Hemp agrimony (Eupatorium cannabinum)

Present distribution

Scientific name:	Eupatorium cannabinum L.
Common name(s):	Hemp agrimony

This weed is not known to be naturalised in Victoria

Habitat:

A large perennial herb it has been reported in marshes, fens and other wetland habitats, riparian habitats, moist woods, coastal dunes, meadows, pastures and permanently cultivated land such as fruit trees (Clapham et al 1952; Cosyns et al 2001; Hanf 1983; Heenan et al 1999). It has been shown to be capable of continuing to grow while only receiving 7% full daylight and therefore could invade forest habitats (Lenssen et al 2003). It has been reported occurring at 870m in Germany and therefore could survive in our alpine habitats (Stammel, Kichl & Pfadenhauer, 2003).

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:
Forest private plantation; forest public plantation
Broad vegetation types
Coastal scrubs and grassland; coastal grassy woodland; lowland forest; swamp scrub; sedge rich woodland; moist foothills forest; montane moist forest; sub-alpine woodland; grassland; plains grassy woodland; valley grassy forest; herb-rich woodland; sub-alpine grassy woodland; montane grassy woodland; riverine grassy woodland; riparian forest; Aquatic areas including; Riparian Strip, 10m Rivers, 5m Creeks; Shallow wetlands

Colours indicate possibility of Eupatorium cannabinum 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 hemp agrimony

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

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	A 1.8m tall herb, which can form dense monocultures in wetlands and riparian habitats (Heenan et al 1999; ISSG 2005). Therefore likely to have high nuisance value around water ways.	mh	m
2. Reduce tourism?	Clarkson et al (2003) report an infestation of 1900 stems per hectare as having a “large visual impact” in the Ihupuku swamp.	ml	mh
3. Injurious to people?	Used in traditional folk medicine and chemical components are being investigated for medicinal properties (Grieve 1994; Sharma et al 1998). High doses can induce vomiting and may cause liver disease (PFAF 2007).	mh	m
4. Damage to cultural sites?	Clarkson et al (2003) report an infestation of 1900 stems per hectare as having a “large visual impact” in the Ihupuku swamp.	ml	mh
Abiotic
5. Impact flow?	Prefers to occur above the water line and mainly described in swamps and wetlands not associated with significant water flow (Lenssen et al 1999). It may cause some impact in riparian systems during high flow events.	l	h
6. Impact water quality?	Unknown	m	l
7. Increase soil erosion?	Reported to occur on stream banks (Heenan et al 1999). May therefore provide some buffer against erosion.	ml	m
8. Reduce biomass?	Reported to replace vegetation with a dense monoculture (ISSG 2005). Therefore likely to cause direct replacement to possibly an increase in biomass.	ml	m
9. Change fire regime?	Unknown.	m	l
Community Habitat
10. Impact on composition (a) high value EVC	EVC= Plains Grassy Wetland (E); CMA= North Central; Bioreg= Goldfields; VH CLIMATE potential. Reported to replace vegetation with a dense monoculture (ISSG 2005).	h	m
(b) medium value EVC	EVC= Wet Sands Thicket (R); CMA= Corangamite; Bioreg= Otway Ranges; VH CLIMATE potential. Reported to replace vegetation with a dense monoculture (ISSG 2005).	h	m
(c) low value EVC	EVC= Riverine Swamp Forest (LC); CMA= North Central; Bioreg= Murray Fans; H CLIMATE potential. Reported to replace vegetation with a dense monoculture (ISSG 2005).	h	m
11. Impact on structure?	Reported to replace vegetation with a dense monoculture (ISSG 2005).	h	m
12. Effect on threatened flora?	A potential threat to endangered wetland plants of New Zealand (ISSG 2005). There is no evidence reported for impact upon Australian species.	mh	l
Fauna
13. Effect on threatened fauna?	There is no evidence of this reported.	mh	l
14. Effect on non-threatened fauna?	Unknown; there is no specific evidence reported, however significant alteration of the vegetation in terms of species composition and structure is likely to significantly impact on habitat values for fauna species.	m	l
15. Benefits fauna?	Visited by insects (ISSG 2005).	mh	m
16. Injurious to fauna?	Contains potentially harmful alkaloids (PFAF 2007). Unknown however to if this has any specific impacts on fauna.	m	l
Pest Animal
17. Food source to pests?	Goats may eat it (Grieve 1994).	ml	mh
18. Provides harbor?	Can grow to 1.8 m tall and form dense stands (Heenan et al 1999; ISSG 2005). It is possible therefore for the species to provide habitat for pest species, there is no evidence of this occurring however.	m	l
Agriculture
19. Impact yield?	Invasion of pasture would reduce carrying capacity. Unknown to what extent this would impact upon yield.	m	l
20. Impact quality?	Other species of Eupatorium have contaminated milk of grazing animals resulting in milk sickness in humans (Sharma et al 1998). It is not known if this occurring with E. cannabinum.	m	l
21. Affect land value?	There is no evidence of this occurring.	l	m
22. Change land use?	Unknown.	m	l
23. Increase harvest costs?	Unknown.	m	l
24. Disease host/vector?	No evidence of this reported.	l	m

