Plant Assessment Form

Carduus acanthoides

Synonyms: Carduus fortior

Common Names: plumeless thistle; bristly thistle; giant plumeless thistle; spiny thistle

Evaluated on: 1/19/05

List committee review date: 08/07/2005

Re-evaluation date:

Evaluator(s)

Gina Skurka
CDFA
1220 N Street, Sacramento, CA 95814
(916) 654-0768
gskurka@cdfa.ca.gov
Joseph DiTomaso
University of California-Davis
Dept. Plant Sci., Mail Stop 4, Davis, CA 95616
530-754-8715
jmditomaso@ucdavis.edu

List commitee members

Carla Bossard
John Randall
Carri Pirosko
Dan Gluesenkamp
Gina Skurka
Brianna Richardson

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? Limited
Alert Status? No Alert
Documentation? 3 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes C Reviewed Scientific Publication
Impact?
Four-part score CBBD Total Score
B
1.2 ?Impact on plant community B. Moderate Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels B. Moderate Other Published Material
1.4 ?Impact on genetic integrity D. None Other Published Material
2.1 ?Role of anthropogenic and natural disturbance in establishment C. Minor Reviewed Scientific Publication
Invasiveness?
Total Points
8 Total Score C
2.2 ?Local rate of spread with no management D. Declining
2.3 ?Recent trend in total area infested within state C. Stable Observational
2.4 ?Innate reproductive potential
(see Worksheet A)
A. High Other Published Material
2.5 ?Potential for human-caused dispersal C. Low Observational
2.6 ? Potential for natural long-distance dispersal C. Rare Reviewed Scientific Publication
2.7 ?Other regions invaded C. Already invaded Other Published Material
3.1 ?Ecological amplitude/Range
(see Worksheet C)
B. Moderate Other Published Material
Distribution?
Total Score C
3.2 ?Distribution/Peak frequency
(see Worksheet C)
D. Very low Observational

Table 3. Documentation

Scores are explained in the "Criteria for Categorizing Invasive Non-Native Plants that Threaten Wildlands".

Section 1: Impact
Question 1.1 Impact on abiotic ecosystem processes? C Reviewed Scientific Publication
Identify ecosystem processes impacted:

Possesses taproots that are generally long, thick, fleshy, occasionally branched, and capable of penetrating the soil to depths of 40 cm or more. Minor alteration of ecosystem processes, such as soil water table.


Sources of information:

Desrochers, A.M, J.F. Bain, and S.I. Warwick. 1988. The Biology of Canadian weeds. 89. Carduus nutansL. and Carduus acanthoides L. Can. J. Plant Sci. 68: 1053-1068.


Question 1.2 Impact on plant community composition,
structure, and interactions?
B Reviewed Scientific Publication
Identify type of impact or alteration:

Compete with desirable plants, reducing forage production. Moderate alteration of plant community by reduction in survivorship of native species.


Sources of information:

Roche, C. Weeds. A Pacific Northwest Extension Publication. December 1992.
Desrochers, A.M., J.F. Bain, and S.I. Warwick. The Biology of Canadian Weeds. 89. Carduus nutans L. and Carduus acanthoides L., Canadian Journal of Plant Science. 68: 1053-1068, October 1988.


Question 1.3 Impact on higher trophic levels? B Other Published Material
Identify type of impact or alteration:

Spiny leaves and stems hinder live-stock form grazing forage growing near them. Resumable they would do the same with wildlife. As they invade natural vegetation in parks and along roads, their spiny presence may restrict recreational activities. Minor alterations of higher trophic level populations, communities or interactions by minor reduction in foraging sites as livestock and wildlife avoid it.


Sources of information:

Roche, C. Weeds. A Pacific Northwest Extension Publication. December 1992.


Question 1.4 Impact on genetic integrity? D Other Published Material

Plumeless thistle and musk thistle, C. nutans, readily hybridize with one another, and plants with intermediate characteristics may be found where their ranges overlap. Insect-pollinated. No known hybridization with natives.


Sources of information:

DiTomaso, J and E. Healy. Weeds of CA and other Western States. Unpublished.
Roche, C. Weeds. A Pacific Northwest Extension Publication. December 1992.


Section 2: Invasiveness
Question 2.1 Role of anthropogenic and natural disturbance
in establishment?
D
Describe role of disturbance:

In general, thistles compete poorly with healthy, established grasses and other vegetation. Disturbances such as fire, overgrazing, or trampling can create prime sites for thistle colonization. Activities that disturb the soil, weaken competitive vegetation, and allow light to the soil surface speed thistle invasion and thicken thistle stands. This species is primarily restricted to highly disturbed or degraded areas. Old fields, stock ponds, and ditch berms are areas usually infested. Restoration fields can become infested with this thistle due to disturbance from discing, which exposes mineral soil and works up existing seeds.


