BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Distichlis spicata | Saltgrass 



GENERAL BOTANICAL CHARACTERISTICS : 
Saltgrass is a native, perennial, rhizomatous, warm-season grass 4 to 16
inches (10-40 cm) tall [83].  Under conditions of extreme salinity,
plants are often dwarfed [80].  Plants are dioecious.  The male panicle
often extends above the leaves, but the female panicle is normally
enclosed within the leaves [83].  Panicles of both sexes are 1.5 to 3
inches (4-8 cm) long with only a few spikelets [13].  The blue-green to
gray-green leaves are stiff, sharp pointed, coarse, spread along the
entire stem, and cure to a golden brown at the end of the growing
season.  Rhizomes are vigorous, scaly and up to 71 inches (180 cm) long
[32].  In a Colorado study, saltgrass rhizomes were found growing 4.2
inches (10.7 cm) below the soil surface in a layer between the B2 and C
soil horizons [51].  Saltgrass typically has a shallow root system.  In
a Nevada study, roots were never found deeper than 16 inches (40 cm)
below the soil surface [10].

Saltgrass has many physiological adaptations which allow it to occupy
saline environments.  Plants contain salt glands that are active in the
extrusion of salt.  This helps retain sufficient ion concentrations in
the leaf tissue to maintain adequate osmotic potentials [32].  The
lacunae tissue of the roots is apparently continuous with the rhizome
and leaf sheath which allows for gas exchange under partial inundation
by water and in heavy soils [32].  Vesicular-abuscular mycorrhizal fungi
have been observed on inland saltgrass roots and are thought to further
enhance salt tolerance [38].


RAUNKIAER LIFE FORM : 
   Geophyte


REGENERATION PROCESSES : 
Saltgrass is a poor seed producer.  Seed production is often restricted
to favorable sites which support dense, healthy stands [10].
Reproduction is mainly vegetative; plants spread through a
well-developed system of deep underground rhizomes.  Rhizomes sprout
even when buried under 12 inches (30 cm) of sediment [50].

Germination:  Better than 80 percent germination of saltgrass seed from
New Mexico was achieved with alternating temperatures above 81.5 degrees
Fahrenheit (27.5 deg C) for 8 hours and 62 to 73 degrees Fahrenheit
(16.5-23 deg C) for 16 hours [61].  For Nevada seed, alternating
temperatures of 104 degrees Fahrenheit (40 deg C) for 8 hours and 50
degrees Fahrenheit (10 deg C) for 16 hours gave 58 percent germination
[10].  In this study, temperature fluctuations of at least 36 degrees
Fahrenheit (20 deg C) and an osmotic potential of -0.1 MPa were required
for greater than 10 percent germination.  Germination is inhibited by
high levels of salinity.  One study attained up to 72 percent
germination of scarified seed placed in distilled water but only 21
percent germination of scarified seed in a 1.0 percent solution of
sodium chloride [53].

These germination studies show that saltgrass seeds require relatively
high temperatures, low salinities, and moist soils to germinate.  In
natural seedbeds, these conditions rarely occur [60].  Under natural
conditions probably only a few seeds will germinate, unless
precipitation or soil moisture is unusually high in the summer, a time
when soil temperatures would be warm enough for large numbers of seeds
to germinate [60].  Although plants can grow in soils with very low
osmotic potentials and very high salt concentrations, seeds cannot
germinate in such soils [10].  Germination only takes place in less
saline soils.

Seedbanking:  Soil samples taken from a Utah marsh show that numerous
marsh plants have viable seeds stored in the soil.  When soil samples
taken from an saltgrass-dominated community at this marsh were placed in
a greenhouse under conditions favorable for germination, 340 saltgrass
seedlings per square meter of surface soil were produced [68].
Saltgrass seeds were also present in soil samples from other vegetation
types within the same marsh.  Seeds can remain dormant for at least 4
years [63].  Seedbanking may allow plants to become established in large
numbers when favorable conditions for germination are met.

Seed dispersal:  Seeds are dispersed by wind and water [71].


SITE CHARACTERISTICS : 
Saltgrass attains best development in depressed areas that receive
seasonal runoff or have water tables near the soil surface.  Typical
sites supporting lush saltgrass growth include prairie and grassland
swales, salt flats, desert playas and valley bottoms, intermittent
ponds, saline meadows, and along the borders of springs, streams and
lakes.  Soil characteristics are the most important factors influencing
distribution.  Saltgrass tends to form a dense sod only on soils
that have a high salt content, a fine texture, and a good supply of soil
moisture throughout the year.  Soil attributes are summarized below:

  Salinity - Saltgrass tolerates a wide range of soil salinity.
  It occurs on highly saline and nonsaline soils.  It has been found
  growing on soils ranging from .03 to 5.6 percent total salts [80].
  Because many other grasses cannot survive in soils with high
  salinities, saltgrass is often a dominant, forming a sod with
  2,000 to 3,000 stems per square meter, when the salt content of the
  soil becomes greater than about 0.33 to 0.5 percent [8,78,,80].  It
  can survive on sites where the soil surface is encrusted with a layer
  of salt.

  pH - Saltgrass is usually found on alkaline soils, with a pH
  between 7.5 and 8.5 [8,66,80,86].  Extremes in pH may range from 6.8
  to 10.5 [40,83].