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	In the Ihupuku swamp Clarkson et al (2003) report the population structure to have a normal distribution, and therefore suggest that the species is not dependent on disturbance for germination but occurs in spring.	mh	mh
2. Establishment requirements?	Under experimental conditions a 36 day old seedling continued growing when available light was reduced to 7% of full daylight (Lenssen, Menting & Van der Putten 2003). Therefore the species is presumed to be able to establish under a moderate canopy.	mh	mh
3. How much disturbance is required?	Has invaded wetlands and riparian habitats in New Zealand (Heenan et al 1999).	mh	h
Growth/Competitive
4. Life form?	Large perennial herb with a rhizomatous root system (Clarkson, Mc Queen & Walbert 2003).	ml	mh
5. Allelopathic properties?	Species of the Eupatorium genus are reported to have allelopathic properties (Sharma et al 1998). Eupatorium cannabinum is not specifically described with such properties.	m	l
6. Tolerates herb pressure?	The chemical compounds the plant possesses are an effective defence mechanism against grazing pressure (Stammel, Kichl & Pfadenhauer 2003). Increased in frequency under a number of cutting regimes (Rowell, Guarino & Harvey 1985). Reported to be an undesirable forage plant for Konik horses and donkeys in Belgian coastal dunes, however as the inflorescences were preferred over the leaves this may have some implication on the plants capability of sexual reproduction (Cosyns et al 2001). Therefore the species is generally not preferred by grazing animals, but may be consumed.	mh	h
7. Normal growth rate?	Species of the Eupatorium genus are reported to have fast growth rate (Sharma et al 1998). Can out compete New Zealand wetland species and form monocultures (ISSG 2005). Therefore E. cannabinum it thought to be at least competitive with species of the same life form.	mh	m
8. Stress tolerance to frost, drought, w/logg, sal. etc?	It is often reported in marshes and wetlands, typically located above the waterline (Lenssen et al 1999). The plant has also been found to be tolerant of iron toxicity that can occur in waterlogged anoxic soils (Hendry & Brocklebank 1985). Lenssen et al (1998) however reported the species to have low survival rate after a eight week flood event where the plants were submerged. Therefore the species has tolerance of waterlogging but only a minimal tolerance to inundation. Tolerant of frosts, hardy to zone 5 (PFAF 2007). Occurs in estuaries (ISSG 2005). Therefore has some tolerance of salinity. Unknown tolerance of drought and fire, however at it occurs in naturally wet areas they are likely not to have significant impact on the species.	mh	mh
Reproduction
9. Reproductive system	Reproduces sexually; flowering and then setting seed (ISSG 2005).	ml	m
10. Number of propagules produced?	Reported to produce thousands of seeds (ISSG 2005). Thousands would indicate more than 2000.	h	m
11. Propagule longevity?	Unknown.	m	l
12. Reproductive period?	Can form monocultures (ISSG 2005).	h	m
13. Time to reproductive maturity?	Based on growth rates Clarkson et al (2003) suggest that the plants probable time to reproductive maturity to be by the second year of growth.	m	m
Dispersal
14. Number of mechanisms?	Seed is dispersed by wind (ISSG 2005). As the species occur in wetland and riparian habitats there may also be some element of water dispersal, but this is not reported.	mh	m
15. How far do they disperse?	Unknown.	m	l

