Pacific Island Ecosystems at Risk (PIER)

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Acacia spp.
Mill., Fabaceae
No images for this taxon


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 (Belau ) (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)


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This page was created on 1 JAN 1999 and was last updated on 12 NOV 2006.