Index of Species Information
SPECIES: Scolochloa festucacea
SPECIES: Scolochloa festucacea
AUTHORSHIP AND CITATION:
Carey, Jennifer H. 1994. Scolochloa festucacea. In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station,
Fire Sciences Laboratory (Producer). Available:
On 23 October 2018, the common name of this species was changed in FEIS
from: common river grass
to: common rivergrass. Images were also added.
NRCS PLANT CODE:
The scientific name for common rivergrass is Scolochloa festucacea (Willd.)
Link (Poaceae) [13,14,16,19,23]. There are no currently accepted infrataxa.
FEDERAL LEGAL STATUS:
See OTHER STATUS
The Nature Conservancy Heritage Program lists common rivergrass as critically
imperiled in Wyoming because of extreme rarity .
DISTRIBUTION AND OCCURRENCE
SPECIES: Scolochloa festucacea
Common rivergrass has a circumpolar distribution. In North America, it occurs
primarily in the Northern Great Plains and Prairie Pothole region of the
United States and Canada from Nebraska and Iowa north through Manitoba,
Saskatchewan, and Alberta to the Northwest Territories. Disjunct
populations occur in eastern Oregon, Utah, Wyoming, Montana, and Alaska
|Distribution of common rivergrass in North America. Map courtesy of USDA, NRCS. 2018. The PLANTS Database.
National Plant Data Team, Greensboro, NC. [2018, October 23] .
FRES17 Elm - ash - cottonwood
FRES37 Mountain meadows
FRES38 Plains grasslands
FRES41 Wet grasslands
AK IA MN MT NE ND OR SD UT WY
AB BC MB NT SK
BLM PHYSIOGRAPHIC REGIONS:
5 Columbia Plateau
8 Northern Rocky Mountains
9 Middle Rocky Mountains
14 Great Plains
16 Upper Missouri Basin and Broken Lands
KUCHLER PLANT ASSOCIATIONS:
K049 Tule marshes
K066 Wheatgrass - needlegrass
K067 Wheatgrass - bluestem - needlegrass
K074 Bluestem prairie
K075 Nebraska Sandhills prairie
K098 Northern floodplain forest
SAF COVER TYPES:
HABITAT TYPES AND PLANT COMMUNITIES:
Common rivergrass occurs in emergent communities of seasonally flooded wetlands.
It often occurs in bands along the shore, bordered by cattail (Typha
spp.) or bulrush (Scirpus spp.) in deeper water and slough sedge (Carex
atherodes) on the shallower, drier side . It also occurs in shallow
basins within common reed (Phragmites australis) stands .
Common rivergrass forms monospecific stands in moderately saline wetlands. It is
not as likely to attain dominance in fresh or saltwater wetlands .
Common rivergrass is most commonly associated with slough sedge [3,6,36]. Other
important associates include common spikerush (Eleocharis macrostachya),
American sloughgrass (Beckmannia syzigachne), American mannagrass
(Glyceria grandis), and bluejoint reedgrass (Calamagrostis canadensis)
[4,25,36]. Minor associates include perennial sow thistle (Sonchus
arvensis), Canada thistle (Cirsium arvense), smartweed (Polygonum spp.),
field mint (Mentha arvensis), rough bugleweed (Lycopus asper), marsh
hedgenettle (Stachys palustris), and Canada germander (Teucrium
canadense) . Common rivergrass is listed as a dominant or codominant in the following
1. Landscape classification and plant successional trends in the
Peace-Athabasca Delta 
2. Riparian dominance types of Montana 
3. The vegetation of the Canadian prairie provinces. III. Aquatic and
semi-aquatic vegetation 
4. The vegetation of the Canadian prairie provinces. III. Aquatic and
semi-aquatic vegetation, Part 2. Freshwater marshes and bogs 
5. The vegetation of Alberta 
SPECIES: Scolochloa festucacea
IMPORTANCE TO LIVESTOCK AND WILDLIFE:
Common rivergrass provides important habitat for nesting waterfowl
[10,39]. Dabbling ducks including mallards, northern pintails,
gadwalls, widgeons, northern shovelers, blue-winged teals,
and green-winged teals nest in common rivergrass. White-winged scoters,
redheads, and lesser scaups occasionally nest in common rivergrass .
American bitterns, northern harriers, and short-eared owls nest in tall
coarse wet-meadow or marsh vegetation including common rivergrass . Common
rivergrass provides valuable forage for cattle .
PALATABILITY: Common rivergrass is highly palatable to livestock .
Kirby and others  measured percent digestibility, protein, and
phosphorus during four seasons: late spring, early summer, mid-summer,
and late summer. Common rivergrass had good protein and digestibility levels
early in the season, but levels declined rapidly after seedfill .
Smith  investigated the effect of growth stage, mowing, and burning
on common rivergrass nutrient levels. Two growth stage patterns emerged:
common rivergrass nitrogen levels decreased through the flowering stage, then
increased, and potassium levels decreased throughout the growing season.
