Invasive Alien Species Fact Sheets

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file icon Gracilaria salicorniahot!Tooltip 09/12/2019 Hits: 260
SYSTEM
Marine
 
COMMON NAMES
English: red alga
Philippines: canot-canot; caocaoayan
 
DESCRIPTION
Gracilaria salicornia varies in colour from a bright yellow at the tips to orange, green or brown at the base. The thallus is cylindrical (0.5cm in diameter) and dichotomously branched with constrictions at the base of each dichotomy. In Hawai’i it generally grows in three-dimensional mats that are tightly adherent to hard substrata and can be up to 25-40cm in thickness; in calm environments it may grow in an upright and more openly branching form (Smith Pers. Comm. 2003).
 
KNOWN INTRODUCED RANGE
ASEAN: Indonesia, Malaysia, Philippines, Singapore, Thailand, Viet Nam
World: Australia, Fiji, India, Iran, Kenya, Madagascar, Mauritius, Mozambique, Oman, Seychelles, Solomon Islands, Sri Lanka, Tanzania, United States, Yemen, China, Guam, Japan, Kuwait, Micronesia, Northern Mariana Islands, Pakistan, Reunion, South Africa, Taiwan
 
PATHWAY
Transport – Ship/boat ballast water; Ship/boat hull fouling
Intentional release
 
REASON FOR INTRODUCTION
Gracilaria salicornia was introduced intentionally to two reefs on O'ahu, Hawai'i, in the 1970s for experimental aquaculture for the agar industry (Smith et al. 2004).A likely vector of transport of invasive marine algae is through ship fouling and/or ballast water. In Hawaii many alien algae were first collected in or around harbors and gradually dispersed to neighbouring areas (Smith Hunter and Smith 2002).
 
IMPACTS
In tropical regions, blooms of indigenous algae (such as Gracilaria salicornia) have often been tied to reductions in grazing intensity and increases in anthropogenically derived nutrient levels (Miller et al. 1999, McClanahan et al. 2001, McCook et al. 2001, Smith et al. 2001, Stimson et al. 2001, Thacker et al. 2001, in Smith Hunter and Smith 2002). G. salicornia is likely to damage native coral environments by over-growing native benthic organisms such as algae and marine invertebrates. Because of its large morphological stature and the dense mats it forms (5 to 10cm thick), G. salicornia can have large effects on benthic ecology by monopolising stratum (Smith et al. 2004). In many cases, red alga becomes ecologically dominant and grows over coral reefs. For example, in areas of Hawaii such as Waikiki G. salicornia has become the single-most dominant benthic species in an area that before invasion was home to over 60 species of macroalgae (Doty 1969, in Smith et al. 2004. The long-term consequences of phase shifts from coral to algal dominance may include the loss of biodiversity, a decrease in the intrinsic value of the reef, changes in the community structure (eg: a reduction in the numbers of reef fish dependent upon corals for habitat and shelter), and erosion of the reef (Hughes 1994, in Smith Hunter and Smith 2002).
 
Source: Global Invasive Species Database (GISD) 2015. Species profile Gracilaria salicornia. Available from: http://www.iucngisd.org/gisd/species.php?sc=1026 [Accessed 09 September 2019]
file icon Charybdis japonicahot!Tooltip 09/12/2019 Hits: 199

SYSTEM

Marine, Terrestrial

COMMON NAMES

English: Asian crab, paddle crab, Asian paddle crab, swimming crab, blue crab

DESCRIPTION
 
Charybdis japonica have a carapace width of up to 12cm (Gust et al. 2003). They have a pilose (hairy) carapace (although amount of hair varies to little or none). The carapace has ridges with six frontal teeth, triangular and sharp. The inner supraorbital lobe is broadly triangular (Smith et al. 2003). Wee and Ng (1995) record the colour of C. japonica in Japan as mottled cream and purple. In the Waitemata harbour (New  Zealand) specimens varied from pale green and off-white, through olive green to a deep chestnut with purplish markings on the carapace and upper surfaces of the appendages (Smith et al. 2003). In addition, most Waitemata specimens have yellow-orange markings, some with only a hint of yellow-orange and some with very noticeable brown-orange on parts of the carapace and the legs, especially on the chelae where the upper colouration grades into the white to off-white ventral surfaces (Smith et al. 2003).

