Détails de cette espèce dans Australia
Statut d'envahissement: Envahissant
Occurrence: Établi(e) - en expansion
Source: Walden et al. 1999
Date d'introduction: pre-1981
Mode d'Introduction: Intentionnelle, légalement
Notes sur l'espèce pour cette localité:
Mimosa pigra was probably introduced to the Northern Territory, Australia, at the Darwin Botanic Gardens in the 20 years prior to 1891, either accidentally in seed samples, or intentionally, as a curiosity, because of its sensitive leaves (Miller and Lonsdale 1987, in Walden et al. 1999).
It is now one of the worst environmental weeds in Australia. It causes dense infestations that may either reduce biodiversity or compete with pasture grasses and hinder livestock access to water. It poses great a threat to the pastoral and tourism industries. The plant thrives in seasonally inundated areas and has invaded paper-bark (Melaleuca sp.) swamp-forests. In the Northern Territory it covers more than 800 square km.Mimosa pigra is in Australia in the following land cover types:
- Grassland (Mitchell Grass) with Woodland (Eucalyptus)
- Savanna (Eucalyptus, Melaleuca)
- Eucalyptus Woodland
- Woody Savanna (Eucalyptus Melaleuca)
- Grassland (Mitchell Grass)
- Savanna (Eucalyptus)
- Grassland with Shrubland
In Australia, this weed has invaded about 80,000 ha of floodplains over a 700 km arc from the Arafura Swamp in central Arnhem Land to the Fitzmaurice River near the border with Western Australia (Anon, 1997, in Frono Fichera and Prior 1999). M. pigra is firmly established and spreading rapidly over many areas of the Northern Territory, including Kakadu National Park. It is not yet known to occur in Western Australia. In September 2001, however, a small infestation of mimosa was identified on a Northern Territory property just 100 kilometres from the Western Australia/Northern Territory border, according to the Western Australian Department of Agriculture.
Notes sur la gestion de l'espèce dans cette localité:
A program to find safe and effective biological control agents for M. pigra in Australia commenced in 1979 with surveys in the native range of this weed to find suitable insects and pathogenic fungi. During surveys in Mexico in the mid-1980’s, early instar larvae of the moth, Neurostrota gunniella (Busck) (Gracillariidae), were observed mining the pinnae of young leaves of mimosa. Older larvae were observed tunneling into the tips of mimosa stems. It was introduced into Australia in 1986. Following extensive host range studies it was released in 1989. Although the moth was known to breed to a certain extent on M. pudica and some species of Neptunia (including N.dimorphantha, N. gracilis, N. major and N. monosperma) damage to these species was assessed as insignificant.
At least two of the species used for biological control are known to compete with each other. One of the fungal plant pathogens, Phloeospora mimosae-pigrae, causes significantly less disease symptoms on plants also harbouring N. gunniella (Paynter and Hennecke 2001).
Altération d'habitat: Mimosa has transformed grasslands and sedgelands to monospecific or near-monospecific tall shrublands and has invaded billabongs and swamplands of Melaleuca spp. (Lonsdale et al. 1995, in Frono Fichera and Prior 1999).
Menace pour les espèces en danger: The yellow chat (Alligator Rivers subspecies) (see Epthianura crocea tunneyi) listed as “endangered” is restricted to a small geographic area in northern Australia that encompasses the floodplains from the Mary River to the East Alligator River. It is probable that the yellow chat is being negatively affected by the expansion of exotic weeds in the floodplain habitats (notably by M. pigra, para grass (Brachiaria mutica) and gamba grass (Andropogon gayanus) in addition to habitat change. (Parks and Wildlife Commission UndatedA).
The bare-rumped sheathtail bat (see Saccoilamus saccoilamus) is listed as “critically endangered”. Little is known about the distribution of the species but vegetation change associated with invasion by exotic species (such as M. pigra) is though to be one of the factors reducing habitat suitability for this species (Parks and Wildlife Commission UndatedB).
The magpie goose is known to be threatened by the spread of M. pigra. It lives in shallow lowland grasslands and swamps and feeds on seeds, tubers and grass species. It is restricted to northern Australia and its breeding habitat is being invaded by para grass (Brachiaria mutica), M. pigra and introduced ponded pasture plants (such as Hymenachne amplexicaulis). These species are replacing its natural principal food sources (Garnett and Crowley 2000).
Also, the Arnhem Sheathtail Bat (Taphozous kapalgensis) (considered to be a “near threatened” species by the Northern Territory) is losing suitable habitat due to the vegetation change associated with the invasion of exotic species such as M. pigra (Parks and Wildlife Commission UndatedC).
Réduction de la biodiversité indigène: In general, mimosa thickets support fewer birds and lizards, less herbaceous vegetation, and fewer tree seedlings than native vegetation (Braithwaite et al. 1989, in Walden et al. 1999).
Dernière mise à jour: 30/05/2006 3:07:10 p.m.