Appendix II

List and brief information on preliminarily recognized invasive plant species in Pakistan:

Fourteen invasive plant species were preliminary recognized from Pakistan in the one-day workshop on Alien Invasive Species in Pakistan, 17 September 1999, NARC, Islamabad. These are briefly described below, arranged according to the apparent impact intensity:

A. Species invading natural and semi-natural habitats.

1. Broussonetia papyrifera (Family : Moraceae)

English name: Paper mulberry Local name: Gul toot

Origin: A native of South East Asia.

Description: A medium sized dioecious tree up to 16 m tall. Trunk whitish -grey. Leaves 4-18 X 3-14 cm, broadly ovate to elliptic-ovate, sometimes palmately lobed, subcordate, scabrid above, softly hairy on undersurface. Male catkins appearing before the leaves, 3-5 cm long. Fruit Juicy, orange-red, in globose heads, 3 cm broad.

History of introduction: The introduction of this species in subcontinent is more than 100 years old. According to Parker (1924) it was first introduced in 1880 at Saharanpur and until 1924 it had spread up to Lahore along irrigation channels and into Shahdra plantation. Parker at that time predicted that this tree would become common in the sub Himalayan tract as well as in the more heavily irrigated portions of the plains especially the places where any prior vegetation was scant. (Dr. Surraya Khatoon, University of Karachi, Pers. Comm. 1999).

Affected areas and impacts: Paper mulberry is the most problematic invasive in northern Pakistan. It is distributed from Lahore to Peshawar valley through Salt range, but worst affected are the federal capital Islamabad and Rawalpindi. It has the typical features of invasiveness by fast growth rate, seed dispersal through birds, and ability to vegetative propagation. Its fruits are relished by crows who thus acts as the vector for its seed dispersal; therefore both crows and paper Mulberry are promoting each other. The increased population of crows has become a nuisance for the residents of affected areas. It was introduced in Islamabad to make capital green. In less than thirty years period it became a highly invasive species in the natural ecosystem of Himalayan foothills. Around Rawal Lake it has replaced the entire natural vegetation. Margalla Hills is a National Park representing good examples of Himalayan foothill vegetation. This invasive species is a growing threat to the natural vegetation of National Park and other valleys in the East of Islamabad up to south Azad Jammu and Kashmir.

Besides threatening the natural vegetation, it is also a human-health hazard. In a report of Pakistan Medical Research Council (1995), about 45.5 % of allergic patients in Islamabad and Rawalpindi showed positive sensitivity to the pollen of B. papyrifera

Control measures: The newly sprouting shoots from trees stumps and ground covers are being cut and burnt. First phase of this operation in Islamabad started from Faisal Avenue and the trees are being replaced with better timber trees. This operation started in 1992 but is not effective as it continues to stage a comeback due to its invasive nature (Mazhar Hussain, Director Environment, CDA).

Researchable aspects: Survey of natural enemies of B. papyrifera in its native area, and trying the host specific natural enemies for its control in Pakistan.

Possibilities should be explored for use of different plant parts before deciding for its control e.g. bark of this plant is used in Japan for painting, fibre from its bark is used in making paper, rope etc in Thailand and Japan (Dr Iqbal Sial, Chris Shank, IUCN Pers.Comm. 1999). However, commercial exploitation would put a pressure to maintain large populations of this species, which would continue to be a threat for native biodiversity and human health.

Legislation for cutting this tree by private citizens for different uses, making compulsory at the same time replacing the cut trees with native trees like shisham, poplar, amaltas, etc should also be considered.

2. Prosopis juliflora (Family: Mimosaceae)

English name: Mesquite. Local name: Kikar

Origin: A native of West Indies and Mexico.

Description: It is a large spiny shrub or small tree with pinnately compound leaves. Flowers minute, greenish yellow, arranged in dense, hanging spikes. Pod 14-20 X 1-1.5 cm, yellow, containing a sweet pulp eaten by birds.

Histrory of introduction: It was introduced in 1878 by the British for afforesting deserts of Sindh and southern Punjab (Parker, 1924).

