| Andropogon gayanus | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Clade: | Commelinids |
| Order: | Poales |
| Family: | Poaceae |
| Subfamily: | Panicoideae |
| Genus: | Andropogon |
| Species: | A. gayanus |
| Binomial name | |
| Andropogon gayanus | |
Andropogon gayanus, commonly known as gamba grass, Rhodesian blue grass, tambuki grass, and other names, is a species of grass native to most of the tropical and subtropical savannas of Africa.
Andropogon gayanus was recognised and named by 1833. [1] Its common names include gamba grass, bluestem (Africa, Australia); Rhodesian andropogon (southern Africa); Rhodesian blue grass (Zimbabwe); onga, tambuki grass (north-west Africa); and sadabahar (India). [2]
This tufting perennial bunchgrass can grow 4 m (13 ft) tall and 70 cm (2.3 ft) in diameter, and has hairy leaves. Most of its roots are fibrous, [2] spreading close to the surface of the soil for up to 1 m (3 ft 3 in), [3] but it also has thick cord roots which store starch and anchor the plant as well as vertical roots able to extract water from a greater depth during the dry season. [2]
It produces large numbers of light, fluffy seeds (up to 244,000 seeds each year, with 65% viability [3] ), which can be spread by wind, animals or machinery. [2] It spreads rapidly where vegetation is disturbed, but most seeds fall within 5 m (16 ft) of the parent plant. [3]
The grass is native to most of the tropical and subtropical savannas of Africa, [4] also extending southwards into Mozambique, Botswana, Namibia and South Africa in regions with long dry seasons. It occurs naturally in xerophytic grasslands on doleritic, sandy or clay soils, at altitudes of up to 1,500 m (4,900 ft), and is very drought-tolerant. However it does not do well where mean minimum temperatures dip below 4.4 degrees Celsius, and it is not frost-tolerant. [2] It has also been introduced around the world as a pasture crop in Australia and Brazil. [5]
A. gayanus was introduced as a pasture crop in many parts of the world, including Australia, tropical countries of the Americas, as well as naturalising in Brazil [2] [3] It has also been introduced in Nigeria to reclaim land that has been overgrazed. [2] [3]
Strips of the grass are also planted in millet fields help to reduce wind erosion of the soil. [2]
In some African countries, the stems are also used as thatch and for making pen. [2]
Gamba grass forms dense patches, out-competing native species and altering ecosystems. Areas of dense infestation have a significantly higher fire risk than native pastures. [6] [7] It is highly resistant to both cutting and fire, and ungrazed tussocks can generate very intense fires, [2] leading to loss of tree cover and long-term environmental damage. It replaces native grasses, reducing natural biodiversity on ungrazed land. Being highly invasive, it can move into conservation areas, semi-urban residential land and mining leases. [3]
This has led to its declaration as a noxious species, officially being declared a "Weed of national significance" in Australia since 2012. [8] [2] [9] Western Australia, the Northern Territory and Queensland all have state legislation which prohibits planting of new plants and requires land managers to control infestations. [8]
Gamba grass was introduced into the Northern Territory of Australia in 1931 for trial as cattle feed. [9] There are now large swathes of the plant over 532,900 hectares between Darwin and Katherine. [10] Gamba grass already accounts for as much as 20% of Litchfield National Park, around 30,000 hectares of the 144,000-hectare park, contributing to worsening fire seasons. [11] [12] Researchers estimate that this will increase to as much as 30% by 2033, a major threat to the park's future due to extreme fire risk. [13] Conservationist Mitch Hart has described gamba grass as a "triple threat" to people's lives, the economy and the potential destruction of Australia's northern savanna. [9] Two zones of management have been declared. Class A requires eradication and class B requires growth and spread to be controlled. [10] The Gamba Army, a partnership between the Northern Territory Government and Territory NRM are working to control spread in priority areas. [14]
Gamba grass was imported into the state of Queensland as a pasture grass in 1942, but was not planted on a large scale until about 1983. Almost all known locations in Queensland are in areas below 980 m (3,220 ft) altitude that receive 400–1,500 mm (16–59 in) annual rainfall. [3] It is declared a class 2 pest under the Land Protection (Pest and Stock Route Management) Act 2002, making it an offence to introduce, keep or supply the species without a permit and requiring land managers to keep land free of the species. [15]
Gamba grass has effectively been eradicated from Western Australia, where infestations were not as widespread as the NT and Queensland. The Gamba Grass Eradication Program, a collaborative project supported by the Department of Biodiversity, Conservation and Attractions, the Department of Primary Industries and Regional Development, El Questro Station and Kimberley Rangelands Biosecurity Association began in 2011 and has been highly successful. It reduced the number of plants to 3,000 by 2018, leaving just 23 by 2020. They found only eight plants in the 2021 wet season. However it currently receives no funding from the federal government and monitoring is necessary for a further five years to ensure that there is no future spread. [9]
Salvinia molesta, commonly known as giant salvinia, or as kariba weed after it infested a large portion of Lake Kariba between Zimbabwe and Zambia, is an aquatic fern, native to south-eastern Brazil. It is a free-floating plant that does not attach to the soil, but instead remains buoyant on the surface of a body of water. The fronds are 0.5–4 cm long and broad, with a bristly surface caused by the hair-like strands that join at the end to form eggbeater shapes. They are used to provide a waterproof covering. These fronds are produced in pairs also with a third modified root-like frond that hangs in the water. It has been accidentally introduced or escaped to countless lakes throughout the United States, including Caddo Lake in Texas, where the invasive species has done extensive damage, killing off other life.
