Schizachyrium condensatum risk assessment

Pacific Island Ecosystems at Risk (PIER)

Schizachyrium condensatum

RISK ASSESSMENT RESULTS: High risk, score: 8

Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i.
Information on Risk Assessments
Original risk assessment

	Schizachyrium condensatum (bush beardgrass) Synonym: Andropogon condensatus Kunth. Family - Poaceae.	Answer	Score
1.01	Is the species highly domesticated? (If answer is 'no' then go to question 2.01)	n	0
1.02	Has the species become naturalized where grown?
1.03	Does the species have weedy races?
2.01	Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical”	2
2.02	Quality of climate match data (0-low; 1-intermediate; 2-high) see appendix 2	2
2.03	Broad climate suitability (environmental versatility)	n	0
2.04	Native or naturalized in regions with tropical or subtropical climates	y	1
2.05	Does the species have a history of repeated introductions outside its natural range? y=-2	n
3.01	Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05	y	2
3.02	Garden/amenity/disturbance weed y = 1*multiplier (see Append 2)	n	0
3.03	Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2)	n	0
3.04	Environmental weed y = 2*multiplier (see Append 2)	y	4
3.05	Congeneric weed y = 1*multiplier (see Append 2)	n	0
4.01	Produces spines, thorns or burrs	n	0
4.02	Allelopathic	n	0
4.03	Parasitic	n	0
4.04	Unpalatable to grazing animals	n	-1
4.05	Toxic to animals	n	0
4.06	Host for recognized pests and pathogens	n	0
4.07	Causes allergies or is otherwise toxic to humans	n	0
4.08	Creates a fire hazard in natural ecosystems	y	1
4.09	Is a shade tolerant plant at some stage of its life cycle	n	0
4.1	Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island)
4.11	Climbing or smothering growth habit	n	0
4.12	Forms dense thickets	y	1
5.01	Aquatic	n	0
5.02	Grass	y	1
5.03	Nitrogen fixing woody plant	n	0
5.04	Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers)	n	0
6.01	Evidence of substantial reproductive failure in native habitat	n	0
6.02	Produces viable seed.	y	1
6.03	Hybridizes naturally
6.04	Self-compatible or apomictic
6.05	Requires specialist pollinators	n	0
6.06	Reproduction by vegetative fragmentation	n	-1
6.07	Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1	2	0
7.01	Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)	y	1
7.02	Propagules dispersed intentionally by people	n	-1
7.03	Propagules likely to disperse as a produce contaminant	y	1
7.04	Propagules adapted to wind dispersal	y	1
7.05	Propagules water dispersed	n	-1
7.06	Propagules bird dispersed	n	-1
7.07	Propagules dispersed by other animals (externally)	n	-1
7.08	Propagules survive passage through the gut	n	-1
8.01	Prolific seed production (>1000/m2)	y	1
8.02	Evidence that a persistent propagule bank is formed (>1 yr)
8.03	Well controlled by herbicides	y	-1
8.04	Tolerates, or benefits from, mutilation, cultivation, or fire	y	1
8.05	Effective natural enemies present locally (e.g. introduced biocontrol agents)
	Total score:		8

Supporting data:

	Notes	Reference
1.01	No evidence
1.02
1.03
2.01	(1)"Native: SOUTHERN AMERICA Northern South America: French Guiana; Guyana; Suriname; Venezuela Brazil: Brazil Western South America: Bolivia; Colombia; Ecuador; Peru Southern South America: Argentina; Paraguay; Uruguay" (2)Native range - tropical and subtropical America.	(1)http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl (2)http://www.hear.org/Pier/species/schizachyrium_condensatum.htm
2.02
2.03	Probably not - Five out of the 6 herbarium specimens in the native range were collected from below 500 m except one that was collected from a roadside cliff at 1100 m.	http://mobot.mobot.org/cgi-bin/search_vast
2.04	(1)"Native: SOUTHERN AMERICA Northern South America: French Guiana; Guyana; Suriname; Venezuela Brazil: Brazil Western South America: Bolivia; Colombia; Ecuador; Peru Southern South America: Argentina; Paraguay; Uruguay" (2)Native range - tropical and subtropical America.	(1)http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl (2)http://www.hear.org/Pier/species/schizachyrium_condensatum.htm
2.05	Introduced to Hawaii. [No further evidence of introduction to other regions outside its native range.]	(1))http://www.hear.org/Pier/species/schizachyrium_condensatum.htm
3.01	(1)Naturalized in Hawaii. (2)"In Hawai‘i, "naturalized along roadsides and in open sites in mesic shrubland and grassland, 210-1,310 m"	(1))http://www.hear.org/Pier/species/schizachyrium_condensatum.htm
3.02	No evidence
3.03	No evidence
3.04	(1)This plant is considered invasive by the authoritative sources noted below. - HEAR USDI, Geological Survey. 1999. Information Index for Selected Alien Plants in Hawaii(http://www.hear.org, October 20, 1999). Hawaiian Ecosystems at Risk Project, Biological Resources Division, Haleakala Field Station. Makawao, Hawaii. (2)"It is becoming a major threat to native vegetation in these regions as it is one of the first plants to colonize landslides and areas disturbed by Hurricane Iniki in 1992".	http://plants.usda.gov/java/profile?symbol=SCCO10
3.05	No evidence
4.01	No evidence of such structures.	Clayton, W.D., Harman, K.T. and Williamson, H. (2002 onwards). World Grass Species: Descriptions, Identification, and Information Retrieval. http://www.kew.org/data/grasses–db.html. [accessed 01 August 2005; 15:30 GMT]*.
4.02	No evidence
4.03	No evidence
4.04	Probably not - "Rocky, dry areas may become very productive grasslands, and the perennial grasses may give way to annuals (or in wet areas to rank, unpalatable grasses). Examples of dramatic change are the spread of fountain grass (Pennisetum setaceum) on the western side of Hawai`i Island, and bush beardgrass (Schizachyrium condensatum) and broomsedge (Andropogon virginicus) on the eastern side."	http://72.14.253.104/search?q=cache:1DsTOOKls4kJ"> http://72.14.253.104/search?q=cache:1DsTOOKls4kJ: www.hear.org/books/apineh1992/pdfs/apineh1992vii4crandillingham.pdf +%22Schizachyrium+condensatum%22graze%7Cgrazing&hl=en&gl=us&ct=clnk&cd=2
4.05	No evidence
4.06	The following fungi were listed to be associated with Scizachyrium condensatum: Phyllachora andropogonis: Venezuela - 5833 Puccinia kaernbachii: Bolivia - 5833 Puccinia posadensis: Argentina - 5833 ; Mexico - 5833 Sphacelotheca guaranitica: Argentina - 5833 ; Brazil - 5833 ; Venezuela - 5833 Sporisorium guaraniticum: Paraguay - 37633 [No evidence that the above are economic pests].
4.07	No evidence
4.08	(1)"Recent surveys suggest that fires fueled by Schizachyrium in this area, have a very dramatic and negative effect on native woody species." (2)The introduced C4 bunchgrass, Schizachyrium condensatum, is abundant in unburned, seasonally dry woodlands on the island of Hawaii, where it promotes the spread of fire.	(1)D'Antonio, Carla M.; Hughes, R. Flint; Mark, Michelle, et al. The response of native species to removal of invasive exotic grasses in a seasonally dry Hawaiian woodland Journal of Vegetation Science 9 (5) : 699-712 Oct., 1998 (2)D'Antonio, Carla M.; Hughes, R. Flint; Vitousek, Peter M. Factors influencing dynamics of two invasive C4 grasses in seasonally dry Hawaiian woodlands Ecology (Washington D C) 82 (1) : 89-104 January, 2001
