Source: California Invasive Plant Council


URL of this page: http://www.cal-ipc.org/site/paf/543
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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.

Clematis vitalba

Synonyms:
Additional Latin binomial names for this species. Separate multiple names with a ; character. Please avoid narrative descriptions, and list only the binomial names.
Anemone vitalba
Common names:
Common names for this species. Separate multiple names with a ; character.
old man's beard; traveler's joy
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.
December 23, 2016
Evaluator #1 Mona Robison/Science Program Manager
Cal-IPC
916-802-2004
rrobison@cal-ipc.org
List committee members: Elizabeth Brusati, Tim Hyland, Eric Wrubel, Irina Irvine, Holly Forbes
Committee review date: January 25, 2017
List date: June 2, 2017
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.
C. vitalba has only recently been identified in California (2014). It is not included in the Jepson Manual, and in Muir Woods it was misidentified for many years as C. ligusticifolia, which may be true elsewhere in the state. These two species can only be reliably differentiated in flower.

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

Moderate

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

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

3.2 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.
B. Moderate Reviewed Scientific Publication
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
BABC

Total Score
B
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.
B. Moderate Reviewed Scientific Publication
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.
C. Minor / Low 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.
B. Moderate Reviewed Scientific Publication
Invasiveness
Section 2 Scoring Matrix
Total pointsScore
17-21A
11-16B
5-10C
0-4D
More than two U’sU


Total Points
18

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 Observational
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. Stable Observational
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 Reviewed Scientific Publication
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.
A. High 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 Reviewed Scientific Publication
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.
A. Invades 3 or more ecological types Reviewed Scientific Publication
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.
B. Moderate Observational
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
C
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.
D. Very low Observational

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

Reviewed Scientific Publication B 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:
In California, C. vitalba has smothered over 1.5 acres of riparian oak-bay woodland at Muir Woods, where it forms large monocultures. The dense canopy suppresses all vegetation below by significantly reducing light availability (Wrubel, pers. comm.). Restricts light availability for species under the canopy. Hill et al. (2001) report that, "Vines can climb the tallest forest trees, forming a dense, light-absorbing canopy that suppresses all vegetation beneath it. C. vitalba can be so vigorous that the weight of foliage and stems breaks the supporting trees, reducing once-healthy forest to a low, long-lived thicket of vines scrambling over stumps and logs". However Ogle et al. (2000) observe that the vines ascend to the canopy of forest but are unable to climb large diameter emergent trees unless shrubs and smaller trees provide a series of stepping stones to the crown of tall trees. Their study findings (study area Taihape reserve, New Zealand) indicate that the numbers and variety of understorey trees and shrubs that have been severely reduced following the infestation of C. vitalba correlates with observations of the growth habit of C. vitalba. Ogle et al. showed e.g. that not a single canopy tree species had been lost from the Taihape Reserves though 25% or so of the understorey trees and shrubs species had been lost.

Sources of information:
GISD 2005 Ogle et al. 2000 Hill et al. 2001 Wrubel, E., Personal communication.

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:
In California, C. vitalba has smothered over 1.5 acres of riparian oak-bay woodland at Muir Woods, where it forms large monocultures. The dense canopy suppresses all vegetation below. Shrub and herb diversity is severely reduced under dense infestations (Wrubel, pers. comm.). This is also consistent with its behavior in Santa Cruz County (Hyland pers. comm.). Forms dense, smothering blanket over trees. Loss of forest structure and biodiversity at ecosystem and species levels, loss of recruitment of native shrubs in New Zealand. Dense, smothering cover can block movement through trees. It is invasive because it forms a dense smothering blanket over native trees, impeding their growth and increasing wind and ice damage. The vine rapidly climbs into the crown by its leaf tendrils. It invades forests from the edge or in canopy gaps, alters their structure and reduces the diversity of native understory species (Weber 2003).

Sources of information:
Bungard 1996 Ogle et al. 2000 Weber 2003 Hyland, T., Personal communication. Wrubel, E., Personal communication.

