Plant Assessment Form

More Arctotheca calendula resources

Arctotheca calendula

Synonyms: Arctotheca calendulacea (R. Br.) Lewin, Arctotis calendula L.; Cryptostemma calendulaceum (L.) R.Br

Common Names: fertile capeweed

Evaluated on: 12/9/04

List committee review date: 11/02/2005

Re-evaluation date:

Evaluator(s)

Ed Finley
California Dept. of Food and Agriculture
20235 Charlanne Dr., Redding, CA. 96002
530-224-2425, fax 530-224-2427
efinley@cdfa.ca.gov

List committee members

Carla Bossard
John Randall
Cynthia Roye
Jake Sigg
Peter Warner

General Comments

Two forms of capeweed occur in California, a fertile seed producing form with limited distrubtion in the state and a sterile form available from nurserys. The fertile form is currently A-rated by CDFA, but the sterile form is not rated. The fertile form was first intercepted as a contaminant of Australian subterranean clover seed in 1974 and the first established infestation was reported in 1988 on a dairy in Humboldt County (Barbe, Doug. 1988. CDFA Pest Detection Advisory, PD33-88). This assessment will address the fertile form.

Removed second scientific name, Arctotheca calendula (without fertile form), 3/28/17. Ramona Robison

Table 2. Criteria, Section, and Overall Scores

Overall Score? Moderate

Alert Status? Alert

Documentation? 3.5 out of 5

Score

Documentation

1.1

?Impact on abiotic ecosystem processes

C. Minor

Reviewed Scientific Publication

Impact?
Four-part score CBDD Total Score
B

1.2

?Impact on plant community

B. Moderate

Reviewed Scientific Publication

1.3

?Impact on higher trophic levels

D. Negligible

Reviewed Scientific Publication

1.4

?Impact on genetic integrity

D. None

Reviewed Scientific Publication

2.1

?Role of anthropogenic and natural disturbance in establishment

C. Minor

Reviewed Scientific Publication

Invasiveness?
Total Points
11 Total Score B

2.2

?Local rate of spread with no management

B. Increases less rapidly

Reviewed Scientific Publication

2.3

?Recent trend in total area infested within state

C. Stable

Other Published Material

2.4

?Innate reproductive potential
(see Worksheet A)

A. High

Other Published Material

2.5

?Potential for human-caused dispersal

A. High

Reviewed Scientific Publication

2.6

? Potential for natural long-distance dispersal

D. None

Observational

2.7

?Other regions invaded

C. Already invaded

Reviewed Scientific Publication

3.1

?Ecological amplitude/Range
(see Worksheet C)

B. Moderate

Reviewed Scientific Publication

Distribution?
Total Score C

3.2

?Distribution/Peak frequency
(see Worksheet C)