Affected areas and impacts: It is a highly invasive species established in Pakistan and can be seen everywhere from mountains to seacoast. It is now present in the Pabbi Hills , the Salt Range the piedmont area, the mining wastes, plains, riparian forests, waste agricultural lands, saline and waterlogged areas, desert Suleiman Range and anywhere one can visualize. It is found on almost all the linear land strips like highways, canals and railway tracks.

The worst hit by all accounts, is the riparian forest of Acacia nilotica in Sindh severely invaded by this species. Prosopis juliflora forms almost pure populations wherever it invades, excluding all native species due to its allelopathy. Therefore it is a great danger to native biodiversity. It provides cheap fuel wood but nothing else. While indigenous Acacia nilotica is a multipurpose species, as a source of timber wood, fuel wood, tannins and enhancer of soil fertility by nitrogen fixation. P. juliflora is right now invading the Indus delta mangrove forests which is a real reason of concern. Despite the known invasiveness of mesquite, it is presently being introduced along Makran coast for sand-dune stabilization by the forest department. Like many other invasives this plant contains toxic metabolites which keep local herbivores away and also prevent the growth of indigenous plant species in the vicinity (Khatoon and Ali, the Herald annual 1999).

Control measures: Only mechanical removal of the plant by cutting the bushes and trees is practised by the forest department and is also sometimes allowed to general people to meet the fire wood demand.

Researchable aspects: Survey of natural enemies from its native area and try the host specific ones for its control. Controlled cutting of the plant to meet the fire wood demand along with replacement with more useful local plants like Acacia nilotica may be considered.

3. Eichhornia crassipes (Family: Pontederiaceae)

English name: Water hyacinth Local name: Gul-e-Bakauli

Origin: Native of Amazon basin, S. America.

Description: A perennial aquatic herb, free floating or rooting in mud, rhizomatous or stoloniferous, rooting from the nodes, roots long sometimes dark; leaves in rosettes petioles spongy and typically swollen, serving as a float; flowers showy, blue or bluish purple, in large (15 cm or more) upright racemes; capsule membranous, many seeded as many as 50 per capsule; seed ovoid, ribbed.

History of introduction: Water Hyacinth was first brought outside its native home as an ornamental plant, but it became an aggressive invader in all tropical and subtropical countries. Exact time of arrival in Pakistan is not known.

Affected areas and impacts: This species is widely distributed in water bodies of most parts of Pakistan, except in the high altitude and cold regions. It is a highly invasive species due to extremely fast growth rate and gregarious nature. Like in many other tropical countries, it is becoming a troublesome invasive in Pakistan also. It destroys water ecosystem by forming impenetrable layer on water surface which competes with native biota for oxygen causing massive die-off from asphyxiation. Therefore it exerts severe negative impact on freshwater fisheries; as well as it can modify the characterstics of wetlands, affecting their ecological fucntions. Insect vectors of human and animal diseases seek harbor in the mats of this weed.

It is choking water bodies in Sindh and Punjab. Flow of water is impeded in irrigation canals, drainage ditches are closed and great water loss occurs from the reservoirs and distribution systems. The weed clogs the irrigation pumps and interferes with hydroelectric schemes. It can render waterways and lakes unnavigable. Due to enormous transpiration, it can dramatically reduce the water volume in reserviors, canals and natural wet-lands. The problem of water hyacinth would become more profound with the contiual eutrophication of water bodies through agriculture runoffs and domestic and industrial pollution. Eutrophication is known to enhance its growth rate by several times

Control measures: Mechanical removal can be done in case of small-scale infestations. Several insect species as biological control of this species are known from many tropical countries. A fungus, Alternaria eichhorniae has also been shown effective in greenhouse to curtail water hyacinth growth and needs testing in field (Shabana et al. 1994).

Researchable aspects: Biological control of the weed.

4. Salvinia molesta (Family: Salviniaceae)

English name: Kariba weed, Water fern, Salvinia Local name: Not available

Origin: A native of South America

Description: It is a free floating rapid mat forming annual or perennial aquatic fern; individual plants up to 30 cm long with numerous leaves which forms mat, slender horizontal floating rhizome producing at each node two short petioled or sessile fronds on upper side and feathered root like frond downward; leaves (fronds) in groups of three from delicate stem, the surface leaves are light green and submerged leaves are brownish, the aerial leaves have club shaped hairs. The presence of club shaped hairs on the upper surface of aerial leaves is very distinctive and characteristic to distinguish this species

(from Holm et al, 1977).

