Plant Assessment Form

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 commitee 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.

Table 2. Criteria, Section, and Overall Scores

Overall Score? Limited
Alert Status? No Alert
Documentation? 3 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes D Other Published Material
Impact?
Four-part score DCDD Total Score
C
1.2 ?Impact on plant community C. Minor Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels D. Negligible Reviewed Scientific Publication
1.4 ?Impact on genetic integrity D. None Other Published Material
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Other Published Material
Invasiveness?
Total Points
11 Total Score B
2.2 ?Local rate of spread with no management U. Unknown
2.3 ?Recent trend in total area infested within state C. Stable Other Published Material
2.4 ?Innate reproductive potential
(see Worksheet A)
A. High Reviewed Scientific Publication
2.5 ?Potential for human-caused dispersal C. Low Anecdotal
2.6 ? Potential for natural long-distance dispersal A. Frequent Reviewed Scientific Publication
2.7 ?Other regions invaded C. Already invaded Other Published Material
3.1 ?Ecological amplitude/Range
(see Worksheet C)
A. Widespread Other Published Material
Distribution?
Total Score B
3.2 ?Distribution/Peak frequency
(see Worksheet C)
C. 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? 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?
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? 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? 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?
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? U
Describe rate of spread:

Sources of information:

Question 2.3 Recent trend in total area infested within state? 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? 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? 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? 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? 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? 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? 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.


Worksheet A - Innate reproductive potential

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?

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?
Marine Systemsmarine systems
Freshwater and Estuarine lakes, ponds, reservoirs
Aquatic Systemsrivers, streams, canals
estuaries
Dunescoastal
desertD, < 5%
interior
Scrub and Chaparralcoastal bluff scrub
coastal scrub
Sonoran desert scrubD, < 5%
Mojavean desert scrub (incl. Joshua tree woodland)C, 5% - 20%
Great Basin scrubD, < 5%
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
chaparral
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairie
valley and foothill grassland
Great Basin grassland
vernal pool
meadow and seep
alkali playaD, < 5%
pebble plain
Bog and Marshbog and fen
marsh and swamp
Riparian and Bottomland habitatriparian forest
riparian woodland
riparian scrub (incl.desert washes)
Woodlandcismontane woodland
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): 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