Sphaerophysa salsula_C135-02
Photo courtesy UC Davis Weeds of California

Sphaerophysa salsula Risk Assessment

Common names: alkali swainsonpea

Sphaerophysa salsula -- California

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Evaluation Summary
Summary: 
General Evaluation Information
Date of Evaluation: 
October 4, 2016
Evaluation Time (hrs): 
3 Hours
Evaluation Status: 
Completed
Plant Information
Plant Material: 
If the plant is a cultivar, and if the cultivar's behavior differs from its parent's (behavior), explain how: 
Regional Information
Region Name: 
Climate Matching Map
These maps were built using a toolkit created in collaboration between GreenInfo Network, PlantRight, Cal-IPC, and Agricultural Sustainability Institute at UC Davis.
Climate Matching Maps PDF: 
Invasive History and Climate Matching
1. Has the species (or cultivar or variety, if applicable; applies to subsequent "species" questions) become naturalized where it is not native?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
High
Answer / Justification: 
Extirpated from California (Jepson). Occurs in other western states and Canada (USDA NRCS).
Reference(s): 
2. Is the species (or cultivar or variety) noted as being naturalized in the US or world in a similar climate?
Yes or No: 
Yes
Points: 
2
Confidence Level: 
High
Answer / Justification: 
Extirpated from California (Jepson). Occurs in other western states and Canada (USDA NRCS). The distribution of S. salsula matches California in Washington, Oregon, Nevada, Idaho, Utah, and Montana according to the Cal-IPC climate map.
Reference(s): 
3. Is the species (or cultivar or variety) noted as being invasive in the U.S. or world?
Yes or No: 
Yes
Points: 
2
Confidence Level: 
Medium
Answer / Justification: 
S. salsula seeds are contaminants in Alfalfa seed and are difficult to separate because they are similar size and weight. Therefore invasiveness is based on economic impacts to crops.
Reference(s): 
4. Is the species (or cultivar or variety) noted as being invasive in the US or world in a similar climate?
Yes or No: 
Yes
Points: 
3
Confidence Level: 
Medium
Answer / Justification: 
S. salsula seeds are contaminants in Alfalfa seed and are difficult to separate because they are similar size and weight. Therefore invasiveness is based on economic impacts to crops. The distribution of S. salsula matches California in Washington, Oregon, Nevada, Idaho, Utah, and Montana according to the Cal-IPC climate map.
Reference(s): 
5. Are other species of the same genus (or closely related genera) invasive in a similar climate?
Yes or No: 
No
Points: 
0
Confidence Level: 
High
Answer / Justification: 
S. salsula is the only species of Sphaerophysa listed in Randall (2012).
Reference(s): 
6. Is the species (or cultivar or variety) found predominately in a climate matching the region of concern?
Yes or No: 
Yes
Points: 
2
Confidence Level: 
Medium
Answer / Justification: 
The distribution of S. salsula is not well documented in its native range, but appears to be predominately similar to California based on the Cal-IPC climate map.
Impact on Native Plants and Animals
7. Does this plant displace native plants and dominate (overtop or smother) the plant community in areas where it has established?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Low
Answer / Justification: 
It has high potential for establishment along streams, irrigation canals, waste ways, pastures and meadows with a high water table. Has become a problem in some poorly drained marshy, or saline areas of the Western U.S. (DiTomaso 2013). It is possible that it could displace native plants or dominate natural communities in these areas.
Reference(s): 
8. Is the plant noted as promoting fire and/or changing fire regimes?
Yes or No: 
No
Points: 
0
Confidence Level: 
Low
Answer / Justification: 
There is not evidence that S. salsula promotes or changes fire regimes.
Reference(s): 
9. Is the plant a health risk to humans or animals/fish? Has the species been noted as impacting grazing systems?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
High
Answer / Justification: 
Unpalatable to humans and livestock (DiTomaso 2013).
Reference(s): 
10. Does the plant produce impenetrable thickets, blocking or slowing movement of animals, livestock, or humans?
Yes or No: 
No
Points: 
0
Confidence Level: 
Low
Answer / Justification: 
S. salsula can reach 5 feet in height, but there is no documentation that it forms impenetrable thickets or blocks movement of animals or humans.
Reference(s): 
Reproductive Strategies
11. Does this species (or cultivar or variety) reproduce and spread vegetatively?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
High
Answer / Justification: 
Reproduces by seed and vegetatively from creeping roots (CDFA).
Reference(s): 
12. If naturally detached fragments from this plant are capable of producing new plants, is this a common method of reproduction for the plant?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
High
Answer / Justification: 
Reproduces by seed and vegetatively from creeping roots.
Reference(s): 
13. Does the species (or cultivar or variety) commonly produce viable seed?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
High
Answer / Justification: 
Reproduces by seed and vegetatively from creeping roots.
Reference(s): 
14. Does this plant produce copious viable seeds each year (> 1000)?
Yes or No: 
Points: 
Confidence Level: 
Answer / Justification: 
There is no evidence on the number of seeds produced by S. salsula per year.
Reference(s): 
15. Is there significant germination (>25%) of seeds the next growing season, with no requirement of an infrequent environmental condition for seeds to germinate (i.e. fire) or long dormancy period?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Medium
Answer / Justification: 
In one study, the germination percentage of S. salsula seed before storage was 30% (Ju-Hong 2012).
Reference(s): 
16. Does this plant produce viable seed within the first three years (for an herbaceous species) to five years (for a woody species) after germination?
Yes or No: 
Points: 
Confidence Level: 
Answer / Justification: 
There is no information on the time it takes from germination for S. salsula to form viable seeds.
Reference(s): 
17. Does this plant continuously produce seed for >3 months each year or does seed production occur more than once a year?
Yes or No: 
Points: 
Confidence Level: 
Answer / Justification: 
Flowering occurs from May to July. There is no information on the length of seed production.
Reference(s): 
Dispersal
18. Are the plant’s propagules frequently dispersed long distance (>100 m) by mammals or birds or via domestic animals?
Yes or No: 
No
Points: 
0
Confidence Level: 
High
Answer / Justification: 
There is no evidence that S. salsula seeds are dispersed by animals.
Reference(s): 
19. Are the plant’s propagules frequently dispersed long distance (>100 m) by wind or water?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Low
Answer / Justification: 
It is possible that S. salsula seeds could be dispersed by water since "it has high potential for establishment along streams, irrigation canals, waste ways, pastures and meadows with a high water table. Has become a problem in some poorly drained marshy, or saline areas of the Western U.S. (DiTomaso 2013)."
Reference(s): 
20. Are the plant’s propagules frequently dispersed via contaminated seed (agriculture or wildflower packets), equipment, vehicles, boats or clothing/shoes?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Medium
Answer / Justification: 
The main dispersal mechanism of S. salsula is assumed to be contaminated seed since the seeds are similar in shape and weight to alfalfa seeds (DiTomaso 2013 and CDFA).
Reference(s): 
Evaluation Notes
Total PRE Score

  • < 13 : accept (low risk of invasiveness)
  • 13 - 15 : evaluate further
  • > 15 : reject (high risk of invasiveness)

PRE Score: 
18
Number of questions answered: 
17
Screener Confidence (%): 
64.7
PRE Content Access and Privacy
Evaluation visibility: 
Public - accessible to all site users

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