Plant Assessment Form

More Asparagus asparagoides resources

Asparagus asparagoides

Synonyms: Myriophyllum asparagoides, Asparagus medeoloides, Dracaena medeoloides, Elachanthera sewelliae, Luzuriaga sewelliaea, Medeola asparagoides

Common Names: bridal creeper; African Asparagus fern; ornamental Asparagus; smilax Asparagus

Evaluated on: 1/24/05

List committee review date: 08/07/2005

Re-evaluation date:

Evaluator(s)

Elizabeth Brusati, project manager
California Invasive Plant Council
1442A Walnut St. #462, Berkeley, CA 94709
510-843-3902
edbrusati@cal-ipc.org

Joseph M. DiTomaso
University of California, Davis
Dept. Plant Sci., Mail Stop 4, Davis, CA 95616
530-754-8715
jmditomaso@ucdavis.edu

List committee members

Jake Sigg
Peter Warner
Bob Case
John Knapp
Elizabeth Brusati

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? Moderate

Alert Status? Alert

Documentation? 2.5 out of 5

Score

Documentation

1.1

?Impact on abiotic ecosystem processes

B. Moderate

Reviewed Scientific Publication

Impact?
Four-part score BACD Total Score
B

1.2

?Impact on plant community

A. Severe

Other Published Material

1.3

?Impact on higher trophic levels

C. Minor

Observational

1.4

?Impact on genetic integrity

D. None

Other Published Material

2.1

?Role of anthropogenic and natural disturbance in establishment

B. Moderate

Reviewed Scientific Publication

Invasiveness?
Total Points
13 Total Score B

2.2

?Local rate of spread with no management

U. Unknown

2.3

?Recent trend in total area infested within state

U. Unknown

2.4

?Innate reproductive potential
(see Worksheet A)

A. High

Other Published Material

2.5

?Potential for human-caused dispersal

B. Moderate

Other Published Material

2.6

? Potential for natural long-distance dispersal

A. Frequent

Reviewed Scientific Publication

2.7

?Other regions invaded

A. Invades 3 or more ecological types

Other Published Material

3.1

?Ecological amplitude/Range
(see Worksheet C)

D. Narrow

Other Published Material

Distribution?
Total Score D

3.2

?Distribution/Peak frequency
(see Worksheet C)

