Plant Assessment Form

Holcus lanatus

Common Names: common velvet grass; Yorkshire fog

Evaluated on: 3/17/05

List committee review date: 08/07/2005

Re-evaluation date:

Evaluator(s)

Jeffrey Corbin
UC Berkeley
Dept. of Integrative Biology, University of CA, Berkeley, CA 94720-3140
510-643-4993, 510-703-4904
corbin@berkeley.edu
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

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? Moderate
Alert Status? No Alert
Documentation? 3 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes C Observational
Impact?
Four-part score CACD Total Score
B
1.2 ?Impact on plant community A. Severe Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels C. Minor Anecdotal
1.4 ?Impact on genetic integrity D. None Other Published Material
2.1 ?Role of anthropogenic and natural disturbance in establishment A. Severe Reviewed Scientific Publication
Invasiveness?
Total Points
15 Total Score B
2.2 ?Local rate of spread with no management A. Increases rapidly Reviewed Scientific Publication
2.3 ?Recent trend in total area infested within state B. Increasing less rapidly Observational
2.4 ?Innate reproductive potential
(see Worksheet A)
A. High Other Published Material
2.5 ?Potential for human-caused dispersal C. Low Other Published Material
2.6 ? Potential for natural long-distance dispersal C. Rare Other Published Material
2.7 ?Other regions invaded B. Invades 1 or 2 ecological types Reviewed Scientific Publication
3.1 ?Ecological amplitude/Range
(see Worksheet C)
B. Moderate Other Published Material
Distribution?
Total Score A
3.2 ?Distribution/Peak frequency
(see Worksheet C)
A. High 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? C Observational
Identify ecosystem processes impacted:

Some effects on water, N levels - especially compared to exotic annual grasses


Sources of information:

Not much. I have done my own studies on water and N, but they're not published
Jeff Corbin, UC Berkeley, personal observations.


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

Holcus is capable of forming almost monospecific stands, especially in coastal habitats. It is also a demonstrated problem in New Zealand.


Sources of information:

Hektner, M.M. and T.C. Foin. 1977. Vegetation analysis of a northern California Coastal prairie: Sea Ranch, Sonoma County, California. Madrono 21:83-103.
Corbin J.D. and C.M. D'Antonio. In prep. Out of the frying pan: Invasion of exotic perennial grasses into California coastal prairie grasslands.
Meredith Thomsen, Dept. of Integrative Biology, UC Berkeley, unpublished data.
Jesson, L., D. Kelly, et al. (2000). "The importance of dispersal, disturbance, and competition for exotic plant invasions in Arthur's Pass National Park, New Zealand." New Zealand Journal of Botany 38(3): 451-468.


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

Not very palatable forage. Does well in grazed areas.


Sources of information:

Jeff Corbin, personal observations.
Very little info.


Question 1.4 Impact on genetic integrity? D Other Published Material

None. No native species of Holcus in California.


Sources of information:

Hickman, J. C. (ed.) 1993. The Jepson Manual, Higher Plants of California. University of California Press. Berkeley, CA


Section 2: Invasiveness
Question 2.1 Role of anthropogenic and natural disturbance
in establishment?
A Reviewed Scientific Publication
Describe role of disturbance:

Invades intact and undisturbed grasslands, including grasslands where grazing is removed. Also, unpublished documentation of its invasion into native-dominated coastal prairies (D'Antonio and Corbin).


Sources of information:

Question 2.2 Local rate of spread with no management? A Reviewed Scientific Publication
Describe rate of spread:

At Sea Ranch (Foin and Hetkner 1986), it went from 6% cover to 21% cover in 4 years There is plenty of anecdotal evidence, too..


Sources of information:

Foin and Hektner 1977;
Peter Connors, Reserve Manager. pers. comm. for Bodega Marine Reserve. pgconnors@ucdavis.edu.


Question 2.3 Recent trend in total area infested within state? B Observational
Describe trend:

Species well distributed in state and has the potential to spread more. Currently spreading.


Sources of information:

DiTomaso, observational
Dan Gluesenkamp, Audubon Canyon Ranch, pers. obs.


Question 2.4 Innate reproductive potential? A Other Published Material
Describe key reproductive characteristics:

Produces MANY seeds, every year, and can produce rhizomes.


Sources of information:

DiTomaso and Healy. 2006. Weeds of California. UC DANR Publ. #3488.
Jeff Corbin, UC Berkeley, personal observations


Question 2.5 Potential for human-caused dispersal? C Other Published Material
Identify dispersal mechanisms:

Very light seeds, wind dispersed. Also, can catch in shoes easily, but these probably do not contribute much to movement further than 1 km.


Sources of information:

DiTomaso and Healy. 2006. Weeds of California. UC DANR Publ. #3488.
Jeff Corbin, UC Berkeley, personal observations


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

Wind, and stuck in mud on shoes. The seeds are very small and can easily be blown around, but not 1 km. Often grows close to water and can move long distances by this mechanism.


Sources of information:

DiTomaso and Healy. 2006. Weeds of California. UC DANR Publ. #3488.
J. Corbin, personal observations


Question 2.7 Other regions invaded? B Reviewed Scientific Publication
Identify other regions:

Sources of information:

Jesson, L., D. Kelly, et al. (2000). "The importance of dispersal, disturbance, and competition for exotic plant invasions in Arthur's Pass National Park, New Zealand." New Zealand Journal of Botany 38(3): 451-468.


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

Widespread in coastal grasslands. Can also be found further inland.


Sources of information:

CalFlora,
Jeff Corbin, UC Berkeley, personal observations


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

Most common in northern California coastal prairie.


Sources of information:

DiTomaso and Corbin, observational.
John Randall, The Nature Conservancy, and Dan Gluesenkamp, Audubon Canyon Ranch, pers. obs.


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 No
Seeds remain viable in soil for three or more years No
Viable seed produced with both self-pollination and cross-pollination No
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes Yes
Fragments easily and fragments can become established elsewhere No
Resprouts readily when cut, grazed, or burned Yes
Total points: 6
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
desert
interior
Scrub and Chaparralcoastal bluff scrub
coastal scrubC, 5% - 20%
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 prairieA, > 50%
valley and foothill grasslandD, < 5%
Great Basin grassland
vernal pool
meadow and seepC, 5% - 20%
alkali playa
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): A

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