Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: acacia, wattle

Habit:  shrub/tree

Description:  "Almost all trees or shrubs; often prickly or spiny; leaves bippinnate; adult foliage often reduced to petiolar phyllodes; flowers in cylindric spikes or globose heads, generally yellow; bracts often 2; flowers 5-3-merous, bisexual or polygamous; calyx tubular or of nearly free sepals; petals usually connate, rarely absent; stamens numerous, exserted, free or partly connate; ovary 2-several-many-ovulate; fruit straight or contorted, that or terete, dehiscent or not; seeds sometimes arillate. About 900 species" (Stone, 1970; p. 295).

Habitat/ecology:  While many Acacia species favor drier sites, others are adapted to more moist conditions.

Acacias tend to be prolific seed producers, self-fix nitrogen, and are often well adapted to reproducing after fire or other disturbance. As such, they have the potential to be invasive. One species, planted in species trials on Yap (A. cinnimomi [?])was observed to be spreading from new shoots coming up from the roots of existing trees.

Some acacia species that are known invaders are listed separately, but all acacia should be suspect. If they are introduced, they should be closely monitored for invasiveness (or, better yet, not introduced at all).

Propagation:  Seed. The seed pods of many species are eaten by grazing animals. The seeds pass through the digestive tract unharmed; in fact, scarification my improve their ability to germinate. Pods and/or seeds of some species are carried by water. The seeds of most species remain viable for many years, building up a seed bank in the soil and germinating when disturbance occurs.

Native range:  Africa, Asia to Australia and the Pacific, South America.

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Chile (offshore islands) Rapa Nui (Easter) Island	Rapa Nui (Easter) Island (Isla de Pasqua)	introduced cultivated	Meyer, Jean-Yves (2008) (pp. 30, 35, 41) Acacia cf. karroo, Acacia dealbata, Acacia cf. saligna
Fiji Fiji Islands	Fiji Islands		Bishop Museum (Honolulu) (1935) (voucher ID: BISH 152362) Taxon name on voucher: Acacia polystachya A. Cunningham ex Bentham
Fiji Fiji Islands	Vanua Levu Island		Bishop Museum (Honolulu) (1960) (voucher ID: BISH 34259) Taxon name on voucher: Acacia (Genus of Fabaceae)
Fiji Fiji Islands	Viti Levu Island		Bishop Museum (Honolulu) (1963) (voucher ID: BISH 14453) Taxon name on voucher: Acacia polystachya A. Cunningham ex Bentham
Fiji Fiji Islands	Viti Levu Island		Bishop Museum (Honolulu) (1963) (voucher ID: BISH 697235) Taxon name on voucher: Acacia polystachya A. Cunningham ex Bentham
French Polynesia Society Islands	Raiatea (Havai) Island		Bishop Museum (Honolulu) (1990) (voucher ID: BISH 640866) Taxon name on voucher: Acacia spirorbis Labillardière
French Polynesia Society Islands	Tahiti Island		Bishop Museum (Honolulu) (1982) (voucher ID: BISH 491183) Taxon name on voucher: Acacia (Genus of Fabaceae)
French Polynesia Society Islands	Tahiti Island		Bishop Museum (Honolulu) (1986) (voucher ID: BISH 546517) Taxon name on voucher: Acacia (Genus of Fabaceae)
French Polynesia Society Islands	Tahiti Island		Bishop Museum (Honolulu) (1984) (voucher ID: BISH 554185) Taxon name on voucher: Acacia (Genus of Fabaceae)
French Polynesia Society Islands	Tahiti Island		Bishop Museum (Honolulu) (1983) (voucher ID: BISH 558092) Taxon name on voucher: Acacia (Genus of Fabaceae)
French Polynesia Tuamotu Archipelago	Fangataufa (Ahunui) Atoll		Bishop Museum (Honolulu) (1987) (voucher ID: BISH 664035) Taxon name on voucher: Acacia simplex (Sparrm.) Pedley
New Caledonia New Caledonia	New Caledonia Islands		Bishop Museum (Honolulu) (1963) (voucher ID: BISH 152428) Taxon name on voucher: Acacia (Genus of Fabaceae)
New Caledonia New Caledonia	New Caledonia Islands		Bishop Museum (Honolulu) (1963) (voucher ID: BISH 152429) Taxon name on voucher: Acacia (Genus of Fabaceae)
New Caledonia New Caledonia	New Caledonia Islands		Bishop Museum (Honolulu) (1970) (voucher ID: BISH 664462) Taxon name on voucher: Acacia decurrens
New Caledonia New Caledonia Archipelago	Île Grande Terre		Bishop Museum (Honolulu) (1949) (voucher ID: BISH 449742) Taxon name on voucher: Acacia (Genus of Fabaceae)
New Caledonia New Caledonia Archipelago	Île Grande Terre		Bishop Museum (Honolulu) (1992) (voucher ID: BISH 652342) Taxon name on voucher: Acacia (Genus of Fabaceae)
Palau Palau (main island group)	Babeldaob Island		Bishop Museum (Honolulu) (1991) (voucher ID: BISH 1000105) Taxon name on voucher: Acacia (Genus of Fabaceae)
Solomon Islands Solomon Islands	Guadalcanal Island		Bishop Museum (Honolulu) (1997) (voucher ID: BISH 29202) Taxon name on voucher: Acacia (Genus of Fabaceae)
Solomon Islands Solomon Islands	Ndeni (Santa Cruz) Island		Bishop Museum (Honolulu) (1971) (voucher ID: BISH 80357) Taxon name on voucher: Acacia (Genus of Fabaceae)

