Source: California Invasive Plant Council


URL of this page: http://www.cal-ipc.org/site/paf/323
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Cal-IPC Plant Assessment Form

For use with "Criteria for Categorizing Invasive Non-Native Plants that Threaten Wildlands"
by the California Invasive Plant Council and the Southwest Vegetation Management Association

Table 1. Species and Evaluator Information

Species name
(Latin binomial):
The official Latin binomial name for this species. Specify only one name here. Additional species names may go into the Synonyms field.

Delairea odorata

Synonyms:
Additional Latin binomial names for this species. Separate multiple names with a ; character. Please avoid narrative descriptions, and list only the binomial names.
Senecio mikanioides
Common names:
Common names for this species. Separate multiple names with a ; character.
Cape-ivy; German ivy; Italian ivy; ivy groundsel; parlor ivy; water ivy
Evaluation date:
The date(s) when this species PAF was filled out, modified, or reviewed. This is free-form text, so it may include multiple dates or other notes.
12/29/04
Evaluator #1 Gina Skurka, Agricultural Technician
California Department of Food and Agriculture
1220 N Street, Room A-357, Sacramento, CA 95814
(916) 654-0768
gskurka@cdfa.ca.gov
Evaluator #2 Elizabeth Brusati, project manager
California Invasive Plant Council
1442-A Walnut St. #462, Berkeley, CA 94709
510-843-3902
edbrusati@cal-ipc.org
List committee members: Joe DiTomaso, John Randall, Carla Bossard
Committee review date: 3/11/05
List date:
Re-evaluation date(s):
General comments
on this assessment:
Enter any additional notes about this assessment, such as factors affecting the reliability or completeness of the answers, likely affects of impacts, or research which is not specific to California but is still relevant in the evaluation of this species.

Table 2. Criteria, Section, and Overall Scores

Overall Score

Plant scoring matrix
Based on letter scores from Sections 1 through 3 below

ImpactInvasivenessDistribution
AA BAnyHighNo Alert
AC DAnyModerateAlert
BA BA BModerateNo Alert
BA BC DModerateAlert
BC DAnyLimitedNo Alert
CAA BModerateNo Alert
CAC DLimitedNo Alert
CBAModerateNo Alert
CBB DLimitedNo Alert
CCAnyLimitedNo Alert
DAnyAnyNot ListedNo Alert

High

Alert Status

Plant scoring matrix
Based on letter scores from Sections 1 through 3 below

ImpactInvasivenessDistributionAlert
AA or BC or DAlert
BA or BC or DAlert

No Alert

Documentation

The total documentation score is the average
of Documentation scores given in Table 2.

Reviewed Scientific Publication4 points
Other Published Material3 points
Observational2 points
Anecdotal1 points
Unknown or No Information0 points

2.4 out of 5

Score Documentation
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.
A. Severe Other Published Material
Impact
Section 1 Scoring Matrix
Q 1.1Q 1.2Q 1.3Q 1.4Score
AAAnyAnyA
ABA,BAnyA
ABC,D,UAnyB
AC,D,UAnyAnyB
BAAAnyA
BABAA
BAB,CB-D,UB
BAC,D,UAA
BAC,D,UB-D,UB
BBAAA
BC,D,UAAB
BB-DAB-D,UB
BB-DB-D,UAnyB
BD,UC,D,UA-BB
BD,UC,D,UC,D,UC
C-D,UAAAnyA
CBAAnyB
CA,BB-D,UAnyB
CC,D,UAnyAnyC
DA,BBAnyB
DA,BC,D,UAnyC
DCAnyAnyC
DD,UAnyAnyD
UAB,CAnyB
UB,CA,BAnyB
UB,CC,D,UAnyC
UUAnyAnyU


Four-part score
AAAD

Total Score
A
1.2 Impact on plant community
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.
A. Severe Reviewed Scientific Publication
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.
A. Severe Other Published Material
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. None Other Published Material
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.
A. Severe Other Published Material
Invasiveness
Section 2 Scoring Matrix
Total pointsScore
17-21A
11-16B
5-10C
0-4D
More than two U’sU


Total Points
19

Total Score
A
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
A. Increases rapidly Other Published Material
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
A. Increasing rapidly Other Published Material
2.4 Innate reproductive potential
(see Worksheet A)
Assess the innate reproductive potential of this species. Worksheet A is provided for computing the score.
A. High
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.
B. Moderate Other Published Material
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. Frequent Other Published Material
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.
B. Invades 1 or 2 ecological types Other Published Material
3.1 Ecological amplitude/Range
(see Worksheet C)
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.
A. Widespread
Distribution
Section 3 Scoring Matrix
Q 3.1Q 3.2Score
AA, BA
AC,D,UB
BAA
BB,CB
BDC
CA,BB
CC,DC
DAB
DB,CC
DDD
A,BUC
C,DUD
UUU


Total Score
B
3.2 Distribution/Peak frequency
(see Worksheet C)
To assess distribution, record the letter that corresponds to the highest percent infested score entered in Worksheet C for any ecological type.
C. Low

Table 3. Documentation

Scores are explained in the "Criteria for Categorizing Invasive Non-Native Plants that Threaten Wildlands".
Short citations may be used in this table. List full citations at end of this table.

