Invasive Alien Species Fact Sheets

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file icon Vachellia niloticahot!Tooltip 10/23/2018 Hits: 256
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: 407
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
file icon Stachytarpheta jamaicensishot!Tooltip 10/23/2018 Hits: 416
VERBENA FAMILY
Verbenaceae
 
COMMON NAMES
English: blue porter weed, blue snake weed, Brazilian tea, Jamaica snakeweed, porterweed, snake weed
Indonesia: gewongan, jarong
Malaysia: ramput tahi babi, selaseh dandi
Philippines: albaka, bilu-bilu, bolomaros, kandi-kandilaan, limbagat, sentemiento, verbena de las antilles
Viet Nam: cây duôi chuot, hai tiên
 
DESCRIPTION
Evergreen shrubby herb (60–120 cm high), young stems green or purplish, mostly hairless and square in cross-section becoming rounded, light brown and woody as they mature; woody rootstock.
Leaves: Green with a bluish or greyish tinge, leathery, hairless or with a few hairs on veins on undersides, simple, leaves eggshaped, oval or somewhat elongated with almost parallel sides (2–12 cm long and 1–5 cm wide) with rounded tips, margins sharp but finely toothed; leaves held opposite each other on stems on stalks 5–35 mm long.
Flowers: Light blue, blue or mauve, tubular (7–11 mm long and 8 mm across) on long, curved and thick spikes (15–50 cm long and 3–7 mm thick) at the end of branches.
Fruits: Capsules (dry fruits that open at maturity), green turning dark brown, dark purple or black as they mature, small, somewhat elongated with almost parallel sides (3–7 mm longand 1.5–2 mm across).
 
ORIGIN
Belize, Brazil, Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Suriname, south-eastern USA, Venezuela, and the Caribbean.
 
REASON FOR INTRODUCTION
Medicine and ornament.
 
INVADES
Roadsides, disturbed sites, wastelands, fallow land, plantations, managed pasture, gardens, drainage ditches, savannah, forest edges/gaps, woodland edges/gaps, lowlands, floodplains and coastal environs.
 
IMPACTS
Forms dense stands outcompeting native plants for water and nutrients. Probable host of cucumber mosaic cucumovirus in India (Mathew and Balakrishnan, 1991).
 
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 Sphagneticola trilobatahot!Tooltip 10/23/2018 Hits: 349
DAISY FAMILY
Asteraceae
 
COMMON NAMES
English: creeping oxeye, creeping daisy, creeping wedelia, Singapore daisy
Indonesia: seruni, widelia, wedelia
Malaysia: panchut-panchut
Philippines: imelda
Viet Nam: son cúc ba thùy
 
DESCRIPTION
Creeping, mat-forming evergreen herb with scrambling or climbing habit [15–30 (–70) cm tall]; stems green or reddish (up to 2 m long), slightly hairy, rounded, rooting at the joints.
Leaves: Dark green, glossy, almost hairless, simple, fleshy (40–180 mm long and 15–80 mm wide), three-lobed, margins toothed, held in opposite pairs on stem, stalkless or on short stalks.
Flowers: Bright yellow to orange, daisy-like (20–35 mm across), borne singly on upright stalks (3–15 cm long).
Fruits: Achene (small, dry, one-seeded fruit that does not open at maturity), brown, elongate (4–5 mm long).
 
ORIGIN
Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, Suriname, Venezuela and the Caribbean.
 
REASON FOR INTRODUCTION
Medicine, erosion control and ornament.
 
INVADES
Roadsides, disturbed areas, wasteland, drainage ditches, forest edges/gaps, woodland edges/gaps and lowlands.
 
IMPACTS
Forms a dense ground cover to the detriment of other plant species. It is also allelopathic enhancing its competitiveness (Zhang et al., 2004). Even low infestation levels have a negative impact on plant diversity. In a study on Hainan Island, China, S. trilobata already starts decreasing plant community diversity at 10% cover (Qi et al., 2014). In south-east Viti Levu and Taveuni Island, Fiji, it has invaded taro [Colocasia esculenta (L.) Schott; Araceae] fields (Macanawai, 2013).
 
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 Solanum viarumhot!Tooltip 10/23/2018 Hits: 253
TOMATO FAMILY
Solanaceae
 
COMMON NAMES
English: tropical soda apple
Viet Nam: cà trái vàng
 
DESCRIPTION
Evergreen, erect herb [50–150 (–200) cm tall], with densely hairy stems and branches with recurved (2–5 mm long) and straight spines (up to 20 mm long) on the leaf stalks and the leaf veins.
Leaves: Dark green, glossy above, duller below, hairy, simple, broadly egg-shaped [6–20 cm long and 6–15 cm wide], bluntly lobed, with spines on the veins and hairs on both sides, leaf stalks are 3–7 cm long with prickles. Flowers: White (1.5 cm across), in clusters of 1–5.
Fruits: Berries (fleshy fruits that don’t open at maturity), mottled light and dark green becoming pale yellow as they mature, smooth (2–3 cm across), containing 400 brown seeds (2–3 mm in diameter).
 
ORIGIN
Argentina, southern Brazil, Paraguay and Uruguay.
 
REASON FOR INTRODUCTION
Medicine and accidentally as a contaminant.
 
INVADES
Grassland, forest edges/gaps and riparian vegetation.
 
IMPACTS
Dense stands displace other plant species by crowding or shading them out. The prickles on the plants reduce wildlife forage and prevent movement of animals through invaded areas (USDA-FS, 2005). The foliage and stems are unpalatable to cattle, considerably reducing livestock-carrying capacities (Medal et al., 2012). Control costs of S. viarum to ranchers in Florida were estimated at US$ 6.5–16 million per year (Thomas, 2007). It has also caused poisoning of goats in Florida (Porter et al., 2003). It is an alternative host for many plant diseases including the cucumber mosaic virus, gemini virus, potato leafroll virus, potato virus Y, tobacco etch virus, tomato mosaic virus, tomato mottle virus and the fungal pathogen, Alternaria solani (Cooke, 1997). It is also a host for a number of insect pests (Sudbrink et al., 2000; Medal et al., 2012).
 
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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