Invasive Alien Species Fact Sheets

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file icon Senna occidentalishot!Tooltip 10/23/2018 Hits: 265
PEA FAMILY
Fabaceae; subfamily: Caesalpiniaceae
 
COMMON NAMES
English: ant bush, arsenic bush, coffee senna, sicklepod, stinkweed.
 
DESCRIPTION
Annual or lives for more than one year but less that two, erect herb or shrub (0.5–2.5 m tall); stems reddish-purple, smooth, hairless or sparsely hairy, four-angled or grooved when young becoming greenish-brown and rounded.
Leaves: Green, once-divided (15–20 cm long), with 3–5 pairs of oppositely held egg-shaped or oval leaflets (3–10 cm long and 2–3 cm wide) with broad and rounded bases, tapering towards the end with pointed tips; conspicuous gland at the base of each leaf stalk; alternately held on stems on reddish stalks (3–5 cm long).
Flowers: Bright yellow (20–30 mm across) in small clusters of 2–6 flowers in forks of uppermost leaves.
Fruits: Pods (several-seeded dry fruits that split open at maturity), green turning brown as they mature, flattened, slightly curled (75–130 mm long and 8–10 mm wide), held upright.
 
ORIGIN
Argentina, Belize, Bolivia, Brazil, Cayman Islands, Costa Rica, Dominican Republic, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Haiti, Nicaragua, Panama, Peru, Suriname and Venezuela.
 
REASON FOR INTRODUCTION
Coffee substitute, medicine and ornament.
 
INVADES
Roadsides, wasteland, disturbed land, fallow land, managed pastures, drainage ditches, woodland edges/gaps, savannah, riparian vegetation and gullies.
 
IMPACTS
Dense stands can displace native plant species, and reduce livestock carrying capacities in managed and natural pastures. Being allelopathic, it inhibits the germination and growth of other plants. Studies have shown that it has a negative impact on maize (Arora, 2013) and cotton yields (Higgins et al., 1986), and is an alternative host for crop diseases (Suteri et al., 1979). The seeds of S. occidentalis are highly toxic, containing compounds that damage the liver, the vascular system and the heart and lungs of domestic livestock, often leading to death in cattle (Barros et al., 1999), horses (Riet-Correa et al., 1998), goats (Suliman et al., 1982; Suliman and Shommein, 1986), pigs (Martins et al., 1986), poultry (Haraguchi et al., 1998), and rabbits (O’Hara and Pierce, 1974). Consumption of the seeds in western Uttar Pradesh, in India, resulted in the deaths of nine children within five days (Vashishtha et al., 2007).
 
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 Ruellia tuberosahot!Tooltip 10/23/2018 Hits: 250
ACANTHUS FAMILY
Acanthaceae
 
COMMON NAMES
English: bluebell, iron root, large bell-flower, minnieroot, popping pod, ruellia, sheep potato, spearpod
Cambodia: phka arch kok, phka smau, smau leach phtoush
Indonesia: pletekan
Viet Nam: cây Qua no
 
DESCRIPTION
Biennial (lives for 1–2 years) herb, creeping or upright [60 (–70) cm tall], stems four-sided and hairy, swollen and purplish at the nodes with thick, elongated spindle-shaped tuberous roots. Leaves: Green, glossy, almost hairless, simple, oval to eggshaped [5–9 (–18) cm long and 2–4 (–9) cm wide], margins entire, leaf stalk is 5–7 mm long.
Flowers: Mauve to blue-violet, solitary, tubular (5–5.5 cm long and 3.5 cm across), showy.
Fruits: Capsule, hairless, elongated with almost parallel sides (2.2–3 cm long), containing 24–28 seeds.
 
ORIGIN
Colombia, French Guiana, Guyana, Peru, Suriname, Venezuela and the Caribbean.
 
REASON FOR INTRODUCTION
Medicine and ornament.
 
INVADES
Roadsides, railway lines, disturbed land, drainage ditches and lowlands.
 
IMPACTS
Forms dense stands displacing native plants and the organisms associated with them.
 
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 Piper aduncumhot!Tooltip 10/23/2018 Hits: 286
PEPPER FAMILY
Piperaceae
 
COMMON NAMES
English: bamboo piper, false matico, jointwood, piper
 
DESCRIPTION
Evergreen shrub or small tree (6–8 m tall), with short stilt roots, often in thickets, branches are erect, but with drooping twigs and swollen, purplish nodes, foliage and twigs aromatic. Bark: Yellow-green, finely hairy stems and enlarged, ringed nodes.
Leaves: Green, softly hairy beneath, broadly sword- to oval-shaped (13–25 cm long and 3.5–8 cm wide), tapering into long tips with the base asymmetric, short leaf stalks.
Flowers: Yellowish, tiny, in long curving spikes opposite the leaves.
Fruits: Berries (fleshy fruits that don’t open at maturity), green, small, egg-shaped, compressed into greyish, worm-like spikes.
 
ORIGIN
Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, Suriname, Venezuela, and the Caribbean.
 
REASON FOR INTRODUCTION
Medicine, spice and ornament.
 
INVADES
Roadsides, disturbed land, fallow land, plantations, forest edges/gaps, lowlands and riparian zones.
 
