Alhagi maurorum Medik.

Title: Alhagi maurorum Medik.

Scientific Name:

Alhagi maurorum Medik.

Common Name:

camel thorn, Caspian manna

Source & more images (via ALA)

Habitat:

Subhumid and semi-arid temperate and subtropical regions - growing best in alkaline soils. Occurs as a weed in arid to semi-arid areas particularly where there is a high moisture level in the subsoil, and it also grows well under irrigation. It is found mostly in pastures and neglected areas.

Distribution:

Original source via CABI

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? “Seeds germinate in spring. Aerial growth dies in autumn and new shoots emerge from roots each spring.” “Seeds appear to need special conditions for germination, for example, in North America, seedlings are usually found only in bovine dung suggesting that scarification of the seed coat…may be necessary.” Established plants re-shoot from roots each spring. Requires natural seasonal disturbance for germination or root development., (Parsons and Cuthbertson, 2001).

2. Establishment requirements? “Seeds appear to need special conditions for germination.” It is found mostly in pastures and neglected areas and, in the northern parts of Victoria, is usually associated with irrigation. It is not documented to occur in undisturbed natural ecosystems, however, in the United States it is known to be abundant along riverbanks, canals and irrigation ditches., (Parsons & Cuthbertson, 2001).

3. How much disturbance is required? “Camelthorn has become a troublesome weed overseas in cereal and horticultural crops where repeated cultivation aids its spread.” Most commonly occurs in highly disturbed or neglected environments., (Parsons and Cuthbertson, 1992).

GROWTH / COMPETITIVE

4. Life form? “An erect perennial shrub.” A member of the Fabaceae family (legume), (Parsons and Cuthbertson, 1992).

5. Allelopathic properties? None documented.

6. Tolerates herb pressure? “Camelthorn is grazed…by cattle and sheep in the United States and Australia.” Consumed, but root system remains intact to produce new shoots., (Parsons and Cuthbertson, 1992).

7. Normal growth rate? “Seeds germinate in spring and rapid root growth ensures establishment ahead of most other species.” Rapid growth rate is likely to exceed most other species of same life form., (Parsons and Cuthbertson, 1992).

8. Stress tolerance to frost, drought, w/logg, sal. etc? “Plants are sensitive to low temperatures.” Will not withstand flooding for extended period (weeks). While there is no documented evidence of the plant’s ability to survive drought, its deep root system may ensure the plant endures through periods of drought., (Parsons & Cuthbertson, 2001).

REPRODUCTION

9. Reproductive system? Reproduces vegetatively and sexually, (Parsons and Cuthbertson, 2001).

10. Number of propagules produced? In the United States, “Flower production is high under hot, dry conditions (700–4,000 per plant). There are 5 to 8 seeds in the pod.” Plants could produce more than 2,000 seeds annually, (SWEPIC).

11. Propagule longevity? “Seed viability in semi-arid soils may extend over a number of years.”
“Seeds remain viable for many years.” >25% of seed survive 5–10 years. include other propagule material e.g. roots increase from ML to MH, (SWEPIC ;Parsons & Cuthbertson, 2001).

12. Reproductive period? A perennial shrub with an extensive and vigorous root system. “It is strongly competitive with other plants and, in the Merbein infestation, has eliminated most other vegetation.” Long-lived, by does not establish as a monoculture, (Parsons & Cuthbertson, 2001).

13. Time to reproductive maturity? “Plants generally do not flower until they are 1 year old.” Propagules produced after 1 year, (Parsons & Cuthbertson, 2001).

DISPERSAL

14. Number of mechanisms? “Camelthorn is grazed…cattle and sheep in the United States and Australia.” Cultivation equipment can also spread root fragments, (Parsons & Cuthbertson, 2001).

15. How far do they disperse? Cattle and sheep graze the plant, and machinery may spread propagules. These vectors could spread the plant by more than 200 metres from infestation, (Parsons & Cuthbertson, 2001).

Impact Assessment

RECREATION

1. Restrict human access? Erect perennial shrub 40 to 100 cm high with rigid, much branched stems bearing numerous sharp spines 1.0 to 2.5 cm long. The spines can puncture human skin and break off in the wound. Dense infestations would restrict human access, (P & C, 2001; Geoff Tyers pers coms).

2. Reduce tourism? The size and spiny nature of the plant may reduce some recreational activities, (P & C, 2001).

3. Injurious to people? Woody stems remain after the plant dies back in autumn. Spines present for most of the year. The spines can break off in the skin, (P & C, 2001 ; Geoff Tyers ; CDFA)

4. Damage to cultural sites? The plant has an extensive and vigorous root system. In north-western Victoria “…shoots regularly break through a sealed bitumen road and the roots have extended the patch by a distance of about 6 metres.” It has the potential to cause serious structural damage to cultural sites, (P & C, 2001).

