''Andropogon gayanus''. commonly known as gamba grass, Rhodesian blue grass, tambuki grass, and other names, is a species of
grass
Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...
native to most of the tropical and subtropical
savanna
A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) 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 ...
s of Africa.
History and naming
''Andropogon gayanus'' was recognised and named by 1833. Its common names include gamba grass, bluestem (Africa, Australia); Rhodesian andropogon (southern Africa); Rhodesian blue grass (
Zimbabwe
Zimbabwe (), officially the Republic of Zimbabwe, is a landlocked country located in Southeast Africa, between the Zambezi and Limpopo Rivers, bordered by South Africa to the south, Botswana to the south-west, Zambia to the north, and Mozam ...
); onga, tambuki grass (north-west Africa); and sadabahar (India).
Description
This tufting perennial
bunchgrass
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 ...
can grow tall and in diameter, and has hairy leaves. Most of its roots are fibrous,
[ spreading close to the surface of the soil for up to ,][ 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.][
It produces large numbers of light, fluffy seeds (up to 244,000 seeds each year, with 65% viability][), which can be spread by wind, animals or machinery.][ It spreads rapidly where vegetation is disturbed, but most seeds fall within of the parent plant.][
]
Habitat
The grass is native to most of the tropical
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in
the Southern Hemisphere at S. The tropics are also referred to ...
and subtropical
The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Geographical z ...
savannas of Africa, also extending southwards into Mozambique
Mozambique (), officially the Republic of Mozambique ( pt, Moçambique or , ; ny, Mozambiki; sw, Msumbiji; ts, Muzambhiki), is a country located in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi ...
, Botswana
Botswana (, ), officially the Republic of Botswana ( tn, Lefatshe la Botswana, label=Setswana, ), is a landlocked country in Southern Africa. Botswana is topographically flat, with approximately 70 percent of its territory being the Kalahar ...
, Namibia
Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...
and South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...
in regions with long dry seasons. It occurs naturally in xerophytic
A xerophyte (from Greek ξηρός ''xeros'' 'dry' + φυτόν ''phuton'' 'plant') is a species of plant that has adaptations to survive in an environment with little liquid water, such as a desert such as the Sahara or places in the Alps or th ...
grasslands on doleritic, sandy or clay soils, at altitudes of up to , 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.[
However, it has been introduced to many parts of the world, including tropical countries of the Americas, and has ]naturalised
Naturalization (or naturalisation) is the legal act or process by which a non-citizen of a country may acquire citizenship or nationality of that country. It may be done automatically by a statute, i.e., without any effort on the part of the i ...
in Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
[ and other countries. It was mainly introduced for use as an improved ]pasture
Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep, or swine ...
plant.[ Text may have been copied from this source, which is available under ]
Attribution 4.0 International (CC BY 4.0)
licence
/ref>
Gamba grass was introduced into the Northern Territory of Australia
The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an Australian territory in the central and central northern regions of Australia. The Northern Territory shares its borders with Western Aust ...
in 1931 for trial as cattle feed
There are different systems of feeding cattle in animal husbandry. For pastured animals, grass is usually the forage that composes the majority of their diet. Cattle reared in feedlots are fed hay supplemented with grain, soy and other ingredi ...
,[ and was imported into the state of ]Queensland
)
, nickname = Sunshine State
, image_map = Queensland in Australia.svg
, map_caption = Location of Queensland in Australia
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, established_ ...
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 altitude that receive annual rainfall.[
]
Uses
''A. gayanus'' is used as a pasture crop for cattle in many countries,[ including in ]far north Queensland
Far North Queensland (FNQ) is the northernmost part of the Australian state of Queensland. Its largest city is Cairns and it is dominated geographically by Cape York Peninsula, which stretches north to the Torres Strait, and west to the Gulf C ...
in Australia.[ and has been used in ]Nigeria
Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...
to reclaim land that has been overgrazed.[
Strips of the grass planted in ]millet
Millets () are a highly varied group of small-seeded grasses, widely grown around the world as cereal crops or grains for fodder and human food. Most species generally referred to as millets belong to the tribe Paniceae, but some millets al ...
fields help to reduce wind erosion
Aeolian processes, also spelled eolian, pertain to wind activity in the study of geology and weather and specifically to the wind's ability to shape the surface of the Earth (or other planets). Winds may erode, transport, and deposit materials ...
of the soil.[
In some African countries, the stems are used as ]thatch
Thatching is the craft of building a roof with dry vegetation such as straw, water reed, sedge (''Cladium mariscus''), rushes, heather, or palm branches, layering the vegetation so as to shed water away from the inner roof. Since the bulk of ...
