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

Dissotis rotundifolia [Dissotis plumosa, dissotis]

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

n

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

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

4.11

Climbing or smothering growth habit

y=1, n=0

y

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

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

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

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

n

7.04

Propagules adapted to wind dispersal

y=1, n=-1

n

7.05

Propagules water dispersed

y=1, n=-1

7.06

Propagules bird dispersed

y=1, n=-1

n

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

n

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:

10

Source

Notes

1.01

No evidence

1.02

(1)sparingly naturalized in Hawaii (2)A dominant weed in Australia

(1)Wagner, W.L., D.R. Herbst and S.H. Sohmer. 1999. Manual of the flowering plants of Hawai‘i. Revised edition. University of Hawai‘i Press, Honolulu. p. 907. (2)http://www.cpitt.uq.edu.au/chromolaena/3/3ut4.html

1.03

No evidence

2.01

Native to tropical Africa.

http://translate.google.com/translate?hl=en&sl=de&u=http://www.heimwerker.de/service/garten-lexikon/dissotis.htm&prev=/search%3Fq%3DDissotis%2Bplumosa%26hl%3Den%26lr%3D%26ie%3DUTF-8%26safe%3Doff%26sa%3DG

2.02

2.03

Demands moist conditions.

http://edis.ifas.ufl.edu/EH139

2.04

Native to tropical Africa.

http://translate.google.com/translate?hl=en&sl=de&u=http://www.heimwerker.de/service/garten-lexikon/dissotis.htm&prev=/search%3Fq%3DDissotis%2Bplumosa%26hl%3Den%26lr%3D%26ie%3DUTF-8%26safe%3Doff%26sa%3DG

2.05

(1)Grown as a groundcover in Hawaii (2)A groundcover in Florida (3)A dominant weed controled by slashing in Australia

(1)Criley, R. A. (1976) Growth retardants for control of ground covers. Departmental Paper, Hawaii Agricultural Experiment Station, 1976, No.46, 8 pp., 2 ref. (2)http://edis.ifas.ufl.edu/EH139
(3)http://www.cpitt.uq.edu.au/chromolaena/3/3ut4.html

3.01

(1)sparingly naturalized in Hawaii (2)A dominant weed in Australia

(1)Wagner, W.L., D.R. Herbst and S.H. Sohmer. 1999. Manual of the flowering plants of Hawai‘i. Revised edition. University of Hawai‘i Press, Honolulu. p. 907. (2)http://www.cpitt.uq.edu.au/chromolaena/3/3ut4.html

3.02

No evidence

3.03

(1)Dissotis rotundifolia is a weed and subjected to chemical control in Africa where it is native (2)A dominant weed controled by slashing in Australia (3)In some countries it becomes an aggressive weed in pastures and other sunny places

(1)Melifonwu, A. A.; Orkwor, G. C. (1990) Chemical weed control in ginger (Zingiber officinale ) production from minisetts. Nigerian Journal of Weed Science, 1990, Vol.3, pp.43-50, 11 ref. (2)http://www.cpitt.uq.edu.au/chromolaena/3/3ut4.html (3)Whistler, W.A. 2000. Tropical ornamentals. Timber Press.

3.04

(1)infestations are common, particularly on Babeldaob [Palau]. The worst example of what the future may hold for this plant is at the old Ngatpang village, where it is forming a dense mat in the forest understory, crowding out or excluding other species. This behavior was also seen in Samoa. (2)Extensive areas of Dissotis rotundifolia (dissotis, pink lady) were seen on both Upolu and Savai‘i, the worst infestations seen so far in the Pacific. It forms dense mats, shading out other species, occasionally even climbing over small shrubs.

(1)http://www.hear.org/pier/reports/preport.htm(2)http://www.hear.org/pier/reports/sreport.htm

3.05

No evidence

4.01

Not described

Whistler, W.A. 2000. Tropical ornamentals. Timber Press.

4.02

No evidence

4.03

No evidence

4.04

Don’t know.

