlands and eventually the number of trees in the ecosystem are reduced, resulting in a change from native savanna woodlands to exotic grasslands. It is currently causing most concern in the semi-arid rangelands of northern Queensland and the Northern Territory, where it is abundant and continuing to spread. However, it also appears in the list of the top 200 most invasive plants of south-eastern Queensland, and is in the New South Wales North Coast environmental weed list. It is also seen as a potentially significant threat to the Kimberley region in northern Western Australia, though it is not yet very widespread in this region. Grader grass (Themeda quadrivalvis) is also an important weed of crops in many parts of northern Australia. It is particularly troublesome in sugar cane, but can also be found in lucerne and other legume seed crops. It is regarded as a major weed of crops in coastal northern and central Queensland, and is also a minor crop weed in inland central Queensland and the Northern Territory.This species is a also very common weed of roadsides, where it can quickly become a safety hazard by reducing visibility on corners.
Location
Location
Characteristics
Characteristics
Similar Species
Similar Species
rangelands, particularly in areas that are overgrazed or disturbed. It replaces native plants and forms tall thickets that can cover large tracts of land. Due to its greater biomass than the native plants it replaces, and hence its higher fuel loads, grader grass (Themeda quadrivalvis ) alters the fire regime. It does this by carrying more wildfires that are of a much greater intensity than the native plants are used to. Each of these hot fires, during the late dry season, cause a thinning of the native woodlands and eventually the number of trees in the ecosystem are reduced, resulting in a change from native savanna woodlands to exotic grasslands. It is currently causing most concern in the semi-arid rangelands of northern Queensland and the Northern Territory, where it is abundant and continuing to spread. However, it also appears in the list of the top 200 most invasive plants of south-eastern Queensland, and is in the New South Wales North Coast environmental weed list. It is also seen as a potentially significant threat to the Kimberley region in northern Western Australia, though it is not yet very widespread in this region. Grader grass (Themeda quadrivalvis) is also an important weed of crops in many parts of northern Australia. It is particularly troublesome in sugar cane, but can also be found in lucerne and other legume seed crops. It is regarded as a major weed of crops in coastal northern and central Queensland, and is also a minor crop weed in inland central Queensland and the Northern Territory.This species is a also very common weed of roadsides, where it can quickly become a safety hazard by reducing visibility on corners.
