Pacific Island Ecosystems at Risk (PIER)


Senecio madagascariensis


RISK ASSESSMENT RESULTS: High risk, score: 23


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

Senecio madagascariensis Poir.; fireweed, Madagascar ragwort

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

y

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

y

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

n

4.05

Toxic to animals

y=1, n=0

y

4.06

Host for recognized pests and pathogens

y=1, n=0

n

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

4.1

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

y=1, n=0

y

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

n

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

y

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

1

7.01

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

y=1, n=-1

y

7.02

Propagules dispersed intentionally by people

y=1, n=-1

n

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

y

7.04

Propagules adapted to wind dispersal

y=1, n=-1

y

7.05

Propagules water dispersed

y=1, n=-1

n

7.06

Propagules bird dispersed

y=1, n=-1

n

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

y

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

y

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

n

Total score:

23

Supporting data:

Notes

Source

1.01

no evidence

1.02

"Fireweed is native to Madagascar and southern Africa and was first recorded in Australia in the Hunter Valley in 1918. It is not known how it was introduced but it could have been brought in privately as a garden plant. It spread slowly at first but in the last 30 years it has rapidly increased its range, most likely aided by modern transport and rural practices." [suggested, by no direct evidence of being grown]

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

1.03

Senecio inaequidens DC. (Asteraceae) is a perennial plant originally growing in South Africa which has unintentionally been introduced independently into several sites in Europe from 1889 onwards. Senecio inaequidens, Senecio madagascariensis Poir. and Senecio harveianus Mac Owan are three Senecio species growing in South Africa frequently confused by the botanists. Molecular studies have shown that South African S. madagascariensis was more closely related to South African S. inaequidens than to Madagascan S. madagascariensis. However chromosome counts revealed that individuals of S. inaequidens are tetraploids in Europe whereas Australian individuals of S. madagascariensis, which have a South African origin, are diploids. In order to precise the taxonomic identity of S. inaequidens and the history of colonisation in Europe, we compare some South African populations of S. inaequidens, S. madagascariensis and S. harveianus in controlled conditions and study ploidy level of different South African populations

Lucile Lafuma, Ludovic Vimond & Sandrine Maurice. Identity and origin of the polyploïd invasive weed Senecio inaequidens (Asteraceae) in Europe. http://www.ufz.de/index.php?en=1135

2.01

Fireweed is native to Madagascar and southern Africa

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

2.02

2.03

(1) "Fireweed seems equally at home in low-elevation, arid pastures as in high-elevation, moist pastures." [in Hawaii]
(2) AB: The visible frost injury and mortality rate of greenhouse-grown seedlings of 2-10 week old S. madagascariensis which were subjected to -3 to -5 deg C in a forced draft freezing cabinet and to -7.5 deg in the field at Tamworth, New South Wales, indicated that young seedlings were more sensitive to frost than older plants, and that sensitivity increased at lower temp. Flowering, shoot wt and root wt were all significantly reduced (p<0.05) as a result of frosting. Frosting also made plants more prone to disease infection, so that even when regeneration of shoots occurred, plants often died. These results support the hypothesis that low temp. (specifically, frost) is an important factor in limiting the distribution of S. madagascariensis in Australia.
(3) "In southern Africa fireweed is believed to occur up to 4,921 ft (1500 m)"; "Fireweed occurs at high altitudes 2,600 m (8,530 ft) to 2,

(1) http://www2.ctahr.hawaii.edu/oc/freepubs/pdf/WC-2.pdf

(2) Sindel, B. M. Michael, P. W. (1989) Frost as a limiting factor in the distribution of Senecio madagascariensis Poir. (fireweed) in Australia. Proceedings, 12th Asian-Pacific Weed Science Society Conference., 1989, No. 2, pp. 453-459, 11 ref.

(3) http://www.hear.org/species/reports/senmad_fskm_awwa_report.pdf

2.04

Fireweed is native to Madagascar and southern Africa

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

2.05

(1) "Senecio inaequidens DC. (Asteraceae) is a perennial plant originally growing in South Africa which has unintentionally been introduced independently into several sites in Europe from 1889 onwards.
(2) "The plant was introduced into Australia go the Hunter Valley region around 1918 (most probably through shipping) from its native range in southern Africa and Madagascar.
(3) "a native of Madagascar and South Africa, has become a serious weed of pastures on the islands of Hawaii and Maui."

(1) Lucile Lafuma, Ludovic Vimond & Sandrine Maurice. Identity and origin of the polyploïd invasive weed Senecio inaequidens (Asteraceae) in Europe. http://www.ufz.de/index.php?en=1135
(2) http://nb.au.com/nswweedsoc/NoxiousWeeds/Fireweed.html
(3) http://www2.ctahr.hawaii.edu/oc/freepubs/pdf/WC-2.pdf

3.01

"Fireweed is native to Madagascar and southern Africa and was first recorded in Australia in the Hunter Valley in 1918. It spread slowly at first but in the last 30 years it has rapidly increased its range, most likely aided by modern transport and rural practices."

