Plumeless thistle (Carduus acanthoides)

Present distribution

Scientific name:	Carduus acanthoides L
Common name(s):	Plumeless thistle

This weed is not known to be naturalised in Victoria

Habitat:

The native distribution of plumeless thistle is Europe and Asia. It is very common in eastern parts of Europe, but absent from most of southwestern and northern Europe (http://www.invasive.org/eastern/biocontrol/21PlumelessThistle.html). The species establishes in pastures, rangelands, croplands, highway verges, prefers fertile soil over limestone, but is highly adaptable and can even grow in shallow soil, emerging from stone quarries. Typically, plumeless thistle inhabits pastures, stream valleys, fields, roadsides, and disturbed areas (http://www.agdepartment.com/noxiousweeds/pdf/Plumelessthistle.pdf).

Potential distribution

Potential distribution produced from CLIMATE modelling refined by applying suitable landuse and vegetation type overlays with CMA boundaries

Map Overlays Used

Land Use:
Horticulture perennial; horticulture seasonal; pasture dryland; pasture irrigation; water

Ecological Vegetation Divisions
Riparian; granitic hillslopes; basalt grassland; alluvial plains grassland; semi arid Woodland (non-eucalypt); riverine woodland/forest

Colours indicate possibility of Carduus acanthoides infesting these areas.

In the non-coloured areas the plant is unlikely to establish as the climate, soil or landuse is not presently suitable.

