Source: California Invasive Plant Council


URL of this page: http://www.cal-ipc.org/site/paf/263
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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.

Atriplex semibaccata

Synonyms:
Additional Latin binomial names for this species. Separate multiple names with a ; character. Please avoid narrative descriptions, and list only the binomial names.
Atriplex denticulata, Atriplex flagellaris
Common names:
Common names for this species. Separate multiple names with a ; character.
Australian saltbush; berry saltbush; creeping saltbush; scrambing berry saltbush
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.
8/6/2004
Evaluator #1 John J. Knapp, Invasive Plant Program Manager
Santa Catalina Island Conservancy
PO Box 2739 Avalon, CA 90704
310.510.1299
knappweed@catalinaisp.com
Evaluator #2 Brianna Richardson, Project Manager
California Invasive Plant Council
1442-A Walnut St. #462, Berkeley, CA 94709
510.843.3902
brichardson@cal-ipc.org
List committee members: Joe DiTomaso, John Randall, Cynthia Roye, Alison Stanton, Jake Sigg, Peter Warner.
Committee review date: 8/27/2004
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.
Native origin--Australia. On Santa Catalina Island, A. semibaccata populations are underestimated because the extent of large populations could not be recorded accurately due to the lack of visibility, which is restricted by other vegetation, flat topography, the species' prostrate habit, and distance in the case of aerial and coastal surveys.

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

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

2.9 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.
C. Minor 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
CADC

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 Other Published Material
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.
D. Negligible 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.
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 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
12

Total Score
B
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
C. Stable 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
C. Stable 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 Other Published Material
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.
B. Occasional 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.
C. Already invaded 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 Other Published Material
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 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

Other Published Material C 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:
Alters fire intensity. Increases local soil moisture and nutrient content by bringing minerals, water, and chemicals to the soil surface. Can be used to revegetate mining sites. May reduce SE levels in soil. Minor alteration of fire, water, and nutrient regimes.

Sources of information:
Randall, JM and MC Hoshovsky. 2000. Atriplex semibaccata. In, Invasive Plants of California's Wildlands. C. Bossard, J. Randall, M. Hoshovsky (eds.) 59-61. University Press, Los Angeles. Banuelos, GS, DW Meek. 1990. Accumulation of selenium in plants grown on selenium-treated soil. Journal of Envirnomental Quality. V.19: 772-777. (2) Stone, C.P., C.W. Smith, and J.T. Tunison, eds. 1992. Alien plant invasions in native ecosystems of Hawai’i: Management and research. University of Hawai’I Cooperative National Park Resources Unit, Honolulu, Hawai’i.

Other Published Material 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:
A ground spreading plant, displaces native plants. One plant can form a mat up to 4 ft in diameter. Has a dramatic effect on island grassland populations. Forms dense stands, reduces native vegetation, creates thick ground cover.

Sources of information:
Randall, JM and MC Hoshovsky. 2000. Atriplex semibaccata. In, Invasive Plants of California's Wildlands. C. Bossard, J. Randall, M. Hoshovsky (eds.) 59-61. University Press, Los Angeles. (2) Stone, C.P., C.W. Smith, and J.T. Tunison, eds. 1992. Alien plant invasions in native ecosystems of Hawai’i: Management and research. University of Hawai’I Cooperative National Park Resources Unit, Honolulu, Hawai’i. Personal observation: John Knapp, Santa Catalina Island Conservancy.

Other Published Material D 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:
Seeds eaten by birds. Flowers used by the pygmy blue butterfly. No negative impacts to higher trophic levels documented in the literature. May cause damage through extirpation of native vegetation used as cover and for food. Could rate a "C."

