Pacific Island Ecosystems at Risk (PIER)

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Acacia nilotica
(L.) Willd. ex Delile, Fabaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results: 

Reject, score: 13 (Go to the risk assessment (Australia))
High risk, score: 14 (Go to the risk assessment (Pacific))
Medium-high risk:  (Go to the risk assessment (United States)) (PDF format)
Risk assessment for Acacia nilotica from the Government of Queensland, Australia (PDF format)

Other Latin names:  Acacia adansonii Guill. & Perr.; Acacia adstringens (Schumach.) Berhaut; Acacia arabica (Lam.) Willd.; Acacia scorpioides (L.) W. Wight; Mimosa nilotica L.; Vachellia nilotica (L.) P. J. H. Hurter & Mabb.

Common name(s): [more details]

English: Egyptian acacia, Indian gum-arabic-tree, Nile acacia, babul acacia, black babul, gum arabic tree, prickly acacia, scentedthorn, thorn-mimosa, thorny acacia

French: acacia à gomme, gommier rouge

Other: tiare

Spanish: acacia espinosa, acacia gomifera

Habit:  tree

Description:  "A shrub or small tree from 7 to 9 m high, having feathery leaves… Stems: Whitish and pubescent when young becoming darker with age; woody; to 7 m long, branching almost from the base. Leaves: Bipinnate, consisting of 3 to 10 pairs of primary leaf segments 3.5 to 4 cm long, each bearing 10-to 25 pairs of linear-oblong leaflets 3 to 6 mm long, 0.5 to 1.5 mm wide; a petiolar gland occurs between the 2 pairs of segments closest to the stem; a pair of stout stipular spines, 5 to 50 mm long, occurs at the base of each leaf on younger stems but may be absent on older stems. Flowers: Bright yellow, numerous, in fluffy globular heads 1.2 cm diameter, usually in clusters of 2 to 6, on individual pubescent axillary stalks 1.5 to 2 cm long, each stalk with pair of bracts near its mid-point. Fruit: Gray-green, softly hairy flattened pod 6 to 25 cm long, 1 to1.5 cm wide, strongly constricted between each seed; pods slightly sticky internally. Seed: Depressed, subglobular. Root: A deep woody taproot with several branching surface laterals" (Parsons and Cuthbertson, 1992; pp.435-438).

Habitat/ecology:  "Grows best on cracking clay soils that have high water holding capacity, but can also grow on sandy soil in areas of higher rainfall. It grows best around waterways and on seasonally inundated floodplains receiving 350-1500 mm of annual rainfall"  (Australian Weed Management Guide).  "Grassland, savanna"  (Weber, 2003: p. 18).  Favors steams in semi-arid areas.

In New Caledonia, "abondamment naturalisé dans un secteur côtier de la commune de Paita; non vu ailleurs. Considéré comme un arbre fourrager utile bien que les jeunes pieds épineux forment des fourrés difficiles à pénétrer" (MacKee, 1994; p. 76). Arid lowlands in the Galápagos Islands (McMullen, 1999; p. 67).

Propagation:  Seed. Seeds can remain dormant in the soil for long periods. Seeds are eaten by cattle and spread by passing through the digestive system.

Native range:  Africa and western Asia.