D. Very low

Other Published Material

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? Consider the impact on the natural range and variation of abiotic ecosystem processes and system-wide parameters in ways that significantly diminish the ability of native species to survive and reproduce. Alterations that determine the types of communities that can exist in a given area are of greatest concern. Examples of abiotic processes include: - fire occurrence, frequency, and intensity; - geomorphological changes such as erosion and sedimentation rates; - hydrological regimes, including soil water table; - nutrient and mineral dynamics, including salinity, alkalinity, and pH; - light availability (e.g. when an aquatic invader covers an entire water body that would otherwise be open). Select the one letter below that best describes this species' most severe impact on an abiotic ecosystem process: A. Severe, possibly irreversible, alteration or disruption of an ecosystem process. B. Moderate alteration of an ecosystem process. C. Minor alteration of an ecosystem process. D. Negligible perceived impact on an ecosystem process. U. Unknown.	C Reviewed Scientific Publication
Identify ecosystem processes impacted: Capeweed probably impacts soil moisture and nutrient avilability. Capeweed infestations in agriculture may attain percent plant cover ratios approaching 100%. Such a dominance would likely affect soil moisture and nutrient availablity to the detrement of other species, but capeweed does not seem to compete well in wildland situations, thus it would normally pose only a minor alteration of these ecosystem processes. Sources of information: McIvor, J.G.; Smith D.F. 1973. Competitive growth of capeweed, Arctotheca calendula, and some annual pasture species. Australian Journal of ExperimentalAgriculture & Animal Husbandry. 13(61): 185-189. Anonymous. Capeweed Arctotheca calendula. Http://weeds.tassie.net.au//txts/capeweed.html. Accessed on 8/16/1999 Finley, Ed. 2004. Personal observations of fertile capeweed on a Humboldt County dairy, 2001 to present. 530-224-2425 efinley@cdfa.ca.gov
Question 1.2 Impact on plant community composition, structure, and interactions? Consider the cumulative ecological impact of this species to the plant communities it invades. Give more weight to changes in plant composition, structure, and interactions that involve rare or keystone species or rare community types. Examples of severe impacts include: - formation of stands dominated (>75% cover) by the species; - occlusion (>75% cover) of a native canopy, including a water surface, that eliminates or degrades layers below; - significant reduction or extirpation of populations of one or more native species. Examples of impacts usually less than severe include: - reduction in propagule dispersal, seedling recruitment, or survivorship of native species; - creation of a new structural layer, including substantial thatch or litter, without elimination or replacement of a pre-existing layer; - change in density or depth of a structural layer; - change in horizontal distribution patterns or fragmentation of a native community; - creation of a vector or intermediate host of pests or pathogens that infect native plant species. Select the one letter below that best describes this species' impact on community composition, structure and interactions: A. Severe alteration of plant community composition, structure, or interactions. B. Moderate alteration of plant community composition. C. Minor alteration of community composition. D. Negligible impact known; causes no perceivable change in community composition, structure, or interactions. U. Unknown.	B Reviewed Scientific Publication
Identify type of impact or alteration: Capeweed seems to be a relatively poor competitor with native species, but if established may pose a moderate impact on native plant communities. Capeweed has the potential to invade disturbed areas (bare ground) and establish nearly pure stands, thereby excluding native plants from re-colonizing such areas and possibly expanding into surrounding plant communities. Again, capeweed seems to be a relatively poor competitor, thus posing a moderate threat. Sources of information: McIvor, J.G.; Smith D.F. 1973. Competitive growth of capeweed, Arctotheca calendula, and some annual pasture species. Australian Journal of ExperimentalAgriculture & Animal Husbandry. 13(61): 185-189 Eaton, Ronnie. Alameda County Dept. of Agriculture. 2004. Obersavation on fertile capeweed at a private ranchette in San Mateo County, 2003 to 2004. Personal communication, 02/28/03. (510)670-5232. Finley, Ed; Griffin, Denis; Oliver, Brad. Personal observations on a fertile capeweed infestation at a vineyard in Monterey County, April, 2001. 530-224-2425, efinley@cdfa.ca.gov
