Plant Assessment Form

Cortaderia selloana

Common Names: pampasgrass; white pampasgrass

Evaluated on: 5/14/04

List committee review date: 08/07/2005

Re-evaluation date:

Evaluator(s)

Alison E Stanton
BMP Ecosciences
2163 Cornelian Drive South Lake Tahoe, CA 96150
530 573 1177
alisonestanton@sbcglobal.net

List commitee members

Alison E Stanton
Joe DiTomaso
Cynthia Roye
Joanna Clines
Doug Johnson

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? High
Alert Status? No Alert
Documentation? 3 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes B Reviewed Scientific Publication
Impact?
Four-part score BAAD Total Score
A
1.2 ?Impact on plant community A. Severe Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels A. Severe Other Published Material
1.4 ?Impact on genetic integrity D. None Reviewed Scientific Publication
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Observational
Invasiveness?
Total Points
17 Total Score A
2.2 ?Local rate of spread with no management A. Increases rapidly Observational
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 Reviewed Scientific Publication
2.5 ?Potential for human-caused dispersal A. High Observational
2.6 ? Potential for natural long-distance dispersal A. Frequent Reviewed Scientific Publication
2.7 ?Other regions invaded C. Already invaded Reviewed Scientific Publication
3.1 ?Ecological amplitude/Range
(see Worksheet C)
A. Widespread Reviewed Scientific Publication
Distribution?
Total Score B
3.2 ?Distribution/Peak frequency
(see Worksheet C)
C. 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:

fire intensity, fire frequency These large plants produce significant amounts of biomass that is extremely flammable, increasing both the frequency and intensity of fire. The large size also significantly reduces light availability, especailly in mono-specific stands.


Sources of information:

1.Gadcil, R.L. A.L. Knowles, and J.A. Zabkiewicz. 1984. Pampas-A new forest weed problem. Proc. 37th New Zealand Weed and Pest Control Conference. p187-190.
2.Gadcil, R.L., A.M. Sandberg, P.J. Allen, and S. S. Gallagher. 1990. Partial suppression of pamaps grass by other species at the seedling stage. Proceedings of an Internation al Conference, Rotorua, New Zealand, July 1989. Ministry of Forestry FRI Bulletin 155.
3.Gadcil, R.L., P.G. Barton, P.J. Allen, and A.M. Sandberg. 1990. Growth of pampas grass (Cortaderia spp.) in New Zealand Pinus radiata forests. New Zealand Journal of Forestry Science 20(2):176-183.
4.Harradine, A.R. 1991. The impact of pampas grass as weeds in southern Australia. Plant Protection Quarterly 6:111-115.


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

Alters plant community conposition and structure. Develops mono-specific stands with >75% cover, eliminates lower layers, displaces native species, and creates a new layer in maritime chaparral and other scrub ecossystems. San Diego plants?


Sources of information:

1. Lambrinos, J. G. 2000. The impact of the invasive alien grass Cortaderia jubata (Lemoine) Stapf on an endangered mediterranean-type shrubland in California. Diversity and Distributions. 6:217-231
2. Rawling, J.L. 1988. The ecology and distribution of pampas grass (Cortaderia selloana) in Sydney bushland. Masters thesis. Macquerie University, Australia.


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

Total alteration of native plant communities decreases forage and nesting sites for native animals, although rats, some snakes, and rabbits have been observed in dense infestations. Rare plants and animals in San Diego?


Sources of information:

USFWS


Question 1.4 Impact on genetic integrity? D Reviewed Scientific Publication

No native congeners


Sources of information:

1. 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 Observational
Describe role of disturbance:

Often found in distrubed areas, including roadsides, logged forests, and railroad tracks. Also colonize narturally occuring landslides Germination requires light, but seedlings occasionally establish in undisturbed areas.


Sources of information:

1. Drewitz, J.J., and J. M. DiTomaso. 2000. Seed biology and control of jubatagrass. Proceedings of the California Exotic Pest Plant Council Symposium 2000. 6:32
2. Tschohl, A. 2000. Jubatagrass vs. pampasgrass: a growth analysis and comparison of invasive potential. Proceedings of the California Exotic Pest Plant Council Symposium 2000. 6:32-33
3.Costas-Lippmann, M. 1976. Ecology and reproductive biology of the genus Cortaderia in California. Doctoral dissertation, University of California, Berkeley
4.Stanton, A.E. 2000. Cortaderia in California:seedling ecology and management. Masters thesis. University of California, Davis.


