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  • Centaurea biebersteinii flower (Photo: Norman E. Rees, USDA ARS, www.forestryimages.org)
  • Centaurea biebersteinii plant (Photo: University of Idaho Archives, University of Idaho, www.forestryimages.org)
  • Centaurea biebersteinii plant (Photo: Linda Wilson, University of Idaho, www.forestryimages.org)
  • Centaurea biebersteinii stand (Photo: Norman E. Rees, USDA ARS, www.forestryimages.org)
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Common name
gefleckte Flockenblume (German), spotted knapweed (English), gewöhnliche Rispen-Flockenblume (German)
Synonym
Centaurea maculosa , auct. non Lam.
Acosta maculosa , auct. non Holub
Similar species
Acroptilon repens, Centaurea diffusa, Centaurea jacea, Centaurea nigra, Centaurea nigrescens, Centaurea trichocephala
Summary
Centaurea biebersteinii is a biennial or short-lived perennial composite and a very aggressive invader. It has been reported to grow on a wide variety of habitats, especially industrial land, including gravel pits, stockpiles, power lines, grain elevators, railroad, equipment yards, pasture, range, and timbered range. It is often associated with irrigation, preferring areas of high available moisture. It appears best adapted to well-drained, light- to coarse-textured soils that receive summer rainfall. Seeds may germinate over a wide range of soil depths, soil moisture content and temperatures. Dispersal is generally passive as seeds are shaken from drying capitula. Movement over greater distances requires transport by rodents, livestock, vehicles, or hay or commercial seed.
Species Description
Mauer et al. (1987) report that Centaurea biebersteinii is a biennial or short-lived perennial composite with a stout taproot. It has 1-20 slender, upright stems, 3-10 dm tall, most branching in the upper half. Seedling leaves form a rosette; stem leaves are canescent (gray-coloured, pubescent), the lower once or twice pinnately divided into linear or lanceolate lobes on each side of center vein, tapered at both ends, the broadest part above the middle to 10cm long and 3cm wide; the upper with fewer lobes or entire, becoming smaller up the stem to less than 1cm long. Heads are solitary, terminal, egg-shaped to oblong, 1.5-2.5cm broad and 1.3cm tall. The involucre (whorl of small bracts beneath the flower) is pale and 1-1.4cm high. Phyllaries (individual bracts of the involucre) are not spiny but have obvious veins, the lower and middle bracts egg-shaped, green to brown, all with a dark, pectinate tip and the upper margin fringed with 5-7 pairs of cilia. The slender, tubular flowers are whitish to pink or purplish; the marginal florets somewhat enlarged. Seeds are oval, brown to black with pale lengthwise lines; the pappus (bristly, feathery, or fluffy whorl crowning the ovary) is copious and whitish.
Notes
Zouhar (2001) reports that the scientific name for spotted knapweed is Centaurea stoebe L. ssp. micranthos. In North America, the name Centaurea maculosa has been misapplied to Centaurea stoebe ssp. micranthos, which is a polycarpic, perennial tetraploid that originated in eastern Europe. C. maculosa is a monocarpic, biennial diploid from central Europe. As of 2001, C. maculosa does not occur in North America. There is evidence of hybridisation between spotted and diffuse knapweed (Centaurea diffusa) in at least 7 U.S. states. The hybrid is named Centaurea × psammogena Gayer. VDCR / VNPS (Undated) states that spotted knapweed has been renamed by plant taxonomists and is now known as Centaurea bierbersteinii DC.
Lifecycle Stages
