Plant Assessment Form

More Cakile maritima resources

Cakile maritima

Common Names: European sea rocket

Evaluated on: 5/20/04

List committee review date: 03/12/2017

Re-evaluation date:

Evaluator(s)

John J. Knapp/ Invasive Plant Program Manager
Catalina Island Conservancy
P.O. 2739 Avalon, CA 90704
(310) 510-1299
jknapp@catalinaconservancy.org

Joseph M. DiTomaso
University of California, Davis
Dept. Plant Sci., Mail Stop 4, Davis, CA 95616
530-754-8715
jmditomaso@ucdavis.edu

List committee members

Jake Sigg
Peter Warner
Bob Case
John Knapp
Elizabeth Brusati

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? Limited

Alert Status? No 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 CCCD Total Score
C

1.2

?Impact on plant community

C. Minor

Other Published Material

1.3

?Impact on higher trophic levels

C. Minor

Other Published Material

1.4

?Impact on genetic integrity

D. None

Other Published Material

2.1

?Role of anthropogenic and natural disturbance in establishment

B. Moderate

Other Published Material

Invasiveness?
Total Points
12 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

Reviewed Scientific Publication

2.4

?Innate reproductive potential
(see Worksheet A)

B. Moderate

Reviewed Scientific Publication

2.5

?Potential for human-caused dispersal

C. Low

Reviewed Scientific Publication

2.6

? Potential for natural long-distance dispersal

A. Frequent

Reviewed Scientific Publication

2.7

?Other regions invaded

C. Already invaded

Reviewed Scientific Publication

3.1

?Ecological amplitude/Range
(see Worksheet C)

D. Narrow

Reviewed Scientific Publication

Distribution?
Total Score B

3.2

?Distribution/Peak frequency
(see Worksheet C)