Litchfield National Park, covering approximately 1500 km2, is near the township of Batchelor, 100 km south-west of Darwin, in the Northern Territory of Australia. Each year the park attracts over 260,000 visitors.
A savanna or savannah is a mixed woodland-grassland biome and ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses. Four savanna forms exist; savanna woodland where trees and shrubs form a light canopy, tree savanna with scattered trees and shrubs, shrub savanna with distributed shrubs, and grass savanna where trees and shrubs are mostly nonexistent.
The yellow crazy ant, also known as the long-legged ant or Maldive ant, is a species of ant, thought to be native to West Africa or Asia. They have been accidentally introduced to numerous places in the world's tropics.
Cryptostegia grandiflora, commonly known as rubber vine, is a woody-perennial vine that is native to south-west Madagascar. It is also a significant weed in northern Australia, sometimes regarded as the worst weed in all of Australia. It has also been introduced to most other tropical and subtropical regions by man, because of its attractive flowers and the fact that its latex contains commercial quality rubber. It is now naturalised in the Caribbean, East Africa, Mauritius, India, Southeast Asia, Indonesia, Latin America, the southern United States, Fiji and New Caledonia. It is very similar to the purple rubber vine, which is also native to Madagascar.
Imperata cylindrica is a species of perennial rhizomatous grass native to tropical and subtropical Asia, Micronesia, Melanesia, Australia, Africa, and Southern Europe. It has also been introduced to Latin America, the Caribbean, and the Southeastern United States. It is a highly flammable pyrophyte, and can spread rapidly by colonizing disturbed areas and encouraging more frequent wildfires.
Cenchrus ciliaris is a species of grass native to most of Africa, southern Asia, southern Iran, and the extreme south of Europe (Sicily). Other names by which this grass is known include dhaman grass, anjan grass, koluk katai and buffelgrass.
Miconia crenata, commonly called soapbush, clidemia or Koster's curse, is a perennial shrub. It is an invasive plant species in many tropical regions of the world, causing serious damage.
Andropogon glomeratus is a species of grass known by the common names bushy bluestem and bushy beardgrass. This bunchgrass is native to the Americas, where it is widespread. It has also naturalized in other areas.
Macroptilium atropurpureum, commonly referred to as purple bush-bean, or siratro is a perennial legume recognized by its climbing, dense, green vines and deep purple flowers. The plant is indigenous to the tropical and subtropical regions of North, Central, and South America, as far north as Texas in the USA and as far south as Peru and Brazil. It has been introduced for use as a food for stock to many tropical regions around the world. It has become an invasive pest plant in a number of areas, including the north-eastern coast of Australia. Rich in protein, M. atropurpureum is commonly used for cattle pastures intercropped with grass, used in hay, or as a ground cover to prevent soil erosion and to improve soil quality.
Tussock grasses or bunch grasses are a group of grass species in the family Poaceae. They usually grow as singular plants in clumps, tufts, hummocks, or bunches, rather than forming a sod or lawn, in meadows, grasslands, and prairies. As perennial plants, most species live more than one season. Tussock grasses are often found as forage in pastures and ornamental grasses in gardens.
Taeniatherum is a genus of Eurasian and North African plants in the grass family.
Megathyrsus maximus, known as Guinea grass and green panic grass, is a large perennial bunch grass that is native to Africa and Yemen. It has been introduced in the tropics around the world. It has previously been called Urochloa maxima and Panicum maximum. It was moved to the genus Megathyrsus in 2003.
Bela "Bert" Grof was a Hungarian-born Australian agricultural researcher with contributions to grassland and forage research in the tropics.
Themeda quadrivalvis is a species of grass known by the common names grader grass, habana grass, and kangaroo grass, not to be confused with Themeda triandra, which is also known as kangaroo grass. It is native to India, Nepal, and Malaysia. It can also be found in many other places as an introduced species and often a noxious weed. It occurs in the United States, New Caledonia, Fiji, Mauritius, Thailand, Indonesia, Papua New Guinea, China, the Middle East and tropical America. It is a troublesome exotic weed in Australia, especially in northern regions. It is also an agricultural weed in crops such as sugar cane and lucerne.
In Australia, Mimosa pigra has been declared a noxious weed or given similar status under various weed or quarantine Acts. It has been ranked as the tenth most problematic weed and is listed on the Weeds of National Significance. It is currently restricted to the Northern Territory where it infests approximately 80,000 hectares of coastal floodplain.
Derrick Thomas was a British agricultural researcher with special contributions to grassland and forage research in the tropics.
Urochloa mutica, commonly known as para grass, buffalo grass, Mauritius signal grass, pasto pare, malojilla, gramalote, parana, Carib grass, and Scotch grass, is a species of grass. Despite its common name of California grass, it does not occur in California; it is native to northern and central Africa and parts of the Middle East, where it is cultivated for fodder. It was introduced elsewhere and it is now cultivated throughout tropical regions of the world for this purpose.
Lolium rigidum is a species of annual grass. Common names by which it is known include annual ryegrass, a name also given to Italian ryegrass, rigid ryegrass, stiff darnel, Swiss ryegrass and Wimmera ryegrass. It is a native of southern Europe, northern Africa, the Middle East and the Indian subcontinent and is grown as a forage crop, particularly in Australia, where it is also a serious and economically damaging crop weed.
Chrysopogon fallax is a perennial tufted grass endemic to Australia found in all mainland states except Victoria. It is commonly known as golden beard grass, ribbon grass, and weeping grass.
Text may have been copied from this source, which is available under a Attribution 4.0 International (CC BY 4.0) licence. 
| Authority control databases: National |
|---|
