Smooth Cordgrass (Spartina alterniflora)
Thomas Pham
Fish 423
Aquatic Invasion Ecology
Final Report: Fall 2011
Diagnostic information
Scientific name
Order: Poales
Family: Poaceae
Genus: Spartina
Species: alterniflora
Common names: Smooth cordgrass, saltmarsh
cordgrass,
saltwater
cordgrass,
Atlantic
cordgrass, oystergrass
Basic identification key
Using the Key to West Coast Spartina
Species’ dichotomous key one can properly
identify Spartina alterniflora among the other
Spartina species. According to the key S.
Figure 1. Spartina alterniflora at a salt marsh in East
alterniflora
Sandwich, Massachusetts. Nelson DeBarros @
has
leaf
blades
when
fresh,
internodes that are fleshy, a leaf width that is at
USDA-NRCS PLANTS Database
most 25mm, reddish streaks or red pigment
often present at the base of young and healthy
shoots.
Additionally,
the
USDA
Life-history and basic ecology
Natural
Resources Conservation service describes S.
Life cycle, environmental optima and tolerances
alterniflora as a grass with long hollow
Spartina alterniflora is a perennial rhizomatous
rhizomes. It ranges from 2 to 7 feet tall and has
grass that grows in intertidal zones (Subudhi et
leaf blades that are around 12-20 inches long.
al. 2009). In specific it grows in salt marsh, mud
Lastly, during the months of September and
flat, and sand flat habitats. It prefers habitats
October, seedheads are present that are around
with low or moderate wave action. Furthermore,
12 inches in length and can carry spikes that
this plant is highly adapted to grow in very high
carry 12-15 spikelet seeds.
salinity concentrations and can grow in water
salinities up to 60‰ (Bertness 1991). It can
grow in a variety of substrates including: sand,
silt, cobble, clay, and gravel. S. alterniflora is a
spikelets
seeds
which
that
hold
generally
develop in July through
October.
Pollination
is
achieved by wind and
seeds
are
primarily
dispersed
dispersed
by
water which can carry the
seeds long distances due
to
tides
and
currents.
Vegetative fragmentation
is the process in which
segments of the plant
break off and form a new
Figure 2. An inundated Spartina alterniflora marsh
plant but is genetically
identical to the original.
particularly persistent species that tolerate a
varying degree of abiotic conditions. It can
survive in complete submersion of water for up
to 12 hours and in water with pH levels ranging
from 4.5 to 8.5 (Landin 1991). Nutrient supply
Lastly, S. alterniflora can also spread clonally
by rhizomes. When pieces of rhizome root break
off, they can sometimes regrow into a new plant
that is also a genetic clone to the original.
is a limiting factor for S. alterniflora. Bursesh et
al. (1980) found that nitrogen is an important
Current geographic distribution
determining factor for growth and productivity
for S. alterniflora in Louisiana salt marshes.
Additionally, they observed a greater influence
of nitrogen added to inland meadows compared
to streamside meadow.
Distribution in the United States
According
to
the
United
States
Department of Agriculture Natural Resources
Conservation
Service
Spartina
alterniflora
currently resides among 21 different states
Reproductive strategies
Spartina alterniflora has three methods
of reproduction that involve both sexual and
clonal processes. It reproduces by seed, rhizome,
or vegetative fragmentation (Daehler and Strong
1994). It produces inflorescences containing
including: Alabama, California, Connecticut,
Delaware,
Florida,
Georgia,
Louisiana,
Massachusetts, Maryland, Maine, Mississippi,
North Carolina, New Hampshire, New Jersey,
New York, Oregon, Rhode Island, South
Carolina, Texas, Virginia, and Washington.
Figure 3. Current distribution of Spartina alterniflora across the United States (USGS)
History of invasiveness
Spartina alterniflora is non-native to the state of
Washington. There are three main regions of
Spartina alterniflora is a rhizomatous
grass native to the Atlantic and Gulf coast
marshes of North America (Xiao et al. 2011). It
dominates the marshes in its native range. S.
alterniflora has been introduced to new regions
both intentionally and unintentionally. It has
been introduced to the west coast of the United
States, Great Britain, the Atlantic coast of
Europe, and New Zealand (Marchant et al 1970;
Partridge et al 1987; Hitchcock et al. 1969).