Question 1.3 Impact on higher trophic levels? Consider the cumulative impact of this species on the animals, fungi, microbes, and other organisms in the communities that it invades. Although a non-native species may provide resources for one or a few native species (e.g. by providing food, nesting sites, etc.), the ranking should be based on the species' net impact on all native species. Give more weight to changes in composition and interactions involving rare or keystone species or rare community types. Examples of severe impacts include: - extirpation or endangerment of an existing native species or population; - elimination or significant reduction in native species' nesting or foraging sites, cover, or other critical resources (i.e., native species habitat), including migratory corridors. Examples of impacts that are usually less than severe include: - minor reduction in nesting or foraging sites, cover, etc. for native animals; - minor reduction in habitat connectivity or migratory corridors; - interference with native pollinators; - injurious components, such as awns or spines that damage the mouth and gut of native wildlife species, or production of anti-digestive or acutely toxic chemical that can poison native wildlife species. Select the one letter below that best describes this species' impact on community composition and interactions: A. Severe alteration of higher trophic populations, communities, or interactions. B. Moderate alteration of higher trophic level populations, communities, or interactions. C. Minor alteration of higher trophic level populations, communities or interactions. D. Negligible impact; causes no perceivable change in higher trophic level populations, communities, or interactions. E. Unknown.	D Reviewed Scientific Publication
Identify type of impact or alteration: Fertile capeweed probably would have little effect on higher trophic levels. Since fertile capeweed is distributed mainly in agricultural situations, its impact on higher trophic levels would be negligible. Though not preferred, stock may feed on fertile capeweed. Sources of information: Anonymous. Capeweed Arctotheca calendula. Http://weeds.tassie.net.au//txts/capeweed.html. accessed on 8/16/1999
Question 1.4 Impact on genetic integrity? Consider whether the species can hybridize with and influence the proportion of individuals with non-native genes within populations of native species. Mechanisms and possible outcomes include: - production of fertile or sterile hybrids that can outcompete the native species; - production of sterile hybrids that lower the reproductive output of the native species. Select the one letter below that best describes this species' impact on genetic integrity: A. Severe (high proportion of individuals). B. Moderate (medium proportion of individuals). C. Minor (low proportion of individuals). D. No known hybridization. U. Unknown.	D Reviewed Scientific Publication
There are no reports of fertile capeweed hybridization in California. There are no native species of Arctotheca in California. Sources of information: Hickman, James C., ed. 1993. The Jepson Manual Higher Plants of California. University of California Press, Berkeley and Los Angeles, California
Section 2: Invasiveness
Question 2.1 Role of anthropogenic and natural disturbance in establishment? Assess this species' dependence on disturbance: both human and natural: for establishment in wildlands. Examples of anthropogenic disturbances include: - grazing, browsing, and rooting by domestic livestock and feral animals; - altered fire regimes, including fire suppression; - cultivation; - silvicultural practices; - altered hydrology due to dams, diversions, irrigation, etc.; - roads and trails; - construction; - nutrient loading from fertilizers, runoff, etc. Examples of natural disturbance include: - wildfire; - floods; - landslides; - windthrow; - native animal activities such as burrowing, grazing, or browsing. Select the first letter in the sequence below that describes the ability of this species to invade wildlands: A. Severe invasive potential: this species can establish independent of any known natural or anthropogenic disturbance. B. Moderate invasive potential: this species may occasionally establish in undisturbed areas but can readily establish in areas with natural disturbances. C. Low invasive potential: this species requires anthropogenic disturbance to establish. D. No perceptible invasive potential: this species does not establish in wildlands (though it may persist from former cultivation). U. Unknown.	B Reviewed Scientific Publication
Describe role of disturbance: It appears that fertile capeweed needs anthropogenic disturbance to establish. Distributions of fertile capeweed are generally in agricultural situations, particularly swards, pastures, and vineyards. There is very little spread into wildland situations without some disturbance, typically caused by agricultural practices (cultivation and transportation of stock fodder) or actual planting of specimens. Sources of information: Wood, Helen. 1994. The Introduction and spread of Capeweed, Arctotheca calendula, (l.) Levyns (Asteraceae) in Australia. Plant Protection Quarterly. 9(3): 94-100. Eaton, Ronnie. Alameda County Dept. of Agriculture. 2004. Obersavation on fertile capeweed at a private ranchette in San Mateo County, 2003 to 2004. Personal communication, 02/28/03. (510)670-5232. Finley, Ed; Griffin, Denis; Oliver, Brad. Personal observations on a fertile capeweed infestation at a vineyard in Monterey County, April, 2001. 530-224-2425, efinley@cdfa.ca.gov
Question 2.2 Local rate of spread with no management? Assess this species' rate of spread in existing localized infestations where the proportion of available habitat invaded is still small when no management measures are implemented. Select the one letter below that best describes the rate of spread: A. Increases rapidly (doubling in <10 years) B. Increases, but less rapidly C. Stable D. Declining U. Unknown	B Reviewed Scientific Publication