History of introduction: I t is a recent introduction through an unknown source, first noticed in Keenjhar lake, Thatta few years back.

Affected areas and impacts: Salvinia molesta is one of most dreaded aquatic invasives in the world. It is highly invasive due to its rapid growth and vegetative propagation. In certain States of USA, keeping or selling this species is prohibited by the law. It is a pestilential invasive in many countries of Africa and other tropical and subtropical parts of the world. In Pakistan, it is fast spreading in the wetlands and irrigation channels of Thatta district.(Observations of Dr. Khatoon, University of Karachi). Its root-like fibrous leaves form a close-knit mat which along with closely-placed green leaves completely covers the water surface, eliminating most of the indigenous aquatic flora and fauna. It destroys the fresh water fisheries, choke the water ways making them unnavigable, impairs irrigation system, can interfere with power production and industries by clogging their intake ducts. The weed harbors snails and insects, which are vectors of human and animal diseases.

Control measures: Mechanical removal of the weed is recommended by some authors. Certain biological control organisms are known from many tropical and subtropical countries. Since it is in initial stage of invasion in Pakistan, it would be wise to take immediate action for controlling further spread of this species.

Researchable aspects: Estimation of the magnitude of invasion. Biological control of the weed.

5. Lantana camara (Family: Verbenaceae)

English name: Lantana Local name: Panch phuli

Origin: A native of Americas

Description: L. camara is an aromatic perennial erect shrub, 2-5 m tall, stems four angled armed with recurved prickles; leaves 2.5-10 cm long, 1.75-7.5 cm wide, margins crenate to dentate, rough above hairy below; flowers minute, arranged in dense groups of 2.5 cms across, generally yellow and pink on opening but changing to orange and red, sometimes blue or purple; fruit a small drupe globular, dark purple to black.

The species is distinguished by the strong unpleasant odor of its leaves when crushed, its four angled stems with recurved prickles and its flat topped multicolored flower clusters

(from Holm et al, 1977).

History of introduction: Exact time and source of introduction is not known, but probably a quite old intoduction.

Affected areas and impacts: Widely distributed in Pakistan, more common in the northern Punjab and especially problematic in and around Islamabad. It is a highly invasive fast growing aggressive species, forming dense thickets at the base of the Margalla hills around Rawal Lake and along Murree Road towards Bharako. Sizeable areas have been taken over by this weed. The seeds are carried by birds and where it establishes quickly covers over open areas and forms dense thorny thickets, therefore threatening the indigenous flora. It has taken over much of natural grazing ground. L. camara thickets are potential breeding places for rats, wild pigs, insects (mainly a host of cotton white fly, Bemisia tabaci ), etc. The leaves and seeds are toxic to many animals. Photosensitivity, gastrointestinal disturbances and deaths have followed the ingestion of the plant parts by sheep and calves (Observations of participants of workshop on Alien Invasive Species, 17 September 1999, NARC, Islamabad).

Control measures: Conventional control methods such as burning, slashing and digging are applied for controlling this weed. Using herbicides for its control are not economical and also have several implications (Mazhar Hussain, Environment Directorate, CDA Pers. Comm., 1999).

Researchable aspects: Biological control of the weed. Numerous natural enemies, i.e. predator insects are known for controlling this pantropical weed in many countries (Julien, 1992). Host-specifity needs to be carefully tested before introducing any of these into Pakistan.

6. Parthenium hysterophorus (Family: Compositeae)

English name: White top, Congress grass, Carrot grass Local name: Not available

Origin: Mexico, Central America

Description: It is a perennial, much branched erect herb, 1.5-2.0 m or more tall. The juvenile stage exists as a rosette with large dark green leaves and reduced stem. It is characterized by highly divided leaves, abaxial and adaxial surfaces covered with trichomes, capitulum with five fertile ray florets each having two attached subjacent seeds.