Distribution in Washington State
Washington State that S. alterniflora has
established populations: Puget Sound, Grays
Harbor, and Willapa Bay. It is believed that it
was introduced by accident into Willapa Bay
around the late nineteenth century as a
hitchhiker with oysters shipped from the
Atlantic coast (Dennis et al. 2011). Seeds of S.
alterniflora likely were inadvertently brought
into the same barrels that the oysters were being
shipped in. Furthermore, Stiller and Denton
(1995)
performed
polymorphic
DNA
random
(RAPD)
amplified
analysis
to
determine the genetic history of the S.
fish and wildlife habitat”. It is currently
alterniflora populations in Willapa. Their data
classified as a Class A noxious weed meaning
suggests that the entire S. alterniflora population
that eradication of this plant is required by law.
inhabiting the Willapa Bay region descended
Unlike the populations in Willapa Bay, S.
from a single introduced clonal colony. The
alterniflora was intentionally introduced into
establishment of this population was spread
Puget Sound by landowners. It was introduced
primarily by seed dispersal. Rhizome and
into Padilla Bay sometime between 1940 and
vegetative fragmentation contributed little to the
1946 by the Dike Island Gun Club in order to
spread in this region (Civille et al. 2005). S.
stabilize the land that the gun club was on
alterniflora was recognized as a pest weed in
(Parker and Aberle 1979). A hybrid species
Willapa Bay and was placed on Washington
Spartina anglica is able to hybridize with S.
State’s noxious weed list in 1989. The
alterniflora and was introduced to Puget Sound
Washington State Noxious Weed Control Board
in 1961 (Hacker et al. 2001).
defines a noxious weed as “the traditional, legal
Populations of S. alterniflora also exist in Grays
term for any invasive, non-native plant that
Harbor. However, the pathway of introduction
threatens agricultural crops, local ecosystems of
of it is not known for this particular region. In
addition to S. alterniflora, Spartina densiflora is
also found here.
Distribution in Oregon
S. alterniflora is also present in the State
of Oregon, although at much lower densities
than observed in Washington State. As of now
three infestations of S. alterniflora have been
observed in Oregon. One of the colonization’s
took place in the Siuslaw River in Florence,
Oregon. It was intentionally planted around the
1970’s at the Port of Siuslaw (Frenkel 1990,
Strong and Ayres 2009).
S. alterniflora was also detected in Coos Bay in
2005 at a dredge material disposal site (Oregon
Figure 4. Distribution of Spartina alterniflora sites in
Response Plan 2007). It is believed that
Washington State 2010 (WSDA)
unintentional transplantation was the vector for
the introduction of it into Coos Bay.
Finally, the third and most recent infestation of
Factors influencing establishment and spread
S. alterniflora in Oregon was discovered in 2008
There are a number of factors that influence the
at Youngs Bay (ODA Plant Division Annual
establishment of Spartina alterniflora. One
Report 2010). However, early detection found
factor that actually slowed the rate of invasion of
the patch to be only 800 square feet in size and
it into the Pacific Northwest was Allee effects
was dealt with quickly. As of 2010 no new
which is “a positive relationship between any
plants have been found in Youngs Bay.
component of fitness of a species and density of
conspecifics” (Stephens et al. 1999). Davis et al.
(2004) conducted an experiment and discovered
Invasion process
that pollen limitations can cause an Allee effect
Pathways, vectors and routes of introduction
Spartina alterniflora historically has
invaded
the
Pacific
Northwest
by
on S. alterniflora meaning that it can slow its
rate of colonization. Additionally, without Allee
both
effects S. alterniflora would have spread across
intentional and unintentional introductions. The
Willapa Bay at a much higher rate (Taylor et al.
initial pathway that has led to S. alterniflora’s
2004) and likely would have covered the entire
invasion into Washington has been through
bay a long time ago (Strong and Ayres 2009).
aquaculture, in particular the stocking of oysters.
S. alterniflora was introduced into Willapa Bay
Potential ecological and/or economic impacts
in the late nineteenth century as part of the
Spartina alterniflora is an ecosystem
oyster cultivation efforts (Dennis et al. 2011). S.
engineer. Jones et al. (1994) coined the term
alterniflora seeds hitchhiked along with oyster
ecosystem
shipments by train from Atlantic marshes where
“organisms that directly or indirectly modulate
its native region lay.
the
In addition to unintentional introductions, there
themselves) to other species, by causing physical
have also been intentional introductions of S.
state changes in biotic or abiotic materials. In so
alterniflora. In its native range, S. alterniflora is
doing they modify, maintain and/or create
valued for its ability to alleviate erosion
habitats”. S. alterniflora alters the ecosystem in
(Simenstad and Thom. 1995). The very same
which it habitats by a number of different
properties have led to intentional introduction
means.