Zouhar (2001) states that seeds germinate when moisture and temperature conditions are suitable. Temperatures for germination range from 45 to 93 degrees Fahrenheit (7-34 °C), and germination is optimal at 66 degrees Fahrenheit (19 °C). Seeds require at least 55% soil moisture to initiate emergence. Germination increases with increased soil moisture, and 65-70% soil moisture content is optimum for germination. Dormancy may prevent germination at higher temperatures when soil moisture status is fluctuating and at lower temperatures when germination in late fall may make seedlings susceptible to winter kill. Mauer et al. (1987) state that seed dormancy may be induced by exposure to light.
Uses
Zouhar (2001) indicates that the compound cnicin serves as an antimicrobial agent, and it also acts against some human carcinoma cells and L-1210 leukemia. Centaurea provides substantial pollen and nectar for domestic bees in interior British Columbia, the Intermountain West, and Michigan. There has also been research on utilising C. biebersteinii biomass for commercial products. It is a nectar source for the endangered Karner blue butterfly in Wisconsin. In general, use of this invasive by livestock is highest during spring and early summer when plants are green and actively growing in the rosette and bolt stages. Use declines as it matures, and protein and digestibility decrease, although flowerbuds and seedheads may be grazed in the late summer.
Habitat Description
Zouhar (2001) states that Centaurea biebersteinii is found on soils with a wide range of chemical and physical properties, and often on poor soils. It does especially well in coarse-textured soils that are well drained with low water holding capacity. It is poorly adapted to irrigated pastures where saturated soil is common, and does not compete well with vigorously growing grass in moist sites. It establishes and dominates on dry, disturbed sites, especially along roads. Disturbance intensity has the greatest influence in habitat types moister than the Douglas-fir group, with coarse soil texture and steep slopes adding to success. In grass and shrub habitat types, south aspect and disturbance intensity are important variables for its success. It is well adapted to open forested areas, especially after logging or other disturbances It has been observed at elevations ranging from 578 - 3,040m and in precipitation zones ranging from 200 - 2000mm.
Reproduction
Zouhar (2001) reports that Centaurea biebersteinii reproduces almost entirely from seed. Plants are also able to extend lateral shoots below the soil surface that form rosettes adjacent to the parent plant, and multiple rosettes on a single root crown are common. The number of seeds produced may vary with site conditions (available moisture, nutrient availability and competition), herbivory and seed predation, and age of plants. On an irrigated site, it produced an average of 25,260 seeds per plant, compared to about 680 seeds per plant under range conditions in British Columbia. Up to 146,000 seeds per square metre have been reported using calculations based on seed capitula density and seed numbers (Mauer et al., 1987).
Nutrition
Centaurea biebersteinii is found often on poor soils (Zouhar, 2001).
Pathway
A native of Europe, Centaurea bierbersteinii was accidentally introduced to North America most likely in the 1890s in alfalfa seed from Asia Minor (Mauer et al., 1987).It is assumed that soil carried on ships as ballast and unloaded in the port transported knapweed seed to Victoria, British Columbia in 1893 (Mauer et al., 1987).