ABIOTIC

5. Impact flow? Terrestrial species. (Parsons and Cuthbertson, 2001)

6. Impact water quality? Terrestrial species. (Parsons and Cuthbertson, 2001)

7. Increase soil erosion? The aerial parts of the plant die back in autumn leaving the soil surface exposed in dense infestations. The extensive and deep root system (2 m deep and 8 m laterally), provide good soil stability. Potential for low probability of large scale soil movement, (P & C, 2001).

8. Reduce biomass? In Australia, it is found in pastures and neglected areas. Likely to replace existing biomass, (P & C, 2001).

9. Change fire regime? “Woody tissues persist after plant death.” Increase fuel load is likely to increase frequency of fire risk, (CDFA).

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? EVC=Plains grassland; CMA=North Central; Bioreg=Victorian Riverina; VH CLIMATE potential. “It is found mostly in pastures and neglected areas. It is strongly competitive with other plants. In Merbein [Victoria]…it has eliminated most other vegetation.” Major displacement of grasses/forbs., (P & C, 2001).

10(b) Impact on medium value EVC? “It is found mostly in pastures and neglected areas.” Requires pH>6. Unlikely to occur in any medium value EVC in Victoria, (P & C, 2001).

10(c) Impact on low value EVC? “It is found mostly in pastures and neglected areas.” Requires pH>6. Unlikely to occur in any low value EVC in Victoria, (P & C, 2001).

11. Impact on structure? “It is strongly competitive with other plants and, in the Merbein infestation, has eliminated most other vegetation.” Is found mostly in pastures and neglected areas. Likely to have a major impact on the lower strata, (P & C, 2001).

12. Effect on threatened flora? None documented

FAUNA

13. Effect on threatened fauna? This species is not documented as posing an additional risk to threatened fauna.

14. Effect on non-threatened fauna? In Australia, cattle and sheep graze the plant. However, it is also unpalatable and injurious to some animals. A competitive plant, it may impact on the habitat of native fauna, (P & C, 2001 ; WSNWCB).

15. Benefits fauna? Cattle and sheep graze the plant. It may be a limited food source for some species, (P & C ,2001).

16. Injurious to fauna? It is injurious to some animals. The spines are present for much of the year, (WSNWCB).

PEST ANIMAL

17. Food source to pests? “The plant is confined to the northern parts of Victoria usually associated with irrigation.” Rabbits are known to occur in this area and the plant may provide some limited food, (P & C, 2001).

18. Provides harbor? Dense patches may provide limited harbor for rabbits. , (P & C, 2001).

AGRICULTURE

19. Impact yield? Overseas, it is a troublesome weed in cereal and horticultural crops where repeated cultivation aids its spread. It has an extensive root system and strongly competes with other plants. Likely to have serious impacts on yield, (Parsons and Cuthbertson, 2001).

20. Impact quality? No documented impact on quality. In the United States the plant is a potential alfalfa seed contaminant, (WSNWCB).

21. Affect land values? Where it occurs in pasture situations it is unlikely to affect land value. Sheep and cattle graze the plant without apparent harm (from the spines), (P & C, 2001).

22. Change land use? In cropping situations cultivation spreads the weed and may increase shoot density. Land use would have to change until the plant was controlled. Change from cropping to permanent pasture, (CDFA).

23. Increase harvest costs? No evidence

24. Disease host/vector? No evidence

Feedback

Do you have additional information about this plant that will improve the quality of the assessment? If so, we would value your contribution.

Assessment ratings originally made by the Victorian Department of Primary Industries.

The entry of this assessment was made possible through the generous support of The Weed's Network.

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referenced by (2)

wra997: Common Name - C (via Caspian manna)wra997: Common Name - C (via camelthorn)

Article: wra1572 (permalink)
Categories: :wra:a, :wra:inv1, :wra:invmh, :wra:inv2, :wra:invm, :wra:inv3, :wra:invml, :wra:inv4, :wra:inv5, :wra:invl, :wra:inv6, :wra:inv7, :wra:invh, :wra:inv8, :wra:inv9, :wra:inv10, :wra:inv11, :wra:inv12, :wra:inv13, :wra:inv14, :wra:inv15, :wra:imp1, :wra:impmh, :wra:imp2, :wra:imp3, :wra:imph, :wra:imp4, :wra:imp5, :wra:impl, :wra:imp6, :wra:imp7, :wra:imp8, :wra:impml, :wra:imp9, :wra:imp10a, :wra:imp10b, :wra:imp10c, :wra:imp11, :wra:imp12, :wra:impm, :wra:imp13, :wra:imp14, :wra:imp15, :wra:imp16, :wra:imp17, :wra:imp18, :wra:imp19, :wra:imp20, :wra:imp21, :wra:imp22, :wra:imp23, :wra:imp24
Date: 5 October 2009; 2:49:40 PM AEDT

Author Name: Niharika Anand
Author ID: anandn