D. Very low

Observational

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? 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 Reviewed Scientific Publication
Identify ecosystem processes impacted: Dense stems limit light levels (1). Dies back in the summer, leaving a blanket of entwined stems that can be a fire hazard. Sources of information:
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.	A Other Published Material
Identify type of impact or alteration: Outcompetes other vegetation (1). Shoots form a dense canopy which shades shrubs, herbs, and seedlings. The tuber mat forms a thick barrier just below the surface which limits the access of other plants to soil moisture and nutrients. 87% of the plant weight is below ground when it is actively growing (2). Data from Australian literature. No information available from California. It is expected that a similar situation would occur in California if the species became well established. Sources of information:
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.	C Observational
Identify type of impact or alteration: Native vegetation germination and dispersal is reduced by A. asparagoides, but no direct evidence on other tropic levels known in California. Displacement of native vegetation has effects on wildlife.. Frugivorous birds disperse A. asparagoides fruits, therefore competing with native vegetation for avian dispersal and germination. Sources of information: Stansbury and Scott 1999 John Knapp, Catalina Conservancy, Avalon, CA. Per. obs.
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.	D Other Published Material
none No native Asparagus spp. Sources of information: Hickman, J. C. (ed.) 1993. The Jepson Manual, Higher Plants of California. University of California Press. Berkeley, CA enter text here
Section 2: Invasiveness
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.	U
Describe role of disturbance: Occurs as a weed along roadsides, waste places, and other disturbed areas near towns. However, it is generally not found in open areas and can tolerate heavy shade (1).Roadsides, gardens, and woodlands have been invaded, as well as extensive areas of crop lands. Undisturbed native habitats are invaded. A. asparagoides can germinate in a wide range of environmental conditions (2). Sources of information: 1. Parsons and Cuthbertson 2001 2. Stansbury and Scott 1999
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	U
Describe rate of spread: Peak spread in Australia was 0.6m/yr of radial spread for patches of 10 square m. In southwest Australia, A. asparagoides has been observed to spread kilometers per year. It is widespread and highly invasive in Australia. No information available in California. Sources of information: 1. Stansbury and Scott 1999.
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	U
Describe trend: no information Sources of information:
Question 2.4 Innate reproductive potential? Assess the innate reproductive potential of this species. Worksheet A is provided for computing the score.	A Other Published Material
Describe key reproductive characteristics: Perennial, erect or climbing herb. Seeds germinate in autumn or early winter. Plants become dormant over the summer. Roots can survive long droughts and resprout when rains come. Reproduces by seed, tuber, and rhizome. Seed is believed to be viable in California. Many seeds are produced per plant, and has a high fecundity. Seed remains persistant for 2-3 years if buried. Bud bank resprouts after disturbance such as fire and mowing. Time to reproductive maturity occurs between 2-3 years. In Australia, seed production occurs for two months. Information based on Australian literature. Sources of information: 1. Parsons, W. T., and E. G. Cuthbertson. 2001. Noxious weeds of Australia. 2nd edition. CSIRO Publishing. Collingwood, VIC, Australia. Willis, A.J., McKay, R., Vranjic, J.A., Kilby, M.J., and Groves, R.H. 2003. Comparative seed ecology of the engangered shrub, Pimelea spicata and the threatening weed, bridal creeper: smoke, heat and other fire-related germination cues. Ecological Management and Restoration 4(1): 55-65. Brown, K. and Brooks, K. 1996. Bushland Weeds: a practical guide to their management with cases studies from the Swan Coastal Plain and beyond. Environmental Weeds Action Network. Pp. 52-52. Stansbury, C. Observations of birds feeding on bridal creeper (Asparagus asparagoides) fruits within Yanchep National Park, Western Australia. Plant Protection Quarterly. 11(2): 59-60. Stansbury, C.D. 2001. Dispersal of the environmental weed bridal creeper, Asparagus asparagoides, by silvereyes, Zosterops lateralis, in south-western Australia. Emu 101(1): 39-45. Giessow, J. 2001. Plants of Potential Concern Asparagus asparagoides. California Exotic Pest Plant Council News. 9(1):7-8.
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.	B Other Published Material
Identify dispersal mechanisms: Spread by dumped garden refuse (1) or by seeds adhering to animals, clothing, and machinery (2). On Catalina Island, A. asparagoides is commonly seen growing out of holes created by acorn wood peckers in Phoenix palms in the town of Avalon (3). Sources of information: 1. Stansbury and Scott 1999 2. Parsons and Cuthbertson 2001 3. Knapp, J.J. Personal observations from 2001-2004 on Catalina Island, CA. (310) 510-1299, jknapp@catalinaconservancy.org.
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.	A Reviewed Scientific Publication
Identify dispersal mechanisms: Dispersed by frugivorous birds (up to 12 km in Australia) (1). Also dispersed by water. In an Australian study, 93% of bridal creeper occurrences were within 500m of drainage or watercourses (2). Rabbits and foxes can eat and disperse fruits and seeds (3). Sources of information: 1. Stansbury, C. D. 2001. Dispersal of the environmental weed Bridal Creeper, Asparagus asparagoides, by Silvereyes, Zosterops lateralis, in south-western Australia. Emu 101(1): 39-45 2. Pigott, J. P. and P. Farrell. 1996. Factors affecting the distribution of bridal creeper (Asparagus asparagoides) in the lower south-west of Western Australia. Plant Protection Quarterly 11(2): 54-56 3. Anonymous 2000.
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.	A Other Published Material
Identify other regions: Native to South Africa. Considered a noxious weed in Australia, where it invades coastal vegetation, wet and dry schlerophyll forests, heathlands, mallee shrublands, and riparian areas (1), as well as jarrah forest, and low woodland, and Eucalyptus stands (2). USDA does not list it in any other US state. Sources of information:
Section 3: Distribution
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.	D Other Published Material
Invades disturbed areas and fields (1) in Alameda, Santa Barbara, and San Diego counties (2). Invades riparian areas in southern California (3). Sources of information: 1. DiTomaso, J., and E. Healy. in prep. Weeds of California and Other Western States. 2. USDA, NRCS. 2004. The PLANTS Database, Version 3.5 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA 3. Giessow, J. 2000. Plants of Potential Concern Asparagus asparagoides. California Exotic Pest Plant Council News. Winter.
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.	D Observational
Describe distribution: Very uncommon in California. Sources of information: Observational, DiTomaso.

Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less	Yes
Dense infestations produce >1,000 viable seed per square meter	Unknown
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	Unknown
Viable seed produced with both self-pollination and cross-pollination	Unknown
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes	Yes
Fragments easily and fragments can become established elsewhere	Yes
Resprouts readily when cut, grazed, or burned	Yes
Total points:	6
Total unknowns:	3
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).

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? 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 Systems	marine systems
Freshwater and Estuarine	lakes, ponds, reservoirs
Aquatic Systems	rivers, streams, canals
Aquatic Systems	estuaries
Dunes	coastal
	desert
	interior
Scrub and Chaparral	coastal 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, Meadows, and other Herb Communities	coastal prairie
	valley and foothill grassland
	Great Basin grassland
	vernal pool
	meadow and seep
	alkali playa
	pebble plain
Bog and Marsh	bog and fen
Bog and Marsh	marsh and swamp
Riparian and Bottomland habitat	riparian forest
	riparian woodland	D, < 5%
	riparian scrub (incl.desert washes)
Woodland	cismontane woodland
	piñon and juniper woodland
	Sonoran thorn woodland
Forest	broadleaved upland forest
	North Coast coniferous forest
	closed cone coniferous forest
	lower montane coniferous forest
	upper montane coniferous forest
	subalpine coniferous forest
Alpine Habitats	alpine boulder and rock field
Alpine Habitats	alpine dwarf scrub
	Amplitude (breadth):	D
	Distribution (highest score):	D

Infested Jepson Regions

Click here for a map of Jepson regions

Central West
Great Valley
Northwest
Southwest
Sierra Nevada East
Desert Province
Mojave Desert
Sonoran Desert