Desert salt grass (Distichlis spicata)

Present distribution

Scientific name:	Distichlis spicata (L.) Greene
Common name(s):	desert salt grass

Map showing the present distribution of this weed.

Habitat:

Low moist prairie, along roads, near creeks, lakes, potholes & rivers assoc. with moist alkaline or saline soils (Randall 2002). Grassland swales, salt flats, desert playas, valley bottoms, intermittent ponds, saline meadows, along the borders of springs, streams and lakes, soils with high salt content, good soil moisture (Uchytil 1990). Polymorphic, Intertidal river mouth delta, pest in ditches, cotton fields & crops (Randall 2000). Survives stress with underground storage organ (FSFED 2009).

Potential distribution

Potential distribution produced from CLIMATE modelling refined by applying suitable landuse and vegetation type overlays with CMA boundaries

Map Overlays Used

Land Use:
Broadacre cropping; horticulture perennial; horticulture seasonal; pasture irrigation

Ecological Vegetation Divisions
Coastal; grassy/heathy dry forest; treed swampy wetland; lowland forest; foothills forest; forby forest; riparian; basalt grassland; semiarid woodland; ironbark/box; riverine woodland/forest; saline wetland

Colours indicate possibility of Distichlis spicata infesting these areas.

In the non-coloured areas the plant is unlikely to establish as the climate, soil or landuse is not presently suitable.

