Plant Assessment Form

Hedera canariensis

Common Names: Algerian ivy

Evaluated on: 02/26/04 (modified 9/05)

List committee review date: 14/05/2004

Re-evaluation date:

Evaluator(s)

Tim Hyland / Resource Ecologist
California State Parks
303 Big Trees Park Drive, Felton CA 95018
(W) 831-335-6384 (H) 831-464-9141
tim.hyland@parks.ca.gov
Cynthia L. Roye
California State Parks
PO Box 942896, Sacramento, CA 95296-0001
(916) 653-9083
croye@parks.ca.gov

List commitee members

Cythia Roye
Carla Bossard
Alison Stanton
Joe DiTomaso
Peter Warner

General Comments

5/26/17 Note by Ramona Robison
This PAF was originally written for both Hedera helix and Hedera canariensis. It has now been split into two species and the information copied into each. Both PAFs should be updated with current scientific literature.

Table 2. Criteria, Section, and Overall Scores

Overall Score? High
Alert Status? No Alert
Documentation? 2.5 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes B Observational
Impact?
Four-part score BAAD Total Score
A
1.2 ?Impact on plant community A. Severe Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels A. Severe Observational
1.4 ?Impact on genetic integrity D. None Other Published Material
2.1 ?Role of anthropogenic and natural disturbance in establishment A. Severe Observational
Invasiveness?
Total Points
19 Total Score A
2.2 ?Local rate of spread with no management A. Increases rapidly Observational
2.3 ?Recent trend in total area infested within state A. Increasing rapidly Observational
2.4 ?Innate reproductive potential
(see Worksheet A)
A. High Reviewed Scientific Publication
2.5 ?Potential for human-caused dispersal A. High Other Published Material
2.6 ? Potential for natural long-distance dispersal A. Frequent Other Published Material
2.7 ?Other regions invaded C. Already invaded Other Published Material
3.1 ?Ecological amplitude/Range
(see Worksheet C)
A. Widespread Observational
Distribution?
Total Score A
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? B Observational
Identify ecosystem processes impacted:

C; Increased erosion in stream channels. By suppressing seedling establishment of woody understory shrubs dense stands of ivy can reduce the stability of stream banks that are stabalized by these deeply rooted plants.


Sources of information:

Tim Hyland, California State Parks Resource Ecologist pers. obsv.


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

A; Completely replace native vegetation, including trees, shrubs and herbaceous plants. Ivy largely eliminates the ability of other plants to reproduce by outcompeting their seedlings for light. In addition this plant smothers existing shrubs and trees by climbing and finally completely enshrouding them.


Sources of information:

Thomas, L. K. 1980. The impact of three exotic plant species on the Potomac Island. National Park Service Monograph Series. Number 13 Washington, DC.


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

B; Reduction in herbaceous low stature plants. Creation of a physical barrier to birds feeding on the ground. By obscuring the ground and reducing the growth of annual plants that act as a food source this plant reduces foraging habitat quality for ground feeding birds such as Dark-eyed Junco, Spotted and California Towhee etc.. Increased foraging of these species has been observed following the removal of English Ivy in oak woodland at Twin Lakes State Beach. This reduction of food resources in all likelihood would also impact small mamals that rely on these same food sources. These animals serve as food for meso mamals such as coyote, fox, weasels etc.


Sources of information:

Tim Hyland, California State Parks Resource Ecologist


Question 1.4 Impact on genetic integrity? D Other Published Material

D; None There is only one species native to Califorinia that is related at the family level to Hedera spp.. Although this plant Aralia californica occurs in habitats invaded by ivy there is no record of genetic exchange between Aralia and Hedera.


Sources of information:

1993. The Jepson Manual : higher plants of California / James C. Hickman, Editor. University of California Press, Berkeley and Los Angeles, Califronia.


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

A; No disturbance required to establish in native plant communities. Infestations frequently found in intact plant communities away from roads or trails, usually at the base of trees where birds perch.


Sources of information:

Tim Hyland, California State Parks Resource Ecologist pers. obsv.


Question 2.2 Local rate of spread with no management? A Observational
Describe rate of spread:

A; Increases rapidly in favorable habitat. Frequent seed deposition by various bird species serve to increase an already rapid spread by vegetative means. Ivy roots as it goes as well as spreading from fragments.


Sources of information:

Invasive Plants of California's Wildlands, 2000 Carla C. Bossard, John M. Randall, and Marc C. Hoshovsky, editors. University of California Press, Berkeley and Los Angeles, California.


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

B; Increasing Known populations throughout the Santa Cruz District that are not being worked on are actively spreading. This trend is also occuring in State Parks both north and south of the Monterey Bay area.


