Plant Assessment Form
More Salsola tragus resources
Salsola tragus
Synonyms: Salsola australis, S. iberica, S. kali var. tenuifolia, S. kali ssp. ruthenica, S. kali ssp. tenuifolia, S. kali ssp. tragus, S. pestifera, S. ruthenica.
Common Names: Russian thistle; common saltwort; prickly Russian thistle; Russian tumbleweed; tumbleweed; tumbling weed; windwitch; witchweed; prickly glasswort
Evaluated on: 8/10/04
List committee review date: 15/08/2005
Re-evaluation date:
Evaluator(s)
Brianna Richardson, Project Manager
California Invasive Plant Council
1442-A Walnut Street #462, Berkeley, CA 94709
510.843.3902
brichardson@cal-ipc.org
Gina Skurka/Agricultural Technician I/Intern
CDFA/Cal-IPC
1220 N Street, Sacramento, CA 95814
530-400-8992 home/ 916-654-0768 CDFA
gskurka@cdfa.ca.gov
List committee members
Joe DiTomaso
Jake Sigg
Cynthia Roye
Peter Warner
General Comments
There are two types of Salsola tragus, Type A and Type B. This assessment does not distinguish between the two types.
|
|
Overall Score ?
Plant scoring matrix
Based on letter scores from Sections 1 through 3 below
| Impact | Invasiveness | Distribution | | |
| A | A B | Any | High | No Alert |
| A | C D | Any | Moderate | Alert |
| B | A B | A B | Moderate | No Alert |
| B | A B | C D | Moderate | Alert |
| B | C D | Any | Limited | No Alert |
| C | A | A B | Moderate | No Alert |
| C | A | C D | Limited | No Alert |
| C | B | A | Moderate | No Alert |
| C | B | B D | Limited | No Alert |
| C | C | Any | Limited | No Alert |
| D | Any | Any | Not Listed | No Alert |
Limited
|
Alert Status ?
Plant scoring matrix
Based on letter scores from Sections 1 through 3 below
| Impact | Invasiveness | Distribution | Alert |
| A | A or B | C or D | Alert |
| B | A or B | C or D | Alert |
No Alert
|
Documentation ?
The total documentation score is the average
of Documentation scores given in Table 2.
| Reviewed Scientific Publication | 4 points |
| Other Published Material | 3 points |
| Observational | 2 points |
| Anecdotal | 1 points |
| Unknown or No Information | 0 points |
3 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.
|
D. Negligible |
Other Published Material |
Impact?
| Section 1 Scoring Matrix |
|---|
| Q 1.1 | Q 1.2 | Q 1.3 | Q 1.4 | Score |
| A | A | Any | Any | A |
| A | B | A,B | Any | A |
| A | B | C,D,U | Any | B |
| A | C,D,U | Any | Any | B |
| B | A | A | Any | A |
| B | A | B | A | A |
| B | A | B,C | B-D,U | B |
| B | A | C,D,U | A | A |
| B | A | C,D,U | B-D,U | B |
| B | B | A | A | A |
| B | C,D,U | A | A | B |
| B | B-D | A | B-D,U | B |
| B | B-D | B-D,U | Any | B |
| B | D,U | C,D,U | A-B | B |
| B | D,U | C,D,U | C,D,U | C |
| C-D,U | A | A | Any | A |
| C | B | A | Any | B |
| C | A,B | B-D,U | Any | B |
| C | C,D,U | Any | Any | C |
| D | A,B | B | Any | B |
| D | A,B | C,D,U | Any | C |
| D | C | Any | Any | C |
| D | D,U | Any | Any | D |
| U | A | B,C | Any | B |
| U | B,C | A,B | Any | B |
| U | B,C | C,D,U | Any | C |
| U | U | Any | Any | U |
Four-part score
DCDD
Total Score
C
|
| 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.
|
C. Minor |
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.
|
D. Negligible |
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.
|
D. None |
Other Published Material |
|
| 2.1 |
?Role of anthropogenic and natural disturbance in establishment
Assess dependence on disturbance, both human and natural, for establishment of this species 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 points | Score |
| 17-21 | A |
| 11-16 | B |
| 5-10 | C |
| 0-4 | D |
| More than two U's | U |
Total Points
11
Total Score
B
|
| 2.2 |
?Local rate of spread with no management
Assess 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. Unknown |
|
| 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 |
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.
