Pacific Island Ecosystems at Risk (PIER)


Report on invasive plant species on Niue following Cyclone Heta


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1.0 What’s new on Niue – a summary of findings

2.0 Previous work and the basis of this survey

3.0 Survey results

3.1 Species that are subjects of control and eradication programs
3.2 Species that are known to be invasive and are of particular concern on Niue
3.3 Other species that are known to be invasive or weedy and are present on Niue
3.4 Native species or Polynesian introductions exhibiting aggressive behaviour
3.5 Invasive species not known to be on Niue

4.0 General observations and recommendations

5.0 Species-specific recommendations

5.1 Management of invasive plants present on Niue
5.2 Cultivated plants of threat to Niue
5.3 Prevention of introductions
5.4 Other recommendations

Appendix 1.  Species by category

Appendix 2.  Invasive species present in American Samoa, the Cook Islands, Fiji, French Polynesia, Samoa or Tonga but not present on Niue

Appendix 3. Scientific name synonyms

Appendix 4.  Background material and references


 

Report to the Government of Niue and the United Nations Development Programme

Invasive Plant Species on Niue following Cyclone Heta

 James C. Space, Barbara M. Waterhouse, Melanie Newfield and Cate Bull

UNDP NIU/98/G31 – Niue Enabling Activity

17 December 2004

 

 

Report to the Government of Niue and UNDP: Invasive species on Niue following Cyclone Heta

James C. Space (1), Barbara M. Waterhouse(2), Melanie Newfield(3) and Cate Bull(4)

1.0 What’s new on Niue – a summary of findings

On January 6, 2004, the full force of Cyclone Heta, a category 5 cyclone, hit the island of Niue. In addition to the loss of life and property, serious damage was done to the forests and other ecosystems of the island, particularly on the north and west sides. If not blown over, most trees and other large vegetation were stripped of leaves and branches and subjected to salt spray. This sort of disturbance provides an opportunity for new invasive species to become established and for many species already present to flourish. Following the cyclone, personnel from the Cook Islands, Fiji, French Polynesia, New Zealand and other countries visited the island to provide aid and assistance, and equipment and material were brought in to aid in the recovery. Although quarantine procedures were maintained there is always the possibility of inadvertently introducing new plant species during an emergency such as this. During the cleanup process rubble was moved and dumped in new areas, transferring invasive species to new locations.

At the request of the Niue Department of Environment, a post-cyclone survey was conducted 23-31 July, 2004, to search for new invasive plant species and to assess the expansion in range and vigor of species previously recorded. As expected, light-loving species that take advantage of disturbance and new openings in the forest have become more prevalent. These include several species of Crotalaria, Leucaena leucocephala, Justicia betonica, Mikania micrantha, two Salvia species, Stachytarpheta cayennensis and S. jamaicensis, several large grass species, Tithonia diversifolia and the indigenous vine, Merremia peltata. The increased abundance of these species may be transitory; as the forest recovers and establishes a new canopy they will be suppressed in many areas. On the other hand, where gaps were created these species may remain on a more or less permanent basis and, in some cases, require control. The introduced pomea or coral bean tree, Adenanthera pavonina, will also likely take advantage of the disturbed conditions to increase its abundance in the forest.

The branches blown off the trees have greatly increased the fuel loading on the forest floor and consequently increased the risk and difficulty of controlling wildfire. Fires were a serious problem following the cyclone and are likely to be so whenever drought conditions are repeated for some time in the future. Several grass species (particularly Panicum maximum, Pennisetum purpureum and Sorghum arundinaceum) and stands of Mexican sunflower (Tithonia diversifolia) have increased in area, both as a result of continuing spread and cyclone disturbance, and these species contribute fuel that can lead fire into the forest with the potential to seriously damage the native vegetation, which is not fire-adapted. It will be necessary to periodically reduce this hazard, particularly around habitation and sensitive and conservation areas. As a side note, Niue is in serious need of rural/wild-land firefighting equipment, both tools and personal equipment for firefighters and a firefighting truck with a tank and pump that can carry and apply water to forest fires.

Good progress had been made toward eradicating several serious plant pests (Antigonon leptopus, Mimosa diplotricha [=invisa] and Sphagneticola [=Wedelia] trilobata) prior to the cyclone, and this has continued to some degree during the recovery. It is very important that this progress not be lost due to the many other priorities following the cyclone.

There has been a limited amount of control work done on two other species (Epipremnum pinnatum cv. ‘Aureum’ [=Scindapsus aureus] and Clerodendrum chinense) that are serious pests. It would be highly desirable to start control work on Syngonium podophyllum and Macfadyena unguis-cati in the near future. There are also a number of other species that may require management action to prevent impact on sensitive, natural and protected areas.

We closely inspected the vehicles and remaining crushed rock brought in from French Polynesia and found nothing unusual. However, they had already been used widely in post-cyclone cleanup and rebuilding efforts, so hopefully they were free of weed seeds on arrival in Niue. Although the risk appears to be small, the sites where the vehicles and materials were used should be monitored for several years post-wet season to make sure no invasive plant seeds were brought in. We inspected the sites where rubble had been dumped and, except for a new infestation of Clerodendrum chinense at the rubble dump at the end of the airport runway, only the usual ruderal weeds were noted.

A few species not noted in previous surveys were found and collected for the record, but none of them appeared to have arrived and established as a result of post-cyclone activities. Thus, the main task facing Niue is to continue to deal with the serious invasive plants that were present before, a number of which are now expanding in range and vigor encouraged by the cyclone disturbance.

Table A summarizes priority species and recommended management actions. Please refer to Table B for a full list of species that may require management. Of particularly high priority should be continuing the effective work on Antigonon leptopus, Epipremnum pinnatum, Mimosa diplotricha and Wedelia [Sphagneticola] trilobata to protect the investment made thus far, extending control work to Syngonium podophyllum, and beginning eradication of Macfadyena unguis-cati. As a result of cyclone disturbance control action will be needed where invasive species such as Delonix regia, Leucaena leucocephala, Merremia tuberosa (and the native vine, Merremia peltata) impinge on the re-establishment of natural ecosystems. Serious research needs to be done into methods to control Clerodendrum chinense. Finally, control of invasive grasses will be needed when they promote wildfire that can endanger structures or the forest.

The next step should be to review all the species that need action (see Table B) and develop strategic, tactical and operational plans for the management of invasive plant species on Niue. Funds and trained personnel are always limited, so projects must be prioritised. Benefits (economic and non-economic), costs, social impacts and environmental considerations are only some of the factors that must be considered. To be understood, accepted and supported, plans and operations must be developed with public input and involvement. Management of some species likely will exceed the resources available to Niue and will require requests for outside assistance. The authors of this report stand ready to provide input and support as the process proceeds.

Table A. Priority species for management actions.

Scientific name
(family)

Common names (abridged)

Comments and recommendations

Adenanthera pavonina
(Fabaceae)
pomea, coral bean tree Control as needed in sensitive and natural areas.
Alternanthera brasiliana
(Amaranthaceae)
Brazilian joyweed Discourage further planting; monitor spread; control outside of cultivation when a threat to sensitive or natural areas.
Antigonon leptopus
(Polygonaceae)
chain of love, coral bells Continue the eradication program until this species is eliminated.
Asparagus setaceus
(Liliaceae)
ornamental asparagus Strongly discourage further planting; determine distribution, destroy plants outside of cultivation. If public opinion is favourable, work to eradicate this species.
Bryophyllum pinnatum
(Crassulaceae)
tupu he lau, tupu noa, life plant Discourage further planting; determine distribution; control as needed outside of cultivation, especially when a threat to sensitive or natural areas.
Clerodendrum chinense
(Lamiaceae)
Honolulu rose Research control methodology; strongly discourage (prohibit?) additional planting and dumping of garden cuttings.
Delonix regia
(Fabaceae)
pine, flame tree Monitor reproduction and spread; discourage further planting; control in sensitive and natural areas as needed
Dissotis rotundifolia
(Melastomaceae)
dissotis, pink lady Monitor site where previously found, eradicate immediately if found at this or any other location.
Epipremnum pinnatum cv. ‘Aureum’ [=Scindapsus aureus]
(Araceae)
pothos, money plant Continue the campaign to control outside of cultivation, especially when growing in forested areas.
Falcataria moluccana
(Fabaceae)
Molluca albizia Monitor reproduction and spread; discourage further planting; control in sensitive and natural areas as needed. Consider reducing the number of trees if not a desired species.
Hemigraphis alternata
(Acanthaceae)
metal leaf, red ivy Discourage further planting; determine distribution; control as needed outside of cultivation, especially when a threat to sensitive or natural areas.
Hylocereus undatus
(Cactaceae)
night-blooming cereus, pitahaya Discourage further planting; determine distribution; control as needed outside of cultivation, especially when a threat to sensitive or natural areas.
Hyptis suaveolens
(Lamiaceae)
stinking Roger Determine distribution, work with the manager of the Vaiea Farm to eradicate.
Justicia betonica
(Acanthaceae)
white shrimp plant Discourage further planting; monitor spread; control outside of cultivation when a threat to sensitive or natural areas.
Lantana camara
(Verbenaceae)
talatala, talatala talmoa, lantana Check status of previously introduced biocontrol agents and reintroduce or introduce new ones as appropriate; local control as necessary.
Leucaena leucocephala
(Fabaceae)
pepe, leucaena Control as needed in sensitive and natural areas, particularly where it may inhibit natural reproduction; check status of leucaena psyllid.
Macfadyena unguis-cati
(Bignoniaceae)
cat’s claw climber Research control methodologies; determine distribution, initiate eradication project.
Melinis minutiflora
(Poaceae)
molasses grass Monitor for spread, especially if burned; limit burning; reduce in forested areas and around structures as needed to reduce fire hazard
Merremia peltata
(Convolvulaceae)
fue, fue vao, fue kula, merremia (native) Monitor for spread and overtopped trees, cut back vines as necessary; provide advice to landowners on appropriate control measures.
Merremia tuberosa
(Convolvulaceae),
wood rose Control in and near sensitive and natural areas. Discourage further cultivation.
Mimosa diplotricha [=invisa]
(Fabaceae)
giant sensitive plant Continue the eradication program until this species is eliminated.
Panicum maximum
(Poaceae)
Guinea grass Reduce in forested areas and around structures as needed to reduce fire hazard
Pennisetum purpureum
(Poaceae)
elephant grass Reduce in forested areas and around structures as needed to reduce fire hazard.
Sorghum arundinaceum
(Poaceae)
wild sorghum Reduce in forested areas and around structures as needed to reduce fire hazard
Spathodea campanulata
(Bignoniaceae)
African tulip tree Strongly discourage planting; determine distribution, consider an eradication program or at least work to reduce the number of trees.
Sphagneticola [=Wedelia] trilobata
(Asteraceae))
Singapore daisy Continue the eradication program until this species is eliminated.
Syngonium podophyllum
(Araceae)
arrowhead plant, goosefoot plant Control outside of cultivation, especially when growing in forested areas.
Thevetia peruviana
(Apocynaceae)
yellow oleander Discourage further planting; monitor spread; control outside of cultivation when a threat to sensitive or natural areas.
Tithonia diversifolia
(Asteraceae)
matala, Mexican sunflower Control in forested areas and around structures as needed to reduce fire hazard.
Tradescantia zebrina
(Commelinaceae)
wandering jew Discourage further planting and dumping; control outside of cultivation when a threat to sensitive or natural areas.