Map showing the potential distribution of the plumeless thistle

Red= Very high	Orange = Medium
Yellow = High	Green = Likely

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	Carduus acanthoides stands of 90,000 plants per ha were observed in permanent pasture in southern Ontario and parts of Quebec. Such dense infestations are not uncommon in the United States (Desrochers et al., 1988) The stem is erect, branched, and has spiny wings. The plant is 20 to 150 cm tall (Fig. 2). Leaves are hairy on the undersides and are narrower, more deeply lobed, and finely divided than those of C. nutans. (Biological Control of Invasive Plants in the Eastern United States 2002)	mh	mh
2. Reduce tourism?	Nodding and Plumeless Thistles share many of the same features and are commonly mistaken for one another. However, any confusion between the two is unimportant because both are troublesome plants that require the same control measures. Both thistles are extremely invasive pasture plants. They will grow in most soil types and, owing to the mixed age and size of the plants, are difficult and costly to control. If not controlled, the thistles form dense stands that suppress pasture and obstruct livestock movement. (Pest Management Strategy for Taranaki: Plants 2007)	mh	mh
3. Injurious to people?	Thistle fragments and spines may also injure livestock, damage the fleeces or hides of livestock, and may cause scabby mouth in lambs. (Pest Management Strategy for Taranaki: Plants 2007)	mh	mh
4. Damage to cultural sites?	Carduus acanthoides stands of 90,000 plants per ha were observed in permanent pasture in southern Ontario and parts of Quebec. Such dense infestations are not uncommon in the United States (Desrochers et al., 1988)	ml	mh
Abiotic
5. Impact flow?	Typically, plumeless thistle inhabits pastures, stream valleys, fields, roadsides, and disturbed areas. (North Dakota Department of Agriculture 2008)	l	mh
6. Impact water quality?	Typically, plumeless thistle inhabits pastures, stream valleys, fields, roadsides, and disturbed areas. (North Dakota Department of Agriculture 2008)	l	mh
7. Increase soil erosion?	Hybridization between C. acanthoides and C. nutans has been reported (referred to as C. x orthocephalus Wallr.). Flowers of the hybrids are larger than the typical capitula of plumeless thistle, but smaller than capitula of musk thistle (Kok, unpub.). Literature on plumeless thistle is much less extensive than that for musk thistle, but the biology, ecology, history, introduction, and control of both thistles are quite similar. However, plumeless thistle is more tolerant of herbicides and requires a higher rate of application. (Biological Control of Invasive Plants in the Eastern United States 2002) Musk thistle is an early successional species that establishes well on open, disturbed sites. Musk thistle was part of the earliest postfire successional stage in pinyon-juniper communities in Colorado. On a pinyon-juniper site in central Utah that was chained to remove trees and seeded with a grass/forb/shrub mix, musk thistle density increased dramatically over the 3 years following treatment.( Zouhar, Kris. 2002 FEIS) Just like musk thistle, livestock avoid it. Selective grazing and the indirect effects of herbicides used for its control result in bare ground that is ideal for its seed germination the following season. (Biological Control of Invasive Plants in the Eastern United States 2002)	ml	mh
8. Reduce biomass?	Musk thistle is an early successional species that establishes well on open, disturbed sites. Musk thistle was part of the earliest postfire successional stage in pinyon-juniper communities in Colorado. On a pinyon-juniper site in central Utah that was chained to remove trees and seeded with a grass/forb/shrub mix, musk thistle density increased dramatically over the 3 years following treatment.( Zouhar, Kris. 2002 FEIS)	l	mh
9. Change fire regime?	Effects of musk thistle on native fire regimes in temperate grasslands are unknown and research is needed in this area ( Zouhar, Kris. 2002 FEIS)	m	l
Community Habitat
10. Impact on composition (a) high value EVC	Musk thistle may also threaten rare or sensitive species, such as the Mescalero thistle (Cirsium vinaceum) in New Mexico, by crowding into populations.( Zouhar, Kris. 2002 FEIS ) EVC = Valley grassy forest (E); CMA = North East; Bioregion = Northern fall; H CLIMATE potential.	mh	mh
(b) medium value EVC	Musk thistle may also threaten rare or sensitive species, such as the Mescalero thistle (Cirsium vinaceum) in New Mexico, by crowding into populations.( Zouhar, Kris. 2002 FEIS ) EVC = Montane grassy woodland (D); CMA = North East; Bioregion = Highlands Northern fall; H CLIMATE potential.	MH	mh
(c) low value EVC	Musk thistle may also threaten rare or sensitive species, such as the Mescalero thistle (Cirsium vinaceum) in New Mexico, by crowding into populations.( Zouhar, Kris. 2002 FEIS ) EVC = Riparian forest (LC); CMA = East Gippsland; Bioregion = Highlands Southern fall; H CLIMATE potential.	mh	mh
11. Impact on structure?	Carduus acanthoides stands of 90,000 plants per ha were observed in permanent pasture in southern Ontario and parts of Quebec. Such dense infestations are not uncommon in the United States (Desrochers et al., 1988)	mh	mh
12. Effect on threatened flora?	Musk thistle may also threaten rare or sensitive species, such as the Mescalero thistle (Cirsium vinaceum) in New Mexico, by crowding into populations.( Zouhar, Kris. 2002 FEIS)	ml	mh
Fauna
13. Effect on threatened fauna?	It is unpalatable to livestock. Grazing animals focus on native vegetation, giving thistles a competitive advantage. Spiny plumeless thistle can become weedy and form dense colonies. (USFD Northeastern Area, Invasive plants 2008)	ml	mh
14. Effect on non-threatened fauna?	It is unpalatable to livestock. Grazing animals focus on native vegetation, giving thistles a competitive advantage. Spiny plumeless thistle can become weedy and form dense colonies. (USFD Northeastern Area, Invasive plants 2008)	ml	mh
15. Benefits fauna?	No Information	m	l
16. Injurious to fauna?	If not controlled, the thistles form dense stands that suppress pasture and obstruct livestock movement. Thistle fragments and spines may also injure livestock, damage the fleeces or hides of livestock, and may cause .scabby mouth. in lambs.( Pest Management Strategy for Taranaki:Plants 2007)	mh	mh
Pest Animal
17. Food source to pests?	Livestock rarely eat musk thistle foliage; however, cattle and domestic sheep and goats have been observed consuming flowers and seedheads. It is unclear whether this results in musk thistle seed dispersal. A number of species of birds also graze on mature musk thistle seed in Australia. Dense infestations of the plant discourage animals from occupying that portion of the field in which it grows (Zouhar, Kris. 2002 FEIS)	ml	mh
18. Provides harbor?	Carduus acanthoides stands of 90,000 plants per ha were observed in permanent pasture in southern Ontario and parts of Quebec. Such dense infestations are not uncommon in the United States (Desrochers et al., 1988) Capacity to provide harbor and permanent warrens for foxes and rabbits throughout the year.	mh	m
Agriculture
19. Impact yield?	A review by Rees and others suggests that 1 musk thistle plant per 16 square feet (1.5 m²) can reduce forage production by 23%. (Zouhar, Kris. 2002 FEIS)	h	mh
20. Impact quality?	Not found in cropping	l	mh
21. Affect land value?	Infestations of plumeless thistle reduce productivity of pastures and rangeland by suppressing growth of desirable vegetation and preventing livestock from eating plants growing in the vicinity of thistle stands (Desrochers et al., 1988).	ml	m
22. Change land use?	No Info	m	l
23. Increase harvest costs?	No documentation is available of the effect of plumeless thistles in agricultural crops because such areas are usually plowed under during cultivation. (Biological Control of Invasive Plants in the Eastern United States 2002)	l	mh
24. Disease host/vector?	No Info	m	l