Sources of information:

Desrochers, A.M, J.F. Bain, and S.I. Warwick. 1988. The Biology of Canadian weeds. 89. Carduus nutansL. and Carduus acanthoides L. Can. J. Plant Sci. 68: 1053-1068.
The Nature Conservancy Weed Report for Carduus acanthoides, Tall grass prarie preserves, August 25, 1999.


Question 2.2 Local rate of spread with no management? D
Describe rate of spread:

Populations in California are not often encountered. All known populations are currently being managed.


Sources of information:

Question 2.3 Recent trend in total area infested within state? C Observational
Describe trend:

Only seems to be a couple of small populations in the state. Often controlled by CDFA.


Sources of information:

DiTomaso, observational.


Question 2.4 Innate reproductive potential? A Other Published Material
Describe key reproductive characteristics:

Insect-pollinated. Primarily out-crossing, but self-compatible. Reproduce by seed. First flowerheads can produce large numbers of seeds, sometimes 1500 or more seeds per head. Late flowerheads produce fewer seeds, to less than 25 seeds per head.


Sources of information:

DiTomaso, J and E. Healy. Weeds of CA and other Western States. Unpublished.


Question 2.5 Potential for human-caused dispersal? C Observational
Identify dispersal mechanisms:

Little opportunity to disperse long distances by human activities.


Sources of information:

DiTomaso, observational


Question 2.6 Potential for natural long-distance dispersal? C Reviewed Scientific Publication
Identify dispersal mechanisms:

Seeds fall near the parent plant and disperse to greater distances with wind, water, birds, small mammals, and human activities. Achenes are mainly dispersed by wind and fall near the parent plant (within 50 m) with less than 1% being carried further than 100 m.


Sources of information:

DiTomaso, J and E. Healy. Weeds of CA and other Western States. Unpublished.
Desrochers, A.M., J.F. Bain, and S.L. Warwick. 1988. The Biology of Canadian Weeds: Carduus nutans L. Carduus acanthoides. Canadian Journal of Plant Science. 68:1053-1068.


Question 2.7 Other regions invaded? C Other Published Material
Identify other regions:

Present in the northeast, the Great Plains states, and Texas.Plumeless thistle is a state-listed noxious weed in Arizona, California, Colorado, Washington, Wyoming, and a few central and eastern states.


Sources of information:

USDA, NRCS. 2005. The PLANTS Database, Version 3.5 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.


Section 3: Distribution
Question 3.1 Ecological amplitude/Range? B Other Published Material

Thistles typically colonize disturbed open sites, roadsides, pastures, annual grasslands, and waste areas. Eastern North Coast Ranges (se Humboldt, cw Trinity, w Glenn, ne Lake, e Colusa cos.), northern Sierra Nevada (w Nevada Co.), Modoc Plateau (ce Modoc Co.), San Francisco Bay region (nw Marin Co.), to 1300 m.


Sources of information:

DiTomaso and Healy. 2006. Weeds of California. UC DANR Publ. #3488.
DiTomaso, J and E. Healy. Weeds of CA and other Western States. Unpublished. Date?


Question 3.2 Distribution/Peak frequency? D Observational
Describe distribution:

Very uncommon in the state.


Sources of information:

DiTomaso, observational.


Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less Yes
Dense infestations produce >1,000 viable seed per square meter Yes
Populations of this species produce seeds every year. Yes
Seed production sustained over 3 or more months within a population annually Yes
Seeds remain viable in soil for three or more years Yes
Viable seed produced with both self-pollination and cross-pollination Unknown
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes No
Fragments easily and fragments can become established elsewhere No
Resprouts readily when cut, grazed, or burned Unknown
Total points: 7
Total unknowns: 2
Total score: A?

Related traits:

Worksheet B - Arizona Ecological Types is not included here

Worksheet C - California Ecological Types

(sensu Holland 1986)
Major Ecological Types Minor Ecological Types Code?
Marine Systemsmarine systems
Freshwater and Estuarine lakes, ponds, reservoirs
Aquatic Systemsrivers, streams, canals
estuaries
Dunescoastal
desert
interior
Scrub and Chaparralcoastal bluff scrub
coastal scrubD, < 5%
Sonoran desert scrub
Mojavean desert scrub (incl. Joshua tree woodland)
Great Basin scrub
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
chaparral
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairie
valley and foothill grasslandD, < 5%
Great Basin grassland
vernal pool
meadow and seep
alkali playa
pebble plain
Bog and Marshbog and fen
marsh and swamp
Riparian and Bottomland habitatriparian forest
riparian woodland
riparian scrub (incl.desert washes)
Woodlandcismontane woodland
piñon and juniper woodland
Sonoran thorn woodland
Forestbroadleaved upland forest
North Coast coniferous forest
closed cone coniferous forest
lower montane coniferous forest
upper montane coniferous forest
subalpine coniferous forest
Alpine Habitatsalpine boulder and rock field
alpine dwarf scrub
Amplitude (breadth): B
Distribution (highest score): D

Infested Jepson Regions

Click here for a map of Jepson regions

  • Central West
  • Modoc Plateau
  • Northwest
  • Sierra Nevada