NATIVE RANGE

ASEAN: Malaysia, Thailand
World: China, Democratic People's Republic of Korea, Republic of Korea, Taiwan

KNOWN INTRODUCED RANGE

New Zealand
 
PATHWAY
 
Transport – Ship/boat ballast water
 

REASON FOR INTRODUCTION

The paddle crab may have been introduced from ship ballast water (Gust et al. 2003). This is known to be a potential route of spread of the Asian paddle crab.

IMPACTS
 
Disease transmission is one of the key potential impacts of the paddle crab in introduced environments. C. japonica is known to be a host or carrier of the White Spot Syndrome Virus (WSSV) (Maeda et al. 1998, in Potential next pests 2003). WSSV is a serious fisheries threat as it infects a broad spectrum of crustaceans, and can cause cumulative mortalities of up to 100% within 3 to 10 days from the first sign of disease
(Lightner 1996, in Potential next pests 2003).
 
Source: Global Invasive Species Database (GISD) 2015. Species profile Charybdis japonica. Available from: http://www.iucngisd.org/gisd/species.php?sc=1044 [Accessed 09 September 2019]
file icon Xanthium strumariumhot!Tooltip 10/24/2018 Hits: 685
DAISY FAMILY
Asteraceae
 
COMMON NAMES
English: large cocklebur, noogoora bur, sheep bur
Cambodia: kropeatt chrouk
Malaysia: buah anjang
Thailand: kachab
Viet Nam: cây ké dau ngua
 
DESCRIPTION
Annual, much-branched herb with erect stems (20–150 cm high) without spines; stems stout, green, brownish or reddish-brown, roughly hairy.
Leaves: Green, paler below, hairy on both surfaces, broadly eggshaped to triangular (2–8 cm long), margins irregularly toothed or lobed, on long leaf stalks (2–8 cm), held alternately on stems.
Flowers: Green, inconspicuous, in the leaf axils.
Fruits: Burrs, green turning yellowish then brown as they mature (1.5–2.5 cm long), covered with hooked spines (up to 20 mm long) and two terminal beaks.
 
ORIGIN
Uncertain, but probably Central and South America.
 
REASON FOR INTRODUCTION
Bee forage and accidentally as a contaminant.
 
INVADES
Roadsides, wasteland, disturbed land, fallow land, crops, plantations, drainage ditches, savannah, water courses, lowlands, floodplains and sandy and dry riverbeds.
 
IMPACTS
Rapidly forms large stands, displacing other plant species. X.strumarium is a major weed of row crops such as soya beans, cotton, maize and groundnuts in many parts of the world, including North America, southern Europe, the Middle East, South Africa, India and Japan (Webster and Coble, 1997). It also has a damaging impact on rice production in South-east Asia (Waterhouse, 1993). In the USA, high-density cocklebur infestations have resulted in soya bean yield losses of as much as 80% (Stoller et al., 1987; Rushing and Oliver, 1998). Infestations can also decrease soya bean seed quality and harvesting efficiency (Ellis et al., 998). Even low-density cocklebur infestations in cotton fields in the USA have contributed to seed yield losses of 60–90 kg per hectare, or approximately 5% (Snipes et al.,1982). Cocklebur has also caused yield losses in groundnuts of 31–39% and 88% at low and high densities, respectively, in the southern USA (Royal et al., 1997). X. strumarium burs lodge in animal hair and in sheep’s wool, reducing the quality and increasing treatment costs (Wapshere, 1974; Hocking and Liddle, 1986). The plants are toxic to livestock and can lead to death if eaten (Weaver and Lechowicz, 1983). Cocklebur is also an alternative host for a number of crop pests (Hocking and Liddle, 1986).
 