4.05

No evidence

4.06

Did not find information regarding associated pests or pathogens.

4.07

No evidence

4.08

Probably not - as it a herb of wet environments.

Neal, M.C. 1965. In Gardens of Hawaii. Bishop Museum Press. Honolulu.

4.09

Grows in shade

http://edis.ifas.ufl.edu/EH139

4.1

Don’t know

4.11

(1)a fast growing, creeping grounfcove that need to be treated with retardants; (2) D. rotundifolia is known to occasionally climb on shrubs [pictures provide documentation]

(1) Criley, R. A. (1976) Growth retardants for control of ground covers. Departmental Paper, Hawaii Agricultural Experiment Station, 1976, No.46, 8 pp., 2 ref.
(3) http://www.hear.org/pier/dirot.htm

4.12

No evidence

5.01

5.02

Melastomaceae

5.03

Melastomaceae

5.04

A creeping herb from Africa.

Neal, M.C. 1965. In Gardens of Hawaii. Bishop Museum Press. Honolulu.

6.01

Did not find information on reproduction or dispersal.

6.02

D. rotundofolia propagates by seeds and fragments

http://www.hear.org/pier/dirot.htm

6.03

no evidence

6.04

6.05

Grown in butterfly gardens [has a simple, open flower structure typical of Melastomaceae, probably poricidal dehiscence, suggesting bees]

http://www.butterflies.org/hortcltr2.cfm

6.06

(1)propagates by means (root?) of suckers (2)a fast growing, creeping groundcover

(1)http://www.unu.edu/unupress/unupbooks/80364e/80364E0g.htm (2)Criley, R. A. (1976) Growth retardants for control of ground covers. Departmental Paper, Hawaii Agricultural Experiment Station, 1976, No.46, 8 pp., 2 ref.

6.07

Don’t know.

7.01

Possibly through discarded yard waste [spread by vegetative fragments]

7.02

used as a groundcover

Criley, R. A. (1976) Growth retardants for control of ground covers. Departmental Paper, Hawaii Agricultural Experiment Station, 1976, No.46, 8 pp., 2 ref.

7.03

no products

7.04

Fruit a capsule, seeds ca. 1 mm long

Wagner, W.L., D.R. Herbst and S.H. Sohmer. 1999. Manual of the flowering plants of Hawai‘i. Revised edition. University of Hawai‘i Press, Honolulu. p. 907.

7.05

Grows in moist environments providing potential [don't know]

7.06

Fruit a capsule, seeds ca. 1 mm long

Wagner, W.L., D.R. Herbst and S.H. Sohmer. 1999. Manual of the flowering plants of Hawai‘i. Revised edition. University of Hawai‘i Press, Honolulu. p. 907.

7.07

no means of external attachment

Wagner, W.L., D.R. Herbst and S.H. Sohmer. 1999. Manual of the flowering plants of Hawai‘i. Revised edition. University of Hawai‘i Press, Honolulu. p. 907.

7.08

no evidence

8.01

(1)Fruit a capsule, seeds ca. 1 mm long (2)Fruit infrequently formed in cultivation

(1)Wagner, W.L., D.R. Herbst and S.H. Sohmer. 1999. Manual of the flowering plants of Hawai‘i. Revised edition. University of Hawai‘i Press, Honolulu. p. 907. (2)Whistler, W.A. 2000. Tropical Ornamentals. Timber Press

8.02

Congener germination protocol (Dissotis irvingiana) = surface sowing 70-75oF, germination in 10-20 days [probably no dormancy]

http://tomclothier.hort.net/page05.html

8.03

Dissotis rotundifolia is a weed and subjected to chemical control in Africa

Melifonwu, A. A.; Orkwor, G. C. (1990) Chemical weed control in ginger (Zingiber officinale ) production from minisetts. Nigerian Journal of Weed Science, 1990, Vol.3, pp.43-50, 11 ref.

8.04

can spread by fragments

http://www.hear.org/pier/dirot.htm

8.05

Don’t know.