  Texture - Soil textures vary from sand and gravel to clay, but
  saltgrass seems best adapted to medium- and fine-textured soils [63].
  In the Great Plains, depressions and meadows dominated by saltgrass
  generally have soil textures ranging from fine clays to silt
  loams [35,36,86].  

  Moisture - Water tables are often near the surface.  Some sites are
  periodically flooded and remain inundated in the spring.  In Nebraska,
  saltgrass grew best in meadows where the water level was 16 to
  36 inches (41-91 cm) below the soil surface [77].  Along the Rio Grande
  River in New Mexico, it was restricted to areas where
  the water table was within 4 feet (1.2 m) of the soil surface [9].

Soil-moisture gradient and associated communities:  On an ancient lake
bed in Ruby Valley, Nevada, plant distributions along a soil-moisture
gradient were studied.  In order of increasing depth to ground water,
dominant species were baltic bulrush (Juncus balticus), saltgrass,
shrubby cinquefoil (Potentilla fruiticosa), basin wildrye, black
greasewood, and rubber rabbitbrush (Chrysothamnus nauseosus) [52].  In
Montana, adjacent wetter communities tend to be dominated by hardstem
bulrush (Scirpus acutus) and Nevada bulrush (S. nevadensis), while drier
communities are often dominated by black greasewood or upland grasses
[32,35].  In marshes along the Great Salt Lake in Utah, saltgrass
is common in areas that periodically dry out.  Adjacent wetter, less
saline areas are dominated by cattails (Typha spp.), saltmarsh bulrush
(Scirpus maritimus), hardstem bulrush, and reed (Phragmites australis)
[73].

Associates:  Associated grasses include alkaligrass (Puccinellia
nuttalliana), foxtail barley (Hordeum jubatum), western wheatgrass
(Pascopyrum smithii), alkali sacaton (Sporobolus airoides), plains
bluegrass (Poa arida), Rocky Mountain glasswort (Salicornia rubra), and
Pursh seepweed (Suada depressa) [32,47,80,86].

Flood tolerance:  Saltgrass is very flood tolerant [56,63].  Plants
grown in metal containers survived partial (plant crown covered) and
total (entire plant underwater) inundation for 24 days.  Although plants
exhibited loss of vigor, they essentially recovered within 30 days after
the water was drained [1].

Drought tolerance:  Saltgrass has moderate to high drought tolerance
[63].  It can remain dormant for long periods until rain or floodwaters
replenish soil moisture [64].

Elevation:  Elevational ranges for several western states are given
below:

        below 6,000 feet (1,829 m) in AZ [40]
        from 3,500 to 9,000 feet (1,067-2,743 m) in CO [16]
        from 2,740 to 4,300 feet (835-1,311 m) in MT [16]
        below 6,500 feet (1,981 m) in NM [25]
        from 3,640 to 7,515 feet (1,010-2,290 m) in UT [85]
        from 4,000 to 7,500 feet ( 1,219-2,286 m) in WY [16]


SUCCESSIONAL STATUS : 
Saltgrass is a pioneer species.  It invades barren, saline soils that
other grasses cannot tolerate.  Its sharp-pointed rhizomes are well
adapted to piercing heavy clays and shales [32].  Spreading by rhizomes
allows saltgrass to colonize salt flats, inundated playas, lakeshores,
shale cliffs, and other saline barren sites by extending from areas that
are favorable for growth to areas that are less favorable [32,77,78].
Once established, it may aid in forming soils for the subsequent
establishment of other plants.


SEASONAL DEVELOPMENT : 
Saltgrass is a warm-season grass.  It begins growth in the spring about
1 month later than cool-season grasses occurring in the same area.  In
eastern Washington, growth of new tillers begins in late April, and the
shoots remain green all summer when upland grasses go into aestivation
[14].  North Dakota plants were observed in full bloom in August [39].
Flowering in Montana occurs in June and July [16].

At Fish Springs National Wildlife Refuge in Utah, saltgrass phenology
was observed on two areas of a saltmarsh.  On portions of the marsh
influenced by 80 degree Fahrenheit (27 deg C) spring water, saltgrass
showed earlier phenological development [4]:

   date of initial growth                date of anthesis

warm spring      salt marsh          warm spring      salt marsh
water site          site             water site          site

 April 2          April 14             May 30           June 10

Related categories for Species: Distichlis spicata | Saltgrass