Source:
Witt, Arne. 2017. Guide to the Naturalized and Invasive Plants of Southeast Asia. CAB International. Retrieved from http://www.cabi.org/cabebooks/ebook/20173158961 on 24 October 2018
file icon Vachellia niloticahot!Tooltip 10/23/2018 Hits: 469
PEA FAMILY
Fabaceae; Subfamily Mimosaceae
 
COMMON NAMES
English: gum arabic, Nile thorn, prickly acacia, scented thorn
Indonesia: akasia
Viet Nam: keo a rap
 
DESCRIPTION
Evergreen thorny tree or shrub [4–6 (–25) m]; usually singlestemmed, crown scattered when young, later umbrella-shaped; thorns greyish (up to 10 cm long); deep and well-developed root system.
Bark: In young trees tinge of orange and/or green; in older trees brown-black, rough and deeply grooved.
Leaves: Dark green, hairless, twice-divided with 3–10 pairs of leaf branchlets (4 cm long), each with 10–25 pairs of leaflets, which are narrow and somewhat elongated with almost parallel sides (2–6 mm long and 0.5– .5 mm wide); pair of spines (1–5 cm long) at base of each group of leaves in young stems.
Flowers: Pale to golden yellow globular flowerheads (1–1.5 cm across) on 2 cm long stalks, fragrant.
Fruits: Pods (several-seeded dry fruits that split open at maturity), green turning black as they mature, straight or slightly curved (10–20 cm long and 5–17 mm wide), constrictions between each seed in the pod resemble a string of pearls.
 
ORIGIN
India, Myanmar, Oman, Pakistan and Yemen.
 
REASON FOR INTRODUCTION
Fuelwood, building materials, timber, tools, medicine, chicorysubstitute in coffee, fodder, nitrogen fixation, soil conservation, windbreak, firebreak, shade and ornament.
 
INVADES
Roadsides, disturbed land, urban open space, drainage ditches, irrigation channels, woodland edges/gaps, savannah and natural pasture.
 
IMPACTS
In Queensland, Australia, tree cover of just 25–30% has reduced the amount of pasture by 50% (Carter, 1994). Dense thickets also make it difficult to herd livestock, and animals have reduced access to water. In Indonesia, A. nilotica in Baluran National Park has reduced the amount of grazing available for herbivores, threatening the continued existence of the endangered banteng (Bos javanicus d’Alton; Bovidae). Infestations also contribute to increase soil erosion. Because the tree fixes nitrogen it also impacts on soil nutrient cycling.
 
Source:
Witt, Arne. 2017. Guide to the Naturalized and Invasive Plants of Southeast Asia. CAB International. Retrieved from http://www.cabi.org/cabebooks/ebook/20173158961 on 24 October 2018
file icon Tithonia diversifoliahot!Tooltip 10/23/2018 Hits: 603
DAISY FAMILY
Asteraceae
 
COMMON NAMES
English: Mexican sunflower, shrub sunflower, tree marigold
Cambodia: chhouk roth japon
Indonesia: keladi-keladian
Viet Nam: dã quy
 
DESCRIPTION
Annual or evergreen herbaceous shrub, woody at the base [2–3 (–5) m high]; stems slightly ridged and hairy when young.
Leaves: Greyish-green, finely hairy on underside giving a grey appearance, simple (6–33 cm long and 5–22 cm wide) with 3–5 (–7) pointed lobes, margins with a series of curved projections or teeth; held opposite or alternately on stem.
Flowers: Bright yellow, daisy or sunflower-like (up to 10 cm across), held on long and swollen stalks (7–30 cm long) which are velvety below the flowerhead.
Fruits: Achenes (small, dry, one-seeded fruits that don’t open at maturity), brown (4–8 mm long), in a spiky mass.
 
ORIGIN
Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua and Panama.
 
REASON FOR INTRODUCTION
Fodder, medicine, mulch, soil improvement, hedge/barrier and ornament.
 
INVADES
Roadsides, disturbed sites, wastelands, urban open space, fallow land, savannah, lowlands and riparian vegetation.
 
IMPACTS
Forms dense stands displacing native plant species and the animals associated with them. T. diversifolia is displacing native species in the wetlands of the Apete River, Eleyele Lake and Oba Dam in Ibadan, Nigeria, including the invasive and aggressive shrub Chromolaena odorata (Oluode et al., 2011), and is now considered to be one of the most invasive species in Nigeria (Borokini, 2011). Mexican sunflower has the ability to compete with agricultural crops (Ilori et al., 2007) and is contributing to the extinction of local species, including important medicinal plants (Oludare and Muoghalu, 2014). According to reports, it is leading to the abandonment of farms in the Copperbelt region of Zambia.
 
Source:
Witt, Arne. 2017. Guide to the Naturalized and Invasive Plants of Southeast Asia. CAB International. Retrieved from http://www.cabi.org/cabebooks/ebook/20173158961 on 24 October 2018
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