Outcompetes native vegetation for light, water, and nutrients. No evidence of soil chemistry alteration because displaced species are able to recolonize following artichoke removal. Large arching leaves together with a large aggressive tap root system preemptively intercept resources necessary for the growth of other species. .

Kelly, M. Cynara cardunculus. In, Invasive Plants of California's Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley;
Pepper A. and M Kelly. 1994. Portrait of an invader. The ecology and management of the wild artichoke Cynara cardunculus. Cal EPPC News Winter pg. 4-6.

Artichoke thistle is a moderate threat to the Threatened species, California gnatcatcher and Coastal cactus wren. By displacing natives and annual grasses, it reduces the forage value for both livestock and wildlife. It is not used by birds for nesting or predative activities. Alters breeding success for threatened species by displacing native plants. The heavily armoured thistle flowerhead hinders herbivory, hower, the seedlings may be subject to rabbit herbivory and the seeds may provide a food source for birds.

The Nature Conservancy Wildland weed Management and Research 1998-1999 Weed Survey by Trish Smith;
Pepper A. and M Kelly. 1994. Portrait of an invader. The ecology and management of the wild artichoke Cynara cardunculus. Cal EPPC News Winter pg. 4-6.

Seems to require disturbance and most commonly heavily grazed areas. It has been observed to occasionally colonize riparian woodlands and natural openings in chaparral and costal sage scrub.. Artichoke thistle's appearance in California rangelands is linked to its introduction for ornamental and culinary purposes. It is found primarily on distrubed grasslands or abandoned agricultural fields especially those areas subjected to overgrazing practices. . It occurrence along fire maintenance roads is linked to equipement carrying seeds; grazing and fire create openings for new artichoke thistle establishment; fire prone plant communities (grasslands and sage scrub) also tend to exist in climates that are conducive for artichoke thistle growth.

The Nature Conservancy Wildland weed Management and Research 1998-1999 Weed Survey by Trish Smith;
Kelly, M. Cynara cardunculus. In, Invasive Plants of California's Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley;

Infests about 150,000 acres statewide. Contra Costa, Solano, and Orange counties have 95% of the infested acreage. Santa Barabara and San Diego counties have some locally dense stands. California townships of past or present infestation are focused primarily in coastal area of southern California (Orange and San Diego Counties), the eastbay of the San Francisco bay area, and along the rangelands of the central coast. It has been reported that 70, 000 acres focused on the hillsides of Benecia have been infested but have been reduced due to substantial control efforts. In Irvine, 2000 acres are currently infested with another 6000 acres at risk of future invasion. In the 3500 acre Los Penasquitos Canyon Preserve in San Diego one 14 acre site was heavily infested and dense patches exist throughout the preserve. Populations of this plant are either large or they are small. Rarely do you see huge expanses of land covered with species because control measures are instigated soon after these are spotted. Poor grazing practices and soil disturbance on coastal range south of the San Francisco Bay Area will invite new invasions by artichoke thistle.

Thomsen, C.D. , G. Barbe, W. Williams, and M. George. 1986. Escaped artichokes are troublesome pests. California Agriculture March-April 1986 ppg 7-9; Kelly, M. Cynara cardunculus. In, Invasive Plants of California's Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley; The Nature Conservancy Wildland weed Management and Research 1998-1999 Weed Survey by Trish Smith;

Is used for ornamental purposes and indiscriminant disposal of flowers could facilitate its spread. It appears to grow and progress along roadways. Populations move along roadways either because seeds are blown as vehicles pass or the seeds are caught up in tires. Vegetative parts not likely except following mechanical operations, and then only for a short distance.

Kelly, M. Cynara cardunculus. In, Invasive Plants of California's Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley;

Proclaimed a noxious weed throughout Victoria and Queensland South Australia and part of New South Wales. Also found in New Zealand. It also is considered an important weed in the Argentine pampas areas of South America. Appears to be well adapted to Mediterranean regions similar to the California central to southern coasts. Appears to be in grassland or coastal scrub-like communities abroad similar to those currently invaded in California.

Parsons, W.T. 1973. Noxious Weeds of Victoria. Inkara Press, Melbourne. Pg. 70-73.
Kelly, M. Cynara cardunculus. In, Invasive Plants of California's Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley;

Artichoke thistle was presumably introduced to California in the mid-1800s as the cultivated, edible cardoon. Escape from cultivation and subsequent reversion to its 'wild', aggressive biotype probably cntributed to its invasive spread. Escaped cultivation in California in 1860-1864 according to botanical surveys. The most successful invasions are in Contra Costa and Orange counties but also in the rangelands of San Diego, Santa Barabara, and other rangelands on California with coastal influence.

Thomsen, C.D. , G. Barbe, W. Williams, and M. George. 1986. Escaped artichokes are troublesome pests. California Agriculture March-April 1986 ppg 7-9;
Kelly, M. Cynara cardunculus. In, Invasive Plants of California's Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley;