Yellow sedge (Carex viridula)

Present distribution

Scientific name:	Carex viridula (Michx)
Common name(s):	Yellow sedge, Little green sedge

This weed is not known to be naturalised in Victoria

Habitat:

Swamps, bogs, lakeshores and wet meadows in the lowland, steppe and montane zones; common in S BC, less frequent northward; amphiberingian, N to AK, YT and NT, E to NF and S to ME, MA, PA, OH, IN, IL, MN, SD, NM, UT, NV and CA; E Asia.

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:
Pasture dryland; pasture irrigated

Ecological Vegetation Divisions
Coastal; swampy scrub; freshwater wetland (permanent); treed swampy wetland; forby forest; riparian; high altitude wetland; alpine treeless; freshwater wetland (ephemeral); saline wetland;

Colours indicate possibility of Carex viridula infesting these areas.

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

Map showing the potential distribution of yellow sedge

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

Impact*

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	Perennial, densely tufted herb from fibrous roots; stems 10-40 cm tall, longer than the leaves. (Klinkenberg, B 2007) Carex flava L. sensu lato is a small sedge belonging to the section Extensae Fr. It has very short rhizomes and forms small tussocks of closely packed tillers. (Schmid B 1984) Minimal or negligible impact (ie. can go anywhere).	l	h
2. Reduce tourism?	Carex flava L. sensu lato is a small sedge belonging to the section Extensae Fr. It has very short rhizomes and forms small tussocks of closely packed tillers. (Schmid B 1984) Weeds not obvious to the ‘average’ visitor.	l	mh
3. Injurious to people?	Species not known to be poisonous (Klinkenberg, B 2007) No effect, no prickles, no injuries.	l	mh
4. Damage to cultural sites?	Carex flava L. sensu lato is a small sedge belonging to the section Extensae Fr. It has very short rhizomes and forms small tussocks of closely packed tillers. (Schmid B 1984) Little or negligible effect on aesthetics or structure of site.	l	mh
Abiotic
5. Impact flow?	All the taxa of Carex flava group occur in open, wet habitats. (Schmid B 1984) Habitat: Eutrophic fens and marls and calcareous barrens in western Newfoundland.(Robertson 1984) Little or negligible affect on water flow.	l	mh
6. Impact water quality?	Habitat: Eutrophic fens and marls and calcareous barrens in western Newfoundland.(Robertson 1984) No noticeable effect on dissolved 0₂or light levels.	l	mh
7. Increase soil erosion?	Trampling had allowed C. viridula spp viridula to grow in an open vegetation but the abandoned footpaths had become overgrown by 1975 and C. viridula spp. viridula disappeared from them completely. (Schmid B 1984) Low probability of large scale soil movement	L	mh
8. Reduce biomass?	Carex flava L. sensu lato is a small sedge belonging to the section Extensae Fr. It has very short rhizomes and forms small tussocks of closely packed tillers. (Schmid B 1984) Direct replacement of biomass by invader.	ml	mh
9. Change fire regime?	Fire tolerance –High (USDA 2008) Greatly changes the intensity of fire risk.	h	mh
Community Habitat
10. Impact on composition (a) high value EVC	EVC = Plains Grassland/Plains Grassy Woodland (E); CMA = Corangamite; Bioregion = Victorian Volcanic Plain; VH CLIMATE potential All the taxa of Carex flava group occur in open, wet habitats. (Schmid B 1984) Habitat: Eutrophic fens and marls and calcareous barrens in western Newfoundland. (Robertson 1984) Very little displacement of any indigenous spp. Sparse/ scattered infestations.	l	mh
(b) medium value EVC	EVC = Lowland Herb-rich Forest (D); CMA = East Gippsland; Bioregion = East Gippsland Lowlands; H CLIMATE potential All the taxa of Carex flava group occur in open, wet habitats. (Schmid B 1984) Habitat: Eutrophic fens and marls and calcareous barrens in western Newfoundland.(Robertson 1984) Very little displacement of any indigenous spp. Sparse/ scattered infestations.	l	mh
(c) low value EVC	EVC = Heathy Woodland (LC); CMA = Glenelg Hopkins; Bioregion = Glenelg Plain; H CLIMATE potential All the taxa of Carex flava group occur in open, wet habitats. (Schmid B 1984) Habitat: Eutrophic fens and marls and calcareous barrens in western Newfoundland.(Robertson 1984) Very little displacement of any indigenous spp. Sparse/ scattered infestations.	l	mh
11. Impact on structure?	Invasive Status: Carex viridula is not invasive. (Klinkenberg, B 2007) All the taxa of Carex flava group occur in open, wet habitats. (Schmid B 1984) Habitat: Eutrophic fens and marls and calcareous barrens in western Newfoundland.(Robertson 1984) Very little displacement of any indigenous spp. Sparse scattered infestations.	l	mh
12. Effect on threatened flora?	Invasive Status: Carex viridula is not invasive. (Klinkenberg, B 2007) All the taxa of Carex flava group occur in open, wet habitats. (Schmid B 1984) Habitat: Eutrophic fens and marls and calcareous barrens in western Newfoundland.(Robertson 1984) Minor/negligible effects on any Bioregional Priority or VROT spp.	l	mh
Fauna
13. Effect on threatened fauna?	Invasive Status: Carex viridula is not invasive. (Klinkenberg, B 2007) Minor effects on threatened spp.; minor hazard or reduction in habitat/food/ shelter.	ml	mh
14. Effect on non-threatened fauna?	Invasive Status: Carex viridula is not invasive. (Klinkenberg, B 2007) Minor effects on fauna spp.; minor hazard or reduction in habitat/food/ shelter.	ml	mh
15. Benefits fauna?	Grazed by horses, cattle and sheep; also a good seed source for birds (Robertson A 1984) Provides some assistance in either food or shelter to desirable species.	mh	mh
16. Injurious to fauna?	Species not known to be poisonous (Klinkenberg, B 2007) No effect.	l	mh
Pest Animal
17. Food source to pests?	Grazed by horses, cattle and sheep; also a good seed source for birds (Robertson A 1984) Supplies food serious pest (eg. rabbits and foxes), but at low levels (eg. foliage).	mh	mh
18. Provides harbour?	Perennial, densely tufted herb from fibrous roots; stems 10-40 cm tall, longer than the leaves. (Klinkenberg, B 2007) Capacity to harbour rabbits or foxes at low densities or as overnight cover.	mh	mh
Agriculture
19. Impact yield?	Both the numbers of shoots and the fertility of these species, as well as of Carex dioica, C. capillaries, C. flava, C. nigra, Eriophorum angustifolium and E. latifolium, increase as a consequence of scything in fen communities. (Moen A et all 1999) Minor impact on quantity of produce (eg < 5% reduction).	ml	mh
20. Impact quality?	This taxon occurs in natural coastal grasslands in Europe and probably is introduced in North America, where it persists in coastal meadows that were managed as hay fields for colonists’ livestock (eFloras.org 2008) Minor impact on quality of produce (eg < 5% reduction).	ml	mh
21. Affect land value?	No information found, unlikely	l	l
22. Change land use?	No information found, unlikely	l	l
23. Increase harvest costs?	This taxon occurs in natural coastal grasslands in Europe and probably is introduced in North America, where it persists in coastal meadows that were managed as hay fields for colonists’ livestock (eFloras.org 2008). Little or none.	l	mh
24. Disease host/vector?	No information found	m	l

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	All the taxa of Carex flava group occur in open, wet habitats….In nature, seedlings of the C. flava group emerge in summer (Schmid B 1984) Some species (C. demissa, C. davalliana, C. flava) showed a positive response to a stratification period of six months (Schutz 2000) Relatively high temperatures are required for germination of the seeds of C. flava and C. viridula, both species which grow in open sites. (Schutz 2000) Germination only after stratification and fluctuating temperatures: Carex lepidocarpa (long-stalked yellow sedge) (Patzelt, et al 2001) Requires summer temperatures for germination.	mh	mh
2. Establishment requirements?	Trampling had allowed C. viridula spp viridula to grow in an open vegetation but the abandoned footpaths had become overgrown by 1975 and C. viridula spp. Viridula disappeared from them completely. (Schmid B 1984) C. demissa Open habitat (Schutz 2000) C. demissa Wet soil moisture (Schutz 2000) Beside dams in Tasmania (Rozefelds et al 1999) Shade tolerance –Intolerant (USDA 2008) Requires more specific requirements to establish (eg. open space or bare ground with access to light and direct rainfall)	ml	h
3. How much disturbance is required?	Trampling had allowed C. viridula spp viridula to grow in an open vegetation but the abandoned footpaths had become overgrown by 1975 and C. viridula spp. viridula disappeared from them completely. (Schmid B 1984) Establishes in highly disturbed natural ecosystems (eg. roadsides, wildlife corridors, or areas which have a greater impact by humans such as tourist areas or campsites)	ml	h
Growth/Competitive
4. Life form?	Carex flava L. sensu lato is a small sedge belonging to the section Extensae Fr. It has very short rhizomes and forms small tussocks of closely packed tillers. (Schmid B 1984) Geophyte	ml	h
5. Allelopathic properties?	Known Allelopath –No (USDA 2008) None.	l	mh
6. Tolerates herb pressure?	Another large group of species, mainly graminoids, are favoured by cattle grazing (e.g. Carex dioica, Carex flava, Equisetum palustre, Eriophorum angustifolium and Triglochin palustris). (Moen A et all 1999) Consumed but non-preferred capable of flowering /seed production under moderate herbivory pressure (where moderate = normal; not overstocking or heavy grazing).	mh	h
7. Normal growth rate?	Trampling had allowed C. viridula spp viridula to grow in an open vegetation but the abandoned footpaths had become overgrown by 1975 and C. viridula spp. viridula disappeared from them completely. (Schmid B 1984) Maximum growth rate less than many species of the same life form.	ml	h
8. Stress tolerance to frost, drought, w/logg, sal. etc?	All the taxa of Carex flava group occur in open, wet habitats….In nature, seedlings of the C. flava group emerge in summer (Schmid B 1984) Salinity tolerance –High, Fire tolerance –High, Anaerobic tolerance –High, Drought tolerance –Low, Temperature minimum (F)- -38 (USDA 2008) Highly tolerant of fire, waterlogging, and salinity, and is tolerant of frost. Susceptible to drought	mh	mh
Reproduction
9. Reproductive system	Carex flava L. sensu lato is a small sedge belonging to the section Extensae Fr. It has very short rhizomes and forms small tussocks of closely packed tillers. (Schmid B 1984) Both vegetative and sexual reproduction	h	mh
10. Number of propagules produced?	No information found	m	l
11. Propagule longevity?	Although seeds stored dry at room temperature die within 5 years they remain viable for at least 20 years in soil (Schmid B 1984) Greater than 25% of seeds survive 10-20 years in the soil, or lower viability but survives over 20 years.	mh	mh
12. Reproductive period?	The length of life of a genet of C. viridula ssp. viridula may be less than 10 years, for C. flava more than 10 years, and for C. stricta (representing tall, tussock formingsedges) more than 50 years (Costello 1936), but it is hard to say how reasonable these guesses are. (Schmid B 1984) Mature plant produces viable propagules for 10 years or more	h	h
13. Time to reproductive maturity?	Individual seedlings of the C. flava group, kept in pots under garden conditions, established successfully and flowered within 12 months of germination. (Schmid B 1984) Reaches maturity and produces viable propagules in under a year	h	mh
Dispersal
14. Number of mechanisms?	Carex flava var. alpine seeds eaten by domesticated ducks (Anas platyrhynchos) were partly destroyed and partly still intact when they passed the digestive tract within 18h. (Schmid B 1984) For instance, Schmid (1980), based on distribution patterns of Carex viridula spp. Viridula in a pond area, concluded that this small sedge is primarily distributed by humans, probably carried in soil and on shoes. (Allessio Leck M 2005) Grazed by horses, cattle and sheep; also a good seed source for birds (Robertson A 1984) bird dispersed seeds and has edible fruit that is readily eaten by highly mobile animals	h	mh
15. How far do they disperse?	Carex flava var. alpine seeds eaten by domesticated ducks (Anas platyrhynchos) were partly destroyed and partly still intact when they passed the digestive tract within 18h. (Schmid B 1984) Grazed by horses, cattle and sheep; also a good seed source for birds (Robertson A 1984) Very likely that at least one propagule will disperse greater one kilometre.	h	mh

