Plant Assessment Form

Cynodon dactylon

Common Names: Bermuda grass; couch grass; devil grass; wire grass; vine grass

Evaluated on: 5/26/04

List committee review date: 08/07/2005

Re-evaluation date:

Evaluator(s)

John J. Knapp/ Invasive Plant Program Manager
Catalina Island Conservancy
P.O. Box 2739 Avalon, CA 90704
(310) 510-1299
jknapp@catalinaconservancy.org
Joseph DiTomaso
University of California-Davis
Dept. Plant Sci., Mail Stop 4, Davis, CA 95616
530-754-8715
jmditomaso@ucdavis.edu

List commitee members

Carla Bossard
John Randall
Carri Pirosko
Dan Gluesenkamp
Gina Skurka
Brianna Richardson

General Comments

Cal-IPC's concern is effect in desert washes, not in home gardens.

Table 2. Criteria, Section, and Overall Scores

Overall Score? Moderate
Alert Status? No Alert
Documentation? 3.5 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes B Reviewed Scientific Publication
Impact?
Four-part score BBCD Total Score
B
1.2 ?Impact on plant community B. Moderate Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels C. Minor Other Published Material
1.4 ?Impact on genetic integrity D. None Other Published Material
2.1 ?Role of anthropogenic and natural disturbance in establishment C. Minor Reviewed Scientific Publication
Invasiveness?
Total Points
12 Total Score B
2.2 ?Local rate of spread with no management B. Increases less rapidly Other Published Material
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 A. High Reviewed Scientific Publication
2.6 ? Potential for natural long-distance dispersal C. Rare Other Published Material
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)
D. Very 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? B Reviewed Scientific Publication
Identify ecosystem processes impacted:

C. dactyon is considered a potent allelopathic plant. In Arizona, C. dactylon increases substrate stability during floods. Can reduce soil nutrient levels and block light penetration to soil surface.


Sources of information:

Question 1.2 Impact on plant community composition,
structure, and interactions?
B Reviewed Scientific Publication
Identify type of impact or alteration:

C. dactylon forms large dense ground cover mats that can inhibit native flora survival by increasing the density and depth at ground level, thus fragmenting habitat. C. dactylon has been identified as posing a threat to temperate grasslands in North America. Riparian communities in Arizona are severely degraded by C. dactylon. A single shoot from a rhizome may cover 2.5 m2 of soil surface in 150 days after emergence.


Sources of information:

Labrada, R., J.C. Caseley, and C. Parker. 1994. Weed management for developing countries. FAO Plant Production Paper 120. Rome: Food and Agriculture Organization for the United Nations.
Grace, J.B., M.D. Smith, S.L. Grace, S.L. Collins, and T.J. Stohlgren. 2001. Interactions between fire and invasive plants in temperate grasslands of North America. Pp. 40-65 in: Galley, K.E.M. and T.P. Wilson, eds. Proceedings of the invasive species workshop: the role of fire in the control and spread of invasive species. Tallahassee, Florida: Tall Timbers Research Station Miscellaneous Publication No. 11.
Arizona-Sonoma Desert Museum Programs and Research. 1996-2003. Biological survey of Ironwood Forest National Monument: exotic plants assessment. http://www.desertmuseum.org/programs/ifnm_exotic.html.
Dudley, T. 1998. Exotic plant invasions in California riparian areas and wetlands. Fremontia 26(4): 24-29.


Question 1.3 Impact on higher trophic levels? C Other Published Material
Identify type of impact or alteration:

Under drought conditions with high temperatures, C. dactylon may contain hydrocyanic acid (prussic acid), and when ingested it can be poisonous to cattle, sheep, and goats (other herbivores?). C. dactylon has been reported as a host for viral stripe diseases (affecting corn and rice) and several fungal diseases including Bipolaris, Gaeumannomyces, Leptosphaeria, Marasmius, Phyllachora, Puccinia, Sporisorium and Ustilago; however, the impact of these diseases to native flora is unknown. Habitat of the Southwestern willow flycatcher is dominated by C. dactylon. Produces contact dermatitis and is an important cause of hay fever.


Sources of information:

Anderson, W.P. 1999. Perennial weeds: characteristics and identification of selected species. Ames, Iowa: Iowa State University Press.
Wilken, D. and Hannah, L. 1998. Cynodon dactylon. Channel Island National Park Service Literature Review. Unpublished.
Fuller T.C., McClintock E. Poisonous Plants of California. 1986. University of California Press: Berkeley. Pg. 293.


Question 1.4 Impact on genetic integrity? D Other Published Material

No hybridization is known to occur with native California taxa. No native California taxa occur in the genus Cynodon.