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

3.02

no evidence

3.03

(1)"Fireweed is an introduced weed that competes strongly with pasture species and is toxic to livestock. It is responsible for illness, slow growth and poor conditioning of cattle and can result in death." (2)Fireweed (or variable groundsel), Senecio madagascariensis Poiret), a native of Madagascarand South Africa(1), has become a serious weed of pastures on the islands of Hawaii and Maui.On Maui, fireweed infests roadsides and pastures in the Kokomo- Pukalani area.

(1)http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf (2)http://www2.ctahr.hawaii.edu/oc/freepubs/pdf/WC-2.pdf

3.04

(1)"The spread of weeds threatens the sustainability of agriculture and other land uses. Weeds also devastate native plants and animals." (2) #77 on list of 200 environmental weeds in South East Queensland of the invasive - The plants in this list have the ability to invade and destroy native vegetation and habitat. (3)Many of the highly burnt areas have now completely lost the native herbacious plants, their replacement being the exotic Senecio madagascariensis (Fire Weed)

(1)http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf (2)http://www.nrme.qld.gov.au/pests/environmental_weeds/pdf/list.pdf (3)http://www.nccnsw.org.au/bushfire/home/hbc9.html

3.05

(1) S. vulgaris, (2) S. squalidus, (3) S. brasiliensis

(1) Suzuki, M. (2003) Dormancy and germination characteristics of buried main upland weeds in Akita Prefecture. Journal of Weed Science and Technology, 2003, Vol. 48, No. 3, pp. 130-139, 23 ref.
(2) Brennan, A. C. Harris, S. A. Tabah, D. A. Hiscock, S. J. (2002) The population genetics of sporophytic self-incompatibility in Senecio squalidus L. (Asteraceae) I: S allele diversity in a natural population. Heredity, 2002, Vol. 89, No. 6, pp. 430-438, 35 ref.
(3) Oliveira, É. D. M. de Pasini, A. Fonseca, I. C. B. (2003) Association of the soil bug Atarsocoris sp. (Hemiptera: Cydnidae) with the weed Senecio brasiliensis Less. Neotropical Entomology, 2003, Vol. 32, No. 1, pp. 155-157, 13 ref.

4.01

no description of these traits

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

4.02

no evidence

4.03

no evidence

4.04

"Fireweed is generally unpalatable to cattle, so poisoning is most likely to occur when fireweed plants are dense and stock can not feed selectively, or when there is a shortage of pasture and hungry stock are less selective about food. Sheep and goats are less susceptible to fireweed poisoning and can graze in fireweed infested paddocks for at least one season. Toxins found in fireweed are able to taint the milk of goats that graze this plant. Goats for milk production should not be allowed to graze in fireweed infested paddocks." [platable to sheep and goats]

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

4.05

"Fireweed is an introduced weed that competes strongly with pasture species and is toxic to livestock. It is responsible for illness, slow growth and poor conditioning of cattle and can result in death."

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

4.06

no evidence

4.07

no evidence

4.08

no evidence

4.09

"Fireweed does not do well in pastures with weeds taller than 3 ft (1 m). It has been found in both shade and full sun." [conflicting statement?]

http://www.hear.org/species/reports/senmad_fskm_awwa_report.pdf

4.1

"Fireweed grows in a wide range of soils from high fertility, self-mulching clay soils to low fertility, acid sandy soils."

http://www.hear.org/species/reports/senmad_fskm_awwa_report.pdf

4.11

"Fireweed is a low, upright, branched, herbaceous, mid-green plant with golden yellow flowers. Fireweed has a variable growth habit and leaf structure, growing from 10-50 cm tall "

http://www.hear.org/species/reports/senmad_fskm_awwa_report.pdf

4.12

low herbaceous plant

5.01

"Fireweed is an invasive plant that rapidly colonizes heavily grazed or neglected pastures, and cultivated, or disturbed, land"

http://www.hear.org/species/reports/senmad_fskm_awwa_report.pdf

5.02

herb, Asteraceae

5.03

no evidence

5.04

"plant has a shallow, branched, tap root"

http://www.hear.org/species/reports/senmad_fskm_awwa_report.pdf

6.01

no evidence

6.02

"Seeds germinate in mild, warm conditions (150C - 270C) in the presence of light and moisture. Most seedlings appear between March and June then grow quickly to produce their first flowers in 6-10 weeks."