* This assessment included Carex viridula as part of the Carex flava group. More recent studies have since split this group in two, forming the Carex viridula
group and Carex flava group. Both species still exhibit very similar characteristics and are found growing in similar locations. The confidence rating was lowered
to accommodate possible differences.

References

Allessio Leck M, Shultz W 2005 Regeneration of Cyperaceae, with particular reference to seed ecology and seed banks. Perspectives in Plant Ecology, Evolution and Systematics 7 (2005) pp. 95-133

eFloras.org (2008) Flora of North America. Available at http://www.efloras.org/flora_page.aspx?flora_id=1 (verified 2/6/08).

Klinkenberg, Brian. (Editor) 2007. E-Flora BC: Electronic Atlas of the Plants of British Columbia [www.eflora.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 5/22/2008 9:45:30 PM]

Moen A, Nilsen LS, ien D-I, Arnesen T. 1999 Outlying haymaking lands at Solendet, central Norway: effects of scything and grazing. Norsk Geografisk
Tidsskrift - Norwegian Journal of Geography, Volume 53, Issue 2 & 3 January 1999 , pages 93 – 102

Patzelt A, Wild U, Pfadenhauer J (2001) Restoration of Wet Fen Meadows by Topsoil Removal: Vegetation Development and Germination Biology of Fen Species. Restoration Ecology 9(2), 127-136

Rozefelds ACF, Cave L, Morris DI, Buchanan AM (1999) The weed invasion in Tasmania since 1970. Australian Journal of Botany 47, 23-48

Schmid, B. Life histories in clonal plants of the Carex flava group. Journal of Ecology 1984 Vol 72. pages 93-11

Schutz W (2000) Ecology of seed dormancy and germination in sedges (Carex). Perspectives in Plant Ecology, Evolution and Systematics 3(1), 67-89

United States Department of Agriculture. Agricultural Research Service, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. Taxonomy Query. (2008) Available at http://www.ars-grin.gov/cgi-bin/npgs/html/taxgenform.pl (verified 2/6/08).

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 2/6/08).

Global Biodiversity Information Facility (GBIF) (2008) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 2/6/08).

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