Section 1: Impact

Other Published Material A 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.
Identify ecosystem processes impacted:
Dense canopy blocks sunlight from reaching plants underneath. Contains potent alkaloids including pyrrolizidine, which can be leached into water. Due to its shallow root system, cape ivy can contriubte to serious soil erosion problems on hillsides. Flood control function along streems is impacted by infestations Severe or moderate alteration of ecosystem processes. Decreases light availability and releases toxins into the water.

Sources of information:
Bossard, C. 2000. Delairea odorata. In, Invasive Plants of California’s Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley. Nelson, D. 1999. Cape Ivy, Another Problem Plant for the Ventana Wilderness. The Double Cone Quarterly. Spring Equinox 1999, Vol II, No I, <>.

Reviewed Scientific Publication A 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.
Identify type of impact or alteration:
Associated with reductions in the species richness and diversity of both native and nonnative species. Abundance of native and nonnative seedlings were each significantly lower in plots invaded by Cape ivy compared to uninvaded plots. It grows rapidly and forms a thick blanket, which not only covers and smothers the other vegetation on the ground, but it clambers over small shrubs, and up trees and other vertical objects to a height of eight meters, frequently killing these as well. Formation of stands dominated (>75% cover) by this species. Severe alteration of plant community composition and structure.

Sources of information:
Alvarez, M.E and J.H. Cushman. 2002. Community-Level Consequences of a Plant Invasion: Effects on Three Habitats in Coastal California. Ecological Applications 12(5) pp. 1434 - 1444. Balciunas, J, E. Grobbelaar, R. Robison, and S. Neser. Distribution of Cape ivy (Delairea odorata), a growing threat to western riparian ecosystems. For publication in J. Aquatic Plant Management. Bossard, C. 2000. Delairea odorata. In, Invasive Plants of California’s Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley.

Other Published Material A 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.
Identify type of impact or alteration:
Eleven different pyrrolizidine alkaloids, which are potent mammalian hepato-toxins, have been detected in Cape ivy and some of these are consumed and sequestered by migrating monarch butterflies. When dipped into an aquarium, Cape ivy will kill fish and a variety of aquatic insects. Refuges created as reserves for native animal and plant species are rendered worthless when large portions of their acreage are occupied by Cape ivy. Underlying vegetation and pre-invasion microclimates are obliterated. Additional Golden Gate National Recreation Area vegetation communities infested with Cape ivy support two federally endangered butterflies, federally threatened coho salmon and steelhead, and federal endangered freshwater shrimp. Cape ivy's occurrence in habitats used by these species may have some detrimental effects on their declining populations. Endangerment of existing native species/population. Severe/moderate alteration of higher trophic populations.

Sources of information:
Balciunas, J, E. Grobbelaar, R. Robison, and S. Neser. Distribution of Cape ivy (Delairea odorata), a growing threat to western riparian ecosystems. For publication in J. Aquatic Plant Management. Archbald, G. (1995) Biology and Control of German Ivy: An Update for California Department of Fish & Game, Pesticide Applicators Seminar. DiTomaso, J. and E. Healy. Weeds of California and Other Western States, (Unpublished). Robison, R. (2000) Distribution, Reproductive Dynamics and Physiology of Cape ivy (Delairea odorata syn Senecio mikanioides), an Invasive Wildland Weed of the Pacific Coast (Unpublished).

Other Published Material D 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.
Identify impacts:
Cape ivy is not known to reproduce readily by seed in North America; however, viable seed was found in California. No known hybridization.

Sources of information:
Bossard, C. 2000. Delairea odorata. In, Invasive Plants of California’s Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley. Robison, R. (2000) Distribution, Reproductive Dynamics and Physiology of Cape ivy (Delairea odorata syn Senecio mikanioides), an Invasive Wildland Weed of the Pacific Coast (Unpublished). Robison, R. E-mail communication. 1/4/2005.

Section 2: Invasiveness

Other Published Material A 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.
Describe role of disturbance:
Takes over habitats regardless of anthropogenic or natural disturbance. Cape ivy on the west coast prefers and grows vigorously in physically challenging environments such as streamside thickets, willows and poison oak. Severe invasive potential. This species can establish independent of natural or anthropogenic disturbance.

Sources of information:
Archbald, G and J. Sigg. (1998) A Modified Proposal for Biocontrol of Cape Ivy.