Sources of information:

California State Parks Condition Assesment, Ken Moore, founder Wildlands Restoration Team pers. com.. Peter Warner California State Parks Resource Ecologist North Coast Redwoods District. pers. com. Tim Hyland, California State Parks Resource Ecologist pers. obsv.


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

B; Vegetative fragments. Large quantities of seeds attractive to migratory birds 70% of seeds are viable. Seedlings are frequently found in concentrations under desireable roosting sites. American Robins often seen consuming berries. Fragments of plants in contact with soil after removal have been observed to resprout.


Sources of information:

Invasive Plants of California's Wildlands, 2000 Carla C. Bossard, John M. Randall, and Marc C. Hoshovsky, editors. University of California Press, Berkeley and Los Angeles, California. Tim Hyland, California State Parks Resource Ecologist pers. obsv.


Question 2.5 Potential for human-caused dispersal? A Other Published Material
Identify dispersal mechanisms:

A; Frequently sold and planted in landscape trade as groundcover. Found in many commercial landscapes. Some nurseries specialize in the growth of this plant and it's cultivars.


Sources of information:

http://hort.ifas.ufl.edu/shrubs/HEDHELA. The American Ivy Society http://www.ivy.org/. Sunset Western Garden Book. Tim Hyland, California State Parks Resource Ecologist pers. obsv.


Question 2.6 Potential for natural long-distance dispersal? A Other Published Material
Identify dispersal mechanisms:

A; Migratory birds American Robins have been observed eating the fruit of this species. These birds are migratory with a range that covers the entire state of California.


Sources of information:

1992 The National Geographic Society Field Guede to the Birds of North America, The National Geographic Society, Washington D.C. Tim Hyland, California State Parks Resource Ecologist pers. obsv. PCA Alien Plant Working Group. http://www.nps.gov/plants/alien/fact/hehe1.htm


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

C; Eastern seaboard of U.S. Widely planted in areas where it is able to grow.


Sources of information:

Plant invaders of the Mid-Atlantic Natural Areas http://www.nps.gov/plants/alien/pubs/midatlantic/hehe.htm


Section 3: Distribution
Question 3.1 Ecological amplitude/Range? A Observational

A; Widespread. Introduction likely in early 1900s. Although it is found in State Park Units in the Sierra Foothills, it does not seem to be agressively invading. This is not the case with the populations found on the coast where it is currently expanding. This plant was well known to early settlers and is found in abundance near homesteads that were inhabited in the early 1900s


Sources of information:

Invasive Plants of California's Wildlands, 2000 Carla C. Bossard, John M. Randall, and Marc C. Hoshovsky, editors. University of California Press, Berkeley and Los Angeles, California. Tim Hyland, California State Parks Resource Ecologist pers. obsv. 2003. Peter Warner California State Parks Resource Ecologist North Coast Redwoods District. pers. com. 2004


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

A; Widesrpead. Found in Riparian Woodland, Riparian Forest, North Coast Coniferous Forest, Closed Cone Coniferous Forest, Broad Leaved Upland Forest, Lower Montain Coniferous Forest and Coastal Scrub adjacent to Oak Woodland. See worksheet This plant thrives with year round moisture, and a heavy duff layer seems to assist in seedling establishment. It also appears to be much more drought tolerant in shaded sites so does not compete well in grasslands or chaparral communities. Although it will grow near the coast, it seems intolerant of direct salt spray.


Sources of information:

Invasive Plants of California's Wildlands, 2000 Carla C. Bossard, John M. Randall, and Marc C. Hoshovsky, editors. University of California Press, Berkeley and Los Angeles, California. Tim Hyland, California State Parks Resource Ecologist pers. obsv. 2003. Peter Warner California State Parks Resource Ecologist North Coast Redwoods District. pers. com. 2004 Alien Plant Working Group. http://www.nps.gov/plants/alien/fact/hehe1.htm


Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less No
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 No
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 Yes
Fragments easily and fragments can become established elsewhere No
Resprouts readily when cut, grazed, or burned Yes
Total points: 6
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
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 prairie
valley and foothill grassland
Great Basin grassland
vernal pool
meadow and seep
alkali playa
pebble plain
Bog and Marshbog and fen
marsh and swampC, 5% - 20%
Riparian and Bottomland habitatriparian forestB, 20% - 50%
riparian woodland
riparian scrub (incl.desert washes)
Woodlandcismontane woodland
piñon and juniper woodland
Sonoran thorn woodlandC, 5% - 20%
Forestbroadleaved upland forestA, > 50%
North Coast coniferous forestC, 5% - 20%
closed cone coniferous forestD, < 5%
lower montane coniferous forest
upper montane coniferous forest
subalpine coniferous forest
Alpine Habitatsalpine boulder and rock field
alpine dwarf scrub
Amplitude (breadth): A
Distribution (highest score): A

Infested Jepson Regions

Click here for a map of Jepson regions