IMPACTS
P. aduncum establishes dense stands which shade out native species and prevent forest regeneration. In field surveys in Papua New Guinea, it was found to be present in all garden plots, 92% of riverine plots, 80% of young secondary and 65% of old secondary forest plots, and 75% of the gaps (Leps et al., 2002). In regenerating areas, P. aduncum sometimes attained a canopy cover of 75% and suppressed the native species which local communities utilized extensively in the past (Leps et al., 2002). In the Pacific, it is accidentally harvested with kava (Piper methysticum G. Forst), an important crop, lowering its quality. It also competes with kava and other crops and may act as a host for kava pests and pathogensm (Plant Protection Service, 2001). It consumes large quantities of water, drying out the soil, and absorbs significant amounts of nutrients to the detriment of crops.
 
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 Parthenium hysterophorushot!Tooltip 10/22/2018 Hits: 257
DAISY FAMILY
Asteraceae
 
COMMON NAMES
English: carrot weed, carrot grass, congress weed, famine weed, ragweed, white top.
 
DESCRIPTION
Annual erect herb, much branched [0.5–1.5 (–2) m high], forms a basal rosette of leaves when young, green stems are longitudinally grooved or ribbed and covered in short hairs.
Leaves: Pale green, covered with short stiff hairs; rosette and lower stem leaves are deeply divided and large (3–30cm long and 2–12 cm wide); upper stem leaves are shorter and less divided
Flowers: White, in small compact heads (5 mm across), clustered at the tips of branches, each flowerhead has five distinctive petals.
Fruits: Achenes (small, dry, one-seeded fruits that don’t open at maturity), (1.5–2.5 mm long), five in each flowerhead.
 
ORIGIN
Argentina, Bahamas, Barbados, Belize, Bolivia, Cuba, Dominica, Grenada, Grenadines, Guatemala, Guyana, Haiti, Honduras, Jamaica, Martinique, Mexico, Paraguay, Puerto Rico, St. Vincent, Trinidad and Tobago, Uruguay, Virgin Islands and Venezuela.
 
REASON FOR INTRODUCTION
Medicine, ornament and accidentally as a contaminant.
 
INVADES
Roadsides, railways, wasteland, disturbed land, fallow land, crops, plantations, managed pasture, gardens drainage ditches, forest edges/gaps, woodland edges/gaps, grassland, savannah, riversides, lowlands and gullies.
 
IMPACTS
Parthenium disrupts grasslands, invades woodlands and generally disturbs native vegetation through aggressive competition (Evans, 1997). Parthenium is allelopathic, reducing crop yields, and displacing palatable species in natural and improved pasture. In India, parthenium infestations have resulted in yield losses of up to 40% in several crops (Khosla and Sobti, 1979). Parthenium is also a secondary host for a range of crop pests. In terms of pasture production, this noxious weed has been found to reduce livestock carrying capacities by as much as 90% (Jayachandra, 1971). It also poses serious health hazards to livestock, and can cause severe allergenic reactions in people who regularly come into contact with the weed.
 
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 23 October 2018
file icon Opuntia strictahot!Tooltip 10/22/2018 Hits: 247
CACTUS FAMILY
Cactaceae
 
COMMON NAMES
English: Australian pest pear, common pest pear, erect prickly pear, sour prickly pear.
 
DESCRIPTION
Succulent erect, spreading shrub [0.5–1.3 (–2) m high]; thicketforming; modified stems called cladodes are blue-green, longer than broad (10–20 cm long and 7.5–14 cm wide); 3–5 areoles (raised structures or bumps on the stems of cacti, out of which grow clusters of spines) per diagonal row on each cladode; 1–2 straight and flattened yellow spines (1.5–4 cm long) usually restricted to marginal areoles as opposed to O. stricta (Ahw.) Haw. var. dillenii (Ker Gawl.) Benson where there are 4–7 (–11) banded spines (1.5–4 cm long) on most areoles.
Leaves: Cylindrical, minute and shed early.
Flowers: Yellow and large (5–6 cm long and 5–6 cm wide).
Fruits: Berries (fleshy fruits that don’t open at maturity), green turning red-purple as they mature, egg-shaped (4–6 cm long and 2.5–3 cm wide), outer surface smooth with clusters of glochids (barbed hairs or bristles), narrowed at the base, purple sour pulp, white seeds.
 
ORIGIN
Ecuador, Mexico, Southern USA, Venezuela, and the Caribbean.
 
REASON FOR INTRODUCTION
Hedge/barrier and ornament.
 
INVADES
Roadsides, wastelands, disturbed areas, rocky outcrops, savannah, grassland and riverbanks in arid to semi-arid regions.
 
IMPACTS
Can form dense stands, preventing access to homes, water resources and pasture. On Madagascar, O. stricta has invaded land used for crop and pasture production, and has encroached on villages and roads, impeding human mobility (Larsson, 2004). Here, the cactus has had a negative impact on native grasses and herbs, and it is even affecting trees by inhibiting their growth and regeneration (Larsson, 2004). The small spines (known as glochids) on the fruit, when consumed by livestock, lodge in their gums, on their tongues, or in their gastrointestinal tracts, causing bacterial infections, while the hard seeds may cause rumen impaction, which can be fatal, and which often leads to excessive, enforced culling of affected animals (Ueckert et al., 1990). People who consume the fruits develop diarrhoea and may suffer from serious infections caused by the spines (Larsson, 2004). In Kenya, O. stricta infestations have resulted in the abandonment of farmlands.
 
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 23 October 2018
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