Principal source: Element Stewardship Abstract for Centaurea maculosa (Mauer et al., 1987)
\r\nSPECIES: Centaurea stoebe ssp. micranthos (Zouhar, 2001)

Compiler: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)

Review: Michael Carpinelli, Rangeland Scientist USDA-ARS. Burns USA

Publication date: 2006-03-23

Recommended citation: Global Invasive Species Database (2016) Species profile: Centaurea biebersteinii. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=315 on 01-10-2016.

General Impacts
Mauer et al. (1987) report that millions of acres of pasture and rangeland in western North America are infested with C. biebersteinii. The competitive superiority of this species suggests pre-adaptation to disturbance. Once a plant or colony is established, it may invade areas that are relatively undisturbed or in good condition with gradual, broad, frontal expansion. This invasion is associated with a decline in the frequency of some species and a decline in species richness overall. Widespread invasion often results from overgrazing. It has a low palatability, as it contains the bitter compound, cnicin. As the native grasses and forbs are continually eaten, the food reserves of their roots are depleted, and they are less able to compete. It is highly adept at capturing available moisture and nutrients, and it quickly spreads, choking out other vegetation. As the network root system of native species are lost and replaced by taproots of C. biebersteinii, the water storage capacity of the soil decreases and soil erosion increases. Zouhar (2001) states that secondary compounds in C. biebersteinii, such as cnicin, can negatively affect activity and growth of anaerobic rumen microorganisms in domestic sheep, reducing its digestibility. Large-scale infestations can impede access to more desirable forage for livestock and wildlife, especially when the presence of old, dried knapweed stems creates a dense and spiny overstory.
Management Info
For details on chemical, physical, biological control options, please see management information.
Countries (or multi-country features) with distribution records for Centaurea biebersteinii
ALIEN RANGE
NATIVE RANGE
  • austria
  • belarus
  • bulgaria
  • czech republic
  • ex-yugoslavia
  • france
  • germany
  • greece
  • hungary
  • italy
  • latvia
  • lithuania
  • macedonia, the former yugoslav republic of
  • moldova, republic of
  • poland
  • romania
  • russian federation
  • slovakia
  • slovenia
  • switzerland
  • ukraine
Informations on Centaurea biebersteinii has been recorded for the following locations. Click on the name for additional informations.
Lorem Ipsum
Location Status Invasiveness Occurrence Source
Details of Centaurea biebersteinii in information
Status
Invasiveness
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Occurrence
Source
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Species notes for this location
Location note
Management notes for this location
Impact
Mechanism:
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Impact information
Mauer et al. (1987) report that millions of acres of pasture and rangeland in western North America are infested with C. biebersteinii. The competitive superiority of this species suggests pre-adaptation to disturbance. Once a plant or colony is established, it may invade areas that are relatively undisturbed or in good condition with gradual, broad, frontal expansion. This invasion is associated with a decline in the frequency of some species and a decline in species richness overall. Widespread invasion often results from overgrazing. It has a low palatability, as it contains the bitter compound, cnicin. As the native grasses and forbs are continually eaten, the food reserves of their roots are depleted, and they are less able to compete. It is highly adept at capturing available moisture and nutrients, and it quickly spreads, choking out other vegetation. As the network root system of native species are lost and replaced by taproots of C. biebersteinii, the water storage capacity of the soil decreases and soil erosion increases. Zouhar (2001) states that secondary compounds in C. biebersteinii, such as cnicin, can negatively affect activity and growth of anaerobic rumen microorganisms in domestic sheep, reducing its digestibility. Large-scale infestations can impede access to more desirable forage for livestock and wildlife, especially when the presence of old, dried knapweed stems creates a dense and spiny overstory.
Red List assessed species 0:
Management information
For details on chemical, physical, biological control options, please see management information.
Locations
UNITED STATES
Management Category
Control
Bibliography
8 references found for Centaurea biebersteinii

Managment information
Bonneau A. (2000). Centaurea maculosa: Spotted knapweed Department of Plant Sciences, Crop Development Centre, University of Saskatchewan, Canada.
Summary: Short report on taxonomy, key identification points, ecological and physiological relations, and management.
Mauer T., Russo M. J., Evans M. (1987) Element Stewardship Abstract for Centaurea maculosa. The Nature Conservancy.
Summary: An Element Stewardship Abstract containing detail report on description, distribution, dispersal methods, impacts, habitats and control.
Olson, B.E., Wallander, R.T., 2001. Sheep grazing spotted knapweed and Idaho fescue. Journal of range management. {Lakewood Colo. : Society for Range Management.}54, no. 1 (Jan 2001): p.25-30
The Garry Oak Ecosystems Recovery Team (GOERT)., 2007. Exotic plant species in Garry oak and associated ecosystems in British Columbia
Summary: Available from: http://www.goert.ca/pubs_invasive.php#plant_species [Accessed 13 February 2008]
Virginia Department of Conservation and Recreation and Virginia Native Plant Society (VDCR/VNPS), UNDATED. Invasive Alien Plant Species of Virginia: Spotted knapweed (Centaurea maculosa Lam.).
Summary: Detailed report on description, habitat, distribution, reproduction methods, uses, and control.
Available from: http://www.dcr.virginia.gov/natural_heritage/documents/fscema.pdf [Accessed 28 July 2008]
General information
Devlin, R., Witham, F., 1983. Plant physiology. W. Grant Press, Boston.
ITIS (Integrated Taxonomic Information System), 2004. Online Database Centaurea biebersteinii
Summary: An online database that provides taxonomic information, common names, synonyms and geographical jurisdiction of a species. In addition links are provided to retrieve biological records and collection information from the Global Biodiversity Information Facility (GBIF) Data Portal and bioscience articles from BioOne journals.
Available from: http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=501347 [Accessed December 31 2004]
Contact
The following 0 contacts offer information an advice on Centaurea biebersteinii