into Washington and Oregon. Furthermore, it
hydrology, sediment deposition patterns, and
has the ability to trap sediment very well. It has
furthermore it can transform open intertidal
been introduced into New Zealand because of
mudflats into elevated meadows filled with
this property as a tool for estuary restoration
nothing but S. alterniflora (Crooks 2002). These
(Partridge 1987).
impacts have led to significant change in the
engineer
availability
It
can
of
and
defined
resources
change
it
(other
nutrient
as:
than
cycling,
landscape of estuaries and intertidal zones in the
(2000) suggests that a non-native crab Carcinus
Pacific Northwest. In the absence of S.
maenas are more concentrated in areas where
alterniflora estuaries in the Pacific Northwest
Spartina are found.
are generally gently sloped and shallow, bare
S. alterniflora also has the potential to cause
mudflats. However, the S. alterniflora can
massive economic damage as well. Although it
transform them into steep and deep tidal
has not occurred, it has the potential to cause
channels. Furthermore, the once bare mudflats
damage to oyster and commercial fisheries. If
can become completely covered in meadows of
they raise the elevation of the estuaries, they can
S. alterniflora. In addition, it has the ability to
become unsuitable for oyster aquaculture.
increase sedimentation and decrease the effects
Oyster farming is a large industry for both
of wave action (Gleason et al. 1979) while also
Washington and Oregon State and S. alterniflora
causing increased flooding.
has the potential to cause damage to these
S. alterniflora not only affects the abiotic
markets by land alterations. Furthermore they
structure of communities but can also have
can reduce the prey resources for Oncorhynchus
impacts on native fauna and flora. It is a robust
keta (Chum) in its juvenile stage as well as
invader and can out-compete other species such
Parophrys vetulus (English sole) both of which
as Zostera marina (eelgrass). Not only is this
are important commercial fish for Washington
detrimental to Z. marina but also to the species
and Oregon (Noxious Weed Control Board). In
that rely on it such various invertebrates
addition S. alterniflora can also can economic
including
crab
damage by altering beaches which are important
(Metacarcinus magister) (McMillan et al. 1995).
to the tourism markets for Washington and
The loss of Z. marina can also have negatively
Oregon (Oregon Response Plan 2007).
juvenile
Dungeness
cascading effects on Anas Americana (American
wigeon), Anas acuta (Northern Pintail), and
Management strategies and control methods
Branta bernicla (Brant) all of which rely on Z.
marina for forage (Oregon Response Plan 2007).
A large amount of time, money, and
Furthermore, the large colonization of bare
effort has been put into the control and
mudflats of S. alterniflora greatly reduces the
eradication of Spartina alterniflora in the Pacific
open habitat for many different shorebirds and
Northwest. In Washington State, management of
waterfowl. It is currently listed as a threat to
S. alterniflora began in the 1990’s (Hedge et al.
birds by the American Bird Conservancy. The
2003). In 1995, the WSDA was put in control of
disturbance that S. alterniflora can cause on its
its management. In 2003, the Portland State
habitat may even open up opportunities for other
University Center for Lakes and Reservoirs
invasive species. A study by Carr and Dumbauld
created the Oregon Spartina Response Plan with
the goal of “prevent(ing) the establishment and
However, Gustafson et al. (2006) tested the
spread of any Spartina species in Oregon
effects of P. marginata grazing on Spartina
estuaries and coastal wetlands”. A number of
biomass and found that it is does not exert strong
different strategies have been used to control S.
top-down control on S. alterniflora.
alterniflora. Removal by hand has been used but
is limited in a number of ways. It is highly time
Literature Cited
consuming to remove because care must be
taken to remove the entire plant. If residual
Bertness MD (1991). Zonation of Spartina
rhizomes are left behind, they have the potential
Patens and Spartina Alterniflora in New
to
England Salt Marsh. Ecology 72: 138-148.
grow
back.
This
strategy
has
more
effectiveness in controlling younger infestations
Buresh RJ, Delaune RD, Patrick WH (1980).
than mature (Hedge et al. 2003). Another
Nitrogen and Phosphorus Distribution and
method that has been used is mowing. Once
Utilization by Spartina alterniflora in a
again however, this strategy is also limited. It
Louisiana Gulf Coast Marsh. Estuaries 3:
was found to be neither effective nor cheap as
111-121.
sites had to be mowed multiple times to
Carr EM, Dumbauld BR (2000). Status of the
effectively eliminate it. In addition, herbicides
European
have also been used. The only authorized
Washington
herbicide for control of S. alterniflora by the
expansion
Washington
Shellfish Research 19 : 629-630.
