Pacific Island Ecosystems at Risk (PIER)


Cyperus involucratus


RISK ASSESSMENT RESULTS: High risk, score: 17


Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i.

Research directed by C. Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service

Information on Risk Assessments
Original risk assessment

Cyperus involucratus Rottb. (Cyperus alternifolius; umbrella sedge, umbrella plant, dwarf papyrus grass )

Answer

1.01

Is the species highly domesticated?

y=-3, n=0

n

1.02

Has the species become naturalized where grown?

y=-1, n=-1

y

1.03

Does the species have weedy races?

y=-1, n=-1

n

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”

See Append 2

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)

y=1, n=0

n

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

y

2.05

Does the species have a history of repeated introductions outside its natural range? y=-2

?=-1, n=0

y

3.01

Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05

y

3.02

Garden/amenity/disturbance weed y = 1*multiplier (see Append 2)

n=0

n

3.03

Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2)

n=0

y

3.04

Environmental weed y = 2*multiplier (see Append 2)

n=0

y

3.05

Congeneric weed y = 1*multiplier (see Append 2)

n=0

y

4.01

Produces spines, thorns or burrs

y=1, n=0

n

4.02

Allelopathic

y=1, n=0

n

4.03

Parasitic

y=1, n=0

n

4.04

Unpalatable to grazing animals

y=1, n=-1

4.05

Toxic to animals

y=1, n=0

n

4.06

Host for recognized pests and pathogens

y=1, n=0

y

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

n

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

n

4.09

Is a shade tolerant plant at some stage of its life cycle

y=1, n=0

y

4.1

Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island)

y=1, n=0

n

4.11

Climbing or smothering growth habit

y=1, n=0

n

4.12

Forms dense thickets

y=1, n=0

n

5.01

Aquatic

y=5, n=0

n

5.02

Grass

y=1, n=0

n

5.03

Nitrogen fixing woody plant

y=1, n=0

n

5.04

Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers)

y=1, n=0

y

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

6.02

Produces viable seed.

y=1, n=-1

y

6.03

Hybridizes naturally

y=1, n=-1

6.04

Self-compatible or apomictic

y=1, n=-1

6.05

Requires specialist pollinators

y=-1, n=0

n

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

y

6.07

Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1

See left

7.01

Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)

y=1, n=-1

n

7.02

Propagules dispersed intentionally by people

y=1, n=-1

y

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

7.04

Propagules adapted to wind dispersal

y=1, n=-1

n

7.05

Propagules water dispersed

y=1, n=-1

y

7.06

Propagules bird dispersed

y=1, n=-1

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

n

7.08

Propagules survive passage through the gut

y=1, n=-1

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

y

8.02

Evidence that a persistent propagule bank is formed (>1 yr)

y=1, n=-1

n

8.03

Well controlled by herbicides

y=-1, n=1

y

8.04

Tolerates, or benefits from, mutilation, cultivation, or fire

y=1, n=-1

y

8.05

Effective natural enemies present locally (e.g. introduced biocontrol agents)

y=-1, n=1

Total score:

17

Supporting data:

Notes

Source

1.01

Cultivars/Species: Variegatus (white striped leaves, bracts, and stems); Gracilis ( compact; 18”); Nana (dwarf)

1.02

(1)In Hawai`i, "cultivated and naturalized in marshy areas and along streams, 0-460 m. Common along streamsides on Rarotonga and invading wet areas on Aitutaki, Cook Islands. Very prevalent in wet areas, Tongatapu (Tonga). (2)It has naturalized throughout much of Africa and in other tropical regions. (3) Santa Monica Mountains, California

(1)http://www.hear.org/pier/species/cyperus_involucratus.htm (2)http://www.floridata.com/ref/C/cypa_inv.cfm (3)http://www.tchester.org/plants/muns/smm/flora.html

1.03

No evidence

2.01

(1)Native range: Tropical Africa and Arabia (2)This tender perennial is believed to be native to moist boggy areas and lake and river margins on the island of Madagascar (Malagasy Republic). (3)Origin: Eastern Africa

(1)http://www.hear.org/pier/species/cyperus_involucratus.htm (2)http://www.floridata.com/ref/C/cypa_inv.cfm (3)http://www.desert-tropicals.com/Plants/Cyperaceae/Cyperus_involucratus.html

