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Report to the Republic of Palau: 2008 update on Invasive Plant ...

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een planted <strong>on</strong> Babeldaob and is reproducing. Much more prolific reproducti<strong>on</strong> can be<br />

expected if a fire occurs. It has a weed risk assessment <str<strong>on</strong>g>of</str<strong>on</strong>g> 15, “high risk”.<br />

Melia azedarach (Chinaberry, pride-<str<strong>on</strong>g>of</str<strong>on</strong>g>-India, Indian lilac) seedlings were seen beneath and<br />

around cultivated plants at a residence and a business in Airai in <str<strong>on</strong>g>the</str<strong>on</strong>g> 2002 survey. It was also<br />

seen in cultivati<strong>on</strong> <strong>on</strong> Koror. Several seedlings were also noted in Koror that appeared <str<strong>on</strong>g>to</str<strong>on</strong>g> be selfsown,<br />

but <str<strong>on</strong>g>the</str<strong>on</strong>g> source was not immediately apparent. In this survey, <str<strong>on</strong>g>the</str<strong>on</strong>g> species was noted in<br />

cultivati<strong>on</strong> <strong>on</strong> Malakal (in <str<strong>on</strong>g>the</str<strong>on</strong>g> gardens near <str<strong>on</strong>g>the</str<strong>on</strong>g> radio <str<strong>on</strong>g>to</str<strong>on</strong>g>wer), at several additi<strong>on</strong>al residences in<br />

Airai and <strong>on</strong> Ngercheu Island (Carp Resort). This species is a prolific producer <str<strong>on</strong>g>of</str<strong>on</strong>g> seed, which is<br />

spread by birds. In <str<strong>on</strong>g>Palau</str<strong>on</strong>g>, it apparently begins <str<strong>on</strong>g>to</str<strong>on</strong>g> flower at a very young age. It is invasive in a<br />

number <str<strong>on</strong>g>of</str<strong>on</strong>g> Pacific locati<strong>on</strong>s, including <str<strong>on</strong>g>the</str<strong>on</strong>g> Cook Islands, French Polynesia and Hawai‘i as well as<br />

in South Africa. It is a “high risk” species with a weed risk assessment score <str<strong>on</strong>g>of</str<strong>on</strong>g> 14.<br />

Melinis minutiflora (molasses grass) is a species that is particularly dangerous in that it is both<br />

invasive and can cause a serious fire hazard. It has modified fire regimes <strong>on</strong> many islands where<br />

it has been introduced (D’An<str<strong>on</strong>g>to</str<strong>on</strong>g>nio and Vi<str<strong>on</strong>g>to</str<strong>on</strong>g>usek, 1992) and it is reported as a serious threat <str<strong>on</strong>g>to</str<strong>on</strong>g><br />

forests in Brazil (C. Martins, pers. comm.). It was reported present by Fosberg et al. (1979).<br />

Raulers<strong>on</strong> et al. (1996) reported it present <strong>on</strong> Babeldaob but rare. We found it <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> north<br />

extensi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Compact Road in Ngaraard State. An Australian weed risk assessment gives<br />

this species a score <str<strong>on</strong>g>of</str<strong>on</strong>g> 7, indicating it is <str<strong>on</strong>g>of</str<strong>on</strong>g> high risk.<br />

Panicum maximum [=Megathyrsus maximus, Urochloa maxima] (Guinea grass), while not yet<br />

widespread in <str<strong>on</strong>g>Palau</str<strong>on</strong>g> (it is present <strong>on</strong> Koror and Babeldaob), is ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r grass that can help<br />

perpetuate a fire cycle. It seeds pr<str<strong>on</strong>g>of</str<strong>on</strong>g>usely and <str<strong>on</strong>g>the</str<strong>on</strong>g> seeds are dispersed by wind, birds (e.g.<br />

chestnut mannikins) and flowing water or as a c<strong>on</strong>taminant. It can survive l<strong>on</strong>g periods <str<strong>on</strong>g>of</str<strong>on</strong>g><br />

drought. Fire will sweep through stands <str<strong>on</strong>g>of</str<strong>on</strong>g> this grass but it regenerates rapidly from underground<br />

rhizomes. It is a problem species in Guam and Hawai‘i and is very prevalent in Samoa and<br />

T<strong>on</strong>ga, forming dense stands in open and disturbed areas. Its weed risk assessment score is 17,<br />

“high risk”.<br />

Pennisetum setaceum (fountain grass) was found in cultivati<strong>on</strong> at two residences in Airai and a<br />

resort in Ngerkebesang in 2002 but was not seen in <str<strong>on</strong>g>2008</str<strong>on</strong>g>. It is an attractive ornamental but it can<br />

produce large amounts <str<strong>on</strong>g>of</str<strong>on</strong>g> wind-dispersed seed. While it is most likely <str<strong>on</strong>g>to</str<strong>on</strong>g> be invasive in dry<br />

areas, it could possibly spread in <str<strong>on</strong>g>Palau</str<strong>on</strong>g>. It is a serious problem species <strong>on</strong> dryer sites in Hawai‘i.<br />

It has a weed risk assessment score <str<strong>on</strong>g>of</str<strong>on</strong>g> 26, “high risk”.<br />

Pereskia aculeata (Barbados gooseberry, leafy cactus) was found <strong>on</strong> Ngercheu Island (Carp<br />

Resort). It is invasive in Queensland, Australia, particularly in riparian areas, forming large,<br />

impenetrable clumps. It is a declared noxious weed in South Africa, where it has become a<br />

problem in forestry and c<strong>on</strong>servati<strong>on</strong> areas. Seed is bird-dispersed and it can also spread from<br />

stem fragments. Its weed risk assessment indicates that it is <str<strong>on</strong>g>of</str<strong>on</strong>g> high risk, with a score <str<strong>on</strong>g>of</str<strong>on</strong>g> 13.<br />

Pluchea carolinensis (sour bush) and P. indica (Indian fleabane, Indian pluchea, Indian<br />

camphorweed) are present <strong>on</strong> Peleliu and P. indica is present <strong>on</strong> Angaur. They are shrubby<br />

species with wind-dispersed seed. Pluchea carolinensis is naturalizing extensively <strong>on</strong><br />

T<strong>on</strong>gatapu, T<strong>on</strong>ga, and is reported <str<strong>on</strong>g>to</str<strong>on</strong>g> be widespread but not presently abundant <strong>on</strong> Guam. These<br />

species may have been accidentally introduced as a result <str<strong>on</strong>g>of</str<strong>on</strong>g> military activity as both were also<br />

16

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