History of introduction: It is a recent introduction in the subcontinent through unknown source, recorded first in 1956 from Poona (Maharashtra, India). In Pakistan, it was first recorded in 1980s (Dr. S. Khatoon Pers. Comm. 1999). It is a recent introduction in Islamabad and is spreading to other areas in NWFP and Punjab (Dr R. A. Rafiq, NARC Pers. Comm.)

Affected areas and impacts: Although present in many parts of upper Punjab and NWFP, more affected area is Islamabad and environs, where it is highly invasive and has invaded most of the open spaces roadsides, etc and is threatening to indigenous biodiversity. Its impacts on local vegetation are visible on growth of wild jujube in the area where this plant is growing. This plant is competing with some of the alien species like Cannabis sativa, which does not grow in vicinity where Parthenium is growing i.e. a less aggressive invasive is giving way to a more problematic one. Parthenium pollen has allelopathic effect on the stigma of other species, inhibiting their seed-set. This is how it out-competes indigenous species.The weed is reported noxious in the neighbouring country India where it has invaded all types of pasture as well as agricultural lands. It is also reported as a health hazard in India. It is responsible for causing disease like fever and asthma and allergic contact dermatitis in human. Animals may get skin rashes on their udders and whole bodies. Parthenium is responsible for bitter milk disease in cattle buffaloes and goats fed on grass mixed with Parthenium.

Control measures: It is difficult to control. Biological control of this weed has been achieved in some countries that involve various insect and fungus species. In Islamabad only mechanical removal of the weed is being done from roadsides.

Researchable aspects: Distribution, reproductive biology, allelopathic effects, biological control of the weed.

7. Cannabis sativa (Family: Cannabaceae)

English name: Hemp Local name: Bhang

Origin: Native of Central and Western Asia

Description: Annual, herb 1.5 - 2.5 m tall, slender; stem and branches slightly angular with appressed hairs; leaves palmately 3-9 foliate; male flowers 4-6 mm across, greenish, female flowers as large as the perigonium, bracts foliaceous 4-13 mm long, fruit achene 3-4 mm in diameter, shining, yellowish brown, minutely pilose to glabrous, ovate; seed only with fleshy unilateral endosperm.

History of introduction: Appears to be an ancient introduction.

Affected areas and impacts: Distributed in northern Punjab and NWFP. It is not much aggressive with a medium degree of invasiveness. It invades waste areas, fence rows around farm buildings usually on bottomland soil. It is one of the major causes of pollen allergy to humans in urban areas. In a study conducted by Pakistan Medical Research Council, 47.7 % of allergic patients brought to Pakistan Institute of Medical Sciences (PIMS) in 1995 were sensitive to pollens of this plant.

Control measures: Only mechanical methods of control are applied in urban areas.

Researchable aspects: Control strategies. Since it does not pose a major threat to indigenous biodiversity control measure should concentrate on urban areas, because its main impact is on human health.

8. Pistia stratiotes (Family: Araceae)

English name: Water cabbage Local name: Jal kumbi

Origin: It is a native of Old and new World tropics.

Description: A free floating but soon stoloniferous, small aquatic, perennial plant with a tuft of long very fibrous roots beneath, primary roots 2-7 mm in diameter and 1 m long; leaves pale green obovate-cuneate, erect, few to many 2.5- 15 cm long, arranged in arosette, the basal part somewhat velvety- hairy; flowers bisexual, spathes white, densely dotted when dry, finely hairy; spadix bearing the individual flowers shorter than spathe; fruit berry like; seeds usually numerous oblong tapering towards the base.

History of introduction: Apparently an old introduction.

Affected areas and impacts: It is widely distributed in Pakistan and found in water reservoirs, ponds and marshes along the edges of large lakes where they are able to thrive amidst the offshore vegetation and debris, in slow moving or stagnant waters and in old wells. The weed disrupts navigation, plugs grills at hydroelectric plants and interferes with fisheries by creating physical barriers and lowering the oxygen content and pH of the water. The species seriously interferes with crops through transpiration of water. Plants can float into paddy crops, take roots in the soil and competes with crop under shallow water conditions of the field. (Observations of participants of workshop on alien invasive species 17 September 1999).

