Plant Assessment Form

Hypericum canariense

Synonyms: Hypericum floribundum

Common Names: Canary Island St. Johnswort; Grenadillo

Evaluated on: 13-Jan-05

List committee review date: 11/03/2005

Re-evaluation date:

Evaluator(s)

Katrina M. Dlugosch / Doctoral Student
Univeristy of California - Santa Cruz
E E Biology/ EMS Santa Cruz, CA 95064
(831) 459-3677
dlugosch@biology.ucsc.edu

List commitee members

Joe DiTomaso
John Randall
Carla Bossard

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? Moderate
Alert Status? Alert
Documentation? 2 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes U Reviewed Scientific Publication
Impact?
Four-part score UACU Total Score
B
1.2 ?Impact on plant community A. Severe Observational
1.3 ?Impact on higher trophic levels C. Minor
1.4 ?Impact on genetic integrity U. Unknown
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 Anecdotal
2.3 ?Recent trend in total area infested within state B. Increasing less rapidly Anecdotal
2.4 ?Innate reproductive potential
(see Worksheet A)
A. High Observational
2.5 ?Potential for human-caused dispersal C. Low Anecdotal
2.6 ? Potential for natural long-distance dispersal C. Rare Observational
2.7 ?Other regions invaded C. Already invaded Other Published Material
3.1 ?Ecological amplitude/Range
(see Worksheet C)
B. Moderate Other Published Material
Distribution?
Total Score C
3.2 ?Distribution/Peak frequency
(see Worksheet C)
D. Very low Anecdotal

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? U Reviewed Scientific Publication
Identify ecosystem processes impacted:

Sources of information:

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

Formation of monotypic stands, with no additional species below the canopy of this tall shrub.


Sources of information:

K. Dlugosch, Personal observation in California and Hawaii (2001-2005).


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

The entire family of Hypericum is poisonous to livestock. Seed is too small to be food for native species.


Sources of information:

Joe DiTomaso, UC Davis, pers. obs.


Question 1.4 Impact on genetic integrity? U

Some native Hypericum but this species probably doesn't encounter them.


Sources of information:

Joe DiTomaso, UC Davis


Section 2: Invasiveness
Question 2.1 Role of anthropogenic and natural disturbance
in establishment?
B Anecdotal
Describe role of disturbance:

Soil disturbance or vegetation removal may provide sites of reduced competition and abundant light for new seedlings.


Sources of information:

Munz, P. (1968). Supplement to A California Flora. Berkeley, University of California Press.
Smith, C. (1976). A flora of the Santa Barbara region, California: an annotated catalogue of the native and naturalized plants of the Santa Barbara County mainland and nearby Channel Islands. Santa Barbara, Santa Barbara Museum of Natural History.
Wagner, W.L., D.R. Herbst, and S.H. Sohmer. 1999. Manual of the Flowering Plants of Hawai'i. 2 vols. Bishop Museum Special Publication 83, University of Hawai'i and Bishop Museum Press, Honolulu, HI.
Mike Kelly (California Invasive Plant Council) - 2001 Personal communication
K. Dlugosch, Personal observations (2001-2005)


Question 2.2 Local rate of spread with no management? B Anecdotal
Describe rate of spread:

Local land owners/stewards have witnessed large increases in population size over (at least) the past five years.


Sources of information:

Warren McCord (Kula Botanical Gardens - Maui) - 2003 Personal communication
John Wade (Pescadero Conservation Alliance) - 2001 Personal communication
Mary Platter Rieger (US Navy Biology - Point Loma San Diego) - Personal communication


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

Rapid expansion at sites of intial introduction at several locations on the CA coast, but new foci of invasion have rarely been reported from other locations (though expansion through urban San Diego appears to be quite extensive).