Sources of information:

Hickman, J.C. (ed.). 1993. The Jepson manual of higher plants of California. P. 1248. University of California Press, Berkeley.


Section 2: Invasiveness
Question 2.1 Role of anthropogenic and natural disturbance
in establishment?
B Other Published Material
Describe role of disturbance:

Waste places, grazed areas, roads, trails and cultivation are disturbances that lead to C. dactylon establishment. Typically requires disturbance. Occasionally found in undisturbed areas, but is considered primarily a landscape of crop weed.


Sources of information:

Ivens, G.W. 1967. East African weeds and their control. Nairobi: Oxford University Press.
Johnson, B.J. 1992. Common bermudagrass (Cynodon dactylon) suppression in Zoysia spp. with herbicides. Weed Technology 6: 813-819.
Wilken, D. and Hannah, L. 1998. Cynodon dactylon. Channel Island National Park Service Literature Review. Unpublished.


Question 2.2 Local rate of spread with no management? B Other Published Material
Describe rate of spread:

In Arizona, spreads slowly once established.


Sources of information:

Arizona-Sonoma Desert Museum Programs and Research. 1996-2003. Biological survey of Ironwood Forest National Monument: exotic plants assessment. http://www.desertmuseum.org/programs/ifnm_exotic.html.


Question 2.3 Recent trend in total area infested within state? C Other Published Material
Describe trend:

First occurence in 1880, and by 1900, is was widespread throughout central and southern California, and is now grown in cultivation in California. Its current trend is unknown. Not listed as noxious weed in California. Controlled along roadsides, urban areas, and restoration trials in decomissioned hayfields.


Sources of information:

Wilken, D. and Hannah, L. 1998. Cynodon dactylon. Channel Island National Park Service Literature Review. Unpublished.
Knapp, D. 2003. Personal communication.


Question 2.4 Innate reproductive potential? A Reviewed Scientific Publication
Describe key reproductive characteristics:

In California, flowering occurs from March to August. C. dactylon is wind-pollinatied, and can produce 230 seeds per panicle during the first three months after the initial seed set, but is considered a very sparse seed producer except for some biotypes as in California, where the cultivated biotype has a seedset of 95%. Seed in Australia remains viable in the soil for 3-4 years. The axillary buds at the nodes of rhizomes and stolons provide the principal means of spreading and dispersal. Rhizomes can be superficial or very deep from a few centimeters to over a meter in depth, which allows it to survive a wide range of climatic conditions from flooding to droughts. It is also adapted to a wide range of soil conditions from sand to heavy clay, but grows best in moist well drained soils. Seed can remain dormant in the soil, and they maintain their viability well.


Sources of information:

Labrada, R., J.C. Caseley, and C. Parker. 1994. Weed management for developing countries. FAO Plant Production Paper 120. Rome: Food and Agriculture Organization for the United Nations.
Holm, L.G., Doll, J., Holm, E., Pancho, J.V., and Herberger, J.P. 1997. World weeds: natural history and distribution. John Wiley and Sons, New York, USA.
Ivens, G.W. 1967. East African weeds and their control. Nairobi: Oxford University Press.
Wilken, D. and Hannah, L. 1998. Cynodon dactylon. Channel Island National Park Service Literature Review. Unpublished.
Grichar, W. and T. Bosewell. 1989. Bermudagrass (Cynodon dactylon) control with postemergence herbicides in peanut (Arachis hypogaea). Weed Technology 3: 267-271.
Brown, K. and K. Brooks. 2002. Bushland weeds _ a practical guide to their management. Environmental Weeds Action Network. Greenwood, Australia.


Question 2.5 Potential for human-caused dispersal? A Reviewed Scientific Publication
Identify dispersal mechanisms:

Seed can be dispersed by cattle and bison with enhanced germination, and the vegetative reproductive parts can be caught on the mud on the hooves of mammals at watering holes. It can be transported far distances as a contaminant in hay, livestock feed, and soil, and by mowing equipment and vehicles. It is commonly planted in athletic fields, roadsides, airports, lawns in saline conditions in the Southern U.S., and it becomes naturalized in agricultural fields, irrigation canals, orchards, roadsides and waste places. Vegetative structures have been seen clinging to the head and legs of bison on Catalina Island. Transport of soil contaminated with seed to new locations, and horses and cattle disperse it internally also.