Red= Very high	Orange = Medium
Yellow = High	Green = Likely

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	It can form monotypic stands which can be very dense, and it often forms clonal colonies in which individuals support each other's physiologies (WIKI 2009). 4-16 inches 40.5 cm tall. High nuisance value. People and/or vehicles access with difficulty.	MH	MH
2. Reduce tourism?	As it produces extremely dense stands in wet areas (FS.FED 2009) like on the edges of waterbodies it is likely to make access to waterbodies difficult for recreational users. Some recreational uses affected.	MH	MH
3. Injurious to people?	Saltgrass was used as a food source by Native Americans in California (FS.FED 2009). No spines, burrs thorns or toxins (FS.FED 2009). No effect, no prickles, no injuries.	L	MH
4. Damage to cultural sites?	Saltgrass is strongly rhizomatous. Rhizomes are scaly and reach average depths of 4 to 10 inches (10-30 cm) in the soil. Rhizomes and roots of saltgrass create dense mats (FS.FED 2009). Nevertheless this is unlikely to cause structural damage. Moderate visual effect.	ML	MH
Abiotic
5. Impact flow?	Not enough information.	M	L
6. Impact water quality?	“Outstanding plant for water erosion control (FS.FED 2009). Unlikely to affect water quality. No noticeable effect on dissolved 0₂or light levels.	L	M
7. Increase soil erosion?	Outstanding species for controlling wind and water erosion (FS.FED 2009). Low probability of large scale soil movement; or decreases the probability of soil erosion.	L	MH
8. Reduce biomass?	In pure stands, salt grass is extremely dense (FS.FED 2009). Saltgrass is strongly rhizomatous. Rhizomes are scaly and reach average depths of 4 to 10 inches (10-30 cm) in the soil. Rhizomes and roots of saltgrass create dense mats (FS.FED 2009). Direct replacement of biomass by invader.	ML	MH
9. Change fire regime?	Saltgrass establishes after fire through seed and/or lateral spread by rhizomes… Saltgrass is found in southeastern and Gulf Coast marshes where fires may occur once or more every year… Fire top-kills saltgrass. The seeds and rhizomes generally survive fire. (FS.FED 2009). Likely to provide continual fuel source for annual fires.	M	MH
Community Habitat
10. Impact on composition (a) high value EVC	EVC = Wetland formation (E); CMA =Corangamite; Bioregion = Otway plain; VH CLIMATE potential. River mouth deltas, pest in ditches, near creeks, lakes, rivers (Randall 2000). Intermittant ponds (Uchtil 90). Dominat or codominant species under certain conditions (FSFED 2009). Major displacement of some dominant species within a strata/layer (or some dominant spp. within different layers).	MH	H
(b) medium value EVC	EVC = Sedge wetland (R); CMA =West Gippsland; Bioregion = Wilsons prom; VH CLIMATE potential. Prarie and grassland swales (Uchytil 1990). River mouth deltas, pest in ditches, near creeks, lakes, rivers (Randall 2000). Intermittant ponds (Uchtil 90). Dominat or codominant species under certain conditions (FSFED 2009). Major displacement of some dominant species within a strata/layer (or some dominant spp. within different layers).	MH	H
(c) low value EVC	EVC = Low land forest/ riparian scrub complex (LC); CMA = Glenelg Hopkins; Bioregion = Greater grampians; VH CLIMATE potential. Prarie and grassland swales (Uchytil 1990). River mouth deltas, pest in ditches, near creeks, lakes, rivers (Randall 2000). Intermittant ponds (Uchtil 90). Dominat or codominant species under certain conditions (FSFED 2009). Major displacement of some dominant species within a strata/layer (or some dominant spp. within different layers).	MH	H
11. Impact on structure?	“Salt grass occurs in varying densities in many plant communities, but it is only a dominant or codominant under certain conditions. Nearly pure stands of salt grass are indicative of sites where soils are saline and fine textured and where the surface soils are wet at least part of the growing season (FS.FED 2002). Worst case scenario is that it becomes the dominant species in its habitat (low, moist, saline areas) (FS.FED 2009). Major displacement of some dominant spp. within a strata/layer (or some dominant spp. within different layers).	MH	MH
12. Effect on threatened flora?	Saltgrass is shade intolerant and is interfered with by perennial pepperwood which grows to a height of 3 to 8 feet (1-2.5 m) (FS.FED 2009). Not reported to affect a particular threatened species.	M	ML
Fauna
13. Effect on threatened fauna?	Provides food of moderate value and shelter in for some species, not toxic, no spines, burrs, thorns (FS.FED 2009). Often avoided by species (FS.FED 2009). Minor effects on threatened spp.; minor hazard or reduction in habitat/food/ shelter.	ML	M
14. Effect on non-threatened fauna?	Provides food of moderate value and shelter in for some species, not toxic, no spines, burrs, thorns (FS.FED 2009). Minor effects on fauna spp.; minor hazard or reduction in habitat/food/ shelter.	ML	MH
15. Benefits fauna?	Saltgrass provides important cover and to a lesser extent a source of food for waterfowl species in southeastern and Gulf Coast salt marshes… Saltgrass is minimally utilised by ungulates…. Saltgrass seeds and rhizomes provide an important food source for waterfowl… Saltgrass is an important source of food and cover for numerous fish and decapod crustaceans along the coast of Louisiana (FS.FED 2009). Provides an important alternative food source and/or harbour to desirable species.	ML	MH
16. Injurious to fauna?	No toxins, spines, burrs thorns. No effect.	L	MH
Pest Animal
17. Food source to pests?	The seeds of salt grass are a food source for pronghorn throughout the Great Basin of the United States… salt grass is a source of food for mule deer on the Los Padres National Forest, California… Common muskrats graze saltgrass rhizomes during the winter and in early spring in burned meadows on the Gulf Coast of Mexico (FS.FED 2009). Therefore likely to provide food for rats. Supplies food for one or more minor pest spp. (eg. blackbirds or environmental insect pests).	ML	MH
18. Provides harbour?	Saltgrass provides cover for a variety of bird species, small mammals, and arthropods (FS.FED 2009). Capacity to harbour rabbits or foxes at low densities or as overnight cover.	MH	MH
Agriculture
19. Impact yield?	From its native habitat, salt grass has spread to the irrigated lands, & become a pest in ditches, cotton fields, & other crops in the US (Randall 2002).	M	MH
20. Impact quality?	From its native habitat, salt grass has spread to the irrigated lands, & become a pest in ditches, cotton fields, & other crops in the US (Randall 2002). Livestock generally avoid saltgrass due to its coarse foliage… It can be an especially important late summer grass in arid environments after other forage grasses have deceased (FS.FED 2009).	M	MH
21. Affect land value?	Not enough information.	M	L
22. Change land use?	As it has been reported as a pest in crops there may be a change in land use from one crop to another or to livestock.	M	M
23. Increase harvest costs?	Control of D. spicata is likely to increase harvest costs. No specific information.	M	M
24. Disease host/vector?	Not reported to be a disease host/ vector.	M	L