2.0 Previous work and the basis of this survey

Yuncker (1940) and Sykes (1970) published surveys of the flora of Niue. Whistler and Atherton completed a botanical survey of the Huvalu Forest Conservation Area in 1997. These surveys cover all plant species and identify the invasive species present at the time they were made.

In 2000, at the request of the Government of Niue, the US Forest Service sponsored a survey of invasive plant species of environmental concern (Space & Flynn, 2000). That survey made a number of recommendations for the management and control of invasive species on Niue. Control efforts were already underway on some species at that time (particularly eradication of Mimosa diplotricha [=invisa]) and subsequently assistance was received from the Secretariat of the Pacific Community for eradication of Antigonon leptopus, Mimosa diplotricha and Sphagneticola [=Wedelia] trilobata. Following Cyclone Heta, an assessment of the impact on biodiversity (Butler, 2004) recommended a resurvey to identify changes in status or threat since the previous survey and to recommended appropriate management actions. Thus, the basis for this survey, carried out 23-31 July, 2004, which updates and supercedes the findings of the 2000 report.

Travel, accommodation and other expenses for all personnel were funded from the UNDP Enabling Activity in Biodiversity Project. Jim Space and Barbara Waterhouse participated as volunteers and salaries for Melanie Newfield and Cate Bull were covered by the New Zealand Department of Conservation as a contribution to the post-cyclone response. Dave Butler, Consultant to the UNDP Project, established the need for the survey through his post-cyclone investigations on Niue and facilitated arrangements between the participants, UNDP and the Niue Department of Environment. Arrangements for the work on Niue were made by Sauni Tongatule, Department Director, and Judy Nemaia, Biodiversity Project Coordinator, Department of Environment.

During our visit local experts(5) showed us sites of known infestations and previous management actions. We also had available copies of the botanical surveys conducted in the past as well as the field record, voucher specimen information and report of the 2000 survey. The survey team focused on disturbed sites such as roadsides, forest tracks, rubble dumps, areas of severe cyclone damage, the villages and the town of Alofi. A number of agricultural areas were also inspected. Rapid visual inspection and recording of known invasive and potentially invasive species along the routes chosen was accompanied by more detailed inspection at a variety of sites. Herbarium specimens (48) of ‘new’, ‘significant’, taxonomically ‘difficult’ or unknown species were collected for later identification or verification. All voucher specimens and duplicates will ultimately be deposited in herbarium collections at the Queensland, Australia, Herbarium and either the Bishop Museum in Honolulu, Hawai‘i, or the Landcare herbarium in New Zealand.

For the purposes of this report, invasive species occurring in or of threat to Niue have been grouped into five categories:

Species that are subjects of control and eradication programs (5 species).
Species that are known to be invasive and are of particular concern on Niue. These are species that are known to have severe impact elsewhere and are either showing similar behaviour on Niue or have the potential to do so. (40 species).
Other species that are known to be invasive or weedy and are present on Niue. These species would generally be of lower priority for management action (197 species).
Native species and Polynesian introductions that exhibit aggressive behaviour (26 species).
Species that are invasive elsewhere in similar ecosystems but were not seen on our visit and are not reported in the literature as being present on Niue (587 species).

These species are listed in Appendix 1. Additional information about each species is located on an Internet site, http://www.hear.org/pier, and on the PIER-CD, copies of which have been made available to the Departments of Environment and Agriculture, Forestry and Fisheries.

While the team was on Niue, Newfield and Bull more closely investigated priority species for control and eradication and established trials of control measures. Separate reports on these activities are in preparation.

3.0 Survey results

3.1 Species that are subjects of control and eradication programs

Antigonon leptopus (chain of hearts, coral bells), a climbing vine often planted as an ornamental, is a widespread pest on Guam. A small number of examples, mostly in cultivation, were previously seen on Niue. There are two sites left; one that has been treated but requires additional work and another small infestation noted in Alofi. This is a difficult species to eradicate because of underground tubers, but eradication is achievable because of the small number of plants. Eradication work is ongoing.

Infestations of Clerodendrum chinense (Honolulu rose) are common in the villages, spreading into the surrounding forest, and a few infestations elsewhere (a new infestation was seen where rubble was dumped at the end of the airport runway). It is a shade-tolerant species that primarily reproduces from root suckers and can form dense thickets, crowding out other species. This is a problem species in Hawai‘i and a major pest in Samoa and American Samoa. The control strategy to date has been repeated slashing or mowing. Youth groups did some work on it in the villages, but the strong odour of the plant and persistent resprouting discouraged them. Eradication is not feasible for this species but it is still possible to limit the spread and prevent invasion of sensitive and natural areas.

Epipremnum pinnatum cv. ‘Aureum’ [=Scindapsus aureus] is a climbing vine with large green and yellow leaves. It forms a dense mat on the forest floor as well. Spread by cuttings, it is difficult to eradicate as any roots or pieces left behind will sprout. Considerable work has been done in eliminating patches of this species, but much remains to be done. Eradication is not feasible for this species but it is possible to limit the spread and prevent invasion of sensitive and natural areas.

Mimosa diplotricha [=invisa] (giant sensitive plant) is a particularly nasty plant that is covered with thorns and forms dense tangles that are difficult to walk through. It is present at two sites on Niue and was previously treated with Roundup® (Butler, 2004). Presently, crews are visiting the known sites and pulling and burning new specimens. Good progress has been made in eliminating this species. Eradication is feasible and worthwhile objective, but because of the long-lived seeds, will probably require follow-up for 10-20 years.

Sphagneticola [=Wedelia] trilobata (Singapore daisy) is a pest on many Pacific islands. It forms dense, tangled mats that exclude other species. It occupied about 20 small sites around the island prior to the cyclone and many of these have been treated (Butler, 2004). However, this species is difficult to eradicate and small areas remain at sites that have been treated. Progress so far indicates that eradication should be feasible, although further work on locating and mapping sites is needed.

3.2 Species that are known to be invasive and are of particular concern on Niue

These are known invasive plants that are causing trouble in similar ecosystems and have been introduced into Niue. The ones that are widespread may require control action to keep them out of sensitive areas while it may be desirable to take action to prevent further spread of some of the less prevalent ones (see species-specific recommendations).

3.21 Invasive species already widespread on Niue

Adenanthera pavonina (pomea, coral bean tree), invasive in secondary forests throughout the Pacific, is fairly widespread (and not native) on Niue. Coral bean has the ability to overtop many native trees and eventually form monospecific stands. It is quite invasive on Tutuila, American Samoa. It produces huge amounts of seed and takes advantage of openings in the forests so is likely to greatly increase as a result of the cyclone.

Alternanthera brasiliana (Brazilian joyweed) was seen planted and vigorously reproducing at the Matavai Resort and elsewhere. It can spread through discarded cuttings as well as seed. The seeds apparently have the ability to remain dormant for a long period. It is invasive in northern Queensland and the Northern Territory, Australia.

Chamaecrista nictitans (partridge pea) appears to have become more prevalent since the 2000 survey. Several extensive stands of this species were noted, one of which was almost a monoculture. It is likely to take advantage of the cyclone damage to become more widespread.

Lantana camara (talatala, talatala talmoa, lantana) is fairly common. Introduced biological agents are reportedly present and apparently control it to some degree. Birds were reportedly using it as a food source following the cyclone. If so, this could spread it more widely.

Leucaena leucocephala (pepe, leucaena) was not considered widespread in the 2000 survey (it was noted as prevalent but not particularly aggressive) but has obviously greatly increased since and is abundant along roadsides and in other disturbed places. This species produces large amounts of seed and grows well in disturbed areas. From the amount of reproduction observed it has obviously already taken advantage of the cyclone disturbance. It is only a small tree so where there are overtopping trees it is likely to be suppressed when the trees regain their full foliage but elsewhere it may be a more persistent problem.

Mikania micrantha (fue saina, mile-a-minute weed), a smothering vine, is pervasive throughout the island. It is widespread throughout the Pacific and is a major pest wherever it occurs. It is spread both by seed (dispersed by wind, as a contaminant on vehicles and machinery or on clothing or in the hair of animals) and vegetatively from broken stem fragments. Each node of the stem can produce roots. This species has probably been favoured by the disturbance caused by Cyclone Heta.

Passiflora foetida (vine vao, love-in-a-mist) is of limited extent. It is prevalent on most Pacific islands and will probably increase, at least temporarily, as a result of cyclone disturbance.