Reviewed Scientific Publication B 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:
In California, C. vitalba has smothered over 1.5 acres of riparian oak-bay woodland at Muir Woods, where it forms large monocultures. The dense canopy suppresses all vegetation below and may impede movement of humans and animals (Wrubel, pers. comm.). In Santa Cruz County the infestation is 60 acres and there C. vitalba plants also grow over trees and may block movement (Hamey, pers. comm.). The changes caused to habitat structure by the growth of vines over trees and in thick masses on the forest floor would impede the movement of wildlife and change the diversity of plants in the understory.

Sources of information:
Weber 2003 Hamey, N., Personal communication. Wrubel, E., Personal communication.

Other Published Material C 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:
C. vitalba could have the potential to hybridize with the native Clematis species (C. ligusticifolia and C. lasiantha) which overlap with its range, but there is no documentation that this is able to occur. C. vitalba has been artificially hybridized with other species to produce vigorous garden varieties such as C. x jouiniana (C. vitalba x C. davidiana or C. vitalba x C. heracleifolia) and C. 'Paul Farges' ('summer snow') (C. vitalba x C. potanini) (CABI 2015). Since C. vitalba co-occurs with native Clematis this is scored as Minor, without evidence for hybridization.

Sources of information:
CABI 2015

Section 2: Invasiveness

Reviewed Scientific Publication B 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:
This species may occasionally establish in undisturbed areas, but can readily establish in areas with natural disturbance. In Muir Woods, C. vitalba occasionally establishes in undisturbed forest and woodland, and frequently establishes in naturally disturbed riparian vegetation (Wrubel, pers. comm.). In Santa Cruz County C. vitalba is thought to have been introduced in the town of San Vicente which was located in the San Vicente Creek watershed. This historic town was established for workers at a nearby limestone quarry and is now uninhabited (Hamey, pers. comm.). C. vitalba is able to establish in areas with natural or human-caused disturbance, but is not known to establish in undisturbed natural areas. C. vitalba requires high light for growth and reproduction, and is tolerant of moderate shade. In seedling germination studies done in forests, C. vitalba seedlings did not survive in undisturbed forests with low light levels. It was also found that nitrogen may be the limiting nutrient resource (Bungard et al. 1998). C. vitalba is a successful weed because it can tolerate dense shade but also has the ability to grow rapidly in high-light environments, meaning it can establish in areas with very small forest canopy gaps (Baars and Kelly 1996).

Sources of information:
Bungard et al. 1997 Baars and Kelly 1996 Hamey, N. Personal communication. Wrubel, E. Personal communication.

Observational 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:
Without management, C. vitalba has the potential to spread rapidly into disturbed forest edges and canopy gaps where light is available. In Marin County it is reported as spreading rapidly and the population size has doubled since management began (Wrubel, pers. comm.). In Santa Cruz County C. vitalba was first detected in 2009 or 2010, and control work did not begin until 2012. The population is now estimated to be 60 acres and is increasing in density where it occurs (Hamey, pers. comm.).

Sources of information:
Hamey, N. Personal communication. Wrubel, E. Personal communication.

Observational C 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:
Once introduced, C. vitalba has the potential to spread rapidly into forest edges and canopy gaps. In Marin County it is reported as spreading rapidly and the population size has doubled since management began (Wrubel, pers. comm.). In Santa Cruz County C. vitalba was first detected in 2009 or 2010, and control work did not begin until 2012. The population is now estimated to be 60 acres and is increasing in density where it occurs (Hamey, pers. comm.). Given the recent detection of this species in California, and the fact that both known populations are under management, the question is scored as stable and will be changed if more information becomes available.

Sources of information:
Hamey, N. Personal communication. Wrubel, E. Personal communication.