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Stratification and scarification promote saltgrass seed germination (FS.FED 2009).	M	MH
2. Establishment requirements?	Native to the Americas, where it is widespread (WIKI 2009). Occurs “under” other species in forest and shrub communities, although mostly occurs in “open sites” eg. Grasslands, meadows, salt flats (FS.FED2009). Can establish under moderate canopy/litter cover.	MH	MH
3. How much disturbance is required?	Can occur in minor disturbed ecosystems, eg. Grasslands and riparian areas (FS.FED 2009). Saltgrass quickly recovers from small-scale anthropogenic disturbances occurring anytime during the year (FS.FED 2009). Establishes in relatively intact or only minor disturbed natural ecosystems (eg. wetlands, riparian, riverine, grasslands, open woodlands); in vigorously growing crops or in well-established pastures.	MH	MH
Growth/Competitive
4. Life form?	Grass, surviving as a submergent in some environments. E.g. Some sites are periodically flooded and remain inundated in the spring” (FS.FED 1990). Grass, leguminous plant.	MH	MH
5. Allelopathic properties?	No allelopathic properties described.	M	L
6. Tolerates herb pressure?	“Livestock generally avoid the harsh foliage of saltgrass… It is of low to fair palatability for livestock and wildlife (FS.FED 1990). Saltgrass is described as an "increaser" under grazing pressures on rangelands in Montana, but if severely grazed is replaced by other species (FS.FED 2009). Consumed but non-preferred or consumed but recovers quickly; capable of flowering /seed production under moderate herbivory pressure (where moderate = normal; not overstocking or heavy grazing).	MH	MH
7. Normal growth rate?	“Rhizomes quickly sprout and spread”. Because many other grasses cannot survive in soils with high salinities, salt grass is often a dominant” (FS.FED 1990). “Can form pure stands” or monocultures (FS.FED 2009). Moderately rapid growth that will equal competitive species of the same life form.	MH	MH
8. Stress tolerance to frost, drought, w/logg, sal. etc?	Tolerant of salinity, waterlogging/ inundation, fire, drought – as occurs in “moist” habitats, also likely frost as occurs in Canada (FS.FED 1990). Numerous studies have evaluated the importance of saltgrass clonal growth to survive physical stress in hypersaline environments along the Atlantic coast and the deserts of the southwestern United States…. Saltgrass grows in highly stressful environments (FS.FED 2009). Survives fire through re-sprouting (FS.FED 2009). Highly resistant to at least two of drought, frost, fire, waterlogging, and salinity not susceptible to more than one (cannot be drought or waterlogging).	H	MH
Reproduction
9. Reproductive system	“Salt grass is a poor seed producer. Reproduction is mainly vegetative” (FS.FED 2009). Saltgrass reproduces from seeds and rhizomes (FS.FED 2009). Both vegetative and sexual reproduction.	H	MH
10. Number of propagules produced?	Salt grass is a poor seed producer. Seed production is often restricted to favourable sites which support dense healthy stands.” (FS.FED 2009). Only available in Australia as NyPa ForageTM and this selection is vegetative and does not flower or produce seeds (AWI & CRC 2009).. Not enough information to determine maximum possible seed set.	M	L
11. Propagule longevity?	“seeds can remain dormant for at least 4 years” (FS.FED 2009). More than 4 years. Not enough information.	M	L
12. Reproductive period?	“Can form pure stands” or monocultures (FS.FED 2009). Mature plant produces viable propagules for 10 years or more, or species forms self-sustaining monocultures.	H	MH
13. Time to reproductive maturity?	No info on time to reproductive maturity. However, as rhizomes “quickly sprout and spread” (FS.FED 2009), it is likely that plants germinate from rhizomes could produce further vegetative propagules in < 1 year. Reaches maturity and produces viable propagules, or vegetative propagules become separate individuals, in under a year.	H	M
Dispersal
14. Number of mechanisms?	“Seeds are dispersed by wind and water” – “The seeds are eaten/ dispersed by numerous species of waterfowl & small mammals” (FS.FED 2009). Very light, wind dispersed seeds, or bird dispersed seeds, or has edible fruit that is readily eaten by highly mobile animals.	H	MH
15. How far do they disperse?	In marshes, saltgrass seeds are largely dispersed by water, with some dispersal by wind and animals (FS.FED 2009). Waterfowl and small mammals could disperse some seed > 1 km from source.	H	MH

References

AWI & CRC (2009) AWI & CRC Salinity 2006 - Distichlis spicata (L.) Greene. Available at www.saltlandgenie.org.au/LiteratureRetrieve.aspx?ID=23970 (verified 07 May 2009).

Distichlis spicata (L.) Greene. Available at www.mbari.org/staff/conn/botany/seagrass/justin/index.htm

FS.FED (2002) US Forest Service. Available at http://www.fs.fed.us/database (verified 07 May 2009).

Randall, R. P. (2002) A Global compendium of weeds. R. G. and F. J. Richardson.

WIKI (2009)Wikipedia- Distichlis spicata. Available at http://en.wikipedia.org/wiki/Distichlis_spicata (verified 07 May 2009).

Global present distribution data references

Australian National Herbarium (ANH) (2008) Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, Available at http://www.anbg.gov.au/avh/ (verified 07/05/2009).

Department of the Environment and Heritage (Commonwealth of Australia). (1993 – On-going) Australian Plant Name Index (APNI) http://www.cpbr.gov.au/apni/index.html (verified 07/05/2009).

Global Biodiversity Information Facility (GBIF) (2008) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 07 May 2009).

Integrated Taxonomic Information System. (2009) Available at http://www.itis.gov/ (verified 07/05/2009).

Missouri Botanical Gardens (MBG) (2009) w³TROPICOS, Missouri Botanical Gardens Database, Available at http://mobot.mobot.org/W3T/Search/vast.html (viewed 07/05/2009).

United States Department of Agriculture. Agricultural Research Service, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. Taxonomy Query. (2009) Available at http://www.ars-grin.gov/cgi-bin/npgs/html/taxgenform.pl (verified 07/05/2009).

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