Aquatic
Plant
Management
Program Environmental Impact Statement is
Rodeo
whose
main
active
ingredient
is
green
crab
coastal
be
invasion
estuaries:
prevented?
Journal
in
can
of
Civille JC, Sayce K, Smith SD, Strong DR
(2005).
Reconstructing
a
century
of
glyphosate. There have been large variations in
Spartina alterniflora invasion with historical
its effectiveness ranging from no effect to
records and contemporary remote sensing.
complete
Ecoscience 12: 330-338.
elimination.
The
most
effective
method of control in Washington has been a
Crooks (2002). Characterizing Ecosystem-Level
combination of mowing followed up by Rodeo
Consequences of Biological Invasions: The
application after it has regrown to 30-45cm,
Role of Ecosystem Engineers. OIKOS 97:
although it has been found to be highly costly
153-166.
(Hedge et al. 2003). One last control method that
Daehler CC, Strong DR (1994). Variable
has been used is a biological control with the
Reproductive Output Among Clones of
species Prokelisia marginata (Homopteran plant
Spartina alterniflora (Poaceae) Invading
hopper). This particular species feeds on
San
Spartina species, specifically its vascular fluids.
Influence of Herbivory, Pollination, and
Francisco
Bay,
California:
The
Establishment Site. American Journal of
Botany 81: 307-313.
(Gramineae) IV. The cytology of S.
Davis HG, Taylor CM, Lambrinos LG, Strong
DR,
Mooney
Marchant CJ (1970). Evolution in Spartina
HA
(2004).
Pollen
Limitations Causes an Allee Effect in a
Wind-Pollinated Invasive Grass (Spartina
alterniflora). PNAS: 101: 13804-13807.
alterniflora Loisel. in North America.
Botanical Journal of the Linnean Society
63: 321-326.
McMillan RO, Armstrong DA, Dineel PA
(1995). Comparison of intertidal
habitat
Dennis B, Civille JC, Strong DR (2011). Lateral
use and growth rates of two northern Puget
spread of invasive Spartina alterniflora in
Sound cohorts of 0+ age Dungeness crab,
uncrowded
Cancer magister. Estuaries 18: 390-398.
environments.
Biological
Invasions 13: 401-411.
Parker RC, Aberle B (1979). A situation report
Gleason ML, Elmer DA, Pien NC, Fisher JS
on the Spartina infestation in northwest
(1979). Effects of Stem Density upon
Washington. Unpublished report to the
Sediment Retention by Salt Marsh Cord
Washington State Department of game,
Grass,
Mount Vernon
Spartina
alterniflora
Loisel.
Estuaries 2: 271-273.
Partridge TR (1987). Spartina in New Zealand.
Gustafson DJ, Kilheffer J, Silliman BR (2006).
Relative Effects of Littoraria irrorata and
Prokelisia
marginata
on
Spartina
New Zealand Journal of Botany 25: 567575.
Simenstad CA, Thom RM (1995).
Spartina
alterniflora. Estuaries and Coasts 29: 639-
alterniflora
644.
invasive halophyte in Pacific Northwest
Hedge P, Kriwoken LK, Patten K (2003). A
Review
of
Spartina
Management
(smooth
cordgrass)
as
an
estuaries. Hortus Northwest 6:9-12, 38-40.
in
Stiller JW, Denton AL (1995). One hundred
Washington State, US. Journal of Aquatic
years of Spartina altemiflora (Poaceae) in
Plant Management 41: 82-90.
Willapa
Bay,
Washington:
random
Hitchcock CL, Cronquist A, Ownbey M (1969)
amplified polymorphic DNA analysis of an
Vascular Plants of the Pacific Northwest.
invasive population. Molecular Ecology 4:
Part
355-363.
1:
Gymnosperms,
Vascular
and
Cryptogams,
Monocotyledons.
Stephens PA, Sutherland WJ, Freckleton RP
University of Washington Press, Seattle,
(1999). What is the Allee effect? OIKOs
Washington
87: 185-190.
Jones CG, Lawton JH, Shachak M (1994).
Strong
DR,
Ayres
DA
(2009)
Spartina
Organisms as ecosystem engineers. OIKOS
Introductions and Consequences in Salt
69: 373-386.