Burning and mowing during the previous year did not affect common rivergrass
nutrient levels. Postflowering average dry-weight nutrient levels of
common rivergrass, undisturbed by burning or mowing during the previous growing
season, were as follows: 1.02 percent nitrogen, 0.12 percent calcium,
0.08 percent magnesium, 1.2 percent potassium, and 0.0054 percent sodium
Common rivergrass provides good nesting cover for some waterfowl, shorebirds, and
ground-nesting raptors [7,10,39].
VALUE FOR REHABILITATION OF DISTURBED SITES:
OTHER USES AND VALUES:
OTHER MANAGEMENT CONSIDERATIONS:
Neill  studied the effect of fertilizer on common rivergrass marshes in
Manitoba. Common rivergrass biomass increased after 1 year but decreased after 2
years of fertilizing with nitrogen. The second year decrease was
attributed to the mat of litter created by the tall weakened culms which
resulted from the first fertilizer application. Phosphorus had no
effect on common rivergrass biomass .
Moderate to heavy grazing decreases common rivergrass productivity. The soft
rhizomes which are near the soil surface may be damaged by trampling
. If heavily grazed, common rivergrass may be replaced by bulrush .
Eldridge  describes management strategies for maintaining
semipermanent wetlands in the Prairie Pothole region.
BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Scolochloa festucacea
GENERAL BOTANICAL CHARACTERISTICS:
Common rivergrass is an emergent, perennial, rhizomatous cool-season grass which
grows 2.6 to 4.9 feet (0.8-1.5 m) tall. The stout culms are hollow and
0.1 to 0.2 inches (3-5 mm) in diameter near the base. The extensive
rhizomes are soft, thick, and succulent [13,23,36]. Some authors [5,17]
suggest common rivergrass is an introduced species to the United States because
of its scattered distribution. However, abundant collection of common rivergrass
in North Dakota over a long period of time suggests that it is native
RAUNKIAER LIFE FORM:
Common rivergrass regenerates and spreads primarily by shallow rhizomes. In
North Dakota, a road grader removed the vegetation from a site dominated
by hardstem bulrush (Schoenoplectus acutus). The following growing season, the
cleared area was dominated by common rivergrass with 90 stems per square foot
(998 stems/sq m) while water was still 16 inches (40 cm) deep. Common rivergrass
regenerated from rhizomes in the substrate .
Although common rivergrass generally produces abundant seeds, it does so only if
wetlands contain water early in the spring . Seeds are dispersed by
water movement and accumulate in the seedbank [34,43].
Smith  tested the effects of stratification temperatures and times
on germination of wet and dry common rivergrass seeds. Results were variable.
Galinato and van der Valk  reported that stratification does not
improve common rivergrass germination.
Seed burial, which occurs with inundation, is required for common rivergrass
emergence. Anaerobic conditions stimulate fermentation which increases
the germination rate. In summer, anaerobic conditions increase as water
levels decrease and potholes stagnate. Seeds, which have been
stimulated by early season anaerobic conditions, germinate when light
reaches the substrate and the ground is no longer submerged [11,36]. A
seed burial depth of 0.4 inches (1 cm) maximizes emergence and seedling
length and weight . Seedlings can reach the soil surface from a
maximum depth of 2 inches (5 cm) . Smith  found no seedlings in
areas with heavy litter accumulation.
Few common rivergrass seedlings become established. A seedling must have a
rhizome to survive the winter. Seedlings produce a rhizome 30 to 60
days after emergence. The window of time between germination and
dormancy is often too short to produce a rhizome .
Merendino and others [29,30] investigated common rivergrass establishment and
success on artificially created mudflats subject to reflooding 1 year
later at different depths. Mudflats were created at four drawdown
dates: May 15, June 15, July 15, and August 15. Seedling density,
measured on August 30, was highest with the June 15 and July 15
drawdowns. The soil may have been too cold for germination in May. The
plots were reflooded the following May with four depths: 0, 6, 12, and
20 inches (0, 15, 30, and 50 cm). By August 30, most 1-year-old
common rivergrass seedlings had died with 12 inches (30 cm) or more of continuous
McKee and others  investigated root metabolic response of common rivergrass
to flooding. Common rivergrass has insufficient air space development in the
roots to allow complete aerobic metabolism during prolonged flooding.
It is not as tolerant of flooding as hybrid cattail (Typha glauca),
hardstem bulrush, softstem bulrush (Schoenoplectus tabernaemontani), or common reed .
Common rivergrass grows in northern climates where the winters are cold. It
occurs in seasonally flooded wetlands including wet depressed meadows,
prairie potholes, and lake and river margins [4,20,36].
Common rivergrass shoots
have been observed elongating in 32 degree Fahrenheit (0 deg C) water
. Common rivergrass occurs in freshwater and saline wetlands, with optimal
occurrence in oligosaline water [20,26].
Common rivergrass germination is
substantially reduced by soil sodium chloride concentrations of 1,000
parts per million and higher [11,38]. Optimal seedling emergence
occurred in soil containing 250 parts per million sodium chloride.
Seedling emergence decreased steadily as magnesium chloride
concentrations increased from 0 to 6,000 parts per million .