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Ecuador (Galápagos Islands)
San Cristóbal Group
San Cristóbal Island introduced
invasive
cultivated
Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands)
Santa Cruz Group
Santa Cruz Island introduced
invasive
cultivated
Charles Darwin Foundation (2008)
French Polynesia
Society Islands
Tahiti Island   Fosberg, F. R. (1997) (p. 46)
French Polynesia
Society Islands
Tahiti Island introduced
cultivated
Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013)
subsp. indica (G. Bentham) J.P. Brenan
Cultivée
New Caledonia
New Caledonia
New Caledonia Islands introduced
Meyer, Jean-Yves (2000) (p. 100)
"Potential invader".
New Caledonia
New Caledonia Archipelago
Île Grande Terre introduced
invasive
Gargominy, Oliver/Bouchet, Philipe/Pascal, Michel/Jaffre, Tanguy/Tourneu, Jean-Christophe (1996) (p. 381)
Abondamment naturalisée dans un secteur côtier de la commune de Paita; non vu ailleurs. Les jeunes pieds épineux forment des fourrés difficiles à pénétrer.
New Caledonia
New Caledonia Archipelago
Île Grande Terre introduced
invasive
MacKee, H. S. (1994) (p. 76)
Vouchers cited: MacKee 21696, MacKee 24794, MacKee 34586, MacKee 40252
New Caledonia
New Caledonia Archipelago
Île Grande Terre   Bishop Museum (Honolulu) (1978) (voucher ID: BISH 664461)
Taxon name on voucher: Acacia nilotica (L.) Willd. ex Delile
Solomon Islands
Solomon Islands
Solomon Islands introduced
cultivated
Hancock, I. R./Henderson, C. P. (1988) (p. 43)
Wallis and Futuna
Wallis and Futuna (Horne) Islands
Wallis and Futuna Islands   Waterhouse, D. F. (1997) (p. 59)
Pacific Rim
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Australia
Australia (continental)
Northern Territory introduced
invasive
Smith, Nicholas M. (2002) (p. 14)
Australia
Australia (continental)
Northern Territory introduced
invasive
Australian Biological Resources Study (2013)
Australia
Australia (continental)
Queensland introduced
invasive
Smith, Nicholas M. (2002) (p. 14)
Australia
Australia (continental)
Queensland introduced
invasive
Australian Biological Resources Study (2013)
China
China
China (People's Republic of) introduced
ILDIS Co-ordinating Centre (2013)
Indonesia
Indonesia
Indonesia (Republic of) introduced
invasive
Pallawatta, Nirmalie/Reaser, Jamie K./Gutierrez, Alixis T./eds. (2003) (p. 31)
Singapore
Singapore
Singapore (Republic of) introduced
cultivated
Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 9)
Cultivated only
South America (Pacific rim)
South America (Pacific rim)
Ecuador (Republic of) (continental) introduced
invasive
Cronk, Q. C. B./Fuller, J. L. (2001) (p. 133)
Indian Ocean
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Mauritius
Mautitius Islands (Mauritius and Rodrigues)
Mauritius Island introduced
ILDIS Co-ordinating Centre (2013)
Mauritius
Mautitius Islands (Mauritius and Rodrigues)
Mauritius Island introduced
invasive
Kueffer, C./Mauremootoo, J. (2004) (p. 6)
Mauritius
Mautitius Islands (Mauritius and Rodrigues)
Rodrigues Island introduced
ILDIS Co-ordinating Centre (2013)
subsp. adstringens
Mauritius
Mautitius Islands (Mauritius and Rodrigues)
Rodrigues Island introduced
invasive
Kueffer, C./Mauremootoo, J. (2004) (p. 6)
Also reported from
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
United States (continental except west coast)
United States (other states)
United States (other states) introduced
ILDIS Co-ordinating Centre (2013)

Comments:  One of Australia's worst environmental weeds, classed as a "weed of national significance".

Proposed for eradication in the Galápagos Islands (Chris Buddenhagen, pers. com.).

Control: 

Physical: Single trees can be grubbed, cutting the root at least 30 cm below the surface to prevent sprouting. Some control can also be obtained by burning or mowing.

Chemical: Triclopyr in diesel oil may be used as a basal bark or cut stump treatment. Tebuthiuron granules may be applied from the air. For larger trees, picloram or liquid hexazinone may be injected into the main stem at 8 cm intervals when the tree is in full leaf.

Biological: Being investigated in Australia. See Julien (1992), Parson and Cuthbertson (1992; pp. 435-438) and Australian Weed Management Guide.  "The seed-feeding bruchid, Bruchidius sahlbergi, has been released in Australia"  (Cronk & Fuller, 2001; p. 133).


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This page was created on 1 JAN 1999 and was last updated on 3 SEP 2011.