The plant serves as a preferred host for mosquitoes, vectors of malaria, encephalomyelitis and rural filariasis. The Anopheles mosquito, which carries the parasite responsible for malaria, is frequently associated with P. stratiotes because the hydrophyte provides suitable shelter and breeding sites (Holm et al. 1977).

In Pakistan this species in ponds and reservoirs has been shown to cause the decay of native hydrophytes such as Hydrilla, Vallisneria, Najas, and Ceratophyllum species (Chokder, 1965,1968). However, its impacts are not as severe as the preceding species.

Control measures: Mechanical removal could be exercised in small scale infestations. Cretain insect species are known as biological control in various other countries.

Researchable aspects: Biological control of the weed.

9. Ipomoea carnea (Family: Convolvulaceae)

English name and Local name: Railway creeper

Origin: Tropical America

Description: A large robust shrub up to 2.5 m high much branched with hollow stems and ovate leaves. Flowers in terminal clusters, pink-purple, trumpet-shaped up to 70 cm across with a tube of almost same length.

History of introduction: Appears to be an old introduction of colonial era.

Affected areas and impacts: Distributed from plains to 900 m, but more abundant in southern Sindh, especially in the Indus delta; where due to its fast growth rate it is replacing indigenous species. At present apparently it has not become a major problem. However, being mainly a semi-aquatic species, it may have negative effects on wetlands.

Control measures: Where necessary the plants are being removed mechanically.

Researchable aspects: Studies on the biology including pollination and seed-dispersal mechanisms. Assessment of the impacts on indigenous biodiversity, soil and hydrology.

B. Invasive species in cultivated fields (i.e. alien weeds of agriculture)

10. Emex spinosa (Family: Polygonaceae)

English name: Prickly dock Local name: Kafir kanda

Origin: Mediterranean region.

History of introduction: It has been accidentally introduced recently from Afghanistan, Iran. It is spreading fast in Punjab, NWFP and Balochistan.

Affected areas and impacts: It is troublesome weed in the cooler parts of the country. It creates problem in harvesting the crop, reducing crop yield, blocking tracks, bursting vehicles tyres etc.

Control measures: It is difficult to control, herbicides also seem ineffective in controlling this weed.

Researchable aspects: Estimation of total magnitude of invasion, Control strategies.

11. Galium aparine (Family: Rubiaceae)

English name: Catchweed bedstraw Local name: Galium

Origin: It is a native of Europe.

Description: G. aparine is a decumbent, slender annual herb, stems weak four angled, jointed, smooth, with short downward-pointing, bristly hooks along the ridges; leaves in whorls of six to eight at a node, oblanceolate to linear; inflorescence a cyme; flowers perfect, axillary, in clusters of one to three on a peduncle; fruit burlike, prickly, covered with stiff bristles, composed of two spherical halves; seed warted with short spines with a deep pit on one side, 2-3 mm in diameter, gray brown ( From Holm et al, 1977).

History of introduction: Apparently an old introduction.

Affected areas and impacts: Widely distributed in Pakistan from plains to 12000 feet. It is a weed of agricultural importance. The small size of the seeds enhances their mixing with crop seeds; small hooks on the seed coat also provide a special mechanism for attachment to fur, bags and clothing, which help in transportation of the weed seeds from one to other place. It is troublesome weed in winter crops. It interferes with harvesting, encourages lodging, and sometimes smothers an entire crop. It is also considered alternate host of crop pests competes with crops for nutrients and water and result in decrease in crop yield.

Control measures: It is difficult to control this weed with herbicides. The soil treatment with herbicides may control some weeds in crops but increases G. aparine population. The use of phenoxy herbicides in cereals especially is a contributing factor in increase of seriousness of this weed (Observations of participants of workshop on alien invasive species, 17 September 1999, NARC). Preventive measures have been proposed for reducing its population in paddy fields, these include flooding of paddy fields, crop rotation, deep ploughing to bury seeds, use of straw mulch at germination time, application of systemic herbicides to soil before weeds emerge and application of contact herbicides after emergence of weed.( From Holm et al, 1977).

Researchable aspects: Biological control of the weed.

12. Xanthium strumarium (Family: Compositae)

English name: Cocklebur Local name: Puth kando

Origin: It is a New World species.