Describe rate of spread: Fertile capeweed is still only locally distributed in California and has increased its population very slowly, if at all. In Australia, capeweed seems to have the potential for further spread, but apparently in agriculture. In limited disjunct California populations of fertile capeweed, there is little indication of spread ito wildland situation. In Australia, capeweed is still spreading in agriculture. Sources of information: Wood, Helen. 1994. The Introduction and spread of Capeweed, Arctotheca calendula, (l.) Levyns (Asteraceae) in Australia. Plant Protection Quarterly. 9(3): 94-100. Barbe, Doug. 1988. CDFA, Division of Plant Industry, Pest Detection Advisory, PD33-88. Barbe, Doug. 1990. CDFA, Division of Plant Industry, Pest Detection Advisory, PD30-90. Barbe, Doug. 1992. CDFA, Division of Plant Industry, Pest Detection Advisory, PD16-92. Hrusa, Fred. 1999. CDFA, Division of Plant Indusrty, Pest and Damage Record, 1237670. Hrusa, Fred, 2001. CDFA, Division of Plant Industry, Pest and Damage Record, P114622. Finley, Ed; Griffin, Denis; Oliver, Brad. Personal observations on a fertile capeweed infestation at a vineyard in Monterey County, April, 2001. 530-224-2425, efinley@cdfa.ca.gov
Question 2.3 Recent trend in total area infested within state? Assess the overall trend in the total area infested by this species statewide. Include current management efforts in this assessment and note them. Select the one letter below that best describes the current trend: A. Increasing rapidly (doubling in total range statewide in <10 years) B. Increasing, but less rapidly C. Stable D. Declining U. Unknown	C Other Published Material
Describe trend: Disjunct California populations do not seem to be spreading and are declining only with repeated treatments (hand removal or herbicidal). Very small populations in the GGNRAand Point Reyes National Seashore have been eradicated by hand removal. Herbicidal treatments on the larger populations at a dairy in Humboldt County and a vineyard in Monterey County have had only limited success. Sources of information: Barbe, Doug. 1990. CDFA, Division of Plant Industry, Pest Detection Advisory, PD30-90. Barbe, Doug. 1992. CDFA, Division of Plant Industry, Pest Detection Advisory, PD16-92. Finley, Ed. 2004. Personal observations of fertile capeweed on a Humboldt County dairy, 2001 to present. 530-224-2425 efinley@cdfa.ca.gov Finley, Ed; Griffin, Denis; Oliver, Brad. Personal observations on a fertile capeweed infestation at a vineyard in Monterey County, April, 2001. 530-224-2425, efinley@cdfa.ca.gov
Question 2.4 Innate reproductive potential? Assess the innate reproductive potential of this species. Worksheet A is provided for computing the score.	A Other Published Material
Describe key reproductive characteristics: Hickman, James C., ed. 1993. The Jepson Manual Higher Plants of California. University of California Press, Berkeley and Los Angeles, California DiTomasso, J. Healy E. Weeds of California and other Western States. (as yet unpublished) Sources of information: Fertile capeweed may disperse via contaminated seed, hay, fodder, sheep wool, horses, and through direct movement by humans. Fertile capeweed was originally introduced into California via contaminated alfalfa seed, and in Australia by practically all of the above mentioned routes.
Question 2.5 Potential for human-caused dispersal? Assess whether this species is currently spread: or has high potential to be spread: by direct or indirect human activity. Such activity may enable the species to overcome natural barriers to dispersal that would not be crossed otherwise, or it may simply increase the natural dispersal of the species. Possible mechanisms for dispersal include: - commercial sales for use in agriculture, ornamental horticulture, or aquariums; - use as forage, erosion control, or revegetation; - presence as a contaminant (seeds or propagules) in bulk seed, hay, feed, soil, packing materials, etc.; - spread along transportation corridors such as highways, railroads, trails, or canals; - transport on boats or boat trailers. Select the one letter below that best describes human-caused dispersal and spread: A. High: there are numerous opportunities for dispersal to new areas. B. Moderate: human dispersal occurs, but not at a high level. C. Low: human dispersal is infrequent or inefficient. D. Does not occur. U. Unknown.	A Reviewed Scientific Publication
Identify dispersal mechanisms: Fertile capeweed may disperse via contaminated seed, hay, fodder, sheep wool, horses, and through direct movement by humans. Fertile capeweed was originally introduced into California via contaminated alfalfa seed, and in Australia by practically all of the above mentioned routes. Sources of information: Wood, Helen. 1994. The Introduction and spread of Capeweed, Arctotheca calendula, (l.) Levyns (Asteraceae) in Australia. Plant Protection Quarterly. 9(3): 94-100. Barbe, Doug. 1988. CDFA, Division of Plant Industry, Pest Detection Advisory, PD33-88.