Other Published Material A 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
Describe rate of spread:
Cape ivy spread in the Marin headlands from 8.8 acres in 1987 to 67.3 acres in 1996 (765% in 9 years). A 1987 survey in a portion of the Golden Gate National Recreation Area located 3.6 hectares of Cape ivy, which when resurveyed 9 years later, had expanded nearly nine-fold to 27.2 hectares. Increases rapidly, doubling in less than 10 years.

Sources of information:
Nelson, D. 1999. Cape Ivy, Another Problem Plant for the Ventana Wilderness. The Double Cone Quarterly. Spring Equinox 1999, Vol II, No I, <>. Balciunas, J, E. Grobbelaar, R. Robison, and S. Neser. Distribution of Cape ivy (Delairea odorata), a growing threat to western riparian ecosystems. For publication in J. Aquatic Plant Management.

Other Published Material A 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
Describe trend:
D. odorata ranges along the entire California coast and some mesic areas of the Central Valley. Over 500,000 acres are infested in California, and on Catalina Island, 13 populations were detected with 6 in riparian habitats and 1 in island scrub oak chaparral near a riparian area. All populations were small with sparse cover. Many of the plants were less than 2 feet long, indicating new establishment. D. odorata has been targeted for control at the Catalina Island Conservancy, Marin Headlands, Golden Gate National Park, Parks within Santa Cruz County, Dos Palmas Reserve, Lake Mead National Recreational Area, Elkhorn Slough National Estuarine Research Reserve, Big Sur and San Luis Creek and San Simeon in San Luis Obispo. It can tolerate both freezing and drought, indicating a wide range of climatic preferences. On Catalina Island, 13 populations were recorded in 2003 totalling 13,825 square feet.

Sources of information:
Bossard, T. 2000. Delairea odorata. In, Invasive Plants of California’s Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley Knapp, J.J. 2004. Catalina Invasive Plant Ranking Plan for the Catalina Island Conservancy. Unpublished. Starr, F., Starr, K. and Loope, L. 2003. Delairea odorata. Nature Conservancy Stewarship Element Abstract. United States Geological Survey- Biological Resources Division. Hakeakala Field Station, Maui, Hawai'i.Skinner, M. 2003. Personal communication. Sigg, J. 1994. Invasive exotics report. Bulletin of the California Native Plant Society 24(3): 6. Paraphrased in: Restoration and Management Notes 13(1): 132. Shoulders, C., Hatch, D. and Holmes, A.L., Scoggin, S.E. and Geupel, G.R. 2002. Songbird monitoring in the Golden Gate National Recreation Area: a multifaceted tool for guiding the restoration of Redwood Creek. Park Science 21(1):28-32. Elliot, W. 1994. German ivy engulfing riparian forests and heading for the uplands. CalEPPC News 2(1): 9. Alvarez, M.E. and J.H. Cushman. 2002. Community-level consequences of a plant invasion: effects on three habitats in coastal California. Ecological Applications 12(5): 1434-1444. Elkhorn Slough National Estuarine Research Reserve. 2000. Weed control by species. Elkhorn Slough National Estuarine Research Reserve. Pp. 1-57..

A Question 2.4 Innate reproductive potential
Assess the innate reproductive potential of this species. Worksheet A is provided for computing the score.
Describe key reproductive characteristics:
Cape ivy spreads primarily by vegetative means, breaks apart easily and both stem nodes and leaf petioles are capable of rooting. Insect-pollinated. Reproduces vegetatively from rhizomes, stolons, and fragments of rhizomes, stolons and stems and in some locations, by seed. While most seeds produced are not viable, some viable seeds develop in most sites throughout California and Oregon D. odorata is a perennial that reproduces mainly by the proliferation of stolons in California, but produces viable seed in its native range and areas invaded in Australia; however, untill recently in California no viable seed was thought to be produced. Flowering occurs extensively during December to February, and the flowers are self-incompatible. 95% of all stolons containing only 1 node establish. Rapid vegetative regrowth occurs between February and June. Drying stolons in the sun for ten weeks does not inhibit their ability to root. .

Sources of information:
Nelson, D. 1999. Cape Ivy, Another Problem Plant for the Ventana Wilderness. The Double Cone Quarterly. Spring Equinox 1999, Vol II, No I, <>. DiTomaso, J. and E. Healy. Weeds of California and Other Western States, (Unpublished). Robison, R. E-mail communication. 1/4/2005. Balciunas, J. 2001. Viable seed production by cape ivy in California finally confirmed. CalEPPC News 9(2): 13.

Other Published Material B 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.
Identify dispersal mechanisms:
Cape ivy is being sold as an ornamental in North America. Fragments as short as one half inch, carried by runoff or landscape machinery, can take root and colonize new areas. Listed in Sunset Western Garden Book.