|
C. Low |
Anecdotal |
| 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.
|
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 3.1 | Q 3.2 | Score |
| A | A, B | A |
| A | C,D,U | B |
| B | A | A |
| B | B,C | B |
| B | D | C |
| C | A,B | B |
| C | C,D | C |
| D | A | B |
| D | B,C | C |
| D | D | D |
| A,B | U | C |
| C,D | U | D |
| U | U | U |
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 |
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.
|
D
Other Published Material
|
Identify ecosystem processes impacted:
Plants may add oxalate leachate to soil, making phosphorous more available and facilitating colonization. Can increase fire hazard, especially along tree rows and fences when dead plants build up. Can obstruct stream channels. Posess a taproot up to 1.5 m deep with lateral roots spreading up to 1.8 m and can extract deep soil moisture. No additional sources cited these as effects of Salsola tragus invasion. Some alterations (increased P availability) may be beneficial to native plants. Increases fire hazard (though may be a hazard primarily to human landscapes).
Sources of information:
DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published.
Haubensak, K. 1999. Salsola tragus, Chenopodiaceae, Russian thistle, tumbleweed. Source unknown.
Anonymous. Unwanted Poster. The Habitat Restoration Group. date unknown.
Mojave Weed Management Area website. www.mojavewma.org. Accessed 8/10/2004.
CDFA Encycloweedia. <>.
|
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.
|
C
Reviewed Scientific Publication
|
Identify type of impact or alteration:
An alternate host for Circulifer tenellus, which can carry the virus causing curly-top of some native plants. Believed to lack the ability to dominate native plant communities. May influence the abundance of later seral species. On a windy ridgetop in WY, grass density was highest where Salsola was most abundant, possibly due to reduced wind speeds or increased snow accumulation. On disturbed sites, invasion by Salsola may facilitate establishment of later seral species like Nassela pulchra by creating a nutrient island of phosphorous, through added oxalate leached from the Salsola canopy. Other compounds may be produced by Salsola that have other effects on the growth of native plants. Removal of Salsola has decreased the growth of native grasses in WY. Salsola can also compete with native grasses for water and nutrients. Salsola can have a significant effect on the dispersal of wind-borne seeds of native plants by slowing wind currents. Infestations can become dense where adult skeletons build up along a barrier (such as a fence). Most studies refer to Salsola as an early seral stage plant, implying that it is easily displaced by later seral stage plants, and therefore causes a lesser impact on overall plant communities. Salsola can have both positive and negative effects on the growth and establishment of native plants. The net effect is yet to be determined. Might rate a "B" ranking.
Sources of information:
DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published.
Haubensak, K. 1999. Salsola tragus, Chenopodiaceae, Russian thistle, tumbleweed. Source unknown.
Cannon, JP, EB Allen, MF Allen, LM Dudley, JJ Jurinak. 1995. The effects of oxalates produced by Salsola tragus on the phosphorus nutrition of Stipa pulchra. Oecologia V. 102: 265-272.
Vanier, CH., LR Walker. 1999. Impact of a non-native plant on seed dispersal of a native. Madrono. 46(1): 46-48.
Mojave Weed Management Area website. www.mojavewma.org. Accessed 8/10/2004.
CDFA Encycloweedia. www.cdfa.ca.gov. Accessed 8/10/2004. <>.
Haubensak, K and A. Smyth, University of Califorina at Berkeley, for Channel Islands National Park. 11-99.
|
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.
|
D
Reviewed Scientific Publication
|
Identify type of impact or alteration:
It is spiny. Can accumulate oxalates to levels toxic to sheep; however, immature plants in moderation can provide an extra source of nutritious forage for livestock on arid rangeland. Birds feed on the seeds in the canopy in winter (when plants remain intact). In one study, adult Uta inornata (the threatened Coachella Valley fringe-toed lizard) were associated with spring Salsola, but hatchling U. inornata were negatively associated with living Salsola in summer months (due to predation by adult lizards utilizing the Salsola). The lizards use Salsola for shade, and occasionally glean insects from the plant leaves. A recent study by Barrows indicates that S. tragus is a positive component of the habitat of the threatened Coachella Valley fringe-toed lizard (Uta inornata). The data presented show that S. tragus is similar in appearance and microhabitat distribution as native species used by U. inornata for shading, though S. tragus does not provide a food source for the lizards, as native species do. Most documented effects of Salsola on higher trophic levels are positive. No serious negative effects were identified.
