Photo: Keir Morse

Pennisetum ciliare Risk Assessment

Synonyms: Cenchrus ciliaris

Common names: buffelgrass, buffel grass

Pennisetum ciliare -- California

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Evaluation Summary
Buffelgrass is a perennial grass that has been introduced as a forage species and for erosion control in semi-tropical to semi-arid regions across the globe. It was introduced to North America to increase forage production in semi-arid habitats and has expanded into natural areas. It has many characteristics that allow it to become invasive and spread, including asexual seed production, easily dispersed seeds, high seed production and tolerance of drought. Buffelgrass is invasive in the southwestern US and Mexico, and so far only a few populations have been found or have established in California.
General Evaluation Information
Date of Evaluation: 
September 20, 2022
Evaluation Time (hrs): 
Not Recorded
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: 
AttachmentSize
PDF icon Buffelgrass climate matching map.pdf1.08 MB
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: 
Very High
Answer / Justification: 
Buffelgrass has invaded southwestern North America, Arizona, New Mexico, Texas, Mexico incl. Sonora and Chihuahua. Also invading in Australia and South Central Asia (India, Pakistan), and also found in Hawaii. Native to Africa and the Middle East. Buffelgrass is on the Arizona noxious weed list and the New Mexico watch list.
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: 
Very High
Answer / Justification: 
Buffelgrass is invasive in Australia and southwestern North America, where the climate is similar to California including the Sonoran Desert.
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: 
Invasive in US and Australia
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: 
Very High
Answer / Justification: 
Invading southwestern North America and Australia, both of which have climates that match California.
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: 
Very High
Answer / Justification: 
Several other Pennisetum's are also invasive. Including Fountaingrass (Pennisetum setaceum), kikuyu (Pennisetum clandestinum) Chinese fountain grass (P. alopecuroides) . Buffelgrass is also listed as Cenchrus ciliaris, several other Cenchrus' are also invasive (Cenchrus setiger)
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: 
High
Answer / Justification: 
Buffelgrass grows in southern Africa, the middle east, south central Asia, eastern Australia, southwestern North America and all these places match the climate of California. Buffelgrass seems to occur in about half of climate zones that it grows in that also match California. (NOTE: not listed as very high confidence, because there are several large semi-tropical areas where buffelgrass grows that are outside climate of CA, eastern Africa, eastern South America (Brazil), Texas and central Mexico.)
Reference(s): 
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: 
Very High
Answer / Justification: 
Buffelgrass displaces native plants in several locations where it is invasive, including Australia, Hawaii, and Sonoran Desert. It can also overtop and smother smaller native plants.
Reference(s): 
8. Is the plant noted as promoting fire and/or changing fire regimes?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Very High
Answer / Justification: 
Buffel grass adds fuels to desert ecosystems where fuels are historically limited. Buffelgrass also adds fuels to semi-tropical grassland ecosystems altering the fire regime.
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: 
No
Points: 
0
Confidence Level: 
Very High
Answer / Justification: 
Buffelgrass is often introduced to semi-arid ecosystems to increase forage for livestock. Buffelgrass has been viewed as a beneficial forage grass for livestock producers.
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: 
Very High
Answer / Justification: 
While buffelgrass increases fuels and has been planted as a forage grass, it does not create impenetrable thickets for most animal species. The grass is generally less than 1.5 m tall and less than 1 m tall when not in flower. It does alter habitat quality and decrease species richness.
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: 
Buffelgrass can reproduce via stolons or rhizomes. The main mode of reproduction is by seed and is apomictic (produces seed asexually).
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: 
High
Answer / Justification: 
Buffelgrass is a grass and may occasionally reproduce by tillers separating from the parent plant, however this is uncommon and would require the plant to be disturbed.
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: 
Yes, reproduces by seed
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: 
Individual buffelgrass inflorescences can produce over one hundred seeds and individual plants can have dozens of inflorescences.
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: 
Very High
Answer / Justification: 
Germination of buffelgrass seeds was 25-35% in India and similarly as high in Mexico when placed under warm growing conditions. Seed viability drops over time.
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: 
Very High
Answer / Justification: 
Buffelgrass plants can produce seed in two years or less.
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: 
Medium
Answer / Justification: 
Buffelgrass is a C4 grass and generally reproduces during the warm summer rains. It can produce flowers from spring through summer or anytime the soil is wet and warm enough. Jepson lists flowering from April to October.
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: 
Yes
Points: 
1
Confidence Level: 
Very High
Answer / Justification: 
Buffelgrass seeds can disperse via animals, including getting stuck in their fur, and buffelgrass seeds can spread long distances and new patches form long distances from previously known patches.
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: 
Medium
Answer / Justification: 
Seeds have bristles and can be spread by wind or water. Several sources suggest seeds can float. And populations can spread and disperse quickly in variety of patterns (guerrilla and phalanx, see Olssen et al. 2012).
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: 
No
Points: 
0
Confidence Level: 
Low
Answer / Justification: 
Seed dispersal can be on clothes as the seeds have bristles, however references do not suggest the frequency of this type of dispersal. Most often buffelgrass is intentionally dispersed to increase forage, or seeds are dispersed by wind, water or animals. Buffelgrass has been introduced across the globe intentionally as a pasture grass, to remediate reduced forages, while others have viewed its invasiveness as a problem for natural areas (see Marshall et al. 2012).
Reference(s): 
Evaluation Notes

Websites accessed:

Pennisetum ciliare (L.) Link in GBIF Secretariat (2021). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omeiaccessed via GBIF.org on 2022-11-30.

https://keyserver.lucidcentral.org/weeds/data/media/Html/cenchrus_ciliaris.htm accessed 2022-11-30.

https://agriculture.az.gov/pestspest-control/agriculture-pests/noxious-weeds accessed 2022-11-30

https://wiki.bugwood.org/Pennisetum_ciliare#Reproduction accessed 2022-11-30

https://pubs.nmsu.edu/_circulars/CR698/ accessed 2022-11-30

https://www.desertmuseum.org/buffelgrass/learn.php access 2022-11-30

 James P. Smith, Jr. 2012, Pennisetum ciliare, in Jepson Flora Project (eds.) Jepson eFlora, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=36817, accessed on November 30, 2022.

https://keys.lucidcentral.org/keys/v3/pastures/Html/Buffel_grass.htm accessed 2022-11-30

 

 

Total PRE Score

  • < 13 : Low Potential Risk
  • 13 - 15 : Moderate Potential Risk
  • > 15 : High Potential Risk

PRE Score: 
21
Number of questions answered: 
20
Screener Confidence (%): 
90.0
PRE Content Access and Privacy

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