Sources of information:

Holm, L.G., Doll, J., Holm, E., Pancho, J.V., and Herberger, J.P. 1997. World weeds: natural history and distribution. John Wiley and Sons, New York, USA.
Anderson, W.P. 1999. Perennial weeds: characteristics and identification of selected species. Ames, Iowa: Iowa State University Press.
Ivens, G.W. 1967. East African weeds and their control. Nairobi: Oxford University Press.
Johnson, B.J. 1992. Common bermudagrass (Cynodon dactylon) suppression in Zoysia spp. with herbicides. Weed Technology 6: 813-819.
Wilken, D. and Hannah, L. 1998. Cynodon dactylon. Channel Island National Park Service Literature Review. Unpublished.
Knapp, J.J. 2004. Catalina Invasive Plant Ranking Plan for the Catalina Island Conservancy. Unpublished.
Arizona-Sonoma Desert Museum Programs and Research. 1996-2003. Biological survey of Ironwood Forest National Monument: exotic plants assessment. http://www.desertmuseum.org/programs/ifnm_exotic.html.
Knapp, J.J. 2004. Personal observation from 2002-2004, C. dactylon stolons matted to the face of bison on Catalina Island. (310) 510-1299, jknapp@catalinaconservancy.org.


Question 2.6 Potential for natural long-distance dispersal? C Other Published Material
Identify dispersal mechanisms:

Rhizomes and seeds can be dispersed by wind and water, and seeds survive submerged for 50 days. Ants act as short distance vectors.


Sources of information:

Holm, L.G., Doll, J., Holm, E., Pancho, J.V., and Herberger, J.P. 1997. World weeds: natural history and distribution. John Wiley and Sons, New York, USA.
Brown, K. and K. Brooks. 2002. Bushland weeds _ a practical guide to their management. Environmental Weeds Action Network. Greenwood, Australia.
Elkhorn Slough National Estuarine Research Reserve. 2000. Weed control by species. Elkhorn Slough National Estuarine Research Reserve. Pp. 1-57.


Question 2.7 Other regions invaded? C Other Published Material
Identify other regions:

C. dactylon occur in regions from 45 degrees north and south latitudes. In arid regions, it invades river banks and stream beds. It is ranked second among the worst weeds of the world in agricultural areas. It is considered a damaging and aggressively invasive plant in other parts of the world, and is suspected of being so on the Galapagos Islands. Between 1983-1994, bermuda grass jumped from being absent on the Weed Science Society's list of the worst weeds to ranking 10th. Most problems were in the southern states. Scoring as C because already widespread in California.


Sources of information:

Holm, L.G., Doll, J., Holm, E., Pancho, J.V., and Herberger, J.P. 1997. World weeds: natural history and distribution. John Wiley and Sons, New York, USA.
Anderson, W.P. 1999. Perennial weeds: characteristics and identification of selected species. Ames, Iowa: Iowa State University Press.
Tye, A. 2001. Invasive plant problems and requirements for weed risk assessment in the Galapagos Islands. Pp. 153-175. Groves, R.H., F.D. Panetta and J.G. Virtue (eds.). Weed Risk Assessment. CSIRO Publishing: Collingwood, Victoria, Australia
Webster, T. M. and H. D. Coble. 1997. Changes in the weed species composition of the southern United States: 1974-1995. Weed Technology 11(2): 308-317


Section 3: Distribution
Question 3.1 Ecological amplitude/Range? A Other Published Material

In California, the first record appeared in both San Jose and San Bernardino in 1880. It occurs on the all northern Channel Islands and nearly all counties west of the Sierra Nevada.


Sources of information:

Wilken, D. and Hannah, L. 1998. Cynodon dactylon. Channel Island National Park Service Literature Review. Unpublished.


Question 3.2 Distribution/Peak frequency? D Observational
Describe distribution:

Not common in wildlands.


Sources of information:

Knapp, observational.


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 Yes
Viable seed produced with both self-pollination and cross-pollination Unknown
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes Yes
Fragments easily and fragments can become established elsewhere Yes
Resprouts readily when cut, grazed, or burned Yes
Total points: 11
Total unknowns: 1
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
DunescoastalD, < 5%
desert
interior
Scrub and Chaparralcoastal bluff scrub
coastal scrubD, < 5%
Sonoran desert scrub
Mojavean desert scrub (incl. Joshua tree woodland)
Great Basin scrub
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
chaparral
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairieD, < 5%
valley and foothill grassland
Great Basin grassland
vernal pool
meadow and seep
alkali playa
pebble plain
Bog and Marshbog and fen
marsh and swamp
Riparian and Bottomland habitatriparian forest
riparian woodland
riparian scrub (incl.desert washes)D, < 5%
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): D

Infested Jepson Regions

Click here for a map of Jepson regions

  • CA Floristic Province
  • Cascade Range
  • Central West
  • Great Valley
  • Northwest
  • Sierra Nevada
  • Southwest
  • Modoc Plateau
  • Sierra Nevada East
  • Desert Province
  • Mojave Desert
  • Sonoran Desert