Question 2.2 Local rate of spread with no management? A Observational
Describe rate of spread:

Increases rapidly after initial colonization Prolific seed production and light, wind-dispersed seeds facilitate rapid expansion.


Sources of information:

1.Conner, H.E. 1965. Breeding systems in New Zealand grasses V. Naturalized species of Cortaderia. New Zealand Journal of Botany 3:17-23
2.Costas-Lippmann, M. 1976. Ecology and reproductive biology of the genus Cortaderia in California. Doctoral dissertation, University of California, Berkeley


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

Much of the coastal habitat appears to be saturated with infestations, but the total acreage in the state is probably still increasing pampasgrass may be increasing in the Central Valley. It is most prevalent South of Santa Barbara, but is still widely available in the nursery trade.


Sources of information:

1. Lambrinos, J. G. 2000. The impact of the invasive alien grass Cortaderia jubata (Lemoine) Stapf on an endangered mediterranean-type shrubland in California. Diversity and Distributions. 6:217-231
2.Stanton, A.E. 2000. Cortaderia in California:seedling ecology and management. Masters thesis. University of California, Davis.


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

Produces prolific seed, more than 100,00 seed on a single plume, although only about 30% are viable.


Sources of information:

1. Drewitz, J.J., and J. M. DiTomaso. 2000. Seed biology and control of jubatagrass. Proceedings of the California Exotic Pest Plant Council Symposium 2000. 6:32
2. Tschohl, A. 2000. Jubatagrass vs. pampasgrass: a growth analysis and comparison of invasive potential. Proceedings of the California Exotic Pest Plant Council Symposium 2000. 6:32-33
3.Costas-Lippmann, M. 1976. Ecology and reproductive biology of the genus Cortaderia in California. Doctoral dissertation, University of California, Berkeley
4.Stanton, A.E. 2000. Cortaderia in California:seedling ecology and management. Masters thesis. University of California, Davis.


Question 2.5 Potential for human-caused dispersal? A Observational
Identify dispersal mechanisms:

Widely sold in the nursery trade. Humans cut and carry around the plumes including placing plumes on cars and trucks.


Sources of information:

1.Stanton, A.E. 2000. Cortaderia in California:seedling ecology and management. Masters thesis. University of California, Davis.


Question 2.6 Potential for natural long-distance dispersal? A Reviewed Scientific Publication
Identify dispersal mechanisms:

Seed can blow up to 20 miles in the wind. Seed stick to animal fur and get stuck on other vegetation


Sources of information:

1.Costas-Lippmann, M. 1976. Ecology and reproductive biology of the genus Cortaderia in California. Doctoral dissertation, University of California, Berkeley
2.Harradine, A.R. 1991. The impact of pampas grass as weeds in southern Australia. Plant Protection Quarterly 6:111-115.


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

Australia, New Zealand,South Africa


Sources of information:

1.Harradine, A.R. 1991. The impact of pampas grass as weeds in southern Australia. Plant Protection Quarterly 6:111-115.
2. Rawling, J.L. 1988. The ecology and distribution of pampas grass (Cortaderia selloana) in Sydney bushland. Masters thesis. Macquerie University, Australia.


Section 3: Distribution
Question 3.1 Ecological amplitude/Range? A Reviewed Scientific Publication

Distribution is primarily coastal, south of Santa Barbara. Not found on serpentine soils. Co-occurs with jubatagrass in large urban centers, including the North Coast. Escaping in interior regions, esspecially in riparian zones. Introduced to CA in 1872. Tolerates frost, utilizes higher light intensities, survives at higher temperatures.


Sources of information:

Costas-Lippmann, Stanton


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

Sources of information:

Stanton, DiTomaso


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 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 No
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 scrubC, 5% - 20%
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 prairieC, 5% - 20%
valley and foothill grassland
Great Basin grassland
vernal pool
meadow and seepD, < 5%
alkali playa
pebble plain
Bog and Marshbog and fen
marsh and swamp
Riparian and Bottomland habitatriparian forest
riparian woodlandD, < 5%
riparian scrub (incl.desert washes)
Woodlandcismontane woodland
piñon and juniper woodland
Sonoran thorn woodland
Forestbroadleaved upland forest
North Coast coniferous forestD, < 5%
closed cone coniferous forestD, < 5%
lower montane coniferous forest
upper montane coniferous forest
subalpine coniferous forest
Alpine Habitatsalpine boulder and rock field
alpine dwarf scrub
Amplitude (breadth): A
Distribution (highest score): C

Infested Jepson Regions

Click here for a map of Jepson regions

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