References

Clapham A.R., Tutin T.G. & Warburg E.F., 1952, Flora of the British Isles. Cambridge University Press.

Clarkson B.D., Mc Queen J.C. & Walbert K. 2003, Eupatorium cannabinum Invasion of Ihupuku Swamp, Waverly. CBER Contract Report No. 28. Department of Conservation, Wanganui.

Cosyns E., Degezelle T., Demeulenaere E. & Hoffmann M., 2001, Feeding ecology of Konik horses and donkeys in Belgian coastal dunes and its implications for nature management. Belgian Journal of Zoology. 131: 111-118.

Grieve M., 1994, A modern herbal : the medicinal, culinary, cosmetic and economic properties, cultivation and folk-lore of herbs, grasses, fungi, shrubs, & trees with all their modern scientific uses. Tiger Books International, London.

Hanf M., 1983, The arable weeds of Europe : with their seedlings and seeds. BASF.

Heenan P.B., de Lange P.J., Glenny D.S., Breitwieser I., Brownsey P.J. & Ogle C.C., 1999, Checklist of dicotyledons, gymnosperms, and pteridophytes naturalised or casual in New Zealand: additional records 1997-1998. New Zealand Journal of Botany. 37: 629-642.

Hendry G.A.F. & Brocklebank K.J., 1985, Iron-induced oxygen radical metabolism in waterlogged plants. New Phytologist. 101: 199-206.

Invasive Species Specialists Group (ISSG) 2005, The Global Invasive Species Database; Eupatorium cannabinum (herb), viewed 28 May 2007, http://www.issg.org/database/species/ecology.asp?si=802&fr=1&sts=

Lenssen J.P.M., Menting F.B.J. & Van der Putten W.H., 2003, Plant responses to simultaneous stress of waterlogging and shade: amplified or hierarchical effects? New Phytologist. 157: 281-290.

Lenssen J.P.M., ten Dolle G. E. & Blom C.W.P.M., 1998, The effect of flooding on the recruitment of reed march and tall forb plant species. Plant Ecology. 139: 13-23.

PFAF: Plants for a Future. Edible, medicinal and useful plants for a healthier world. viewed 24 May 2007, http://pfaf.org/

Rowell T.A., Guarino L. & Harvey H.J., 1985, The experimental management of vegetation at Wicken Fen, Cambridgeshire. Journal of Applied Ecology. 22: 217-227.

Sharma O.P., Dawra R.K., Kurade N.P. & Sharma P.D., 1998, A Review of the toxicosis and biological properties of the genus Eupatorium. Natural Toxins. 6: 1-14.

Stammel B., Kichl K. & Pfadenhauer J., 2003, Alternative management on fens: Response of vegetation to grazing and mowing. Applied Vegetation Science. 6: 245-254.

Global present distribution data references

Den virtuella floran (DVF) 2007, Naturhistoriska riksmuseet, viewed 9 May 2007, http://linnaeus.nrm.se/flora/

Global Biodiversity Information Facility (GBIF) 2007, Global biodiversity information facility: Prototype data portal, viewed 9 May 2007, http://www.gbif.org/

Missouri Botanical Gardens (MBG) 2007, w³TROPICOS, Missouri Botanical Gardens Database, viewed 9 May 2007, http://mobot.mobot.org/W3T/Search/vast.html

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