A. High

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: C. maritima demonstrates weak allelophy. C. maritima has demonstrated evidence of allelopathic effects in replicated growth chamber experiments; however, the effect was not detected under field experiments. Sources of information: Boyd, R.S. 1993. Replacement of Cakile endentula by C. maritima in the strand habitat of California. American Midland Naturalist, 130(2):209-228.
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.	C Other Published Material
Identify type of impact or alteration: C. maritima has lead to the reduction, and in some situations the extirpation of Abronia spp. However, in most places its impacts are minor. C. maritima is invasive, with the ability to produce more seed, tolerate disturbance, and disperse greater distances than native Abronia spp. Sources of information: Wood, L. 19??. Dune stabilization. Fremontia, ?(?):27. Pers. Obs. Joe DiTomaso, Carla Bossard, Jake Sigg, Peter Warner 9/15/05
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.	C Other Published Material
Identify type of impact or alteration: Competes for pollination visitation with native vegetation but this may not impact native species. Although self-compatible, insect pollination plays an intergral part in reproduction. Sources of information: Barbour, M.G. and Rodman, J.E. 1970. Saga of the west coast sea-rockets: Cakile edentula ssp. californica and C. maritima. Rhodora, 72(791):370-386.
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 Other Published Material
No hybridization is known to occur with native California taxa. No related native California taxa in the genus Cakile. Sources of information: Hickman, J.C. (ed.). 1993. The Jepson manual of higher plants of California. Pp. 406. University of California Press, Berkeley.
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: Establishes quickly on beaches and dunes that are frequently disturbed and have low diversity. Able to colonize beach and dune habitats along coast that are frequently disturbed by surf and wind, and have low biodiversity. Sources of information: Haubensak, K. 1999. Cakile maritima. Channel Islands National Park Sevice Species Literature Review. Unpublished.
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: No populations were recorded in the first Catalina Island flora in 1923, but by 1966, C. maritima was widespread throughout the beaches and dunes of the Island, and has a similar distribution and abundance in 2003. If C. maritima can survive into a second or even a third year of reproduction, it can produce an 18-fold difference in seed output. Seed production is increased during colonization, and has a high fecundity. Sources of information: Thorne, R.F. 1967. A Flora of Santa Catalina Island, California. Aliso, 6(3):1-77. Knapp, J.J. 2004. Catalina Invasive Plant Ranking Plan for the Catalina Island Conservancy. Unpublished. Barbour, M.G. and Rodman, J.E. 1970. Saga of the west coast sea-rockets: Cakile edentula ssp. californica and C. maritima. Rhodora, 72(791):370-386. Boyd, R.S. 1988. Hebivory and species replacement in the west coast searockets (Cakile, Brassicaceae). American Midland Naturalist, 119(2):304-317. Boyd, R.S. 1993. Replacement of Cakile endentula by C. maritima in the strand habitat of California. American Midland Naturalist, 130(2):209-228. Barbour, M.G. 1970. Seedling ecology of Calike maritima along the California coast. Bulletin of the Torrey Botatnical Club, 97(5):280-289.
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 Reviewed Scientific Publication
Describe trend: Occupies all avaliable habitats along the California and Baja coast. Santa Cruz Island. On Catalina Island, 101,225 square feet are infested. C. maritima has similar xeric region of origin similar to California, with the average temperature at Santa Cruz Island being the optimal for germination. Sources of information: Wood, L. 19XX. Dune stabilization. Fremontia, X(X):27. Knapp, J.J. 2004. Catalina Invasive Plant Ranking Plan for the Catalina Island Conservancy. Unpublished. Boyd, R.S. 1988. Hebivory and species replacement in the west coast searockets (Cakile, Brassicaceae). American Midland naturalist, 119(2):304-317. Barbour, M.G. 1970. Seedling ecology of Calike maritima along the California coast. Bulletin of the Torrey Botatnical Club, 97(5):280-289.
Question 2.4 Innate reproductive potential? Assess the innate reproductive potential of this species. Worksheet A is provided for computing the score.	B Reviewed Scientific Publication
Describe key reproductive characteristics: Seed bank persists for al least 2 years in foredunes. C. maritima can survive disturbance into a second or even a third year of reproduction, producing an 18-fold difference in seed output. Seed production is increased during colonization, and has a high fecundity. Self pollination is possible. 90% seed set. Classified as an annual species; however, has shown to be biennial. Seeds are readily buried in foredunes, allowing them to escape predation by deer mice (Peromyscus maniculatus), which can remove 95% of seed, causing only 20% seed survivorship. During colonization of disturbed sites of native Abronia maritima, C. maritima will allocate energy to seed production rather than to biomass to survive until the next year leading to a greater level of invasiveness. C. maritima is a faculative annual, germinating in the winter and fruiting in the summer. One seed per fruit segment. Sources of information: Haubensak, K. 1999. Cakile maritima. Channel Islands National Park Sevice Species Literature Review. Unpublished. Wood, L. 19XX. Dune stabilization. Fremontia, X(X):27. Barbour, M.G. and Rodman, J.E. 1970. Saga of the west coast sea-rockets: Cakile edentula ssp. californica and C. maritima. Rhodora, 72(791):370-386. Boyd, R.S. 1988. Hebivory and species replacement in the west coast searockets (Cakile, Brassicaceae). American Midland Naturalist, 119(2):304-317. Boyd, R.S. 1993. Replacement of Cakile endentula by C. maritima in the strand habitat of California. American Midland Naturalist, 130(2):209-228. Barbour, M.G. 1970. Seedling ecology of Calike maritima along the California coast. Bulletin of the Torrey Botatnical Club, 97(5):280-289. Brown, K. and Brooks, K. 2002. Bushland weeds: a practical guide to their management with case studies from Swan Coastal Plain and beyond. Environmental Weeds Action Network. Greenwood, Australia.
