Plant Assessment Form

Spartina anglica

Common Names: English cordgrass

Evaluated on: 15-Apr-04

List committee review date:

Re-evaluation date:

Evaluator(s)

Dr. Debra Ayres
UC Davis
Evolution and Ecology, 1 Shields Ave., Davis, 95616
530 722 6882
drayres@ucdavis.edu
Cynthia L. Roye/Associate State Park Resource Ecologist
California State Parks
California State Parks Natural Resources DivisionPO Box 242896, Sacramento, CA, 94296-0001
(916) 653-9083
Croye@parks.ca.gov

No list committee members listed

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? Moderate
Alert Status? Alert
Documentation? 3.5 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes A Observational
Impact?
Four-part score ACAD Total Score
B
1.2 ?Impact on plant community C. Minor 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 A. Severe Reviewed Scientific Publication
Invasiveness?
Total Points
13 Total Score B
2.2 ?Local rate of spread with no management C. Stable Reviewed Scientific Publication
2.3 ?Recent trend in total area infested within state C. Stable Reviewed Scientific Publication
2.4 ?Innate reproductive potential
(see Worksheet A)
A. High Reviewed Scientific Publication
2.5 ?Potential for human-caused dispersal C. Low Anecdotal
2.6 ? Potential for natural long-distance dispersal A. Frequent Observational
2.7 ?Other regions invaded C. Already invaded Reviewed Scientific Publication
3.1 ?Ecological amplitude/Range
(see Worksheet C)
D. Narrow Reviewed Scientific Publication
Distribution?
Total Score D
3.2 ?Distribution/Peak frequency
(see Worksheet C)
D. Very low Reviewed Scientific Publication

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? A Observational
Identify ecosystem processes impacted:

A; Sediment accretion S. anglica accretes sediments and elevates marsh surfaces transforming naturally open tidal mudflats into meadows


Sources of information:

This has NOT occurred in SF Bay (observational information); sediment accretion has been observed in other estuaries (including within native British range); sediment accretion has been documented:
Pringle , A. W. 1993. Spartina anglica colonisation and physical effects in the Tamar Estuary, Tasmania 1971-91. Papers and Proceedings of the Royal Society of Tasmania 127: 1-10


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

A; S. anglica is slowly spreading in a single marsh in Marin Co. (Creekside Park) at about the elevation of S. foliosa. Where this species has been introduced, it transforms open mud into cordgrass meadow. However, it is not rapidly spreading in SF Bay, possibly due to climatic restrictions (Daehler and Strong, 1996)


Sources of information:

Ayres DR, Smith DL, Zaremba K, Klohr S, Strong DR. 2004. Spread of exotic cordgrasses and hybrids (Spartina sp.) in the tidal marshes of San Francisco Bay. Biological Invasions. 6: 221-231.
Daehler, C. C., and D. R. Strong. 1996. Status, prediction and prevention of introduced cordgrass Spartina spp. Invasions in Pacific estuaries, USA. Biological Conservation 78: 51-58.


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

A; Potential removal of bird foraging habitat though cordgrass overgrowth of open mud flat habitat _ this is NOT occurring in SF Bay Open mudflat is valuable forage ground for migratory and residential shorebirds


Sources of information:

The Pt. Reyes Bird Observatory has assembled a bibliography on maritime cordgrass impacts to shorebirds. An example (for S. anglica):Goss-Custard, J. D., Clarke, R. T., Dit Durell, S. V., Caldow, R. W., and B. J. Ens. 1995. Population consequences of winter habitat loss in a migratory shorebird. II. Model predictions. Journal of Applied Ecology 32: 337-351.


Question 1.4 Impact on genetic integrity? D Reviewed Scientific Publication

D; S. anglica cannot interbreed with any native species due to wide differences in chromosome numbers (62 for foliosa 122 for anglica)


Sources of information:

Ayres DR, Strong DR. 2001. Origin and genetic diversity of Spartina anglica C. E. Hubbard (Poaceae). American Journal of Botany 88: 1863-1867


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

Sources of information:

Ayres et al, 2004.


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

C; Slow


Sources of information:

Ayres DR, Smith DL, Zaremba K, Klohr S, Strong DR. 2004. Spread of exotic cordgrasses and hybrids (Spartina sp.) in the tidal marshes of San Francisco Bay. Biological Invasions. 6: 221-231.


Question 2.3 Recent trend in total area infested within state? C Reviewed Scientific Publication
Describe trend:

C; slow spread


Sources of information:

Ayres et al, 2004.


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

A; S. anglica produces fertile seed and persists as long-lived clones spreading via rhizomes.


Sources of information:

Ayres DR, Smith DL, Zaremba K, Klohr S, Strong DR. 2004. Spread of exotic cordgrasses and hybrids (Spartina sp.) in the tidal marshes of San Francisco Bay. Biological Invasions. 6: 221-231.


Question 2.5 Potential for human-caused dispersal? C Anecdotal
Identify dispersal mechanisms:

C; none save deliberate introduction.


Sources of information:

Anecdotal.


Question 2.6 Potential for natural long-distance dispersal? A Observational
Identify dispersal mechanisms:

A; seed floating on the tides; seed contained in rafts of cordgrass wrack. Cordgrass seed is able to float for long periods; seed-containing wrack is able to move long distances. Long distance dispersal on tidal currents is feasible.


Sources of information:

Huiskes AHL, Koutstaal BP, Herman PMJ, Beeftink WG, Markusse MM and De Munck W (1995) Seed dispersal of halophytes in tidal salt marshes. Journal of Ecology 83: 559-567;
Kathleen Sayce, personal communication on dispersal of S. alterniflora from Willapa Bay to Greys Harbour, WA


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

C; S. anglica has invaded estuaries worldwide including Puget Sound WA, Tasmania, New Zealand, France, and the UK Open mudflat habitat is native to the Pacific coast and may be vulnerable to invasion by S. anglica


Sources of information:

Daehler and Strong, 1996 (Biological Conservation)


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

C; S. anglica was introduced into the San Francisco Bay during the 1970s restoration of Creekside Park in Marin County. It currently grows in a small total area of the park, growing at the same elevations as the native S. foliosa (channel sides and bottoms; i.e. wetter areas) If species spread would likely impact the native species


Sources of information:

Ayres et al, 2004; Ayres, Strong and Lee, unpublished data


Question 3.2 Distribution/Peak frequency? D Reviewed Scientific Publication
Describe distribution:

D; Plants occur 200 m or less from the original discovery (Spicher, pers. obs.) in Creekside Park, Marin Co. in channels radiating from this plant.


Sources of information:

Ayres DR, Smith DL, Zaremba K, Klohr S, Strong DR. 2004. Spread of exotic cordgrasses and hybrids (Spartina sp.) in the tidal marshes of San Francisco Bay. Biological Invasions. 6: 221-231.


Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less Unknown
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 Unknown
Seeds remain viable in soil for three or more years No
Viable seed produced with both self-pollination and cross-pollination Yes
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: 2
Total score: A?

Related traits:

These are based on observations elsewhere

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
estuariesD, < 5%
Dunescoastal
desert
interior
Scrub and Chaparralcoastal bluff scrub
coastal scrub
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 prairie
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)
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): D
Distribution (highest score): D

Infested Jepson Regions

Click here for a map of Jepson regions

  • Central West