Panicum maximum (Guinea grass), while less extensive than Pennisetum purpureum, is common, especially along roadsides. It seeds profusely and the seeds are dispersed by wind, birds and flowing water or as a contaminant in grass seed. It can survive long periods of drought. It is a problem species in Guam and Hawai‘i and is very prevalent in Samoa and Tonga, forming dense stands in open and disturbed areas.

Pennisetum purpureum (elephant grass) forms dense perennial stands that are difficult to penetrate and inhibit establishment of other vegetation. It is a major problem in the Galapagos Islands, one of the most invasive weeds in Papua New Guinea and the most troublesome grass on Niue. It appears to have significantly increased its range, particularly along roadsides, since the previous survey.

Sorghum arundinaceum (wild sorghum), like Pennisetum purpureum, has increased its range since the last survey, particularly along roadsides. However, it generally forms more scattered, open stands than Pennisetum purpureum.

Fire will sweep through stands of the above three large grasses but they regenerate rapidly from underground rhizomes and seed. Stands of grass are a fire hazard to houses and other structures and if present adjacent to forested areas can lead fire into the forest, causing serious damage to fire-sensitive native species. Since they reproduce well after fire, these grasses can perpetuate a fire cycle (D’Antonio and Vitousek, 1992).

Scattered examples of Ricinus communis  (tuitui, tuitui fua ikiiki, castor bean) were seen. This species is widespread on a number of Pacific islands, including Samoa and Tonga. The seeds are very poisonous. Disturbance favours this species so it may increase, particularly along roadsides and in openings.

Two species of Salvia (S. coccinea and S. occidentalis) (momili, red salvia and pupu elo, sealu, blue sage, respectively) are widely planted as ornamentals and escape to form large clumps. These species were most common in disturbed sites adjacent to villages and along roadsides. They do not appear to thrive in shaded areas.

Stachytarpheta cayennensis (mautofu Samoa, motofu Samoa, blue rat’s tail) is ubiquitous as it is throughout the Pacific. While mostly a pest in open areas, it can invade into the forest, particularly when there has been disturbance. Stachytarpheta jamaicensis (blue porterweed, light blue snakeweed) is also common and the two species are reported to hybridize.

3.22 Invasive species of limited extent

Reproduction of Anacardium occidentale (cashew nut) was seen along the road east of the Vaiea experimental farm. It appears to be doing quite well on Niue, unlike most Pacific islands, and probably has the potential to spread more widely.

Asparagus setaceus (ornamental asparagus) was seen at the entrance to the Matavai Resort and at a few other locations, particularly planted around gravesites. This species is a pest in Hawai‘i, Tonga, Lord Howe Island and parts of mainland Australia. It climbs into the trees and makes travel difficult because of its thorny nature. Its seeds are spread by birds, so it has the potential to spread widely.

Bryophyllum pinnatum (tupu he lau, tupu noa, life plant) was recorded in quite a number of places, usually associated with habitation or formerly inhabited or cultivated sites. It primarily reproduces vegetatively (with each leaf capable of producing numerous new plantlets), but we also saw it in flower. It is a nuisance species in Hawai‘i and on some other Pacific islands. It is a species that loves to grow on rocks and will be difficult to remove if it becomes widely established in the wild.

Quite a lot of reproduction of Delonix regia (pine, flame tree) was noted. This species is widely planted throughout the Pacific and in most places is not a problem, but conditions on Niue appear to be favourable to its spread. It is quite invasive at several sites in north Queensland, Australia.

Dissotis rotundifolia (dissotis, pink lady) was previously found along the road from Alofi to Public Works, across from Tapeu fisheries (probably an escape from cultivation). It could not be found in the present survey. Dissotis is a serious problem in Samoa and some other places, forming dense mats on the ground and shading out other species, occasionally even climbing over small shrubs.

Occasional trees of Falcataria moluccana (Moluccca albizia) were seen. There was substantial seedling growth adjacent to the Limu Pools where severe cyclone disturbance had occurred. This species has the potential, over time, of spreading more widely (as can be seen in Hawai‘i and on Pohnpei and Tahiti). The wood is weak and many of the trees were damaged by the cyclone.

Hemigraphis alternata (metal leaf, red ivy) was noted in several locations. This species is shade tolerant and will spread in the forest understory. It is mostly found planted as an ornamental and along roadsides where cuttings have apparently been dumped.

Hylocereus undatus (night-blooming cereus, pitahaya) was seen on the previous survey, mostly in Alofi, but a large clump was also seen in this survey on the rocky hillside above the Anana viewpoint. This species likes to grow on rocks, and Niue may be a very favourable habitat for it. It mostly spreads vegetatively but birds and fruit bats can spread it if it sets fruit.

A small patch of Hyptis suaveolens (stinking Roger) was observed at the Vaiea Farm. This species had not been recorded previously on Niue and may have been introduced as a contaminant of livestock or hay. It was shown to Miles Hibbert-Foy, manager of the nonu plantation, along with recommendations for its removal by hand pulling and destruction by fire. He subsequently found additional areas elsewhere on the farm and did some initial control.

Justicia betonica (white shrimp plant) is widely planted as an ornamental on Niue, but numerous wild examples were seen. It had not previously been recorded as naturalised. In Hawai‘i it escapes and forms large stands and seems to be doing the same on Niue.

Macfadyena unguis-cati (cat’s claw creeper) was seen beside the Public Works building and at the Vaipapahi experimental farm. The infestation at Public Works seems to have increased in size since the 2000 survey and has also spread along the road toward the golf course and across the road into an abandoned orchard. This aggressive vine climbs trees and also forms a dense mat on the ground. Control is difficult because it has tuberous roots and reproduces from pieces and cuttings. It is a problem species in Hawai‘i as well as northeastern New South Wales and southeastern Queensland in Australia.

Melia azedarach (sili, Chinaberry) is present but not common. This species is a prolific producer of seed, which is spread by birds. It is invasive in a number of Pacific locations, including the Cook Islands, French Polynesia and Hawai‘i as well as in South Africa.

Melinis minutiflora (molasses grass) is a species that is both invasive and can cause a serious fire hazard. It has modified fire regimes on many islands where it has been introduced (D’Antonio and Vitousek, 1992). It is not widespread on the island but could increase as a result of disturbance, particularly fire (it was collected at the end of a borrow pit along the Mutalau-Lakepa road between Fuelala and Vaitafe in the 2000 survey and was re-located at this site during the present survey).

Merremia tuberosa (wood rose), a climbing, smothering vine, is notable for its aggressive behaviour on Niue. It is present at a number of locations—good examples can be seen at the dump and behind the former library, where the cyclone knocked it out of the trees but it otherwise seems to be thriving.

Mimosa pudica (sensitive plant), much smaller than Mimosa diplotricha and with fewer small prickles, can form dense mats. It is already widespread on Niue, but it may become even more prevalent with time. It is a serious weed on many Pacific islands.

A number of specimens of Psidium guajava (kautoga, kautoga tane, lala, guava) were seen in cultivation and as wild saplings. This is a major invasive species in Tonga and the Galapagos Islands as well as a problem in French Polynesia (Marquesas Islands), New Caledonia, Hawai‘i and Fiji. Frugivorous birds, as well as rats and feral pigs, disperse the seeds. Perhaps it may, over time, become more widespread.

A single tree of Senna siamea (cassod tree) was seen at the Vaipapahi Experimental Farm. It is invasive in Australia (Cape York Peninsula) and reported to be weedy on Tahiti.

Senna tora (sicklepod) was noted at Vaipapahi farm and elsewhere, especially along roadsides and margins of cultivated areas. It is a major pest on the island of ‘Eua, Tonga, and probably has the potential to spread more widely on Niue.

Solanum torvum (prickly solanum, devil's fig) is a spiny species of disturbed areas that forms dense, impenetrable thickets. It was collected on Niue in 1975 (Sykes 1126 cited in Whistler, 1988), but was not seen in the 2000 survey or this one. It probably has been eliminated, but if not it certainly must be of very limited extent and would be a candidate for eradication. It is a serious problem for agriculture.

Spathodea campanulata (African tulip tree) is occasionally planted as an ornamental. This tree has become a major problem in Fiji, the Hawaiian Islands and some other places. Large trees do not stand up well to wind. At the Vaipapahi Experimental Station it has begun to spread locally by what appear to be root suckers and possibly by seed.

Syngonium angustatum and S. podophyllum (arrowhead plant, goosefoot plant) are two very similar climbing aroids that escape from cultivation. They have the ability to spread in the deep shade of intact forests, forming a dense mat on the forest floor as well as climbing trees (behaviour similar to Epipremnum pinnatum cv. ‘Aureum’ [=Scindapsus aureus]). They are difficult to eradicate as they are able to reproduce from a single node and bits and pieces of the stems or roots are easily overlooked. They primarily spread from dumped cuttings. Syngonium angustatum is a problem species in American Samoa while S. podophyllum is widespread in Hawai‘i. Syngonium podophyllum was recorded at a number of sites on this survey. While mostly associated with settlements, examples were observed growing along roadsides away from habitation. This species appears to be referred to as "ivy" on Niue.

Thevetia peruviana (yellow oleander) is widely planted and appears to be naturalizing with dense thickets observed at the base of ‘parent’ plants. Immature fruit were observed on some plants but it is possible that some of the regeneration was from suckers. All parts of this plant are poisonous.

Tradescantia zebrina (wandering zebrina) is less prevalent than T. spathacea (talotalo, laupapaki), perhaps because it was more recently introduced. It is shade tolerant and thus has the potential to spread in the forest understory. Once it spreads into the rough upraised coral of the island it will be almost impossible to remove. There are examples, both cultivated and naturalised, at the Matavai Resort and elsewhere. It is commonly spread through the dumping of garden cuttings.