Reviewed Scientific Publication 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:
Roots can resprout. Aerial shoots touching ground after cutting may become rooted. Seed production is high. An estimated 17,000 viable seeds are produced per 0.5 square meters in areas where it is a canopy species. Seed production is possible after one to three years, depending on the exposure to full sunlight. Asexual reproduction is possible after one year. (Washington State Noxious Weed Control Board). A soil seed bank is produced and seeds are easily wind dispersed. Seeds can remain on the vine over winter and well into summer. Aerial shoots touching the ground after cutting may become rooted (Weber 2003). Seed viability in California may be low: 4 of 5 seed accessions stored at UC Botanic Garden seeds were not viable (Forbes, pers. comm.).

Sources of information:
Bungard 1996 CABI 2015 Washington State Noxious Weed Control Board 1999 Weber 2003 Forbes, H. Personal communication.

Other Published Material A 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:
Dumping of garden waste containing C. vitalba vines onto roadsides has been a significant cause of spread in New Zealand. This weed appears to invade along roadsides by seed, possibly aided by the turbulence created by motor vehicles (CABI). Fragments are spread by water, and from garden cuttings (Washington 1999). C. vitalba often grows on roadsides, and the risk of seeds being transported on road vehicles from known infestations to new sites within continents is high. In the past, ornamental Clematis species were often grafted onto C. vitalba rootstocks. It is likely that some incursions of C. vitalba have resulted from reversion of these rootstocks. The highest risk of introduction remains via intentional introduction of the plant as an ornamental, and plants and seed continue to be sold by nurseries, mail order catalogues and websites (CABI). In Santa Cruz County C. vitalba is thought to have been introduced in the town of San Vicente which was located in the San Vicente Creek watershed. This historic town was established for workers at a nearby limestone quarry and is now uninhabited (Hamey, pers. comm.). There is also a risk of inadvertent introduction and increase via seed collection and revegetation projects, since C. vitalba can be mistaken for native clematis species (Wrubel, pers. comm.).

Sources of information:
CABI 2015 Washington Noxious Weed Control Board 1999 Hamey, N. Personal communication. Wrubel, E. Personal communication.

Reviewed Scientific Publication 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:
Can be dispersed by birds and animals in New Zealand. Seeds are also wind-dispersed or water-dispersed in New Zealand. Fragments are spread by water, and from garden cuttings (Washington 1999). A soil seed bank is produced and seeds are easily wind dispersed. Seeds can remain on the vine over winter and well into summer (Weber 2003).

Sources of information:
Bungard 1996 Weber 2003

Reviewed Scientific Publication A 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:
C. vitalba is also naturalized and considered invasive in Oregon, Washington, Australia, New Zealand. C. vitalba is native to Europe, from southern England and the Netherlands to North Africa, and from Spain to the Middle East and the Caucasus (CABI). It occurs in agricultural areas, coastland, natural forests, planted forests, range/grasslands, riparian zones, ruderal/disturbed, scrub/shrublands, and urban areas (GISD 2005). More specifically, outside of its native range, this species is found in forest lands and in the margins and openings of forested lands. It is also found in riparian areas established with willows, in waste areas, and in coastal and lowland areas (GISD 2005). Infestations of C. vitalba occur in forest reserves, gardens, road margins and other places around Taihape in New Zealand (Ogle et al. 2000), infestations of C. vitalba occur in every region of New Zealand except Northland (north of Auckland). Some of the habitat types it has not invaded in California include scrub and shrub-dominated habitats, grasslands, and broad-leaved forests such as oak woodland.

Sources of information:
CABI 2015 GISD 2005 Ogle et al. 2000

Section 3: Distribution

Observational B 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:
C. vitalba was first collected in California in 1957 from the Strybing Arboretum in Golden Gate Park. Since that is a cultivated location C. vitalba was not included in the Jepson Manual and was not thought to be naturalized in California until it was verified in Muir Woods and in Santa Cruz County in 2014 (CCH). In Santa Cruz County C. vitalba was first noticed in 2009 or 2010, and control work did not begin until 2012 (Hamey, pers. comm.). Both California locations are under management and occur in riparian and coast redwood forest edges. It is possible that C. vitalba is more widespread as it closely resembles the native C. ligusticifolia.

Sources of information:
CCH 2016 Hamey, N. Personal communication Hyland, T. Personal communication Wrubel, E. Personal communication

Observational D 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:
The two known locations of C. vitalba in California are in riparian oak bay woodland and coast redwood forest edges.