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Germination occurs mainly in the spring and fall, with resulting plants acting either as winter annuals or as spring or fall biennials (Desrochers et al., 1988).	mh	mh
2. Establishment requirements?	Seedlings usually establish only on bare soil and grow less when shaded by neighbouring plants Seedlings require open microsites for establishment and are sensitive to summer droughts. ( Zouhar, Kris. 2002 FEIS) Musk thistle does not appear to have any specific climatic requirements other than a cool period of vernalization for flowering (Butterfield et al. 1996). Typically, plumeless thistle inhabits pastures, stream valleys, fields, roadsides, and disturbed areas. (North Dakota Department of Agriculture 2008)	ml	mh
3. How much disturbance is required?	Seedlings require open microsites for establishment and are sensitive to summer droughts (Medd & Lovett 1978; Wardle, Nicholson & Rahman 1992). Carduus acanthoides and Carduus nutans L. in the northeastern United States often occupy the same habitats, such as overgrazed pastures and disturbed roadsides, and these species sometimes occur as mixed stands. (Biological Control of Invasive Plants in the Eastern United States 2002)	ml	mh
Growth/Competitive
4. Life form?	Carduus acanthoides is an annual or biennial, reproducing by seed. (Biological Control of Invasive Plants in the Eastern United States 2002)	ml	mh
5. Allelopathic properties?	Researchers have found some evidence of allelopathy in musk thistle. Aqueous extracts, leachates, and ground plant material from musk thistle all showed some inhibition of germination and radicle growth rate of several pasture species. Additionally, growth of musk thistle seedlings appears to be stimulated by adding musk thistle tissue to the soil. Musk thistle may thus stimulate recruitment of its own kind as it invades.( Zouhar, Kris. 2002 FEIS)	mh	mh
6. Tolerates herb pressure?	As thistles are not subjected to grazing or other stress, they easily outcompete forage grasses to become the dominant vegetation in areas where they have become established. In time, they can spread to dominate entire fields (Kok, unpub.).	h	mh
7. Normal growth rate?	No info found	m	l
8. Stress tolerance to frost, drought, w/logg, sal. etc?	Plumeless thistle tends to occupy drier, better-drained sites than C. nutans within the same pasture. It overwinters either as seeds or rosettes. Musk thistle does not appear to have any specific climatic requirements other than a cool period of vernalization for flowering (Butterfield et al. 1996). It occurs in areas with as little as 10” of annual precipitation (FEIS 1996)	ml	mh
Reproduction
9. Reproductive system	Sexual, Plumeless thistle reproduces solely through seed production.. (North Dakota Department of Agriculture 2008)	l	mh
10. Number of propagules produced?	Plants reproduce by seeds that can remain viable for 10 years in the soil. (USFD Northeastern Area, Invasive plants 2008) First flower heads produce up to 1500 seeds, with later flower heads producing only about 25. 99 percent of seeds fall within 150 feet of the adult plant, and are viable for a short time. (USDF, Tonto National Forest) A typical plant produces 35 to 60 capitula. Mean seed et averages 56 to 83 seeds per seed head for C. acanthoides (Biological Control of Invasive Plants in the Eastern United States 2002)	h	mh
11. Propagule longevity?	Plants reproduce by seeds that can remain viable for 10 years in the soil. (USFD Northeastern Area, Invasive plants 2008)	ml	mh
12. Reproductive period?	Carduus acanthoides is an annual or biennial, reproducing by seed. (Biological Control of Invasive Plants in the Eastern United States 2002)	l	mh
13. Time to reproductive maturity?	Germination occurs mainly in the spring and fall, with resulting plants acting either as winter annuals or as spring or fall biennials (Desrochers et al., 1988).	h	mh
Dispersal
14. Number of mechanisms?	Plumeless thistle reproduces solely through seed production. (North Dakota Department of Agriculture 2008)	mh	mh
15. How far do they disperse?	For the different wind velocities tested (upto 5.6 m/s) less than 1% of seed were blown further than 100m. (Smith. L. M 1984)	l	mh