3.3 Other species that are known to be invasive or weedy and are present on Niue

A number of other introduced species that are known to be invasive were noted (see Appendix 1, Table 3). Many of these species are prevalent along roadsides or on disturbed sites while others are yet uncommon or are in cultivation. For the ones that are already widespread, there is probably little that can or should be done, other than local control where they are a problem for agriculture or a threat to sensitive or natural areas. However, some of the uncommon species or those yet in cultivation could become a problem in the future, since there is often a long lag time between introduction and when a species begins to cause serious impact. These species should be monitored for spread and possible control measures, if necessary. A study in New Zealand showed that it is often worth controlling these species even if their likely impact is uncertain (Harris, Timmins and Panetta, 2003)

A number of exotic tree species have been introduced to Niue. The occasional specimen of Bauhinia sp., likely Bauhinia monandra (pine fua loloa, orchid tree), was seen outside of cultivation. Tecoma stans (yellow bells, yellow-elder, yellow trumpetbush) is a serious invader of disturbed areas in Tonga and French Polynesia where it grows in dense stands, commonly with other weedy species. The seeds are wind-dispersed but it was only seen in cultivation on Niue. Casuarina equisetifolia (ironwood) was reproducing to a limited extent along the road east of the Vaiea experimental farm. Ceiba pentandra (vavae, kapok), Moringa oleifera (horseradish tree) and Samanea saman (monkeypod) are present but these should be easily controlled if they appear in unwanted places.

A number of introduced grasses have become established, including Axonopus compressus (carpetgrass), Axonopus fissifolius (narrow-leaved carpetgrass), Bothriochloa bladhii (blue grass), Cenchrus ciliaris (buffelgrass), Cenchrus echinatus (bur grass); Chloris barbata (swollen fingergrass), Chloris gayana (Rhodes grass), Cynodon dactylon (Bermuda grass), Dactyloctenium aegyptium (beach wiregrass), Dichanthium annulatum (bluestem), Digitaria ciliaris (fingergrass, smooth crabgrass), Digitaria violascens (smooth crabgrass), Eragrostis amabilis (Japanese love grass), Paspalum conjugatum (T grass, Hilo grass), Paspalum dilatatum (dallis grass), Paspalum paniculatum (Russell river grass), Sporobolus indicus (smutgrass), Tripsacum laxum (Guatemala grass), Urochloa [=Brachiaria] mutica (para grass) and Urochloa [=Brachiaria] subquadripara (green summer grass). Two additional species of Urochloa were observed growing in unmanaged situations and along roadsides. Specimens were collected and the determinations will be advised at a later date. Unfortunately no fertile material could be found of a species that closely resembles Urochloa [=Brachiaria] decumbens (signal grass).

Allamanda cathartica (allamanda, yellow trumpet vine) is present but uncommon and not recorded on this survey. It is an ornamental species that is becoming invasive in northern Queensland, Australia, Palau and Papua New Guinea.

Annona glabra (pond apple) was seen planted at the Vaipapahi experimental farm.

Some small but dense stands of Breynia disticha (snowbush) were noted in the vicinity of mature cultivated plants. It is thought that this thickening up results from sucker regrowth. This species should be watched for naturalization.

Crotalaria pallida (pine kotalelia, pile, smooth crotalaria, smooth rattlebox) appears to have become much more widespread since the last survey. Crotalaria micans (pine kotalelia, pile) is also common. Dense stands of Crotalaria verrucosa (blue-flower rattlepod) were seen along the road near Taupa village where there was severe cyclone impact. The variety in Niue (and Rarotonga, Cook Islands) has white flowers. These are species that will take advantage of the cyclone disturbance but are considered largely benign by local people as they act to enrich the soil and are easily controlled. Crotalaria verrucosa should be monitored for spread to new areas.

Cuscuta campestris (golden dodder) was seen at both experimental farms and occasionally elsewhere.

Dieffenbachia seguine and/or D. maculata (dieffenbachia, dumb cane), common house and yard plants, were seen in cultivation in several locations. D. seguine is a problem in American Samoa and is reportedly present in the Cook Islands, Fiji, and Tonga. It grows well in low light and can invade the forest understory.

Eugenia uniflora (kafika, kafika palangi, Surinam cherry) was noted in the villages and occasionally elsewhere, but plants observed away from village areas appeared to be remnants of cultivation rather than wild plants. Fruit-eating birds probably spread the seeds. While this species can be invasive (it was observed spreading on the islands of Mangaia and Ma‘uke, Cook Islands) the specimens on Niue do not look very healthy and do not appear to pose a threat.

Furcraea foetida (toua, Mauritius hemp) is widely naturalised on the southern part of the island and occasional examples are seen elsewhere.

Indigofera suffruticosa (indigo) is established on many Pacific islands and is a major weed species in Tonga. It is present but neither widespread nor abundant on Niue.

Lonicera japonica (Japanese honeysuckle) was seen cultivated in several locations. This species is a serious pest in a number of countries, is on the New Zealand noxious weed list and is banned from sale in that country. It can be spread both by birds and cuttings. However, it does not seem to reproduce well on low-elevation tropical islands, so is probably not much of a threat on Niue.

Momordica charantia (bitter-melon, balsam pear), a member of the cucumber family, is a climbing vine and its fruit can be the host for fruit flies. It is reported to be present but was not seen. Possibly it is present in cultivation.

Odontonema tubaeforme (fire spike, cardinal flower) is a widely cultivated ornamental that is invasive in the understory of moist forests in American Samoa and Samoa. It primarily spreads vegetatively, but over time can cover considerable area. Occasional plants were observed in cultivation.

Russelia equisetiformis (coral plant, fountain plant) is common, mostly along roadsides and is reported to have increased or at least become more conspicuous in recent years.

Syzygium cumini (Java plum) is present in cultivation. This species is invasive in the Cook Islands, Hawai‘i and French Polynesia (Raiatea). Syzygium jambos (Malabar plum, rose apple) is present as well and is a major invasive species in French Polynesia, the Galapagos Islands and the Indian Ocean islands of Mauritius and La Réunion.

Tillandsia usneoides (old man’s beard, Spanish moss) was widely cultivated as a yard plant but most of it seems to have been blown away by the cyclone. Small numbers of plants were observed in some of the villages. It is a native of the southern United States, where it is widespread. Given the warm, moist climate of Niue, it has the potential to spread out of cultivation.

Tithonia diversifolia (matala, Mexican sunflower) is widespread along roadsides but it’s a light-loving species and probably won’t penetrate far into the forest. It has obviously increased since the previous survey and following the cyclone, and may well increase further in the short term, particularly in highly disturbed areas. Along with the introduced grasses it can contribute to the fuel loading and fire hazard, thus potentially opening up more areas for invasion.

Tradescantia spathacea (talotalo, laupapaki, boat lily) is widespread and invasive on Niue.

There are a large number of widespread weeds of roadsides, waste places and agriculture including Bidens pilosa (beggar’s tick), Centrosema pubescens (centro), Chamaesyce hirta (garden spurge, hairy spurge), Euphorbia cyathophora (toto uli?, wild poinsettia), Euphorbia heterophylla (milkweed), Macroptilium atropurpureum (siratro), Pilea microphylla (artillery plant, rockweed), Plantago lanceolata (buckhorn plantain), Ruellia prostrata (black weed, bell weed), Senna occidentalis (coffee senna), Synedrella nodiflora (Cinderella weed) and Vernonia cinerea [=Cyanthillium cinereum] (ironweed).

3.4 Native species or Polynesian introductions exhibiting aggressive behaviour

Chrysopogon aciculatus (mosie fisi, moti fisi, Mackie’s pest, lovegrass), indigenous or an early introduction, is an aggressive, noxious grass that readily withstands trampling, poor soils and mowing. Its sharp seeds can penetrate flesh and work their way in, causing festering sores. Its spiked seeds are carried from place to place in fur, feathers, or clothing. It is common on Niue but was inconspicuous throughout the survey because it was outside its main flowering season.

Ipomoea violacea [=macrantha] (fue tea, moonflower) is a widespread native vine.

Merremia peltata (fue, fue vao), indigenous or an early introduction, is quite invasive along forest edges. It is a light-loving opportunist that takes advantage of natural or human-caused disturbance. It was previously of limited extent on Niue, unlike many Pacific islands, but has taken at least temporary advantage of the cyclone disturbance to increase where it occurs and perhaps spread to new areas. Unless it overtops trees, though, it should be suppressed when the forest establishes a closed canopy. Where trees are in danger of being overtopped, cutting back the vines should give the tree the opportunity to recover. However, it will be a continuing problem in and adjacent to areas that are maintained as openings, such as the edges of fields, roads, etc. There, more aggressive action may be needed to control it. In any case, the species should be monitored and, if necessary, control action taken.

Operculina ventricosa (paper rose) is a native vine that through anecdotal reports appears to be increasing in abundance and vigour due to the cyclone and other disturbance.

Some probable Polynesian introductions (Whistler, 1988) include Cardiospermum halicacabum (balloon vine, heart pea), Commelina diffusa (commelina, dayflower), Dioscorea bulbifera (aerial yam), Eleusine indica (wiregrass), Oxalis corniculata (kihikihi, clover sorrel), Physalis angulata (manini, annual ground cherry) and Sida rhombifolia (mautofu, motofu, arrow-leaf sida).

3.5 Invasive species not known to be on Niue

Perhaps because of its location "off the beaten path", many invasive species have yet to reach Niue. These are listed in Appendix 1, Table 5. The following list summarizes the worst of these.

Several Acacia species are invasive on other Pacific islands, notably A. aulacocarpa (brown salwood, brush ironbark wattle, hickory wattle), A. crassicarpa (northern wattle, Papua New Guinea red wattle), A. curassavica (redwood), A. farnesiana, A. mangium, A. mearnsii (black wattle), A. melanoxylon and A. nilotica. A number of other Acacia species are recorded as invasive throughout the world, so caution should be exercised in planting members of this genus. Acacias are often introduced for forestry, wood supply or watershed protection purposes. The Acacia spirorbis planted as a yard tree on Niue does not appear to be a problem—only a few isolated examples away from houses were seen, and even those may have been on long-abandoned homesteads.

