Berteroa incana_John Doyen
Photo courtesy John Doyen

Berteroa incana Risk Assessment

Common names: hoary alyssum

Berteroa incana -- California

Primary tabs

Evaluation Summary
Summary: 
General Evaluation Information
Date of Evaluation: 
August 18, 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: 
Naturalized in California. Present in 4 counties according to Calflora. Also widely naturalized in northern North America.
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: 
Naturalized in California. Present in 4 counties according to Calflora. Also widely naturalized in northern North America in some areas with similar climate.
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: 
Very High
Answer / Justification: 
Noted as invasive in Great Lakes area and Canada, and it is also considered an invasive alien in parts of Europe (Germany, Switzerland and Slovakia) (Warwick and Francis 2006). It is also reported invasive in Colorado and Wyoming (USDA Forest Service). B. incana was listed as a Class B Noxious Weed in California in 2009.
Reference(s): 
California Department of Food and Agriculture (CDFA) (0).  Encycloweedia.
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: 
Noted as invasive in Great Lakes area and Canada, and it is also considered an invasive alien in parts of Europe (Germany, Switzerland and Slovakia) (Warwick and Francis 2006). There is some overlap in its invasive range with the California climate in Colorado, Wyoming and Europe.
Reference(s): 
5. Are other species of the same genus (or closely related genera) invasive in a similar climate?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Medium
Answer / Justification: 
Berteroa is closely related to the Alyssum and Lobularia genera, both of which have invasive members in California and areas with similar climates. Examples include Lobularia maritima in California and Alyssum murale in Oregon.
Reference(s): 
6. Is the species (or cultivar or variety) found predominately in a climate matching the region of concern?
Yes or No: 
No
Points: 
0
Confidence Level: 
Medium
Answer / Justification: 
Most of the distribution points in GBIF do not match California's climate.
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: 
High
Answer / Justification: 
Partly because of its adaptation to less fertile soils, hoary alyssum stands can become quite dense, requiring herbicide control measures, which are rarely used in hay and forage crops. Its ability to compete aggressively with native plants, through both persistence under dry conditions and continuous flowering and fruiting, can not only reduce an area’s productivity for use as grazing land, but can also have a detrimental impact on native ecosystems in park and conservation areas. On restored prairies in Minnesota its presence as an “alien weed” contributed to a reduction in species richness of pollinator communities, as it attracted a minimal number of pollinating insects (Warwick and Francis 2006).
Reference(s): 
8. Is the plant noted as promoting fire and/or changing fire regimes?
Yes or No: 
No
Points: 
0
Confidence Level: 
Medium
Answer / Justification: 
There is no information on whether this species promotes fire. However, since it is an annual and grows in dry upland soils it is not likely to promote fire.
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: 
B. incana can cause toxicity to horses.
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: 
High
Answer / Justification: 
B. incana is an annual or biennial plant up to 43 inches high without spines so would not impede movement.
Reference(s): 
Reproductive Strategies
11. Does this species (or cultivar or variety) reproduce and spread vegetatively?
Yes or No: 
No
Points: 
0
Confidence Level: 
High
Answer / Justification: 
Although the species does form a tap root, its primary means of reproduction and spread is by seed.
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: 
No
Points: 
0
Confidence Level: 
Low
Answer / Justification: 
Although the species does form a tap root, its primary means of reproduction and spread is by seed.
Reference(s): 
13. Does the species (or cultivar or variety) commonly produce viable seed?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Very High
Answer / Justification: 
Hoary alyssum is an annual, biennial or short-lived perennial.
Reference(s): 
14. Does this plant produce copious viable seeds each year (> 1000)?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Very High
Answer / Justification: 
In a North Dakota study, the total number of seeds per plant averaged 2530, with a weight of 0.45 g per 1000 seeds. Another study found up to 300 fruits and 2640 seeds per plant (Warwick and Francis 2006).
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: 
High
Answer / Justification: 
Hoary alyssum seeds germinate either in spring, and plants flower by fall, or they can germinate in fall, over-winter and then flower the following spring.
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: 
Yes
Points: 
1
Confidence Level: 
High
Answer / Justification: 
Hoary alyssum seeds germinate either in spring, and plants flower by fall, or they can germinate in fall, over-winter and then flower the following spring.
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: 
Yes
Points: 
1
Confidence Level: 
Very High
Answer / Justification: 
In B. incana, initiation of flowering requires a day-length of more than 14 hours, and plants most likely to complete a flowering and fruiting cycle would have flowered in late spring or early summer when days are long, and will continue producing flowers and fruits until frost. In some areas of California this could occur for 3 months or more.
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: 
Medium
Answer / Justification: 
Seeds do not appear to travel far from the plants by natural means. There is no information on possible dispersal by such agents as wind, water, animals, or indirectly in manure or bird droppings.
Reference(s): 
19. Are the plant’s propagules frequently dispersed long distance (>100 m) by wind or water?
Yes or No: 
No
Points: 
0
Confidence Level: 
Medium
Answer / Justification: 
Seeds do not appear to travel far from the plants by natural means. There is no information on possible dispersal by such agents as wind, water, animals, or indirectly in manure or bird droppings.
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: 
High
Answer / Justification: 
The most likely means of long-distance dispersal appears to be contamination of seed used for lawns and forage crops. Harvesting of weed-contaminated hay can also contribute to local spread.
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: 
17
Number of questions answered: 
20
Screener Confidence (%): 
76.0
PRE Content Access and Privacy
Evaluation visibility: 
Public - accessible to all site users

Review this Evaluation

1945

Click on the button below to mark this evaluation as "Reviewed". Once you click the button, please wait a second, and the site will return to this Evaluation and your name will be on the "Reviewers List" in the right hand column (below the Evaluation Summary). For more information, please see the help page on How to Review an Evaluation?

Vertical Tabs