Description: This is a coarse erect branching annual herb; stems 30-150 cm tall tough, with short dark streaks or spots and covered with short hairs which give a coarse texture; leaves alternate-ovate to broadly ovate in shape, flowers monoecious, male flowers inconspicuous many flowered heads 5-8 mm across, clustered at the tips of branches or axillaries above the female flowers, female flower heads axillary, greenish, two flowers in the head enclosed by involucre; fruit hard brown, ovoid bur covered with hooked spines; seeds black two in each bur one above the other (From Holm et al, 1977).

History of introduction: Appear to be an old introduction. Now it is widely distributed in Pakistan from plains to 8000' in Sindh, Punjab, NWFP and Balochistan.

Affected areas and impacts: It is a serious weed in a number of crops in most parts of Pakistan. It is troublesome in harvesting crops. Presently its intensity of invasiveness is medium, but may increase in future.

It becomes a serious weed in rangelands, which have degenerated because of overgrazing, or drought, where desirable species have died or thinned out. In such areas the seeds, which are moved about by animals or water, germinate with the onset of rains and favorable weather to create pure stands. When the feed is short animals may feed on the germinating seedlings of Xanthium and become poisoned.

The burs lodge in wool, reduce the quality and require a special acid treatment for their removal.

Control measures: In Pakistan, generally mechanical removal is practised. Biological controls have been tried in some other countries. Epiblemma strenuana, a tortricid, of Mexico origin has been successfully introduced in Australia where it is reducing weed vigour and competitiveness.

Nupserha vexator , a cerambycid, of India origin has established in Austalia and is giving some control of the weed. A fungus, Puccinia xanthii of North American origin introduced accidentally in Australia is giving excellent control of the weed in wetter areas and weed is no longer a problem in most of Queensland, however, it is still a problem in drier areas (Julien, 1992).

Researchable aspects: Biological control of the weed.

13. Leucanea leucocephala (Family: Mimosaceae)

English name: Ipil Ipil ( as adopted locally)

Origin: A native of Central America.

Description: A large shrub or medium sized un-armed evergreen tree, bark greyish brown, slightly fissured , young shoots covered by tomentum. Leaves bipinnate, rachis 15-20 cm long, leaflets 10-17 pairs. Flowers in globose white heads, often in pairs, pod straight, flat, 12.5-20 cm long, seeds 15-25, 5.6 mm long and 4.5mm broad, oval, glaucous, dark brown, with a prominent U- shaped mark on either side.

History of introduction: Introduced here by the British about hundred years back.

Affected areas and impacts: Found in most parts of Pakistan, but more common in Punjab and NWFP. It is health hazardous for livestock, causes itching and gastrointestinal problems to those who feed on these. At present it has not caused a major problem, but its spread indicates that it will soon become a serious weed. It has the characterstics of invasive species like fast growth and high seed-production. It has now become self-sown in disturbed habitats, and spreading fast.

Control measures: Only mechanical removal of the plant is done and is burned for making charcoal

Researchable aspects: Ecology and biology of the plant and control strategies.

14. Lolium temulentum (Family: Gramineae)

English name: Darnel, Rye grass Local name: Dhanak

Origin: Mediterranean region.

Description: Annual, culms 20-120 cm high tufted or solitary, erector geniculate at the base, slender to moderately stout. Leaf blades 6-25 cm long 3-12 mm wide, spikes erect, 5-40cm long, lemmas elliptic to ovate 4.6-8.5 mm long smooth, obtuse, very turgid at maturity, awnlessor with awn up to 23 mm long (Cope, 1982). It is an annual herb having great resemblance with wheat, however, its leaves are dark green and more shining than wheat, crown and seeds are thinner. One plant can produce about 250 seeds.

History of introduction: Apparently an old introduction.

Affected areas and impacts: It is wide spread throughout Pakistan from plains to 2000 feet. It is a grain field winter weed. It is poisonous and toxic materials released by this plant affect the growth of other plants (Ashiq et al, 1996). At present its degree of invasiveness is medium, but could be the most dangerous weed in future.

Control measures: the farmers for controlling this weed use Herbicides.

Researchable aspects: IPM (Integrated Pest Management) strategies should be developed to minimize the use of herbicides.