Question 2.6 Potential for natural long-distance dispersal? We have chosen 1 km as the threshold of "long-distance." Assess whether this species is frequently spread, or has high potential to be spread, by animals or abiotic mechanisms that can move seed, roots, stems, or other propagules this far. The following are examples of such natural long-distance dispersal mechanisms: - the species' fruit or seed is commonly consumed by birds or other animals that travel long distances; - the species' fruits or seeds are sticky or burred and cling to feathers or hair of animals; - the species has buoyant fruits, seeds, or other propagules that are dispersed by flowing water; - the species has light propagules that promote long-distance wind dispersal; - The species, or parts of it, can detach and disperse seeds as they are blown long distances (e.g., tumbleweed). Select the one letter below that best describes natural long-distance dispersal and spread: A. Frequent long-distance dispersal by animals or abiotic mechanisms. B. Occasional long-distance dispersal by animals or abiotic mechanisms. C. Rare dispersal more than 1 km by animals or abiotic mechanisms. D. No dispersal of more than 1 km by animals or abiotic mechanisms. U. Unknown.	D Observational
Identify dispersal mechanisms: It appears that California infestations of fertile capeweed have not spread more than 1 km. The California fertile capeweed populations have been relatively stable. Human-caused dispersal seems to be the primary means of spread. There may be some movement of seed, which is covered by dense wooly hairs, by animals, wind, or water, but so far this is limited. Sources of information: Finley, Ed. 2004. Personal observations of fertile capeweed on a Humboldt County dairy, 2001 to present. 530-224-2425 efinley@cdfa.ca.gov Finley, Ed; Griffin, Denis; Oliver, Brad. Personal observations on a fertile capeweed infestation at a vineyard in Monterey County, April, 2001. 530-224-2425, efinley@cdfa.ca.gov
Question 2.7 Other regions invaded? Assess whether this species has invaded ecological types in other states or countries outside its native range that are analogous to ecological types not yet invaded in your state (see Worksheets B, C, and D for California, Arizona, and Nevada, respectively, in Part IV for lists of ecological types). This information is useful in predicting the likelihood of further spread within your state. Select the one letter below that best describes the species' invasiveness in other states or countries, outside its native range. A. This species has invaded 3 or more ecological types elsewhere that exist in your state and are as yet not invaded by this species (e.g. it has invaded Mediterranean grasslands, savanna, and maquis in southern Europe, which are analogous to California grasslands, savanna, and chaparral, respectively). B. Invades 1 or 2 ecological types that exist but are not yet invaded in your state. C. Invades elsewhere but only in ecological types that it has already invaded in the state. D. Not known as an escape anywhere else. U. Unknown.	C Reviewed Scientific Publication
Identify other regions: Fertile capeweed is an invasive species in agricultural regions in Australia. Fertile capeweed is a pest in swards of Australia, presumably equivelant to coastal praire and scrub ecological types converted to agriculture in California. Sources of information: Wood, Helen. 1994. The Introduction and spread of Capeweed, Arctotheca calendula, (l.) Levyns (Asteraceae) in Australia. Plant Protection Quarterly. 9(3): 94-100. Barbe, Doug. 1988. CDFA, Division of Plant Industry, Pest Detection Advisory, PD33-88.
Section 3: Distribution
Question 3.1 Ecological amplitude/Range? Refer to Worksheet C and select the one letter below that indicates the number of different ecological types that this species invades. A. Widespread: the species invades at least three major types or at least six minor types. B. Moderate: the species invades two major types or five minor types. C. Limited: the species invades only one major type and two to four minor types. D. Narrow: the species invades only one minor type. U. Unknown.	B Reviewed Scientific Publication
It appears that fertile capeweed is capable of moderate tendency to invade different ecological types. In California, fertile capeweed has a distribution so far limited to coastal praire (Humboldt County) and costal scrub (Monterey County). In Australia, it has invaded agricultural areas and is most successful in regions with climates similar to its range in South Africa. Sources of information: Wood, Helen. 1994. The Introduction and spread of Capeweed, Arctotheca calendula, (l.) Levyns (Asteraceae) in Australia. Plant Protection Quarterly. 9(3): 94-100. Barbe, Doug. 1988. CDFA, Division of Plant Industry, Pest Detection Advisory, PD33-88.
Question 3.2 Distribution/Peak frequency? To assess distribution, record the letter that corresponds to the highest percent infested score entered in Worksheet C for any ecological type.	D Other Published Material
Describe distribution: Fertile capeweed has not dominated any of the ecological types in which it occurs. So far, fertile capeweed is limited to two ecological types in California and it has not achieved dominance in either. Sources of information: Barbe, Doug. 1988. CDFA, Division of Plant Industry, Pest Detection Advisory, PD33-88. Barbe, Doug. 1990. CDFA, Division of Plant Industry, Pest Detection Advisory, PD30-90. Barbe, Doug. 1992. CDFA, Division of Plant Industry, Pest Detection Advisory, PD16-92. Hrusa, Fred. 1999. CDFA, Division of Plant Indusrty, Pest and Damage Record, 1237670. Hrusa, Fred, 2001. CDFA, Division of Plant Industry, Pest and Damage Record, P114622.