Sources of information:
Balciunas, J, E. Grobbelaar, R. Robison, and S. Neser. Distribution of Cape ivy (Delairea odorata), a growing threat to western riparian ecosystems. For publication in J. Aquatic Plant Management. Alvarez, M. (1997) Management of Cape-ivy (Delairea odorata) in the Golden Gate National Recreation Area. CalEPPC 1997 Symposium Proceedings. Found in Cal-IPC nursery survey 2004. Brenzel, K. N. 2001. Sunset Western Garden Book. Sunset Publishing Company, Menlo Park, CA

Other Published Material A 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.
Identify dispersal mechanisms:
Seeds disperse with wind, water, and soil movement. If there is a Cape ivy source upstream, high water flows in the winter can be expected to transport pieces of plants down-stream, which can begin new colonies. Occasional long distance dispersal by animals or abiotic mechanisms.

Sources of information:
Moore, K. (1997) Battling the Kudzu of the West: Controlling Cape Ivy (formerly German ivy) by Hand Removal. CalEPPC News, Fall 1997, Page 4.

Other Published Material B 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.
Identify other regions:
Also present in Oregon and Hawaii. Listed as a noxious weed in Australia. Present in Italy and Spain.

Sources of information:
USDA, NRCS. 2004. The PLANTS Database, Version 3.5 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

Section 3: Distribution

A 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.
Describe ecological amplitude, identifying date of source information and approximate date of introduction to the state, if known:
D. odorata was first introduced to the North American east coast in the 1850's, and Marin County and Golden Gate Park, California in the 1950's for landscaping. Within 10 years it became naturalized. In California, populations have been found in following communities: grasslands, open oak forests, coastal scrub, Monterey pine forests, coastal bluff, riparian forests, old growth forests, seasonal wetlands, dunes, serpentine soil, and exotic shrub and forest communities. Also grows under eucalyptus trees, unlike most other species (Bossard, pers. obs.)

Sources of information:
Bossard, C.C. 2000. Delairea odorata. Bossard, C.C., J.M. Randall, and M.C. Hoshovsky, (eds). Pp. 154-158. In, Invasive plants of California’s wildlands. Berkeley, California: University of California Press. Elliot, W. 1994. German ivy engulfing riparian forests and heading for the uplands. CalEPPC News 2(1): 9. Hamingson, E.E. and M.E. Alvarez. 2000. Assessing cape-ivy control in two California National Parks. P. 36 in: Kelley, M. (ed.). 2003. Proceedings of the California Exotic Pest Plant Council Symposium Vol. 6: 2000-2002. Dudley, T. 1998. Exotic plant invasions in California riparian areas and wetlands. Fremontia 26(4): 24-29. Freitzke, S. and P. Moore. 1998. Exotic plant management in National Parks of California. Fremontia 26(4):49-53.

C 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.
Describe distribution:
see 3.1

Sources of information:

Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less Yes, 1 points
Dense infestations produce >1,000 viable seed per square meter No
Populations of this species produce seeds every year. Yes, 1 points
Seed production sustained over 3 or more months within a population annually No
Seeds remain viable in soil for three or more years No
Viable seed produced with both self-pollination and cross-pollination No
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes Yes, 1 points
Fragments easily and fragments can become established elsewhere Yes, 2 points
Resprouts readily when cut, grazed, or burned Yes, 1 points
Total points: 6
Total unknowns: 0
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).
Note any related traits:
Return to Table 2

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 Systemsmarine systems
Freshwater and Estuarine lakes, ponds, reservoirs
Aquatic Systemsrivers, streams, canals
estuaries
Dunescoastal
desert
interior
Scrub and Chaparralcoastal bluff scrubD. < 5%
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, coastal prairieD. < 5%
Meadows, and other Herbvalley and foothill grassland
CommunitiesGreat Basin grassland
vernal pool
meadow and seep
alkali playa
pebble plain
Bog and Marshbog and fen
marsh and swamp
Riparian and Bottomland habitatriparian forestC. 5% - 20%
riparian woodlandD. < 5%
riparian scrub (incl.desert washes)
Woodlandcismontane woodland
piñon and juniper woodland
Sonoran thorn woodland
Forestbroadleaved upland forest
North Coast coniferous forestD. < 5%
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)  
Distribution (highest score)  
Return to Table 2

Addendum J - Jepson Regions Infested
 
Click here for a map of Jepson regions

Infested Jepson Regions:
Check the boxes to indicate the Jepson floristic provinces in which this species is found.














Addendum L - External Links & Resources

Cal-IPC Plant Profile
The Cal-IPC Plant Profile for this species.
http://www.cal-ipc.org/ip/management/plant_profiles/Delairea_odorata.php
Calflora Plant Profile:
The Calflora Plant Profile for this species.
http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=9623
CalWeedMapper:
Load CalWeedMapper with this species already selected.
http://calweedmapper.cal-ipc.org/maps/?species=66