Albizia chinensis (Chinese albizia, silktree) is exceptionally widespread in Samoa. Based on its behaviour in Samoa, other Pacific islands should be very cautious about introducing this tree.

Ardisia elliptica (shoebutton ardisia) is a problem species in the Cook Islands, Hawai‘i, French Polynesia, Samoa and the US (Florida). It produces prolific fruit and crowds out other species in the forest understory. Birds, which eat the fruit, are a major factor in its spread.

Two rubber trees, Castilla elastica (Panama rubber tree) and Funtumia elastica (African rubber tree), are very invasive in Samoa. Castilla elastica is present in French Polynesia as well. Birds spread the seeds of Castilla while those of Funtumia are wind-borne "parachute" seeds. The related species Ficus elastica is present in cultivation on Niue.

Cardiospermum grandiflorum (balloon vine; heart seed) is very invasive on Rarotonga, Cook Islands, and is reported to be invasive in Australia as well. Another species, C. halicacabum, is present on Niue.

Cecropia obtusifolia (trumpet tree, guarumo) is an invasive tree species that is a problem in Hawai‘i and the Cook Islands (Rarotonga). Cecropia peltata (trumpet tree), a similar species, is invasive in French Polynesia.

Cestrum diurnum (day cestrum, day jessamine, inkberry) is a bird-spread species that is a problem on a number of Pacific islands. It is often planted as an ornamental. Cestrum nocturnum (night-flowering cestrum) is already present on Niue.

Chromolaena odorata (chromolaena, Siam weed) is a highly invasive pan-tropical weed. It will likely show up in Niue at some point in time and should be promptly eradicated if found. It has small seeds that can travel on boots, clothing or used cars or equipment. Biological controls are available but are most effective in open areas, less so in shaded stands.

Cinnamomum verum [=zeylanicum] (cinnamon) is actively invading secondary forests in American Samoa and Samoa. It is also present and invasive in the Cook Islands (Rarotonga), Fiji, French Polynesia and Hawai‘i. Cinnamomum camphora (camphor tree) is a serious pest in Australia and Florida (US).

Clerodendrum quadriloculare is an attractive ornamental and is commonly planted for that purpose. It is notorious for being a prolific producer of root suckers and, in fact, the plant is easily propagated by means of root cuttings. It is a potential problem because of its ability to invade intact or relatively intact native forests. It has become widespread on Pohnpei, Federated States of Micronesia. In Hawai‘i it is becoming a problem ornamental, producing numerous root suckers that appear some distance from the parent plant.

Clidemia hirta (Koster’s curse) is a serious problem species in Hawai’i and other locations. This is a very serious weed of the forest understory on many tropical islands and should be immediately eradicated if found. It is present in Samoa and American Samoa, Tonga and Vanuatu.

Coccinia grandis (ivy or scarlet gourd) is a smothering vine that is a serious problem on Saipan. The vines climb over trees and form such dense cover that the forest underneath is completely shaded out and destroyed. It is also invasive in Guam and Hawai‘i and is reportedly present in Fiji and Vanuatu. It is a vegetable commonly used in southeastern Asian cooking and the plant is often introduced for that reason. It readily spreads vegetatively through cuttings and, if fruit is present, by birds and probably pigs.

Cordia alliodora (Ecuador laurel, salmwood) was introduced to Vanuatu as a forestry tree and has become a pest there (Tolfts, 1997). It has similarly been introduced and is widespread on the island of ‘Eua, Tonga.

Cryptostegia grandiflora (rubber vine, India rubber vine) is a climbing vine that has become a serious problem in northeastern Queensland, Australia. Other vines that could be serious problems if introduced into Niue include Thunbergia species, Passiflora species not already present and non-native Ipomoea species.

Elaeocarpus angustifolius [=grandis] (blue fig, blue marble tree, quandong), a native of Australia, is a forestry tree that is invading intact and secondary forests in Samoa.

Erigeron karvinskianus (Mexican daisy, seaside daisy, daisy fleabane) is a major problem on Kauai and is spreading elsewhere in Hawai‘i. It is also a serious weed on La Réunion.

Flemingia macrophylla and F. strobilifera (luck plant, wild hops) have been planted as ornamentals on a number of Pacific islands. Both of these species are prolific seed producers, have naturalised at several of the locations where they have been introduced, and have the potential to become a much more serious problem.

Hiptage benghalensis (hiptage) is a problem species in Hawai‘i and is reported to be a very invasive species on La Réunion and Mauritius. It is also becoming invasive in north Queensland, Australia. The seeds are wind-dispersed and it also can reproduce from cuttings.

Hyptis pectinata (mint weed) is a serious weed of disturbed sites and agriculture. Its seeds stick to clothing and to the fur of animals and can also be spread by vehicles and machinery. It is on the Hawaii State noxious weed list, is a noxious weed in Fiji, is very prevalent in Samoa and is becoming so in Tonga. A related species, Hyptis capitata (knobweed) is also quite invasive.

Imperata cylindrica (cogon grass) is a very serious invasive grass. It is present in Samoa, Tonga and Vanuatu.

Maesopsis eminii (musizi, umbrella tree) is a large African tree that has been introduced into some countries as a forestry tree. Fruit-eating birds (and possibly fruit bats) spread its seed and it has become a problem in a number of locations. It was introduced as a timber tree to Fiji, where it is starting to naturalize.

Miconia calvescens (the purple plague, velvetleaf) is undoubtedly the most destructive invasive plant in the Pacific. It has been a disaster to the forest ecosystems of Tahiti in French Polynesia and has subsequently spread to other islands in French Polynesia (Meyer and Florence, 1996). It has also escaped in Hawai‘i and is the subject of an intensive and costly eradication effort there. It recently was discovered in Queensland, Australia, where an eradication project is also under way. This species is an attractive garden plant and might be introduced this way or as tiny seeds on shoes or used equipment. The possibility of its accidental introduction to Niue as a contaminant of equipment and building supplies from French Polynesia should be kept in mind during future surveys.

Other members of the family Melastomataceae (including Arthrostemma ciliatum (everblooming eavender), Heterocentron subtriplinervium (pearl flower), Medinilla magnifica (chandelier tree), Medinilla venosa (holdtight), Melastoma candidum (Asian melastome, Indian rhododendron, Malabar melastome), Melastoma sanguineum (fox-tongued melastoma, red melastome), Memecylon floribundum, Ossaea marginata, Oxyspora paniculata (bristletips), Tetrazygia bicolor (Florida clover ash) and Tibouchina urvilleana (princess flower) that are not native or presently on Niue should also be excluded.

Mucuna pruriens (cow itch, velvet bean) is commonly introduced as a cover crop and for livestock feed. It is a serious problem on Saipan and is considered a weed species in Mexico, Mozambique, Jamaica and Madagascar. While the utilis variety commonly used in agriculture lacks irritating hairs it can apparently revert to type over time.

Passiflora tarminiana [formerly known as P. mollissima in Hawai‘i] (banana poka, banana passionfruit) is a smothering vine that is a problem in Hawai‘i and New Zealand. P. mollissima is a problem species in New Zealand. These species can smother the forest canopy when the sub-canopy vegetation is disturbed. Passiflora rubra (red passionfruit) is very invasive in the Cook Islands. Other Passiflora species not already present (Passiflora alata (wingstem passionflower), Passiflora caerulea (blue passionflower), Passiflora coccinea (scarlet passionflower), Passiflora pulchella (two-lobed passionflower), etc.) should also be excluded.

Pennisetum setaceum (fountain grass) is a major problem in Hawai’i. It is present in Fiji and French Polynesia. This species is often sold as an ornamental through seed catalogues.

Phyllostachys spp. and other running bamboos are not present on Niue. Phyllostachys and similar bamboo species spread by means of rhizomes, as opposed to bamboos that grow in clumps, and are extremely difficult to control or remove. Phyllostachys nigra (black bamboo) is a problem species in Hawai‘i while P. bissetii is extremely invasive on the island of Mangaia, Cook Islands.

Pimenta dioica (allspice, pimento) is an invasive forest tree. The seeds are bird-dispersed. It is widespread in Tonga (‘Eua), planted in Hawai‘i (where it is naturalizing) and reported to be planted in French Polynesia and Fiji as well. Pimenta racemosa (bay rum tree), while less of a problem, readily naturalizes as well; for example, in the Cook Islands.

Piper aduncum (spiked pepper) is invasive in Fiji, Papua New Guinea, the Solomon Islands, Indonesia and Malaysia. Its tiny seeds are dispersed by birds and fruit bats and can be introduced into new areas on machinery, particularly logging equipment. Locally, it spreads by suckers, forming large clumps.

Piper auritum (eared pepper, also called "false kava") has been introduced to some Pacific islands as a fast-growing form of kava, but it is worthless in this regard. It is becoming widespread in Tonga and is presently subject of an eradication campaign on the island of Pohnpei, Federated States of Micronesia.. See also SPC Pest Alert No. 19, False Kava. The species produces many small seeds that can be spread by birds, rodents and bats and can also be introduced into new areas on machinery. It also suckers profusely, forming large clumps. Even if not introduced deliberately, with its very small seeds it might be brought in inadvertently.

Pithecellobium dulce (Madras thorn) is a thorny tree present in Hawai'i, Fiji and French Polynesia.

Pluchea carolinensis (sour bush) is a widespread pest species in Hawai‘i, commonly invading almost every habitat type, and was seen naturalizing extensively on the islands of Tongatapu, Tonga, and Tarawa, Kiribati. The seeds are spread by wind and as contaminants of vehicles and machinery.

Psidium cattleianum (strawberry guava) is a small tree that forms dense thickets. It is a major problem species in a number of island ecosystems including Hawai'i, Fiji, Tahiti and Rarotonga and Mangaia in the Cook Islands. Varieties with red and yellow fruits are known.