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	Unknown
Seeds remain viable in soil for three or more years	Unknown
Viable seed produced with both self-pollination and cross-pollination	Unknown
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes	Yes
Fragments easily and fragments can become established elsewhere	Yes
Resprouts readily when cut, grazed, or burned	Yes
Total points:	8
Total unknowns:	3
Total score:	A? Scoring Criteria for Worksheet A A. High reproductive potential (6 or more points). B. Moderate reproductive potential (4-5 points). C. Low reproductive potential (3 points or less and less than 3 Unknowns). U. Unknown (3 or fewer points and 3 or more Unknowns).

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? A means >50% of type occurrences are invaded; B means 20% to 50%; C means 5% to 20%; D means present but <5%; U means unknown (unable to estimate percentage of occurrences invaded)
Marine Systems	marine systems
Freshwater and Estuarine	lakes, ponds, reservoirs
Aquatic Systems	rivers, streams, canals
Aquatic Systems	estuaries
Dunes	coastal
	desert
	interior
Scrub and Chaparral	coastal bluff scrub
	coastal scrub	D, < 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 Communities	coastal prairie	D, < 5%
	valley and foothill grassland
	Great Basin grassland
	vernal pool
	meadow and seep
	alkali playa
	pebble plain
Bog and Marsh	bog and fen
Bog and Marsh	marsh and swamp
Riparian and Bottomland habitat	riparian forest
	riparian woodland
	riparian scrub (incl.desert washes)
Woodland	cismontane woodland
	piñon and juniper woodland
	Sonoran thorn woodland
Forest	broadleaved upland forest
	North Coast coniferous forest
	closed cone coniferous forest
	lower montane coniferous forest
	upper montane coniferous forest
	subalpine coniferous forest
Alpine Habitats	alpine boulder and rock field
Alpine Habitats	alpine dwarf scrub
	Amplitude (breadth):	B
	Distribution (highest score):	D

Infested Jepson Regions

Click here for a map of Jepson regions

Central West
Great Valley
Northwest
Sierra Nevada
Southwest

California Invasive Plant Council

Protecting California’s environment and economy from invasive plants

Plant Assessment Form

More Arctotheca calendula resources

Arctotheca calendula

Evaluator(s)

List committee members

General Comments

Table 2. Criteria, Section, and Overall Scores

Table 3. Documentation

Worksheet A - Innate reproductive potential

Related traits:

Worksheet C - California Ecological Types

Infested Jepson Regions