Sources of information:
Randall, JM and MC Hoshovsky. 2000. Atriplex semibaccata. In, Invasive Plants of California's Wildlands. C. Bossard, J. Randall, M. Hoshovsky (eds.) 59-61. University Press, Los Angeles. Las Pilitas Nursery website: www.laspilitas.com/butterflies

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:
31 closely related California natives, some of which are rare or endangered. A. semibaccata can possibly hybridize with two Santa Catalina Island native slabush species (A. coulterie [listed as G2 by NatureServe] and A. pacifica [listed as G3 by NatureServe]). 46 native taxa are in the genus Atriplex in California. A. semibaccata hybridizes readily with A. spinibractea in Australia. No information currently exists on whether A. semibaccata is hybridizing with CA natives. Trials are being conducted on Catalina Island to try to produce a hybrid between A. semibaccata and two native spp

Sources of information:
Randall, JM and MC Hoshovsky. 2000. Atriplex semibaccata. In, Invasive Plants of California's Wildlands. C. Bossard, J. Randall, M. Hoshovsky (eds.) 59-61. University Press, Los Angeles. DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published. Personal communication: B. Richardson w/ John Knapp. Email 8/10/2004. Harden, G.J. 1990. Flora of New South Wales volume 1. New South Wales University Press. Hickman, J.C. (ed.). 1993. The Jepson manual of higher plants of California. Pp. 501-505. University of California Press, Berkeley.

Section 2: Invasiveness

Other Published Material 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:
Prefers areas that have been heavily grazed or disturbed. Readily establishes in areas newly developed, roadsides, margins of cultivated fields, coastal marshes. Most establishment attributed to disturbance.

Sources of information:
Randall, JM and MC Hoshovsky. 2000. Atriplex semibaccata. In, Invasive Plants of California's Wildlands. C. Bossard, J. Randall, M. Hoshovsky (eds.) 59-61. University Press, Los Angeles. Harden, G.J. 1990. Flora of New South Wales volume 1. New South Wales University Press. Wilken, D. and Hannah, L. 1998. Channel Islands National Park Species Literature Review. Unpublished.

Other Published Material C 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:
Naturalized in localzed areas on Santa Catalina Island prior to 1921. Naturalzed widely by 1966 and 2003. Spread by seed and vegetatively is slow. A large amount of unifested habitat exists on Catalina Island.

Sources of information:
Millspaugh, C.F. and Nuttall, L.W. 1923. Flora of Santa Catalina Island. Pp. 91-92. Field Museum of Natural History, Botany v.5. Chicago. Thorne, R.F. 1967. A flora of Santa Catalina Island, California. Aliso, 6(3):1-77. Knapp, J.J. 2003. Prioritized invasive plant management for the Santa Catalina Island Conservancy. Unpublished. USDA. No Date. Conservation plant characteristics for: Australian saltbush. USDA Natural Resources Conservation Service. Observational, Peter Warner, Joe DiTomaso, 2004

Other Published Material 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:
Species not targeted for removal on Catalina as of 2003 (1). Occupies 53,559,275 square ft. on Santa Catalina Island (2). Common on Anacapa Island and in a wide range of habitats on other Northern Channel Islands such as grasslands and disturbed habitats (3). Elkhorn Slough National Estuarine Research Reserve (4). Inland Empire California State Parks (5). A. semibaccata is too widespread for control measures.

Sources of information:
(1) Knapp, D.A. 2001. Personal communication. Santa Catalina Island Plant Ecologist. (2) Knapp, J.J. 2004. Prioritzed invasive plant management plan for the Santa Catalina Island Conservancy. Unpublished. (3) Stone, C.P., C.W. Smith, and J.T. Tunison, eds. 1992. Alien plant invasions in native ecosystems of Hawai’i: Management and research. University of Hawai’I Cooperative National Park Resources Unit, Honolulu, Hawai’i. (4) Elkhorn Slough National Estuarine Research Reserve. 2000. Weed control by species. Elkhorn Slough National Estuarine Research Reserve. Pp. 1-57. (5) California State Parks. 2000. Urban edge effects and their relationship with the natural environment. Pp. 1-30. California State Parks Inland Empire District.

Other Published Material 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:
Reproduces by seed only. Flowers April-December. Seeds produced summer-December. Likely self-pollinating (other Atriplex are). Seeds produced in "large numbers," though others state low seed abundance. Seed persistance in soil is unknown. Resprouts when cut. Produces seed annually on Catalina Island. 6 points.