4.09	(1)"Reproduction was reduced by low light and increased by nutrients in both species. Shading eliminated flower production in Schizachyrium during the time course of this study. However, it is possible that shading simply delayed flowering and that we harvested before it had occurred." (2)"It is becoming a major threat to native vegetation in these regions as it is one of the first plants to colonize landslides and areas disturbed by Hurricane Iniki in 1992". (3)Collection number: 13290 - Open hillside on a road top, Collection number: 30103 - roadside cliff, Collection number: 20369 - grassy roadside. [Probably not - the grass seems to inhabit open areas - suggesting its lack of shade tolerance].	(1)D'Antonio, Carla M.; Hughes, R. Flint; Vitousek, Peter M. Factors influencing dynamics of two invasive C4 grasses in seasonally dry Hawaiian woodlands Ecology (Washington D C) 82 (1) : 89-104 January, 2001 (2)http://hbs.bishopmuseum.org/pdf/op41-19-58.pdf (3)http://mobot.mobot.org/cgi-bin/search_vast?ssdp=01851441
4.1	No evidence regarding soil requirements.
4.11	No evidence
4.12	"Even in natural areas, however, alien grasses and woody species may become established to the exclusion of other vegetation types in monoculture-like stands. The alien grasses Andropogon virginicus and Schizachyrium condensatum form such stands in Hawaii Volcanoes National Park."	http://www.botany.hawaii.edu/faculty/duffy/book/1992_chap/19.pdf
5.01
5.02	Perennial grass - Culms erect; 90–150 cm long; 2–3.5 mm diam	Clayton, W.D., Harman, K.T. and Williamson, H. (2002 onwards). World Grass Species: Descriptions, Identification, and Information Retrieval. http://www.kew.org/data/grasses–db.html. [accessed 01 August 2005; 15:30 GMT]*.
5.03
5.04
6.01	No evidence
6.02	"Propagation by seed."	http://www.hear.org/Pier/species/schizachyrium_condensatum.htm
6.03	No evidence of hybridization in the genus Schizachyrium.
6.04	Don’t know.
6.05	A grass species- probably wind pollinated.
6.06	No evidence of spread by vegetative means.
6.07	A perennial grass species - probably 1 to 2 years. - "Schizachyrium condensatum (formerly Andropogon glomeratus), an erect bunchgrass native to tropical America, sends up new tillers from a small root crown each year. Individual stems grow vertically until they begin to flower; at our sites they reach an mean height of 1.1 m, with a maximum height of 1.8 m. After flowering, entire shoots die and new ones are produced from the root crown."	D'Antonio, Carla M.; Hughes, R. Flint; Mark, Michelle, et al. The response of native species to removal of invasive exotic grasses in a seasonally dry Hawaiian woodland Journal of Vegetation Science 9 (5) : 699-712 Oct., 1998
7.01	Probably yes - it is a grass species that grows in disturbed areas such as along roadsides.
7.02	Probably not - no evidence that the species has ornamental value or is used as forage.
7.03	Probably yes - small wind dispersed grass seeds.
7.04	"In addition, Schizachyrium has greater potential for rapid dispersal to new areas than does Melinis. Both species are wind dispersed, but Schizachyrium's seeds are attached to a large fluffy plume, whereas Melinis's have a soft unforked awn."	D'Antonio, Carla M.; Hughes, R. Flint; Vitousek, Peter M. Factors influencing dynamics of two invasive C4 grasses in seasonally dry Hawaiian woodlands Ecology (Washington D C) 82 (1) : 89-104 January, 2001
7.05	No evidence
7.06	No evidence
7.07	Probably not - no evidence that the species has any means of attachment.
7.08
8.01	Probably yes - a grass with relatively small seeds.	Clayton, W.D., Harman, K.T. and Williamson, H. (2002 onwards). World Grass Species: Descriptions, Identification, and Information Retrieval. http://www.kew.org/data/grasses–db.html. [accessed 01 August 2005; 15:30 GMT]*.
8.02	No evidence regarding longevity of seeds in the soil.
8.03	Foliar application of roundup - 2% in water.	http://www.hear.org/oisc/pdfs/20040929oiscmeetingminutes.pdf
8.04	"Second, we elucidated factors promoting the shift in grass species dominance from Schizachyrium to Melinis after fire, particularly since the former regenerates from root crowns immediately after fire and thus has an initial growth advantage." "Schizachyrium condensatum (formerly Andropogon glomeratus), an erect bunchgrass native to tropical America, sends up new tillers from a small root crown each year. Individual stems grow vertically until they begin to flower; at our sites they reach an mean height of 1.1 m, with a maximum height of 1.8 m. After flowering, entire shoots die and new ones are produced from the root crown."	D'Antonio, Carla M.; Hughes, R. Flint; Vitousek, Peter M. Factors influencing dynamics of two invasive C4 grasses in seasonally dry Hawaiian woodlands Ecology (Washington D C) 82 (1) : 89-104 January, 2001
8.05	Don’t know.

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This page created 26 December 2006