Comments:  Over 40 species of Acacia are considered to be weeds.

The following acacias are reported to be invasive in South Africa: Acacia baileyana F. Muell (Bailey's wattle), A. cyclops A. Cunn. ex G. Don (red eye); A. dealbata Link (silver wattle), A. decurrens (J.C. Wendl.) Willd. (green wattle), A. elata A. Cunn. ex Benth. (peppertree wattle), A. longifolia (Andr.) Willd. (long-leaved wattle), A. mearnsii De Willd. (black wattle), A. melanoxylon R. Br. (Australian blackwood), A. podalyriifolia A. Cunn. (pearl acacia), A. pycnantha Benth. (golden wattle), A. saligna (Labill.) H.L. Wendl. (Port Jackson willow). All are of Australian origin. (Henderson, 1995; pp. 49-59)

Additional information:
Additional online information about Acacia spp. is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Acacia spp. as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Acacia spp. may be available from the Germplasm Resources Information Network (GRIN).

References:

Bishop Museum (Honolulu). 1935. Voucher specimen #BISH 152362 (Wilder, G.P.; collector's voucher number unknown).

Bishop Museum (Honolulu). 1949. Voucher specimen #BISH 449742 (Bryan Jr, E.H. 1630).

Bishop Museum (Honolulu). 1960. Voucher specimen #BISH 34259 (Koroiveibau, D. 12283).

Bishop Museum (Honolulu). 1963. Voucher specimen #BISH 14453 (Parham, J.W. 13565).

Bishop Museum (Honolulu). 1963. Voucher specimen #BISH 152428 (Yoshimoto, C.; collector's voucher number unknown).

Bishop Museum (Honolulu). 1963. Voucher specimen #BISH 152429 (Yoshimoto, C.; collector's voucher number unknown).

Bishop Museum (Honolulu). 1963. Voucher specimen #BISH 697235 (Parham, J.W. 13565).

Bishop Museum (Honolulu). 1970. Voucher specimen #BISH 664462 (MacKee, H.S. 22543).

Bishop Museum (Honolulu). 1971. Voucher specimen #BISH 80357 (Yen, D.E. 19759).

Bishop Museum (Honolulu). 1982. Voucher specimen #BISH 491183 (Florence, J. 2626).

Bishop Museum (Honolulu). 1983. Voucher specimen #BISH 558092 (Florence, J. 4464).

Bishop Museum (Honolulu). 1984. Voucher specimen #BISH 554185 (Florence, J. 7157).

Bishop Museum (Honolulu). 1986. Voucher specimen #BISH 546517 (Florence, J. 7214).

Bishop Museum (Honolulu). 1987. Voucher specimen #BISH 664035 (Jolinon, J.C. 1274).

Bishop Museum (Honolulu). 1990. Voucher specimen #BISH 640866 (Florence 10681).

Bishop Museum (Honolulu). 1991. Voucher specimen #BISH 1000105 (Herbst, D.R. 9430).

Bishop Museum (Honolulu). 1992. Voucher specimen #BISH 652342 (Koyama, H. 4005).

Bishop Museum (Honolulu). 1997. Voucher specimen #BISH 29202 (Giffeu 12).

Csurhes, S./Edwards, R. 1998. Potential environmental weeds in Australia: Candidate species for preventative control. Canberra, Australia. Biodiversity Group, Environment Australia. 208 pp.

Henderson, Lesley. 1995. Plant invaders of Southern Africa. Plant Protection Research Institute Handbook No. 5, Agriculture Research Council, ARC/LNR, Pretoria, South Africa. 177 pp.

Meyer, Jean-Yves. 2008. Rapport de mission d'expertise a Rapa Nui du 02 au 11 Juin 2008: Plan d'action strategique pour lutter contre les plantes introduites envahissantes sur Rapa Nui (Île de pâques) [Strategic action plan to control invasive alien plants on Rapa Nui (Easter Island) [unpublished report]. Délégation à la Recherche, Ministère de l'Education, l'Enseignement supérieur et la Recherche, B.P. 20981 Papeete, Tahiti, Polynésie française. 62 pp. .

Stone, Benjamin C. 1970. The flora of Guam. Micronesica 6:1-659.

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.