2.02

2.03

(1)Hardiness: Zones 7-11 (2)Umbrella plant is happy growing in shallow water but can also handle drier situations (like in your perennial bed) [in nature it is restricted to shallow water habitats] (3)Very high moisture needs; suitable for bogs and water gardens

(1)http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/water-garden/marginalaq/cyperus_alternifolius.html (2)http://www.floridata.com/ref/C/cypa_inv.cfm (3)http://plantsdatabase.com/go/2532

2.04

In Hawai`i, "cultivated and naturalized in marshy areas and along streams, 0-460 m

http://www.hear.org/pier/species/cyperus_involucratus.htm

2.05

(1)Introduced to Hawaii and other Pacific Island. (2)cultivated & naturalized elsewhere in tropics & subtropics

(1)http://www.hear.org/pier/species/cyperus_involucratus.htm (2)http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl?Cyperus+involucratus

3.01

(1)In Hawai`i, "cultivated and naturalized in marshy areas and along streams, 0-460 m. Common along streamsides on Rarotonga and invading wet areas on Aitutaki, Cook Islands. Very prevalent in wet areas, Tongatapu (Tonga). (2)It has naturalized throughout much of Africa and in other tropical regions. (3) Santa Monica Mountains, California

(1)http://www.hear.org/pier/species/cyperus_involucratus.htm (2)http://www.floridata.com/ref/C/cypa_inv.cfm (3)http://www.tchester.org/plants/muns/smm/flora.html

3.02

No evidence

3.03

A major weed of cotton [Australia]

http://www.cotton.crc.org.au/Assets/PDFFiles/WEEDpak/WPj2.pdf

3.04

(1)PIER environmental invasive? - yes. In Hawai`i, "cultivated and naturalized in marshy areas and along streams, 0-460 m. Common along streamsides on Rarotonga and invading wet areas on Aitutaki, Cook Islands. Very prevalent in wet areas, Tongatapu (Tonga). (2)In warm climates umbrella plant may be invasive so do not plant in natural bodies of water. Plant in tubs or otherwise confine roots to prevent runaway growth. The Florida Exotic Pest Plant Council places this species in its Category II: "Invasive exotics that have increased in abundance or frequency but have not yet altered Florida plant communities to the extent shown by Category I species." (3)Environmental weed of south-east Queensland, Australia

(1)http://www.hear.org/pier/species/cyperus_involucratus.htm (2)http://www.floridata.com/ref/C/cypa_inv.cfm (3)http://www.nrme.qld.gov.au/pests/environmental_weeds/pdf/list.pdf

3.05

"In general, Cyperus is economically unimportant and better known for its weeds than its useful plants; several species are pernicious weeds in agriculture."

Nguyen Khac Khoi, 2002. Cyperus L.. [Internet] Record number 206 from TEXTFILE On-line. de Padua, L.S., Bunyapraphatsara, N. and Lemmens, R.H.M.J. (Editors). PROSEA (Plant Resources of South-East Asia) Foundation, Bogor, Indonesia. http://www.proseanet.org. Accessed: Wednesday, 23 June 2004.

4.01

No evidence of such structures.

http://www.hear.org/pier/species/cyperus_involucratus.htm

4.02

No evidence

4.03

No evidence

http://www.omnisterra.com/bot/pp_home.cgi

4.04

Don’t know

4.05

[reportedly eaten by dogs with no ill effects]

http://plantsdatabase.com/go/2532

4.06

Eldana saccharina is a specialist pest

Mazodze, R. Conlong, D. E. (2003) Eldana saccharina (Lepidoptera: Pyralidae) in sugarcane (Saccharum hybrids), sedge (Cyperus digitatus) and bulrush (Typha latifolia) in South-Eastern Zimbabwe. Proceedings of the Annual Congress - South African Sugar Technologists' Association, 2003, No. 77, pp. 266-274, 22 ref.

4.07

No evidence

4.08

Probably not - a sedge that grows in wet/marsh habitats.

http://www.floridata.com/ref/C/cypa_inv.cfm

4.09

(1)Sun or light shade (2)Light: Sun or shade. In bright sun, clumps will be compact and the stems closely packed. Under shady conditions clumps will grow higher and be composed of fewer stems and larger leaves giving a more graceful aspect.

http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/water-garden/marginalaq/cyperus_alternifolius.html

4.1

Probably not -(1) Swamp plant, needs moist to wet soil (2)Soil pH requirements: 5.6 to 6.0 (acidic) 6.1 to 6.5 (mildly acidic)