References

Biological Control of Invasive Plants in the Eastern United States 2002, Available at http://www.invasive.org/eastern/biocontrol/21PlumelessThistle.html (verified 15/4/2008)

Pest Management Strategy for Taranaki: Plants 2007 Available at http://www.trc.govt.nz/environment/plants/pdf/plants.pdf (verified 15/4/2008)

North Dakota Department of Agriculture (NDDofA), Invasive Species Web-Based Manual/ plumeless thistle. Available at http://www.agdepartment.com/noxiousweeds/pdf/Plumelessthistle.pdf (verified 15/4/2008)

Desrochers, A. M., J. F. Bain, and S. I. Warwick. 1988. The biology of Canadian weeds. 89. Carduus nutans L. and Carduus acanthoides L. Canadian Journal of Plant Science 68: 1053-1068.

Butterfield, C., J. Stubbendieck, and J. Stumpf. 1996. Species abstracts of highly disruptive exotic plants. Jamestown, ND: Northern Prairie Wildlife Research Center Home Page. Available at: http://www.npwrc.usgs.gov/resource/othrdata/exoticab/exoticab.htm (Version 16 Jul 97).

Medd, R. W.; Lovett, J. V. 1978. Biological studies of Carduus nutans (L.) ssp. nutans. I. Germination and light requirement of seedlings. Weed Research. 18: 363-367

Wardle, D. A.; Nicholson, K. S.; Rahman, A. 1992. Influence of pasture grass and legume swards on seedling emergence and growth of Carduus nutans L. and Cirsium vulgare. Weed Research. 32(2): 119-128

Smith, Lane M., II; Kok, L. T. 1984. Dispersal of musk thistle (Carduus nutans) seeds. Weed Science. 32: 120-125.

US Forestry service (USFD) Northeastern Area, Invasive plants – Weeds of the week, Spiny plumless thistle (http://www.na.fs.fed.us/fhp/invasive_plants/weeds/spiny-plumeless-thistle.pdf) (verified 15/4/2008)

US Forestry service (USFD) Tonto National forest , Invasive plants – plumless thistle Available at (www.fs.fed.us/r3/tonto/naturalResources/Invasive-Weeds/weeds/iw_plumeless_thistle.shtml) (verified 15/4/2008)

Zouhar, Kris. 2002. Carduus nutans. In: Fire Effects Information System (FEIS), [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis [2008, April 15].

Global present distribution data references

Australian National Herbarium (ANH) (2008) Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, Available at http://www.anbg.gov.au/avh/ (verified 15/4/2008).

Calflora: Information on California plants for education, research and conservation. [web application]. (2008) Berkeley, California: The Calflora Database [a non-profit organization]. Available at http://www.calflora.org/ (verified 15/4/2008)

Department of Sustainability and Environment (DSE) (2006) Flora information system [CD-ROM], Biodiversity and Natural Resources Section, Viridans Pty Ltd, Bentleigh.

Global Biodiversity Information Facility (GBIF) (2008) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 15/4/2008)

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