Sources of information:
Randall, JM and MC Hoshovsky. 2000. Atriplex semibaccata. In, Invasive Plants of California's Wildlands. C. Bossard, J. Randall, M. Hoshovsky (eds.) 59-61. University Press, Los Angeles. Elkhorn Slough National Estuarine Research Reserve. 2000. Weed control by species. Elkhorn Slough National Estuarine Research Reserve. Pp. 1-57. Wilken, D. and Hannah, L. 1998. Channel Islands National Park Species Literature Review. Randall, J.M. and Hoshovsky, M.C. 2000. Atriplex semibaccata. In, Invasive Plants of California's Wildlands. (eds.) C. Bossard, J. Randall, and M. Hoshovsky. Pp. 59-61. University Press, Los Angeles. Knapp, J.J. 2004. Prioritized invasive plant management plan for the Santa Catalina Conservancy. Unpublished. USDA. No Date. Conservation plant characteristics for: Australian saltbush. USDA Natural Resources Conservation Service.

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:
Was promoted as livestock forage, as a ground cover, for erosion control, and to attract birds. Recently promoted as a fire-rsistant ground cover and for reclamation of mined sites in the southwest. Seeds dispersed by human activities. Disposal of soil from urban areas to the Interior may transport seed to new locales. Sold horticulturally. Currently sold horticulturally and for revegetation. Readily moved by soil transport.

Sources of information:
Randall, JM and MC Hoshovsky. 2000. Atriplex semibaccata. In, Invasive Plants of California's Wildlands. C. Bossard, J. Randall, M. Hoshovsky (eds.) 59-61. University Press, Los Angeles. DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published. de Villiers, AJ, MW van Rooyen, GK Theron, AS Claassens. 1996. Tolerance of six Namaqualand pioneer species ot saline soil conditions. South African Journal of Plant and Soil 14(1): 38-42. Las Pilitas Nursery website: www.laspilitas.com/butterflies Wilken, D. and L. Hannah. 1998. Channel Islands National Park Species Literature Review. Knapp, JJ. Personal observations from 2001-2004 on Santa Catalina Island, CA. 310.510.1299. Observational, Peter Warner, Joe DiTomaso, 2004.

Other Published Material B 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:
Fruits are dispersed by frugivores: mammals, birds, reptiles, and ants. Seeds dispersed by water, in mud or soil movement, and animals. Fleshy bright red fruits make them attractive to vectors, and have been found as a dietary constitute of several fauna, which can disperse the seeds over long distances.

Sources of information:
Randall, JM and MC Hoshovsky. 2000. Atriplex semibaccata. In, Invasive Plants of California's Wildlands. C. Bossard, J. Randall, M. Hoshovsky (eds.) 59-61. University Press, Los Angeles. DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published. Wilken, D. and L. Hannah. 1998. Channel Islands National Park Species Literature Review. Observational, Peter Warner, Joe DiTomaso, 2004.

Other Published Material C 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:
Found in NV, AZ, NM, UT, TX. Introduced to South Africa, Chile, Tasmania, Hawaii, Canary Island, South America, central Asia. Similar habitats to those invaded in CA.

Sources of information:
DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published. Wilken, D, L. Hannah. 1998. Atriplex semibaccata R. Br. (Chenopodiaceae) Australian saltbush, creeping saltbush. Santa Barbara Botanic Garden. de Villiers, AJ, MW van Rooyen, GK Theron, AS Claassens. 1996. Tolerance of six Namaqualand pioneer species ot saline soil conditions. South African Journal of Plant and Soil 14(1): 38-42. Wilken, D. and L. Hannah. 1998. Channel Islands National Park Species Literature Review.