All Rubus species (raspberries, blackberries, thimbleberries and brambles) should be excluded. These include Rubus alceifolius (giant bramble), invasive in Australia (Queensland) and La Réunion and native to Southeast Asia; Rubus moluccanus (Molucca bramble), a serious pest in the Mascarine Islands and native in New Guinea and Rubus rosifolius (roseleaf raspberry, thimbleberry), very invasive in French Polynesia and Hawai‘i and also native to New Guinea. A number of other Rubus species are invasive. In Hawai‘i, R. argutus (prickly Florida blackberry) and R. niveus (hill or Mysore raspberry) are problems. Introduced Rubus species (in particular, R. niveus) are a major problem in the Galapagos Islands. In general, where Rubus species are not present on tropical islands, they should not be introduced. If already introduced, they should be evaluated as candidates for eradication. The vines form thorny thickets and the fruits are widely dispersed by birds.

Schefflera actinophylla (octopus tree) has bird-dispersed fruits and is invasive in Hawai‘i, French Polynesia and elsewhere in Micronesia.

Schinus terebinthifolius (Christmas-berry, Brazilian pepper) is a major problem species in Hawai‘i was well as Florida (US) and the Indian Ocean islands of La Réunion and Mauritius. The fruits are very attractive to birds, aiding its spread. It is present, though uncommon, in Guam.

Sesbania grandiflora (katurai, hummingbird tree, scarlet wisteria tree) is cultivated as an ornamental in American Samoa and Samoa and was observed to be spreading out of cultivation there.

Setaria palmifolia (palmgrass, short pitpit) is spectacularly invasive in Samoa, growing in dense, monospecific stands. It is also invasive in Tahiti and Hawai‘i and is on the New Zealand noxious weed list. The seeds are dispersed by wind and possibly by granivorous birds.

Solanum capsicoides (cockroach berry, devil’s apple, soda apple) has been introduced to several South Pacific islands as an ornamental. It is becoming well established in Tonga, particularly on Vava’u. Although small, it is quite spiny and would probably be a problem for agriculture as well as a general nuisance. It produces large amounts of small, tomato-like fruit. Spread may be by birds or pigs or by humans who use the fruit in lei-making.

Solanum mauritianum (bugweed, wild tobacco, tree tobacco) is quite prevalent throughout Tonga and is a noxious weed in South Africa. In Hawai‘i, it is naturalised on slopes and ridges in disturbed wet forest.

Thunbergia grandiflora (blue trumpet vine, Bengal trumpet) is an aggressive vine that can smother trees. The plant forms large underground tubers and is difficult to eradicate because of regeneration from the tubers and root and stem fragments. It is a problem species in Australia (a noxious weed in Queensland), Palau and Singapore.

Tibouchina herbacea (glorybush or cane ti) is another species that is a major problem in Hawai'i.

Turnera ulmifolia (yellow alder, sage rose) is commonly planted as an ornamental throughout the Pacific region. The seed is reported to be carried by ants (Staples et al., 2000) and the species is widely naturalised in the tropics.

In addition to the grasses mentioned above, a number of other potentially invasive grass species are not yet present on Niue, including Andropogon glomeratus, Andropogon virginicus, Arundinaria graminea, Arundo donax, Axonopus micay, Brachiaria eruciformis, Cenchrus brownii, Chloris divaricata, Chloris radiata, Chloris virgata, Cortaderia jubata, Cortaderia selloana, Cymbopogon refractus, Cyrtococcum patens, Cyrtococcum trigonum, Dactylis glomerata, Digitaria bicornis, Digitaria eriantha, Digitaria fuscescens, Digitaria horizontalis, Digitaria insularis, Digitaria sanguinalis, Echinochloa polystachya, Echinochloa stagnina, Eragrostis cilianensis, Eragrostis elongata, Eragrostis pilosa, Eragrostis tenuifolia, Eragrostis tremula, Eragrostis unioloides, Eremochloa ophiuroides, Eriochloa procera, Eustachys petraea, Hymenachne amplexicaulis, Hyparrhenia rufa, Imperata conferta, Imperata cylindrica, Isachne globosa, Ischaemum polystachyum, Ischaemum rugosum, Ischaemum timorense, Leersia hexandra, Lolium multiflorum, Melinis repens, Microlaena stipoides, Neyraudia reynaudiana, Olyra latifolia, Oplismenus burmannii, Panicum decompositum, Panicum polygonatum, Panicum repens, Paspalum fimbriatum, Paspalum notatum, Paspalum setaceum, Paspalum urvillei, Pennisetum clandestinum, Pennisetum glaucum, Pennisetum macrourum, Pennisetum polystachion, Pennisetum setaceum, Rottboellia cochinchinensis, Saccharum spontaneum, Sacciolepis indica, Sacciolepis interrupta, Schizachyrium condensatum, Setaria barbata, Setaria italica, Setaria palmifolia, Setaria parviflora, Setaria pumila, Sorghum halepense, Sporobolus elongatus, Sporobolus pyramidatus, Stenotaphrum secundatum, Themeda gigantea, Themeda quadrivalvis, Tripsacum latifolium, Urochloa [=Brachiaria] brizantha, Urochloa [=Brachiaria] decumbens, Urochloa [=Brachiaria] humidicola(6) and Urochloa [=Brachiaria] reptans. Grasses are easily introduced as contaminants in imported seed, imported sand and gravel or on used machinery, and by their nature tend to be invasive.

The best indicator that a species might be invasive is the fact that it is invasive elsewhere. However, each island ecosystem is unique and invasiveness cannot be predicted with certainty. A good strategy is to be extremely cautious and exclude these and other species known to be invasive or weedy (although the best strategy is to exclude all species not shown by risk assessment to be of acceptable risk). These and other known problem species that have the potential to cause problems in tropical island ecosystems and are not yet present in Niue are listed in Appendix 1, Table 5. These species should be excluded through plant quarantine and, if establishment is detected, promptly evaluated for eradication. In addition, species that are reported to be present in American Samoa, the Cook Islands, Fiji, French Polynesia, Samoa and Tonga but are not present in Niue are listed in Appendix 2. These species would be of high risk of introduction from any air and ship traffic between these points and Niue.

4.0 General observations and recommendations

The first line of defense against invasive species is to keep them out. Control at ports of entry is essential, and those concerned with the protection of natural ecosystems should work closely with plant protection and quarantine officials to combat known and potential invasive plant species. Plant quarantine officers should be familiar with both agricultural plant pests and those that threaten natural ecosystems. A list of known noxious species to be excluded should be developed and exclusion of these species should be backed by the force of law and regulation. Better yet is to utilize the "precautionary principle" (now used by Australia and New Zealand and under serious consideration by a number of other countries) to exclude all alien species not shown to be of acceptable risk. Risk assessment and management techniques can be used to assess the likelihood and effects of possible introductions and to develop exclusion and eradication strategies. Quarantine inspectors should continue their close inspection of boots, camping equipment and other material for soil and seeds, particularly when they have been used in countries where Chromolaena odorata, Miconia calvescens and other small-seeded species are present.

At the time of the previous survey, Niue had formed an Invasive Species Committee. Consideration should be given to reconstituting this committee. Close coordination and cooperation between the various government Departments and Divisions is essential. Such a committee can be effective both for long-term strategic actions, such as review and strengthening of relevant laws and regulations, as well as short-term tactical and operational problems, such as action when a new species is found to have been introduced and publicity campaigns discouraging dumping of garden waste. In addition to a management plan, the committee should draw up a prioritized action plan. This would include critical areas to be protected and species subject to control or eradication as well as which governmental agency is to take the lead in control or eradication measures. Time, money and people are always in limited supply and must be directed to the places where they will do the most good. Economic analysis can be used to assess the costs and benefits of management strategies and prioritize action. Some recommendations are made below as to possible actions against individual plant species, but these should be tested against available resources and other priorities.

Foresters, conservation officers, extension agents and others that spend time in the field should be alert to new species that exhibit invasive behaviour. Most pest species are deliberately or inadvertently introduced by people and tend to first become established on farms or in gardens and disturbed areas. Suspicious plant species should be promptly reported. Periodically scheduled surveys can also be conducted for new or expanding infestations. A good time for surveys is immediately after the wet season to pick up any annual species before they die off during the dry season. An evaluation should be conducted for any new species that appears to be invasive or is known to be invasive elsewhere. Assistance by an expert who is familiar with the species and methods for its eradication or control should be requested if needed. Prompt action is essential, since once a species becomes widespread, control or eradication can be extremely costly or impossible. Assistance is also available on-line from experts through the Pacific Pestnet list-server.

Niue has laws and regulations in place to deal with quarantine and new introductions, but it would be appropriate for the Invasive Species Committee to review them to see if they might need to be strengthened. In the case of Niue, where most land is privately owned, the ability of government to require the control of noxious species on private lands or to take action on private lands if the landowner cannot be located or does not take prompt action is essential. Provision for emergency funds to deal with immediate problems should also be in place. New Zealand and some of its town councils have strong laws and regulations that can be used as models.

Steam cleaning or power washing of all used cars, trucks and equipment coming into Niue must be enforced. This is desirable not only from the standpoint of excluding invasive plants, but also insects and diseases. Especially suspect are roadbuilding machinery, military equipment and off-road vehicles. Quarantine inspectors should be especially vigilant to make sure used cars, trucks and equipment from Asia, Australia, Fiji, French Polynesia, New Zealand, Samoa and Tonga are clean as many dangerous weeds are present in these locations that are not yet in Niue. Likewise, importation of sand, gravel, seed and other easily contaminated material from outside the country should be subject to restriction, inspection and monitoring. Although the crushed rock imported from French Polynesia following the cyclone appeared on inspection to be weed-free, sites where it was used should be monitored.

A number of species used in ornamental plantings are, at least to some degree, invasive. While many of these species have desirable ornamental or physical characteristics, planting exotics as opposed to native species is a policy question that needs to be carefully considered. Most species that naturalize to any extent will gradually spread throughout available and suitable habitat, given enough time. Existing exotic species should be monitored for spread and new introductions should be carefully assessed to minimize risk.