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

6.03

indcates hybridization

Sindel, B. M. , Radford, I. J. , Holtkamp, R. H. , Michael, P. W. 1998. The biology of Australian weeds. 33. Senecio madagascariensis Poir.. Plant Protection Quarterly, , Vol. 13, No. 1, pp. 2-15

6.04

no evidence

6.05

"Fireweed is utilised by bees as a pollen source in the winter and spring on the NSW North Coast. "

http://www.honeybee.com.au/Library/pollen/madagascariensis.html

6.06

"Spreads locally by rooting from nodes."

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

6.07

"Seeds germinate in mild, warm conditions (150C - 270C) in the presence of light and moisture. Most seedlings appear between March and June then grow quickly to produce their first flowers in 6-10 weeks."

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

7.01

"Seeds are light and have a pappus that enables them to be carried by the wind. The seeds also have rows of short hairs that can loosely cling to animals. Fireweed can be spread short distances by wind and stock. However, it is spread greater distances in pasture seed, hay, turf, mulch and with stock transport. Fireweed seed can also be spread as a contaminant in transported materials such as hydromulch and grass seed."

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

7.02

"Value to humans: No references of fireweed being used by humans has been found. However, it is possible that the plant could be grown for ornament with its pretty, yellow, daisy like flowers."

http://www.hear.org/species/reports/senmad_fskm_awwa_report.pdf

7.03

"Seeds are light and have a pappus that enables them to be carried by the wind. The seeds also have rows of short hairs that can loosely cling to animals. Fireweed can be spread short distances by wind and stock. However, it is spread greater distances in pasture seed, hay, turf, mulch and with stock transport. Fireweed seed can also be spread as a contaminant in transported materials such as hydromulch and grass seed."

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

7.04

"Seeds are light and have a pappus that enables them to be carried by the wind. The seeds also have rows of short hairs that can loosely cling to animals. Fireweed can be spread short distances by wind and stock. However, it is spread greater distances in pasture seed, hay, turf, mulch and with stock transport. Fireweed seed can also be spread as a contaminant in transported materials such as hydromulch and grass seed."

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

7.05

no evidence

7.06

no evidence

7.07

The seeds also have rows of short hairs that can loosely cling to animals.

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

7.08

[incidental seed consumption by grazers is likely, but no data on seed survival]

8.01

"In ideal conditions fireweed will grow to 50 cm tall with multiple branches, long wide leaves (6 cm x 2 cm) and about 100 flowers.The flowers are bright yellow, daisy-like with a diameter of approximately 2 cm and produce up to 100 seeds each. Seeds are small, cylindrical in shape, and 2-3 mm long. Each seed has rows of very fine short hairs and a silky pappus (parachute). Flowers and seeds are produced continuously over the growing season. An average plant can produce over 10,000 seeds during this time."

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

8.02

(1) "The seed is long-lived, making fireweed a permanent problem in infested pastures" [sugestion of seed bank]
(2) AB: "Germination studies were conducted in a controlled environment. Non-dormant seeds of S. madagascariensis did not require light for germination. Innate and induced dormancy (both by low or high temp.) were found which were broken by alternating temp., 20 mM KNO3 and light. " [dormancy exist]
(3) "Most seeds germinate over the year, but greatest germination occurs from March to June. Plants can produce flowers 6-10 weeks after emergence. Seeds can germinate as soon as they leave the parent plant. Seeds are thought to remain viable for up to several years"

(1) http://www2.ctahr.hawaii.edu/oc/freepubs/pdf/WC-2.pdf
(2) Alonso, S. I. Fernadez, O. N. Langero, S. I. Verona, C. A. (1982) Characteristics of seed germination of Senecio madagascariensis Poiret (Compositae). Ecología, 1982, No. 7, pp. 95-116, 50 ref.
(3) http://www.hear.org/species/reports/senmad_fskm_awwa_report.pdf

8.03

"Herbicides are most effective if sprayed before plants reach maturity. However, application during flowering will be effective if higher recommended rates of herbicide are applied."

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

8.04

"Slashing is usually not effective as it may lead to increased stock poisoning. Slashing tends to give a good visual effect because it removes the flowers but at best it delays flowering and seeding and at worst it damages the pasture, making conditions more favourable for fireweed." [tolerate slashing]
"Heavy infestations of fireweed often result from two principal causes:
• neglect of steadily increasing fireweed infestations in previous years,
• lack of good ground cover caused by overgrazing, drought, fire or slashing." [benefit from fire]

http://www.nrme.qld.gov.au/factsheets/pdf/pest/PP31.pdf

8.05

Biological control. Australian scientists have collected several insects that feed on fireweed. However, because fireweed is closely related to Senecio lautus Forster f. ex Willd., a native Australian plant that is not a weed, the scientists are pessimistic about chances that release of these insects for fireweed control in Australia will be approved (Dr. G. White, personal communication). Researchers in Hawaii may get the opportunity to conduct field tests of one or more of these biocontrol agents. [no known effective enemies released in Hawaii]

http://www2.ctahr.hawaii.edu/oc/freepubs/pdf/WC-2.pdf


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