Common rivergrass has been reported in water with specific conductivity as low as
0.1 and as high as 12.1 millisiemens per centimeter, with a mean of 3.4
[20,38]. Common rivergrass
occurs in the shallow marsh zone which is inundated by snowmelt
water until June or July . The soil surface does not dry out except
possibly at the end of the growing season . The thick, corky
epidermis of the rhizomes prevents desiccation by drying or freezing
. Established common rivergrass is generally tolerant of continuous flooding
for 1 to 2 years, with individual plants surviving as many as 5 to 6
years . Common rivergrass grows on mineral soils high in clay with some organic matter
[15,36]. In the Peace-Athabasca Delta of Alberta, average particle
distribution of the mineral fraction of common rivergrass sites was 5 percent
sand, 49 percent silt, and 46 percent clay. Organic content in the
upper 12 inches (30 cm) averaged 23 percent, and soil pH averaged 6 .
Common rivergrass colonizes exposed mud flats [14,20,43]. Once established, it
persists under a seasonally flooded regime. Common rivergrass occupies a fairly
specific environment with respect to water level. It is replaced by
cattail and bulrush when average water levels rise and by sedge (Carex
spp.) and American mannagrass when average water levels drop [4,32].
On nutrient-rich saline sites with stable water levels, common rivergrass and
slough sedge replace cattail as the pond bottom gradually builds up with
silt and organic matter .
Common rivergrass shoot emergence is initiated from mid-April to mid-May while
the ground is still inundated with water. Deeply submerged plants break
the water surface at the same time as plants in shallow water. Flowers
develop in May. Seeds mature from mid-June to late July. Germination
of 1-year-old or older seeds occurs from mid-July to late August when
the ground surface is no longer inundated. Rhizomes are produced from
late August to mid-September. Dormancy begins in late September and
early October .
SPECIES: Scolochloa festucacea
FIRE ECOLOGY OR ADAPTATIONS:
Common rivergrass resists fire by sprouting from rhizomes. It occurs on sites
that most often experience fire in late summer or early fall when no
longer flooded. Fire benefits common rivergrass stands by removing excess litter
which suppresses common rivergrass growth . Fire may also create openings in
other plant communities, allowing common rivergrass to establish .
POSTFIRE REGENERATION STRATEGY:
Rhizomatous herb, rhizome in soil
Find fire regime information for the plant communities in which common
rivergrass may occur by entering the species name in the FEIS home page under
"Find Fire Regimes".
SPECIES: Scolochloa festucacea
IMMEDIATE FIRE EFFECT ON PLANT:
Common rivergrass is probably top-killed by fire. Rhizomes may be damaged by
fires which occur during drought when the soil is dry and litter
moisture content is low.
PLANT RESPONSE TO FIRE:
Common rivergrass sprouts from rhizomes after fire. Fall fire removes the dead
standing culms and accumulated litter, allowing unimpeded spring growth.
In North Dakota, spring growth was initiated earlier on burned sites
than on unburned sites, possibly because soil and water temperatures
were higher where the litter had been removed by fire .
In Saskatchewan, each of 13 marsh stands composed of common rivergrass, slough
sedge, and common spikerush was burned one to four times during a
10-year study period. The species composition did not change .
In Manitoba, common rivergrass shoots emerged 5 days after a late July fire and
were 4 inches (10 cm) tall after 10 days. At the end of the growing
season, common rivergrass on burned and unburned areas averaged 19.5 inches (49.5
cm) and 37.4 inches (95.0 cm) tall, respectively. Stem density was less
on burned areas. After the next full growing season, common rivergrass stem
height was still less but stem density was greater on burned areas. The
fire opened up stands of common reed and stimulated growth of common rivergrass
within these stands. Red goosefoot (Chenopodium rubrum) established
with the regenerating common rivergrass, especially where common rivergrass roots had been
killed as peaty humus burned .
FIRE MANAGEMENT CONSIDERATIONS:
Prescribed fall burning of common rivergrass increases biomass production [4,37].
In North Dakota, burned stands averaged 11,580 kilograms per hectare and
unburned stands averaged 7,480 kilograms per hectare. Fire did not
affect the nutrient levels in common rivergrass .
Diiro  investigated the effects of burning and mowing on common rivergrass
ponds and associated wildlife in Manitoba. Fall fires were conducted
after the first hard frost and spring fires were conducted during dry
days from early April to June. Fall prescribed burns had greater stem
densities and biomass the following growing season than did unburned
control sites, mowed sites, spring prescribed burns, or sites
undisturbed for one growing season.
Diiro  concluded that prescribed burning to increase common rivergrass biomass
has detrimental effects on wetland wildlife. Burning is most feasible
in dry years when wildlife are most susceptible because of decreased
habitat availability. Ponds are more likely to contain water in the
spring if they were not burned in the fall. Dead, standing common rivergrass
culms catch and retain snow, and fall burning decreases this moisture
retention capability. Diiro  recommended fall prescribed burning
only in areas that do not rely on snow trapped within ponds as a water
source. Even when feasible, he does not recommend spring fires because
they destroy nests.
SPECIES: Scolochloa festucacea
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