It would be a good idea to review any records of introductions at the experimental farms or for forestry/agroforestry purposes against the list of known invasive species on the Pacific Island Ecosystems at Risk web site/CD. If there are introduced species of concern that were not found in this survey, the areas where they were planted can be searched to see if they are still present. In any case, areas previously used for agricultural and forestry species trials as well as other areas where exotic species have been planted should be more thoroughly checked for dangerous species than was possible during this survey.

Risk rating is useful in evaluating known and potential invasive species for their risk of introduction, spread and potential damage. The US Forest Service’s Institute of Pacific Islands Forestry and the University of Hawai‘i Botany Department have adapted the Australian risk assessment system to the needs of the Pacific. A large number of risk assessments have been developed and posted at the University of Hawai‘i Botany web site (http://www.botany.hawaii.edu/faculty/daehler/wra/wra_input.asp) and also on the PIER web site and CD. Eventually we hope to rate all the species listed in the PIER database. In the meantime, risk assessments can be performed on individual species to help evaluate their potential for invasion and spread.

Niue has set aside areas to be maintained in natural condition as a heritage for future generations, for the protection of native biodiversity and tourism values and as examples of Niue’s original forest cover. Protection of these areas will involve a continuous and long-term effort, even on a small scale, due to the continuing pressure from invading species. Keeping out shade-tolerant species that can invade closed forests and protection from fire are the biggest problems. Intact native forests are the most resistant to invasion and any measures that limit the amount of disturbance will help keep invasive species out of these areas. Planting of introduced species for ‘beautification’ of conservation areas increases the risk of escape of potential invasive species and should be discouraged.

Suggestions for public education and control and eradication strategies are given in a separate report (Newfield and Bull, in preparation). Strong quarantine enforcement, discouraging planting of certain species, prohibiting the introduction of dangerous species and educating the public about discarding garden cuttings would do a lot to protect Niue from invasive plants.

5.0 Species-specific recommendations

5.1 Management of invasive plants present on Niue

Table B shows the most serious invasive plant species in Niue and summarizes recommendations for their management. For priority species, more detailed information and recommendations follow the table.

Table B. Summary of major invasive species present in Niue with recommendations for their management

Scientific name
(family)

Common names (abridged)

Comments and recommendations

Adenanthera pavonina
(Fabaceae)
pomea, coral bean tree Control as needed in natural areas.
Allamanda cathartica
(Apocynaceae)
allamanda, yellow trumpet vine Discourage planting; remove when a problem.
Alternanthera brasiliana
(Amaranthaceae)
Brazilian joyweed Discourage further planting; monitor spread; control outside of cultivation when a threat to sensitive or natural areas.
Anacardium occidentale
(Anacardiaceae)
cashew nut Monitor spread, control as needed.
*† Annona glabra
(Annonaceae)
pond apple Eliminate example at the Vaipapahi Farm if not needed.
* Antigonon leptopus
(Polygonaceae)
chain of love, coral bells Continue the eradication program until this species is eliminated.
*† Asparagus setaceus
(Liliaceae)
ornamental asparagus Strongly discourage further planting; determine distribution, destroy plants outside of cultivation. If public opinion is favourable, work to eradicate this species.
Bryophyllum pinnatum
(Crassulaceae)
tupu he lau, tupu noa, life plant Discourage further planting; determine distribution; control as needed outside of cultivation, especially when a threat to sensitive or natural areas.
Calliandra sp.
(Fabaceae)
powderpuff, calliandra Monitor for spread, discourange further planting, consider eliminating it if not widespread (several plants were observed at Vaipapahi) .
Calotropis gigantea
(Ascelepiadaceae)
calotrope, crown flower, madar Monitor for spread.
Casuarina equisetifolia
(Casuarinaceae)
toa, casuarina, ironwood, Australian pine Monitor for further spread and control as necessary.
Chamaecrista nictitans
(Fabaceae)
partridge pea Control as needed in sensitive and natural areas.
Clerodendrum chinense
(Lamiaceae)
Honolulu rose Research control methodology; strongly discourage (prohibit?) additional planting and dumping of garden cuttings.
Delonix regia
(Fabaceae)
pine, flame tree Monitor reproduction and spread; discourage further planting; control in sensitive and natural areas as needed.
Dieffenbachia spp.
Araceae)
dieffenbachia, dumb cane Discourage dumping of garden cuttings; control outside of cultivation as needed.
*† Dissotis rotundifolia
(Melostomaceae)
dissotis, pink lady Monitor site where previously found, eradicate immediately if found at this or any other location.
Epipremnum pinnatum cv. ‘Aureum’ [=Scindapsus aureus]
(Araceae)
pothos, money plant Continue the campaign to control outside of cultivation, especially when growing in forested areas.
Eugenia uniflora
(Myrtaceae)
kafika, kafika palangi, Surinam cherry Monitor for spread.
Falcataria moluccana
(Fabaceae)
Moluccca albizia Monitor reproduction and spread; discourage further planting; control in sensitive and natural areas as needed. Consider reducing the number of trees if not a desired species.
Hemigraphis alternata
(Acanthaceae)
metal leaf, red ivy Discourage further planting; determine distribution; control as needed outside of cultivation, especially when a threat to sensitive or natural areas.
Hylocereus undatus (Cactaceae) night-blooming cereus, pitahaya Discourage further planting; determine distribution; control as needed outside of cultivation, especially when a threat to sensitive or natural areas.
*† Hyptis suaveolens
Lamiaceae)
stinking Roger Determine distribution, work with the manager of the Vaiea Farm to eradicate.
Indigofera suffruticosa
(Fabaceae)
indigo Monitor for spread.
Justicia betonica
(Acanthaceae)
white shrimp plant Discourage further planting; monitor spread; control outside of cultivation when a threat to sensitive or natural areas.
Lantana camara
(Verbenaceae)
talatala, talatala talmoa, lantana Check status of previously introduced biocontrol agents and reintroduce or introduce new ones as appropriate; local control as necessary.
Leucaena leucocephala
(Fabaceae)
pepe, leucaena Control as needed in sensitive and natural areas, particularly where it may inhibit natural reproduction; check status of leucaena psyllid.
* Macfadyena unguis-cati
(Bignoniaceae)
cat’s claw climber Research control methodologies; determine distribution, initiate eradication project.
Melia azedarach
Meliaceae)
sili, tili, Chinaberry Monitor for invasiveness.
Melinis minutiflora
(Poaceae)
molasses grass Monitor for spread, especially if burned; limit burning; reduce in forested areas and around structures as needed to reduce fire hazard.
Merremia peltata
(Convolvulaceae)
fue, fue vao, fue kula, merremia (native) Monitor for spread and overtopped trees, cut back vines as necessary; provide advice to landowners on appropriate control measures.
Merremia tuberosa
(Convolvulaceae)
wood rose Control in and near sensitive and natural areas.
Mikania micrantha
(Asteraceae)
fue saina, mile-a-minute-weed, mikania Investigate biological control when new techniques become available.
* Mimosa diplotricha
(Fabaceae)
giant sensitive plant Continue the eradication program until this species is eliminated.
Mimosa pudica
(Fabaceae)
sensitive plant Control locally as necessary.
Murraya paniculata
(Rutaceae)
orange jessamine, Chinese box Reduce the number of plants to prevent spread of the citrus psyllid if it should be introduced (currently being propagated at Vaipapahi).
Panicum maximum
(Poaceae)
Guinea grass Reduce in forested areas and around structures as needed to reduce fire hazard.
Pennisetum purpureum
(Poaceae)
elephant grass Reduce in forested areas and around structures as needed to reduce fire hazard.
Pseuderanthemum carruthersii
(Acanthaceae)
false eranthemum Discourage further planting; control outside of cultivation.
Psidium guajava
(Myrtraceae)
kautoga, kautoga tane, lala, guava Monitor for spread.
Quisqualis indica
(Combretaceae)
Rangoon creeper Monitor for invasiveness.
Ricinus communis
(Euphorbiaceae)
tuitui, tuitui fua ikiiki, castor bean Monitor spread; make sure the public is aware of the poisonous nature of this plant.
Russelia equisetiformis
(Scrophulariaceae)
coral plant, fountain plant Control where not wanted.
Salvia coccinea
(Lamiaceae)
momili, red salvia Control as needed in sensitive and natural areas.
Salvia occidentalis
(Lamiaceae)
pupu elo, sealu, blue sage Control as needed in sensitive and natural areas.
  † Senna siamea
(Fabaceae)
cassod tree Monitor for invasiveness.
Sorghum arundinaceum
(Poaceae)
wild sorghum Reduce in forested areas and around structures as needed to reduce fire hazard.
*† Spathodea campanulata
(Bignoniaceae)
African tulip tree Strongly discourage planting; determine distribution, consider an eradication program or at least work to reduce the number of trees.
*

Sphagneticola [=Wedelia] trilobata
(Asteraceae))

Singapore daisy Continue the eradication program until this species is eliminated.
Stachytarpheta cayennensis
(Verbenaceae)
mautofu Samoa, motofu Samoa, blue rat’s tail, dark blue snakeweed Control as needed in sensitive and natural areas.
Stachytarpheta jamaicensis
(Verbenaceae)
blue porterweed, light blue snakeweed Control as needed in sensitive and natural areas.
Syngonium podophyllum
(Araceae)
arrowhead plant, goosefoot plant Control outside of cultivation, especially when growing in forested areas.
Syzygium cumini
(Myrtaceae)
Java plum Monitor for spread.
Tecoma stans
(Bignoniaceae)
yellow bells, yellow trumpetbush Monitor for spread.
Thevetia peruviana
(Apocynaceae)
yellow oleander Discourage further planting; monitor spread; control outside of cultivation when a threat to sensitive or natural areas
Tithonia diversifolia
(Asteraceae)
matala, Mexican sunflower Control in forested areas and around structures as needed to reduce fire hazard.
Tradescantia zebrina
(Commelinaceae)
wandering jew Discourage further planting and dumping; control outside of cultivation when a threat to sensitive or natural areas.

