Plant Assessment Form

Carpobrotus edulis

Common Names: highway iceplant

Evaluated on: 3/17/05

List committee review date: 08/07/2005

Re-evaluation date:


Elizabeth Brusati, project manager
California Invasive Plant Council
1442A Walnut St. #462, Berkeley, CA 94709
Peter Warner
California Dept. of Parks and Recreation
P.O. Box 603, Little River, CA 95456

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? High
Alert Status? No Alert
Documentation? 3.5 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes A. Severe Reviewed Scientific Publication
Four-part score AAUA Total Score
1.2 ?Impact on plant community A. Severe Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels U. Unknown
1.4 ?Impact on genetic integrity A. Severe/High Reviewed Scientific Publication
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Reviewed Scientific Publication
Total Points
16 Total Score B
2.2 ?Local rate of spread with no management A. Increases rapidly Other Published Material
2.3 ?Recent trend in total area infested within state B. Increasing less rapidly Observational
2.4 ?Innate reproductive potential
(see Worksheet A)
A. High Reviewed Scientific Publication
2.5 ?Potential for human-caused dispersal A. High Reviewed Scientific Publication
2.6 ? Potential for natural long-distance dispersal B. Occasional Reviewed Scientific Publication
2.7 ?Other regions invaded C. Already invaded Other Published Material
3.1 ?Ecological amplitude/Range
(see Worksheet C)
A. Widespread Reviewed Scientific Publication
Total Score A
3.2 ?Distribution/Peak frequency
(see Worksheet C)
B. Moderate 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? A Reviewed Scientific Publication
Identify ecosystem processes impacted:

Reduces soil pH and influences nutrient dynamics (1).

Sources of information:

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

Dense fibrous root system interferes with water uptake by other plants. Native shrubs increased in canopy size when iceplant was removed (1). Outcompetes grasses

Sources of information:

Question 1.3 Impact on higher trophic levels? U
Identify type of impact or alteration:

Presumable the plant would have an impact on other organisms within a dune and coastal bluff system, but no information in available to verify this.

Sources of information:

Question 1.4 Impact on genetic integrity? A Reviewed Scientific Publication

Hybridizes with native or long-naturalized congener C. chilensis, creating fertile hybrids (1). High potential for natural hybridization between Carpobrotus species (2). Score depends on whether C. chilensis is considered native.

Sources of information:

Section 2: Invasiveness
Question 2.1 Role of anthropogenic and natural disturbance
in establishment?
A Other Published Material
Describe role of disturbance:

Disturbance of the soil was required for colonization at a coastal grassland site, but soil disturbance did not promote establishment in coastal scrub or backdune. Without disturbance, Carpobrotus cannot become established within the matrix of annual grasses in the grassland. Needs rodent burrowing to open space for invasion (1). Commonly invades maritime chaparral after fire (2).

Sources of information:

Question 2.2 Local rate of spread with no management? A Other Published Material
Describe rate of spread:

Individual plants can expand more than a meter in diameter per year (1).

Sources of information:

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

May have occupied much of its habitat. In addition, there are a number of control programs around that have attempted to manage this species. Nevertheless, it is probably still expanding its range within the state.

Sources of information:

DiTomaso, observational.

Question 2.4 Innate reproductive potential? A Reviewed Scientific Publication
Describe key reproductive characteristics:

Perennial succulent with indehiscent fleshy fruits. Does not need cross-pollination and can produce seeds without fertilization (1). Produces over 1500 seeds/fruit (2,3). Fruits are produced between February and May. Ungerminated seeds remain viable for at least two years. Uneaten fruits remain on the plant for several years (4).

Sources of information:

Question 2.5 Potential for human-caused dispersal? A Reviewed Scientific Publication
Identify dispersal mechanisms:

Planted by the California Department of Transportation along highways (1). Sold as an ornamental (2). Found in Cal-IPC nursery survey 2004.

Sources of information:

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

Deer, brush rabbits, and jackrabbits eat the seeds and pass them intact. Seed germination is enhanced by ingestion. Viable seeds were found in deer feces >1km from the nearest plant, but this is not common (1, 2). Pieces can raft offshore and colonize stacks along coast (3). .enter text here

Sources of information:

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

Native to South Africa. Also an invasive plant in Mediterranean basin of Europe and in Australia (1). Also present in Florida (2). Scoring as C because it already invades many habitats in California.

Sources of information:

Section 3: Distribution
Question 3.1 Ecological amplitude/Range? A Reviewed Scientific Publication

Invades coastal grassland, coastal scrub, dunes (1), coastal bluff scrub, maritime chaparral, oak woodlands, and the margins of wetlands (2). Was introduced into the western United States for dune stabilization in the early 1900's (2).

Sources of information:

1. DAntonio C.M. 1993. Mechanisms Controlling Invasion of Coastal Plant Communities by the Alien Succulent Carpobrotus edulis. Ecology 74(1): 83-95.
2. D'Antonio, Carla M.; Odion, Dennis C.; Tyler, Claudia M. 1993. Invasion of maritime chaparral by the introduced succulent Carpobrotus edulis: The roles of fire and herbivory. Oecologia. 95(1): 14-21.

Question 3.2 Distribution/Peak frequency? B Other Published Material
Describe distribution:

Found in many dune systems throughout California.

Sources of information:

DiTomaso and Healy. 2006. Weeds of California. UC DANR Publ. #3488.

Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less No
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 No
Viable seed produced with both self-pollination and cross-pollination Yes
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: 9
Total unknowns: 0
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
DunescoastalB, 20% - 50%
Scrub and Chaparralcoastal bluff scrubB, 20% - 50%
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
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairieD, < 5%
valley and foothill grassland
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): B

Infested Jepson Regions

Click here for a map of Jepson regions

  • Central West
  • Northwest
  • Southwest