Sources of information:
Barrows, CW. 1997. Habitat relationships of the Coachella Valley fringe-toed lizard (Uma inornata). The Southwestern Naturalist 42(2): 218-223.
Evans, RA., JA. Young. 1982. Russian thistle and barbwire Russian thistle seed and seedbed ecology. USDA-ARS. ARR-W-25: October.
DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published.
Haubensak, K. 1999. Salsola tragus, Chenopodiaceae, Russian thistle, tumbleweed. Source unknown.
CDFA Encycloweedia. <>.
Haubensak, K and A. Smyth, University of Califorina at Berkeley, for Channel Islands National Park. 11-99.
|
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
|
No related CA natives. Russianthistle consists of 2 variants in CA. Both types hybridize with barbwire Russianthistle and each other. No opportunity for hybridization with native species.
Sources of information:
Hickman, JC (ed.) 1993. The Jepson Manual: Higher plants of California. Univeristy of California Press: Berkeley.
CDFA Encycloweedia. <>.
|
| 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:
Seedlings require loose soil for successful establishment. Often the first spp to colonize disturbed sites. Primarily found in disturbed sites. "Russian thistle is so closely associated with human activity" It has been observed to invade undisturbed sage brush areas. Every paper considered referred to Salsola as an invader of disturbed sites. However, the spp is so widespread that it must occassionally be able to establish without disturbance or with only natural disturbance.
Sources of information:
DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published.
Kostivkovsky, V., JA Young. 2000. Invasive exotic rangeland weeds: A glimpse at some of their native habitats. Rangelands 22(6): 3-6.
CDFA-IPC internal document from files at Redding Field Office. Draft 1994 Action Plan for Scotch Thistle Eradication in Modoc and Lassen Counties.
|
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:
Sources of information:
|
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
|
C
Other Published Material
|
Describe trend:
Introduced to SD ~1874, spread to several Canadian provinces and 16 states by 1895. Spreads to suitable habitat rapidly. Introduced to CA ~1890. Common throughout California, but largest infestations occur in the southern region of the state, to eastern North America, Mexico. To 2700 m. At the rate this plant has spread historically, it is highly unlikely that it has not already invaded everywhere it is able in the 100+ years it's been in CA. If management is widespread the plant is likely declining. Without mgmt, it is likely stable.
Sources of information:
Evans, RA., JA. Young. 1982. Russian thistle and barbwire Russian thistle seed and seedbed ecology. USDA-ARS. ARR-W-25: October.
CDFA Encycloweedia. <>.
|
Question 2.4 Innate reproductive potential?
Assess the innate reproductive potential of this species. Worksheet A is provided for computing the score.
|
A
Reviewed Scientific Publication
|
Describe key reproductive characteristics:
DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published.
The Habitat Restoration Group. Unwanted Poster. Date unknown.
Evans, RA., JA. Young. 1982. Russian thistle and barbwire Russian thistle seed and seedbed ecology. USDA-ARS. ARR-W-25: October.
Ryan, FJ., DR Ayres. 2000. Molecular markers indicate two cryptic genetically divergent populations of Russian thistle (Salsola tragus) in California. Canadian Jouranl of Botany. V. 78: 59-67.
CDFA Encycloweedia. www.cdfa.ca.gov. Accessed 8/10/2004.
Sources of information:
Sold as an ornamental. No literature indicated that human dispersal is currently an important factor in the spread of Salsola. Roads and highways may allow wind-blown plants to move further than they would otherwise, spreading seed over a wider area.
|
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.
|
C
Anecdotal
|
Identify dispersal mechanisms:
Sold as an ornamental. No literature indicated that human dispersal is currently an important factor in the spread of Salsola. Roads and highways may allow wind-blown plants to move further than they would otherwise, spreading seed over a wider area.
Sources of information:
Personal inference, Brianna Richardson.
Thompson & Morgan, Onopordum acanthium <>.
|
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:
Adult plants break off at ground level and are blown by the wind, spreading seeds as they roll. Plants have been found to travel between 60-4069m over 6 weeks on fallow fields, dropping an average of 35,600 seeds/plant. Wind-pollinated. Main stems of Russianthistle break off at ground level under windy conditions allowing plants to disperse numerous seeds as they tumble over long distances. Frequently, new infestations appear as a trail of tumblweed seedlings across fields. Skeletons persist for at least one year and are typically found along fences and other structures. Older plants will recover mowing by axial branching below the cutting level. Frequent, long-distance dispersal by animals or abiotic mechanisms.