*High priority for eradication
Eradication can probably be accomplished at low cost

5.2 Cultivated plants of threat to Niue

The species listed in Table C, seen or reported to be only in cultivation, should be closely monitored for spread or, better yet, eradicated if there are only a few examples, as they are documented as invasives elsewhere. They may behave similarly in Niue if they escape cultivation.

Table C. Cultivated species of possible threat to Niue

Scientific Name

Common Names (abridged)

Family

Habit

Invasive in:

Anredera cordifolia filikafa, Madeira vine Basellaceae vine Australia, New Zealand
Calliandra sp. powderpuff, calliandra Fabaceae shrub Indonesia
Calotropis gigantea calotrope, crown flower Ascelepiadaceae shrub Australia, Timor
Cestrum nocturnum ike he po, night-flowering cestrum, night-flowering jasmine, queen (or lady) of the night Solanaceae shrub Cook Islands, Fiji, French Polynesia, Samoa, Tonga
Grevillea robusta silky oak Proteaceae tree Hawai'I, French Polynesia
Murraya paniculata orange jessamine, Hawaiian mock orange Rutaceae shrub/tree SE Queensland (Australia). Alternative host to citrus psyllid
Odontonema tubaeforme fire spike, cardinal flower Acanthaceae shrub American Samoa, French Polynesia, Samoa
Passiflora laurifolia yellow granadilla Passifloraceae vine Hawai'i
Pseuderanthemum carruthersii false eranthemum Acanthaceae shrub Palau
Quisqualis indica Rangoon creeper Combretaceae vine Australia (Northern Territory)
Sambucus mexicana elderberry, Mexican elder Caprifoliaceae small tree American Samoa, Samoa, Tonga
Senna alata mulamula, candle bush Fabaceae shrub Australia, Papua New Guinea
Senna siamea cassod tree, Siamese cassia Fabaceae tree Australia, French Polynesia (Tahiti)
Syzygium cumini Java plum; jambolan plum Myrtaceae tree Cook Islands, French Polynesia
Syzygium jambos malabar plum, rose apple Myrtaceae tree French Polynesia, Galapagos Islands, La Reunion, Mauritius
Tecoma stans yellow bells, yellow-elder, yellow trumpetbush Bignoniaceae small tree Australia

Note: See Appendix 1, Tables 2, 3 and 4 for a complete list of cultivated plants with invasive potential.

5.3 Prevention of introductions

Table D. Priority species for exclusion from Niue

Scientific Name

Common Names (abridged)

Family

Habit

Invasive in:

Acacia aulacocarpa brown salwood Fabaceae tree Cook Islands
Acacia auriculiformis Papuan wattle, earleaf acacia Fabaceae tree US
Acacia crassicarpa northern wattle, Papua New Guinea red wattle Fabaceae tree Cook Islands
Acacia farnesiana Ellington curse, klu, sweet acacia Fabaceae shrub Fiji, French Polynesia, New Caledonia, Solomon Islands, Vanuatu
Acacia glauca redwood Fabaceae tree Cook Islands
Acacia mangium mangium, brown salwood Fabaceae tree Cook Islands
Albizia chinensis Chinese albizia, silktree Fabaceae tree Hawai’i, Samoa, Mauritius
Araujia sericifera moth plant, white bladder flower Ascelepiadaceae vine Australia, New Zealand, US
Ardisia crenata hen's eyes, Hilo holly, coral berry Myrsinaceae shrub Hawai'i
Ardisia elliptica shoebutton ardisia Myrsinaceae shrub Australia, Cook Islands, Samoa
Argyreia nervosa elephant creeper, Hawaiian baby woodrose Convolvulaceae vine Australia
Cardiospermum grandiflorum balloon vine; heart seed Sapindaceae vine Cook Islands
Castilla elastica Panama rubber tree Moraceae tree Samoa
Cecropia obtusifolia trumpet tree, guarumo Cecropiaceae tree Hawai’i, Cook Islands
Cecropia peltata trumpet tree Cecropiaceae tree French Polynesia
Cestrum diurnum inkberry, day cestrum, China berry Solanaceae shrub Cook Islands
Chromolaena odorata chromolaena, Siam weed Asteraceae shrub Pantropical
Cinnamomum camphora camphor tree, camphor laurel Lauraceae tree Australia, US
Cinnamomum verum cinnamon tree Lauraceae tree American Samoa, Cook Islands, Samoa
Clerodendrum quadriloculare bronze-leaved clerodendrum Lamiaceae shrub Micronesia
Clidemia hirta Koster’s curse, soap bush Melastomataceae shrub American Samoa, Fiji, Hawai’i, Palau, Papua New Guinea, Samoa, Solomon Islands, Vanuatu
Coccinia grandis ivy gourd, scarlet-fruited gourd Cucurbitaceae vine Saipan, Hawai’i
Cordia alliodora laurel, Ecuador laurel, salmwood Boraginaceae tree Samoa, Tonga, Vanuatu
Cryptostegia grandiflora rubber vine, India rubber vine Ascelepiadaceae vine Australia (Queensland)
Elaeocarpus angustifolius blue fig, blue marble tree, quandong Elaeocarpaceae tree Samoa
Erigeron karvinskianus Mexican daisy, daisy fleabane Aseraceae herb Hawai'i,La Réunion
Flemingia macrophylla Fabaceae tree Samoa, Cook Islands
Flemingia strobilifera luck plant, wild hops Fabaceae shrub French Polynesia
Funtumia elastica African rubber tree, silkrubber Apocynaceae tree Samoa
Hiptage benghalensis hiptage Malpighiaceae shrub Hawai’i, La Réunion, Mauritius, Australia
Hyptis pectinata comb hyptis, mint weed Lamiaceae herb Fiji, Samoa, Tonga
Imperata cylindrica blady grass, cogon grass, satintail Poaceae grass Many locations
Maesopsis eminii umbrella tree, musizi Rhamnaceae tree Fiji
Miconia calvescens miconia, velvetleaf, purple plague, bush currant Melastomataceae tree French Polynesia, Hawai’i
Mucuna pruriens cow itch, velvet bean, Bengal bean, Mauritius bean Fabaceae vine Saipan
Ocimum gratissimum wild basil Lamiaceae herb Cook Islands
Passiflora rubra red passionfruit Passifloraceae vine Cook Islands
Passiflora tarminiana/molissima banana poka, banana passionfruit, bananadilla Passifloraceae vine Hawai'i, New Zealand
Pennisetum setaceum fountain grass Poaceae grass Hawai'i
Phyllostachys spp. running bamboos Poaceae shrub Cook Islands, Hawai'i
Pimenta dioica pimento, allspice Myrtaceae tree Hawai‘i, Tonga
Pimenta racemosa bay rum tree, bay oil tree, malagueta Myrtaceae tree Cook Islands
Piper aduncum spiked pepper Piperaceae shrub/ tree Fiji, Papua New Guinea, Solomon Islands, Indonesia, Malaysia
Piper auritum eared pepper Piperaceae shrub Hawai’i, Pohnpei, Samoa, Tonga
Pithecellobium dulce Madras thorn Fabaceae tree Hawai’i, Fiji, French Polynesia
Pluchea carolinensis sour bush Asteraceae shrub Hawai’i, Tonga
Psidium cattleianum strawberry guava Myrtaceae tree Hawai’i, French Polynesia, La Réunion, Mauritius
Rubus spp. raspberries, blackberries, brambles Rosaceae shrubs Hawai’i, French Polynesia, etc.
Schefflera actinophylla octopus tree, umbrella tree, ivy palm Araliaceae tree French Polynesia, Hawai’i, Micronesia
Schinus terebinthifolius Brazilian pepper Anacardiaceae tree Hawai’i, US (Florida)
Sesbania grandiflora sesbania, hummingbird tree, sesban Fabaceae small tree Samoa
Setaria palmifolia palmgrass Poaceae grass Hawai‘i, French Polynesia (Tahiti), Samoa
Solanum capsicoides cockroach berry, soda apple Solanaceae herb Hawai‘i, Samoa, Tonga
Solanum mauritianum bugweed, wild tobacco, tree tobacco Solanaceae shrub Hawai‘i, Tonga
Thunbergia grandiflora Bengal trumpet, blue trumpet vine, clock vine Acanthaceae vine Palau
Tibouchina herbacea glorybush, cane ti, tibouchina Melastomataceae shrub Hawai’i
Tribulus cistoides puncture vine, caltrop, goat’s head Zygophyllaceae herb Hawai‘i
Turnera ulmifolia yellow alder, sage rose Turneraceae shrub Fiji, Kiribati, Palau
All grasses all other grass species not already present Poaceae grasses Pan-tropical
All melastomes all other non-native melastomes Melastomataceae   Hawai’i, etc.

Note: Appendix 1, Table 5 is a complete list of invasive and potentially invasive species not yet present on Niue.

5.4 Other recommendations

Appendix 1.  Species by category

Appendix 2.  Invasive species present in American Samoa, the Cook Islands, Fiji, French Polynesia, Samoa or Tonga but not present on Niue

Appendix 3. Scientific name synonyms

Appendix 4.  Background material and references


(1)  Program Manager, Pacific Island Ecosystems at Risk, Volunteer
(2) Australian Quarantine and Inspection Service, Volunteer.
(3) New Zealand Department of Conservation.
(4) New Zealand Department of Conservation.
(5) We would like to sincerely thank Haden Talagi and John Talagi, Department of Environment, and New Aue, Department of Agriculture, Forestry and Fisheries, for their generous assistance in the conduct of the field work.
(6)Urochloa decumbens may be present and naturalised along roadsides in Niue but only sterile material was collected; confirmation requires collection of flowering material. A species of Urochloa collected at two sites has been identified as U. humidicola. Verification awaits submission of the specimens to Queensland Herbarium.


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This page updated 11 January 2005