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.	C Reviewed Scientific Publication
Identify dispersal mechanisms: Sand transport, ship ballast, and trampling account for human-caused dispersal. The relocation of sand from areas infested with C. maritima to new locales, and trampling by hikers and campers in dunes may allow for plant material to roll (tumble weed effect), thus dispersing seed. Sources of information: Rodman, J.E. 1986. Introduction, establishment and replacement of sea-rockets (Cakile, Cruciferae) in Australia. Journal of Biogeography, 13(2):159-171. Wood, L. 19XX. Dune stabilization. Fremontia, X(X):27. Knapp J.J. 2004. Personal observations from 2000-2004 of people walking through infestations on beaches of California and Catalina Island. (310) 510-2821, jknapp@catalinaconservancy.org.
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.	A Reviewed Scientific Publication
Identify dispersal mechanisms: Fruits are adapted for both short and long distance dispersal by wind and water respectively. In California, C. maritima dispersed at a rate of 53 km per year. Deer mice act as microdispersal vectors; however, their herbivory has also impacted C. maritima. Fruits are composed of two segments and have superb dispersability- the upper segment detaches and is carried by the sea, allowing for 50% of detached fruits to stay afloat for over 100 days. The lower segment remains attached to the plant until wind events cause the plant to roll along the surface, thus breaking off the fruits break. Deer mice cachet seeds. Sources of information: Haubensak, K. 1999. Cakile maritima. Channel Islands National Park Sevice Species Literature Review. Unpublished. Rodman, J.E. 1986. Introduction, establishment and replacement of sea-rockets (Cakile, Cruciferae) in Australia. Journal of Biogeography, 13(2):159-171. Boyd, R.S. 1988. Microdistribution of the beach plant Cakile maritima (Brassicaceae) as influenced by a rodent herbivore. American Journal of Botany, 75(10):1540-1548. Boyd, R.S. 1993. Replacement of Cakile endentula by C. maritima in the strand habitat of California. American Midland Naturalist, 130(2):209-228.
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: Eastern North America, western and southern Australia, Tasmania, and New Zealand are invaded. Sources of information: Haubensak, K. 1999. Cakile maritima. Channel Islands National Park Sevice Species Literature Review. Unpublished. Rodman, J.E. 1986. Introduction, establishment and replacement of sea-rockets (Cakile, Cruciferae) in Australia. Journal of Biogeography, 13(2):159-171. Barbour, M.G. 1970. Seedling ecology of Calike maritima along the California coast. Bulletin of the Torrey Botatnical Club, 97(5):280-289.
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.	D Reviewed Scientific Publication
Introduced to California, north of San Francisco in the 1930's. In 1967, Thorne found C. maritima to be well-established, while other botanists found it abundant on Santa Cruz, San Clemente and San Nicolas islands. First recorded on Catalina Island 1966 as well-established on beaches around the Island. Coastal beaches, dunes and sandy stream mouths. Occupies coast line with sandy substrate. On Catalina Island in 2003, 21 populations were recorded and the following are the percentages of habitat infested: beach and dune- 1.4%, and riparian creek mouth-<0.00%. Sources of information: Barbour, M.G. 1970. Seedling ecology of Calike maritima along the California coast. Bulletin of the Torrey Botatnical Club, 97(5):280-289. Barbour, M.G. and Rodman, J.E. 1970. Saga of the west coast sea-rockets: Cakile edentula ssp. californica and C. maritima. Rhodora, 72(791):370-386. Thorne, R.F. 1967. A flora of Santa Catalina Island, California. Aliso, 6(3):1-77. Knapp, J.J. 2004. Catalina Invasive Plant Ranking Plan for the Catalina Island Conservancy. Unpublished. Haubensak, K. 1999. Cakile maritima. Channel Islands National Park Sevice Species Literature Review. Unpublished.
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.	A Other Published Material
Describe distribution: Very common, but not typically in dense patches. Sources of information: Barbour, M.G. 1970. Seedling ecology of Calike maritima along the California coast. Bulletin of the Torrey Botatnical Club, 97(5):280-289. Barbour, M.G. and Rodman, J.E. 1970. Saga of the west coast sea-rockets: Cakile edentula ssp. californica and C. maritima. Rhodora, 72(791):370-386. Thorne, R.F. 1967. A flora of Santa Catalina Island, California. Aliso, 6(3):1-77. Knapp, J.J. 2004. Catalina Invasive Plant Ranking Plan for the Catalina Island Conservancy. Unpublished. Haubensak, K. 1999. Cakile maritima. Channel Islands National Park Sevice Species Literature Review. Unpublished. Rodman, J.E. 1986. Introduction, establishment and replacement of sea-rockets (Cakile, Cruciferae) in Australia. Journal of Biogeography, 13(2):159-171.

Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less	Yes
Dense infestations produce >1,000 viable seed per square meter	No
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	Yes
Viable seed produced with both self-pollination and cross-pollination	Yes
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	No
Total points:	5
Total unknowns:	1
Total score:	B? 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	A, > 50%
	desert
	interior
Scrub and Chaparral	coastal bluff scrub
	coastal scrub
	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
	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):	D
	Distribution (highest score):	A

Infested Jepson Regions

Click here for a map of Jepson regions

Central West
Northwest
Southwest
Sonoran Desert

California Invasive Plant Council

Protecting California’s environment and economy from invasive plants

Plant Assessment Form

More Cakile maritima resources

Cakile maritima

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