Sources of information:

Mike Kelly (California Invasive Plant Council) - 2001 Personal communication
John Wade (Pescadero Conservation Alliance) - 2001 Personal communication
Bob Allen (California State University, Fullerton) - 2004 Personal communication
K. Dlugosch, Personal observations (2001-2005)


Question 2.4 Innate reproductive potential? A Observational
Describe key reproductive characteristics:

Reproductive maturity is reached in as little as one year. Each fruit produces several hundred seeds, and large plants may produce a few hundred fruits. Seed production occurs every year from June through September. Viable fruits can be made via self-pollination or cross-pollination. Seed longevity is unknown. This plant will spread through underground rhizomes, but it is unclear how quickly this occrurs. Control has been attempted via topical herbicide, but plants resprout readily.


Sources of information:

Katrina Dlugosch - unpublished data


Question 2.5 Potential for human-caused dispersal? C Anecdotal
Identify dispersal mechanisms:

Still sold as an ornamental but not widely cultivated.


Sources of information:

Consensus of weed committee.


Question 2.6 Potential for natural long-distance dispersal? C Observational
Identify dispersal mechanisms:

Has very small seeds that fall to ground and probably are not spread far.


Sources of information:

Joe DiTomaso, UC Davis, pers. obs.


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

Invading Mediterranean-type grasslands in Hawaii (Maui) and areas of Victoria and Western Australia, Australia.


Sources of information:

Maui: Wagner, W.L., D.R. Herbst, and S.H. Sohmer. 1999. Manual of the Flowering Plants of Hawai'i. 2 vols. Bishop Museum Special Publication 83, University of Hawai'i and Bishop Museum Press, Honolulu, HI.
Western Australia: Sandy Lloyd (with State Weed Plan - W. Austr. Dept of Agr.) - 2002 Personal communication
Victoria, Australia: Michael Hansford (with Dept of Primary Industries) - 2002 Personal communication


Section 3: Distribution
Question 3.1 Ecological amplitude/Range? B Other Published Material

This species was introduced first as an ornamental at the turn of the 20th century, but was probably introduced to particular areas much later. All known invasions are in coastal areas receiving substantial inputs of fog. This habitat is similar to that of the native range, where H. canariense is common on the foggy sides of the mountainous Canary Islands, but is very rare on the drier faces. It is likely that H. canariense will continue to invade only the coastal areas of the state, but its success in both San Deigo and San Mateo counties suggests that it is a major threat to CA coast.


Sources of information:

Munz, P. (1968). Supplement to A California Flora. Berkeley, University of California Press.
Smith, C. (1976). A flora of the Santa Barbara region, California: an annotated catalogue of the native and naturalized plants of the Santa Barbara County mainland and nearby Channel Islands. Santa Barbara, Santa Barbara Museum of Natural History.
Hickman, J. C. 1993. The Jepson Manual: Higher Plants of California. U of CA Press, Berkeley.
Personal observation in CA, HI and the Canary Islands 2001-2005.


Question 3.2 Distribution/Peak frequency? D Anecdotal
Describe distribution:

Known invading populations:
San Mateo County - coastal grassland and scrub near Franklin Point.
Orange County - Dana Point, San Juan Capistrano
San Deigo city - widespread on coastal grassalnd and sage scrub
Angel Island in San Francisco Bay (unconfirmed)


Sources of information:

K. Dlugosch Personal Observations (2001-2005)
Bob Allen (California State University, Fullerton) - 2004 Personal communicaiton
Dave Boyd (California State Parks) - 2002 Personal communication


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 Yes
Seeds remain viable in soil for three or more years Unknown
Viable seed produced with both self-pollination and cross-pollination Yes
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes Unknown
Fragments easily and fragments can become established elsewhere No
Resprouts readily when cut, grazed, or burned Yes
Total points: 7
Total unknowns: 2
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
estuaries
Dunescoastal
desert
interior
Scrub and Chaparralcoastal bluff scrub
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
chaparral
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): D

Infested Jepson Regions

Click here for a map of Jepson regions

  • Central West
  • Northwest
  • Sierra Nevada
  • Southwest