Section 3: Distribution

Other Published Material 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:
Introduced to CA as livestock forage, Tulare Co in 1910. Found in margins of grassland, scrub, shrubland, and salt marshes, waste places, and woodland below 3,280 ft. Found in the Mojave and Sonoran deserts, and arid parts of the South Coast, Central Coast, SF Bay area, and Central Valley to Glenn Co. Coastal areas and salt marshes from San Diego to Mendocino Co, as well as all Channel Islands. Common in grasslands on Santa Cruz Island. On Santa Catalina Island, 3308 populations were recorded and the following is the percentage of habitat type invaded: bare soil-2.8%, beach-3.1%, coastal scrub-0.1%, coastal scrub/grassland-6.3%, grassland-0.56%, non-native scrub-0.00%, and riparian-0.17% (2). In 1966, coastal bluff scrub was also invaded on Santa Catalina Island (3). Also found in coastal marsh (4). Considered a regional noxious weed by CDFA. Found in at least 6 major and 11 minor ecotypes in CA.

Sources of information:
Randall, JM and MC Hoshovsky. 2000. Atriplex semibaccata. In, Invasive Plants of California's Wildlands. C. Bossard, J. Randall, M. Hoshovsky (eds.) 59-61. University Press, Los Angeles. DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published. Millspaugh, C.F. and Nuttall, L.W. 1923. Flora of Santa Catalina Island. Pp. 91-92. Field Museum of Natural History, Botany v.5. Chicago. Knapp, J.J. 2004. Prioritzed invasive plant management plan for the Santa Catalina Island Conservancy. Unpublished. Thorne, R.F. 1967. A flora of Santa Catalina Island, California. Aliso, 6(3):1-77. Elkhorn Slough National Estuarine Research Reserve. 2000. Weed control by species. Elkhorn Slough National Estuarine Research Reserve. Pp. 1-57. Wilken, D. and Hannah, L. 1998. Channel Islands National Park Species Literature Review. Stone, C.P., C.W. Smith, and J.T. Tunison, eds. 1992. Alien plant invasions in native ecosystems of Hawai’i: Management and research. University of Hawai’I Cooperative National Park Resources Unit, Honolulu, Hawai’i.

Observational 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:
On Catalina Island, ranks a "C." Statewide distribution unknown.

Sources of information:
DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published. Knapp, JJ. 2004. Prioritized invasive plant management plan for the Santa Catalina Island Conservancy. Unpublished. Thorne, RF. 1967. A flora of Santa Catalina Island, California. Aliso 6(3): 1-77. Observational, Peter Warner, Joe DiTomaso, 2004.

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 Unknown
Populations of this species produce seeds every year. Unknown
Seed production sustained over 3 or more months within a population annually Yes, 1 points
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 No
Fragments easily and fragments can become established elsewhere No
Resprouts readily when cut, grazed, or burned Yes, 1 points
Total points: 6
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:
Seeds produced in "large" numbers.
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
DunescoastalU. Unknown
desert
interior
Scrub and Chaparralcoastal bluff scrubU. Unknown
coastal scrubC. 5% - 20%
Sonoran desert scrubU. Unknown
Mojavean desert scrub (incl. Joshua tree woodland)U. Unknown
Great Basin scrub
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrubU. Unknown
chaparral
Grasslands, Vernal Pools, coastal prairieU. Unknown
Meadows, and other Herbvalley and foothill grasslandU. Unknown
CommunitiesGreat Basin grassland
vernal pool
meadow and seep
alkali playa
pebble plain
Bog and Marshbog and fen
marsh and swampU. Unknown
Riparian and Bottomland habitatriparian forest
riparian woodland
riparian scrub (incl.desert washes)U. Unknown
Woodlandcismontane woodlandU. Unknown
piñon and juniper woodland
Sonoran thorn woodland
Forestbroadleaved upland forest
North Coast coniferous forest
closed cone coniferous forest
lower montane coniferous forest
upper montane coniferous forest
subalpine coniferous forest
Alpine Habitatsalpine boulder and rock field
alpine dwarf scrub
Amplitude (breadth)  
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/Atriplex_semibaccata.php
Calflora Plant Profile:
The Calflora Plant Profile for this species.
http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=1003
CalWeedMapper:
Load CalWeedMapper with this species already selected.
http://calweedmapper.cal-ipc.org/maps/?species=154