(1)http://www.desert- (2)http://plantsdatabase.com/go/2532/tropicals.com/Plants/Cyperaceae/Cyperus_involucratus.html

4.11

Not a vine - a sedge.

http://www.hear.org/pier/species/cyperus_involucratus.htm

4.12

No evidence

5.01

Habitat/ecology: Wet places at low elevations. In Hawai`i, "cultivated and naturalized in marshy areas and along streams, 0-460 m" [not truly aquatic]

http://www.hear.org/pier/species/cyperus_involucratus.htm

5.02

Sedge - Robust plants, tufted, with culms up to 12-0 cm tall

http://www.hear.org/pier/species/cyperus_involucratus.htm

5.03

No evidence

5.04

Propagation Methods:
By dividing rhizomes, tubers, corms or bulbs (including offsets)
From seed; direct sow after last frost

http://plantsdatabase.com/go/2532/

6.01

No evidence

6.02

Propagation: Seed, rhizomes

http://www.hear.org/pier/species/cyperus_involucratus.htm

6.03

No evidence

6.04

No evidence

6.05

a sedge. Photo of flowers does not suggest pollination by specialist pollinators.

http://www.floridata.com/ref/C/cypa_inv.cfm

6.06

(1)Propagation Methods:
By dividing rhizomes, tubers, corms or bulbs (including offsets)
From seed; direct sow after last frost (2)We had very heavy rain all Summer that actually beat down some of the "heads," and these are now rooting where they touched the ground for several months. [Wetland plant - vegetative piece may break off due to water currents]

(1)http://plantsdatabase.com/go/2532/ (2)http://plantsdatabase.com/go/2532

6.07

Don’t know

7.01

No evidence that the propagules have any means of attachment.

7.02

often introduced as an ornamental.

http://www.hear.org/pier/species/cyperus_involucratus.htm

7.03

Possible if inflorescenses are used for dried flower arrangements

7.04

fruits is achene. It is a sedge. (2) Dispersal syndrome: aquatic/water?, bird?, vegetatively propagating [achene lacks clear adaptations for wind]

http://hbs.bishopmuseum.org/pdf/op65.pdf

7.05

the species inhabits streams. [Achenes are likely to float]

http://www.hear.org/pier/species/cyperus_involucratus.htm

7.06

Dispersal syndrome: aquatic/water?, bird?, vegetatively propagating [birds are probably seed predators]

http://hbs.bishopmuseum.org/pdf/op65.pdf

7.07

No evidence

7.08

[birds are probably seed predators]

8.01

...glumes ovate, acute at apex, about 2 mm long, membranous, pale green and variegated with rusty-brown, 3- or 5-nerved, the keel prominent; achenes ovate-elliptic, 3-sided, 1/3 to 1/4 as long as glume, maturing brown;' "primary rays numerous, slender, 7-10 cm long, each bearing 4-10 raylets 1-1.5 cm long; leafy bracts many, nearly equal in length, about twice as long as corymb, stiff, flattish, 2-12 mm broad, sub-abruptly acute at apex; spikelets clustered at apices of raylets, lance-oblong to elliptic, flattened, 3-9 mm long, 1.7-3 mm broad, densely 6-30-flowered"
[The seeds are minute and a single culm produces a huge number of flowers. (Each culm has numerous rays with 4-10 raylets, which has numerous spikelets on it bearing 6-30 flowers). ]

http://www.hear.org/pier/species/cyperus_involucratus.htm

8.02

[production of large amounts of volatiles by seeds suggested short seed lifespan]

Zhang, M. , Liu, Y. , Torii, I. , Sasaki, H. , Esashi, Y. 1993. Evolution of volatile compounds by seeds during storage periods.
Seed Science and Technology, , Vol. 21, No. 2, pp. 359-373

8.03

(1)Controlled by Bolero (thiobencarb)

(1)Foell, R. H. 1983. Today's herbicide: Bolero - a rice herbicide.Weeds Today, , Vol. 14, No. 1, pp. 7-8

8.04

(1)"Tall perennial, with short, woody rhizome" [ability to regrow from underground rhizome] (2)dies back in winter (survied 6 inches of snow in 2003) comes back strong; It turns brown here at the first frost, but after cutting back the dead stems in mid-Spring it comes back up larger than ever.

(1)http://www.hear.org/pier/species/cyperus_involucratus.htm (2)http://plantsdatabase.com/go/2532

8.05

Don’t know


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