.[
]
Environmental impact
It has been declared a noxious species, officially a "Weed of national significance" in Australia since 2012, where it forms dense patches, out-competing native species and altering ecosystem
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...
s. Areas of dense infestation have a significantly higher fire risk than native pastures. It is highly resistant to both cutting and fire, and ungrazed tussocks can generate very intense fires,[ leading to loss of tree cover and long-term environmental damage. It replaces native grasses, reducing natural ]biodiversity
Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ...
on ungrazed land. Being highly invasive, it can move into conservation areas, semi-urban residential land and mining leases.[
In the NT, where there are large swathes of the plant between ]Darwin, Northern Territory
Darwin ( ; Larrakia: ) is the capital city of the Northern Territory, Australia. With an estimated population of 147,255 as of 2019, the city contains the majority of the residents of the sparsely populated Northern Territory.
It is the smalle ...
and Katherine
Katherine, also spelled Catherine, and Catherina, other variations are feminine Given name, names. They are popular in Christian countries because of their derivation from the name of one of the first Christian saints, Catherine of Alexandria ...
, conservationist Mitch Hart described gamba grass as a "triple threat": to people's lives, to the economy of Territory, and the potential destruction of Australia's northern savanna,[
]
Control measures
WA, NT and Queensland have state legislation which prohibits planting of new plants, and compels land managers to control infestations.[
David Bowman, a professor of environmental change biology at the ]University of Tasmania
The University of Tasmania (UTAS) is a public research university, primarily located in Tasmania, Australia. Founded in 1890, it is Australia's fourth oldest university. Christ College, one of the university's residential colleges, first pro ...
suggested in 2013 that the introduction of African elephants to Australia could be considered to control the gamba grass, as a rewilding
Rewilding may refer to:
*Rewilding (conservation biology), the return of habitats to a natural state
**Rewilding Europe, a programme to do so in Europe
*** Pleistocene rewilding, a form of species reintroduction
**Rewilding Institute, an organiz ...
trial.
The state of Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
, where infestations have not been as widespread as the NT and Queensland, established the Gamba Grass Eradication Program, a collaborative project supported by the Department of Biodiversity, Conservation and Attractions
The Department of Biodiversity, Conservation and Attractions (DBCA) is the Western Australian government
The Government of Western Australia, formally referred to as His Majesty's Government of Western Australia, is the Australian state de ...
, the Department of Primary Industries and Regional Development
The Department of Primary Industries and Regional Development (DPIRD) is a Western Australian government department responsible for regulating and advancing agricultural and food industries, fisheries and regional development within the state. I ...
, El Questro Station
El Questro Wilderness Park is a wilderness park on El Questro Station, a cattle station that diversified its pastoral operation to include tourism, located in the Kimberley region of Western Australia. It remains a working cattle station with a ...
and Kimberley Rangelands Biosecurity Association. The control program, started in 2011, has been highly successful, reducing the numbers of plants to 3,000 by 2018, and just 23 by 2020. They found only eight plants in the 2021 wet season. However it receives no funding from the federal government
A federation (also known as a federal state) is a political entity characterized by a union of partially self-governing provinces, states, or other regions under a central federal government (federalism). In a federation, the self-governin ...
, and monitoring is necessary for a further five years to ensure that it does not spread again.[
]
References
External links
''Andropogon gayanus''.
National Weeds Strategy.
gayanus
Bunchgrasses of Africa
Flora of Africa
Forages
{{Panicoideae-stub