Marshes. In: Silliman BR (ed), Grosholz
ED (ed), Bertness MD (ed) Human Impacts
http://agr.wa.gov/PlantsInsects/Weeds/Spartina/
on Salt Marshes: A Global Perspective, 1st
docs/SpartinaReport2010.pdf
edn.
University
of
California
press,
Berkeley, CA.
Subudhi PK, Baisakh N (2011). Spartina
Oregon
Department
of
Agriculture
Plant
Division Annual Report 2010
alterniflora Loisel., a halophyte grass model
http://www.oregon.gov/ODA/PLANT/docs/pdf/
to dissect salt stress tolerance. In Vitro
plant_annual_report_2010.pdf?ga=t
Cellular & Developmental Biology – Plant
47: 441-457.
Taylor CM, Davis HG, Civille JC, Grevstad FS,
West Coast Governors’ Agreement on Ocean
Health
Spartina
Eradication
Action
Hastings A (2004). Consequences of an
Coordination Team Work Plan
Allee effect in the invasion of a pacific
http://westcoastoceans.gov/Docs/Spartina_Final
estuary by Spartina alterniflora. Ecology
_Work_Plan.pdf
85: 3254-3266.
Xiao Y, Tang J, Qing H, Zhou C, An S (2011).
Expert contact information in PNW
Effects of salinity and clonal integration on
growth and sexual reproduction of the
Kathleen Sayce
invasive grass Spartina alterniflora. Flora
P.O. Box 91
206: 736-741.
Nahcotta, WA 98637
Phone: (360) 665-5292 (H), (360) 642-1166 (W)
Other key sources of information and
[email protected]
bibliographies
Vanessa Howard
Written Findings of the Washington State
Center for Lake and Reservoirs
Noxious Weed Control Board (1995)
Portland State University
http://www.nwcb.wa.gov/siteFiles/Spartina_alter
P.O. Box 751
niflora.pdf
Portland, OR 97207-0751
Phone: (503) 725-9076
Oregon Spartina Response Plan 2007
Fax: (503) 725-3834
http://www.clr.pdx.edu/docs/OSRP.pdf
[email protected]
Spartina Eradication Program 2010 Progress
Nancy Ness
Report
Grays Harbor County
Noxious Weed Board Coordinator
P.O. Box R
Spartina
alterniflora.
Since
1995,
the
Elma, WA 98541
Washington State Department of Agriculture has
Phone: (360) 482-2265
spearheaded the eradication of Spartina species.
Fax: (360) 482-2662
They have coordinated a number of stakeholders
[email protected]
and entities in working together to manage
Spartina. They have seen great success in
Kyle Murphy
eliminating S. alterniflora as well as other
WSDA Spartina Coordinator
Spartina species in the state. From a record high
P.O. Box 42560
of 9,260 acres of Spartina spp. observed in
Olympia, WA 98504
2003, the WSDA has reduced that amount to 27
Phone: (360) 902-1923
acres as of 2010 (Spartina Eradication Program
[email protected]
2010 Progress Report). The effort continues
although they believe that the last few acres will
Current research and management efforts
be the most difficult to remove. The WSDA
estimates that 7 solid acres of Spartina will
The state of Washington has devoted a
remain in Willapa Bay in 2011, less than 0.05
large amount of time and resources to eradicate
acres in Grays Harbor, and 5 acres in Puget
Figure 5. Solid acres of Spartina by year statewide based on WSDA estimates. The blue line represents historic
Spartina infestations since 2003. The red line indicates the projected Spartina infestation level through 2014.
Projection assumes continued funding.
Sound. Currently, they are continuing to use
integrated pest management techniques such as
mechanical, chemical, manual control, or a
combination of them as previously described,
although more effort is being put into shoreline
surveillance as the numbers of acres of Spartina
have been greatly reduced.
On September 18, 2006 the governors of
California, Oregon, and Washington announced
the West Coast Governors’ Agreement on Ocean
Health. Through this agreement they called for
collaboration to manage and protect the ocean
and coastal resources along the West Coast.
Through this agreement a Spartina eradication
program was developed with the goal of
eliminating non-native Spartina off of the West
Coast by 2018. This program created a
comprehensive work plan and outlined a number
of tasks in order to achieve the goal of complete
eradication. According to the work plan, they are
working on developing an internet based GIS
(geographic information system) to define the
areas in which Spartina has been eradication.
Overall this agreement has combined the efforts
of California, Oregon, and Washington in
eliminating Spartina spp. With the bulk of the
infestations managed, the remaining work is
synthesizing the collective efforts between
agencies and states.