Sources of information:
Hamey, N. Personal communication Hyland, T. Personal communication Wrubel, E. Personal communication

References

List full citations for all references used in the PAF (short citations such as DiTomaso and Healy 2007 may be used in table above). Websites should include the name of the organization and the date accessed. Personal communications should include the affiliation of the person providing the observation. Enter each reference on a separate line.
Baars, R., and Kelly, D. 1996. Survival and growth responses of native and introduced vines in New Zealand to light availability. New Zealand Journal of Botany 34, 389–400. Bungard, R. A., Daly, G. T., McNeil, D. L., Jones, A. V. and Morton, J. D. 1997. Clematis vitalba in a New Zealand native forest remnant: Does seed germination explain distribution? New Zealand Journal of Botany 35, 525–534. Bungard, R.A. 1996. Ecological and physiological studies of Clematis vitalba L. Ph.D., Lincoln University, Canterbury, New Zealand. 197 pp. CABI Datasheet. 2015. Clematis vitalba. http://www.cabi.org/isc/datasheet/14280. Accessed December 6, 2016. Consortium of California Herbaria (CCH). 2016. Specimen return for Clematis vitalba. http://ucjeps.berkeley.edu/cgi-bin/get_consort.pl. Accessed December 23, 2016. Forbes, H. 2017. Personal communication with Holly Forbes, Curator, University of California Botanical Garden at Berkeley. PAF comments, January 2017 Global Invasive Species Database. 2005. http://issg.org/database/species/ecology.asp?si=157. Accessed December 23, 2016 Hamey, N. 2017. Personal communication with Nadia Hamey, Forester. Phone conversation, 1/25/17. Hill, R. L., R. Wittenberg, and A. H. Gourlay. 2001. Biology and Host Range of Phytomyza vitalbae and its Establishment for the Biological Control of Clematis vitalba in New Zealand. Biocontrol Science and Technology 11: 459-473 Hyland, T. 2017. Personal communication with Tim Hyland, California State Parks. Email and PAF comments, January 2017 Ogle, C.C., LaCock, G.D., Arnold, G., and Mickleson, N. 2000. Impact of an exotic vine Clematis vitalba (F. Ranunculaceae) and of control measures on plant biodiversity in indigenous forest, Taihape, New Zealand. Austral Ecology. 25, 539–551. Washington State Noxious Weed Control Board: http://www.nwcb.wa.gov/weeds/old-mans-beard. Accessed December 23, 2016. Washington State Noxious Weed Control Board. 1999. Written findings of the Washington State Noxious Weed Control Board. http://www.nwcb.wa.gov/images/weeds/Clematis_vitalba.pdf. Accessed February 15, 2017. Weber, E. 2003. Invasive plant species of the world: A reference guide to environmental weeds. CABI Publishing, Zurich, Switzerland. P. 112. West, C.J. 1992. Ecological Studies of Clematis vitalba (old man's beard) in New Zealand. DSIR Land Resources Vegetation Report No. 736. Citation from CABI Abstract. Wrubel, E. 2017. Personal communication with Eric Wrubel, National Park Service. Email and PAF comments, January 2017.

Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less Unknown
Dense infestations produce >1,000 viable seed per square meter Yes, 2 points
Populations of this species produce seeds every year. Yes, 1 points
Seed production sustained over 3 or more months within a population annually Unknown
Seeds remain viable in soil for three or more years Yes, 2 points
Viable seed produced with both self-pollination and cross-pollination Yes, 1 points
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: 10
Total unknowns: 2
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:
Insects visit C. vitalba flowers, but flowers do not appear to be self-incompatible (West, 1992), and pollination can be successful without the attention of insects.
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 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, coastal prairie
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 forestD. < 5%
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)   B
Distribution (highest score)   D
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

Calflora Plant Profile:
The Calflora Plant Profile for this species.
http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=8710
CalWeedMapper:
Load CalWeedMapper with this species already selected.