 
Page 1 of 3
Impact Assessment Record
Scientific Name: Onopordum nervosum Boiss. Common name: cotton thistle
QUESTION
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COMMENTS
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RATING
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CONFIDENCE
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Social
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1. Restrict human access?
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No information about the extent of infestations of this plant was found.
|
M
|
L
|
2. Reduce tourism?
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Flowers purplish-pink on thorny plants (ENG, 2002) up to 2.7 m (Tutin, 1980) are likely to be very obvious to the average visitor and have a moderate visual effect. The density of infestations is not known so more serious impacts may be possible, but are not known.
|
M
|
L
|
3. Injurious to people?
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The stems are spinose-winged, ...and the involucral bracts spine-tipped (Tutin, 1980; ENG, 2002). Spines on the infloresence stems may cause some damage at most times of the year.
|
MH
|
MH
|
Abiotic
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5. Impact flow?
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Most species grow in rocky or stony ground, roadsides, waste places and similar dry, open habitats (Tutin, 1980). Terrrestrial species.
|
L
|
MH
|
6. Impact water quality?
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Most species grow in rocky or stony ground, roadsides, waste places and similar dry, open habitats (Tutin, 1980). Terrrestrial species.
|
L
|
MH
|
9. Change fire regime?
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Post senescence “stems can persist into the next season with spiny phyllaries and receptacles attached” (Healy, Enroe & DiTomaso, 2005). In dry, open habitats, where this plant invades (Tutin, 1980) this dried vegetation adds to the fuel load, most likely causing a moderate increase in the intensity of fires.
|
MH
|
MH
|
Community Habitat
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10. Impact on composition
(a) high value EVC
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EVC=Plains grassland (BCS = E) CMA=Mallee; Bioreg=Lowan Mallee; CLIMATE potential=VH. Species has potential to occur in high value EVC although impact on composition unknown. Score medium.
|
M
|
L
| -
medium value EVC
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EVC=Chenopod grassland (BCS = D) CMA=Mallee; Bioreg=Lowan Mallee; CLIMATE potential=VH. Species has potential to occur in medium value EVC although impact on composition unknown. Score medium.
|
M
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L
|
11. Impact on structure?
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No information was found about the density of infestations.
|
M
|
L
|
Page 2 of 3
Impact Assessment Record
Scientific Name: Onopordum nervosum Boiss. Common name: cotton thistle
QUESTION
|
COMMENTS
|
RATING
|
CONFIDENCE
|
12. Effect on threatened flora?
|
No information found.
|
MH
|
L
|
Fauna
|
13. Effect on threatened fauna?
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No information found.
|
MH
|
L
|
14. Effect on non- threatened fauna?
|
No information found.
|
MH
|
L
|
15. Benefits fauna?
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The structure of this spiny plant (as seen in BBG, 2006) is unlikely to provide harbour or food to desireable fauna species.
|
H
|
ML
|
16. Injurious to fauna?
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The stems are spinose-winged ... and the involucral bracts spine-tipped (Tutin, 1980). Spines on the infloresence and stems may cause some damage at most times of the year.
|
MH
|
MH
|
Pest Animal
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17. Food source to pests?
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The stems are spinose-winged ... and the involucral bracts spine-tipped (Tutin, 1980). Spines on the infloresence and stems would deter herbivory by vertebrate species.
|
L
|
MH
|
18. Provides harbor?
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The structure of this spiny plant (as seen in BBG, 2006) is unlikely to provide harbour to pest animals.
|
L
|
ML
|
Agriculture
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|
|
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19. Impact yield?
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No information about the invasiveness of this plant was found.
|
M
|
L
|
20. Impact quality?
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No information about the invasiveness of this plant was found.
|
M
|
L
|
21. Affect land value?
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No information about the invasiveness of this plant was found.
|
M
|
L
|
23. Increase harvest costs?
|
No information about the invasiveness of this plant was found.
|
M
|
L
|
24. Disease host/vector?
|
No information about disease host/vector of this plant was found, however there was very little information available about this species.
|
M
|
L
|
Page 3 of 3
Impact Assessment Record
Scientific Name: Onopordum nervosum Boiss. Common name: cotton thistle
References cited:
Briese DT, Sheppard AW & Reifenberg JM 1995, Open-field host-specificity testing for potential biological control agents of Onopordum thistles,’ Biological Control, Vol. 5, p. 158-166.
Bishop Burton Gardens (BBG) 2003, bishop Burton Gardens – Plant Selection, Bishop Burton Gardens Agricultural College, UK, viewed 07/03/2006, http://class.bishopbcollege.ac.uk/hortic.
Espacia Natural – Galeria (ENG) 2002, Espacio Natural, Spain, viewed: 07/03/2006, www.esapionatural.com/4images/img1598.htm
Healy, EA, Enloe, S & JM DiTomaso 2005, California Department of Food and Agriculture, USA, viewed: 06/12/2005, http://www.cdfa.ca.gov/phpps/ipc/weedinfo/onopordum.htm.
Tutin TG 1980, Flora Europaea, University Press, Cambridge
Revisions
Date Revised by Revision |