Invasive plants of Australian origin
Encyclopedia
There are a number of examples of Australia
n plants that have become invasive species
when introduced into other countries.
into Florida
. As with all Melaleuca
species, M. quinquenervia seeds prolifically. In the absence of natural predators, it spread throughout southern Florida; at one time it was estimated that 12% of southern Florida had been colonised by it. The colonised area included a substantial proportion of the Everglades
, a revered national park and World Heritage Site
. Attempts were made to control the spread by burning off, but this only exacerbated the problem as it encouraged seed dispersal while failing to kill the trees. The spread of Melaleuca is now managed by a combination of regular herbicide
treatment and the introduction of an Australian beetle
as a biological control.
species have become serious environmental pests after being introduced into southern Africa
. The most troublesome species are Acacia cyclops
and Acacia saligna
. Both are Western Australia
n coastal wattles, introduced to help bind drifting sand dunes. They remain serious pests, but some controls have been introduced. In the case of Acacia saligna, the introduction of acacia seed weevils (Melanterius species) has achieved complete control. A lesser degree of control has been achieved for Acacia cyclops by the introduction of a gall rust fungus (Uromycladium species).
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n plants that have become invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
when introduced into other countries.
Melaleucas in the Everglades
Perhaps the best known example of an Australian plant becoming an invasive species is the disastrous introduction of Melaleuca quinquenerviaMelaleuca quinquenervia
Melaleuca quinquenervia, commonly known as Niaouli or Broad-leaved paperbark or the Paper Bark Tea Tree, is a small- to medium-sized tree of the allspice family, Myrtaceae. The plant is native to New Caledonia, Papua New Guinea and coastal Eastern Australia, from Botany Bay in New South Wales...
into Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. As with all Melaleuca
Melaleuca
Melaleuca is a genus of plants in the myrtle family Myrtaceae known for its natural soothing and cleansing properties. There are well over 200 recognised species, most of which are endemic to Australia...
species, M. quinquenervia seeds prolifically. In the absence of natural predators, it spread throughout southern Florida; at one time it was estimated that 12% of southern Florida had been colonised by it. The colonised area included a substantial proportion of the Everglades
Everglades
The Everglades are subtropical wetlands in the southern portion of the U.S. state of Florida, comprising the southern half of a large watershed. The system begins near Orlando with the Kissimmee River, which discharges into the vast but shallow Lake Okeechobee...
, a revered national park and World Heritage Site
World Heritage Site
A UNESCO World Heritage Site is a place that is listed by the UNESCO as of special cultural or physical significance...
. Attempts were made to control the spread by burning off, but this only exacerbated the problem as it encouraged seed dispersal while failing to kill the trees. The spread of Melaleuca is now managed by a combination of regular herbicide
Herbicide
Herbicides, also commonly known as weedkillers, are pesticides used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant...
treatment and the introduction of an Australian beetle
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
as a biological control.
Acacia in southern Africa
A number of AcaciaAcacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...
species have become serious environmental pests after being introduced into southern Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
. The most troublesome species are Acacia cyclops
Acacia cyclops
Acacia cyclops, commonly known as red-eyed wattle or western coastal wattle, is a coastal shrub or small tree in the family Fabaceae...
and Acacia saligna
Acacia saligna
Acacia saligna, commonly known by various names including coojong, golden wreath wattle, orange wattle, blue-leafed wattle, Western Australian golden wattle, and, in Africa, Port Jackson willow, is a small tree in the family Fabaceae...
. Both are Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
n coastal wattles, introduced to help bind drifting sand dunes. They remain serious pests, but some controls have been introduced. In the case of Acacia saligna, the introduction of acacia seed weevils (Melanterius species) has achieved complete control. A lesser degree of control has been achieved for Acacia cyclops by the introduction of a gall rust fungus (Uromycladium species).
Other examples
- Cupaniopsis anacardioidesCupaniopsis anacardioidesCupaniopsis anacardioides, with common names Tuckeroo, Carrotwood, Beach Tamarind and Green-leaved Tamarind,is a species of flowering tree in the soapberry family, Sapindaceae, that is native to eastern and northern Australia. The usual habitat is littoral rainforest on sand or near estuaries...
, the tuckeroo, has become an invasive weed along the coastline of FloridaFloridaFlorida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. The plant there is known as carrotwood. - Eucalyptus globulusEucalyptus globulusThe Tasmanian Blue Gum, Southern Blue Gum or Blue Gum, is an evergreen tree, one of the most widely cultivated trees native to Australia. They typically grow from 30 to 55 m tall. The tallest currently known specimen in Tasmania is 90.7 m tall...
has spread rapidly as an invasive speciesInvasive species"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
since being introduced into CaliforniaCaliforniaCalifornia is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
in the mid-19th century. Its colonization is reducing habitats for native species (often by type shift from grasslands or oak woodlands), and increasing the threats and spread of wildfireWildfireA wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...
s. - Hakea sericeaHakea sericeaHakea sericea, commonly known as Needlebush or Silky Hakea, is a large species of shrub native to Australia. It is native to New South Wales, Victoria and Tasmania but is found outside these states. It grows up to as a spreading and bushy shrub, flowering from winter to early spring.H...
has colonised much of the Table MountainTable MountainTable Mountain is a flat-topped mountain forming a prominent landmark overlooking the city of Cape Town in South Africa, and is featured in the flag of Cape Town and other local government insignia. It is a significant tourist attraction, with many visitors using the cableway or hiking to the top...
fynbosFynbosFynbos is the natural shrubland or heathland vegetation occurring in a small belt of the Western Cape of South Africa, mainly in winter rainfall coastal and mountainous areas with a Mediterranean climate...
since its introduction into south AfricaAfricaAfrica is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
. - Imperata cylindrica
- Melia azedarachMelia azedarachMelia azedarach is a species of deciduous tree in the mahogany family, Meliaceae, that is native to Pakistan, India, Indochina Southeast Asia and Australia...
- Pittosporum undulatumPittosporum undulatumPittosporum undulatum is a tree growing to 15m tall with wavy leaf edges. It is sometimes also known known as Sweet Pittosporum, Native Daphne, Australian Cheesewood, Victorian Box or Mock Orange...
has become invasive in the CaribbeanCaribbeanThe Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
, HawaiiHawaiiHawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, southern BrazilBrazilBrazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
and in the AzoresAzoresThe Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...
. - Schefflera actinophyllaSchefflera actinophyllaSchefflera actinophylla is a tree in the Araliaceae family. It is native to tropical rainforests and gallery forests in Australia , New Guinea and Java. Common names include Umbrella Tree, Octopus Tree and Amate.-Description:S...