Sources of information:
Ryan, FJ., DR Ayres. 2000. Molecular markers indicate two cryptic genetically divergent populations of Russian thistle (Salsola tragus) in California. Canadian Jouranl of Botany. V. 78: 59-67.
CDFA Encycloweedia. <>.
|
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.
|
C
Other Published Material
|
Identify other regions:
Common throughout the entire contiguous US, occupying the same habitat it occupies in CA. Invades the same ecological types in other places that it does in CA.
Sources of information:
DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published.
Ryan, FJ, DR Ayres, DE Bell. 1999. There's more to tumbleweed (Russian thistle) than meets the eye. Proceedings of the California Invasive Plant Council 1999 Symposium.
|
| 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.
|
A
Other Published Material
|
Native to Eurasia. Introduced to SD around 1874 in flax seed from Russia--quickly spread throughout the US. First noted in CA in 1890. Disturbed sites, waste places, roadsides, fields, cultivated fields, disturbed natural and semi-natural plant communities. All continuous states except FL. Invades disturbed areas in Artemisia-dominated vegetation. Found in at least scrub and grasslands in the Sonoran and Mojave deserts and the Great Basin. Likely found in additional sites. Found in desert sand dunes in Coachella Valley. Invades at least (and likely more) 3 major ecotypes and 5 minor in CA.
Sources of information:
DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published.
Ryan, FJ, DR Ayres, DE Bell. 1999. There's more to tumbleweed (Russian thistle) than meets the eye. Proceedings of the California Invasive Plant Council 1999 Symposium.
Barrows, CW. 1997. Habitat relationships of the Coachella Valley fringe-toed lizard (Uma inornata). The Southwestern Naturalist 42(2): 218-223.
Evans, RA., JA. Young. 1982. Russian thistle and barbwire Russian thistle seed and seedbed ecology. USDA-ARS. ARR-W-25: October.
CDFA Encycloweedia. <>.
|
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.
|
C
Observational
|
Describe distribution:
Common throughout CA, esp. in the southern region of the state. No literature documented the extent of this plant's distribution. However, it spreads to suitable habitat rapidly, and likely occurs in all the suitable habitat that exists in the state. It could be rated an "A" with more documentation.
Sources of information:
DiTomaso, J., E. Healy. Weeds of California and Other Western States. Not yet published.
|
| Reaches reproductive maturity in 2 years or less |
Yes |
| Dense infestations produce >1,000 viable seed per square meter |
Yes |
| Populations of this species produce seeds every year. |
Yes |
| Seed production sustained over 3 or more months within a population annually |
Yes |
| Seeds remain viable in soil for three or more years |
No |
| Viable seed produced with both self-pollination and cross-pollination |
Yes |
| 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 |
| Total points: |
7
|
| Total unknowns: |
0 |
| Total score: |
A?
Scoring Criteria for Worksheet A
A. High reproductive potential (6 or more points).
B. Moderate reproductive potential (4-5 points).
C. Low reproductive potential (3 points or less and less than 3 Unknowns).
U. Unknown (3 or fewer points and 3 or more Unknowns).
|
Related traits:
Worksheet B - Arizona Ecological Types is not included here
(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 | |
| estuaries | |
| Dunes | coastal | |
| desert | D, < 5% |
| interior | |
| Scrub and Chaparral | coastal bluff scrub | |
| coastal scrub | |
| Sonoran desert scrub | D, < 5% |
| Mojavean desert scrub (incl. Joshua tree woodland) | C, 5% - 20% |
| Great Basin scrub | D, < 5% |
| 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 | D, < 5% |
| pebble plain | |
| Bog and Marsh | bog and fen | |
| marsh and swamp | |
| Riparian and Bottomland habitat | riparian forest | |
| riparian woodland | |
| 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 dwarf scrub | |
|
Amplitude (breadth): |
B |
|
Distribution (highest score): |
C |
Infested Jepson Regions
Click here for a map of Jepson regions
- CA Floristic Province
- Cascade Range
- Central West
- Great Valley
- Northwest
- Sierra Nevada
- Southwest
- Great Basin Province
- Modoc Plateau
- Sierra Nevada East
- Desert Province
- Mojave Desert
- Sonoran Desert
