Giant Willow herb (Epilobium hirsutum)

Present distribution

Scientific name:	Epilobium hirsutum L.
Common name(s):	Giant Willow herb

Map showing the present distribution of this weed.

Habitat:

Reported to be found exclusively on wet sites in the San valley, Poland by Traba, Wolanski & Oklejewicz. (2004) while the Washington State Department of Ecology reports it being able to invade undisturbed meadows. In addition to that from its present distribution within Victoria it was found in Coastal Grassy woodland and Lowland Forest (ANH).

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:
Horticulture; pasture irrigation.

Broad vegetation types
Coastal scrubs and grassland; coastal grassy woodland; lowland forest; swamp scrub; sedge rich woodland; moist foothills forest; montane moist forest; riverine grassy woodland; riparian forest and a 10m buffer on rivers and 5m buffer on creeks.

Colours indicate possibility of Epilobium hirsutuminfesting 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 giant willow herb

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

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	Can grow densely along the edge of waterways	ml	m
2. Reduce tourism?	The invasion of E.hirsutum has caused a reduction in spp. richness of wetland systems, which could impact on recreational fishing (Wheeler. 1983).	mh	m
3. Injurious to people?	No toxins or prickles reported.	l	mh
4. Damage to cultural sites?	No evidence of this, potentially aesthetic impact on wetland sites.	l	m
Abiotic
5. Impact flow?	Less aggressive when growing in waterlogged and flooded sites (Lenssen, Menting., Van der Putten. & Blom 2000). May restrict flow during flooding events.	ml	mh
6. Impact water quality?	No reports of this, however die back before winter, would leave a large quantity of detritus in the system. Much like willow trees being deciduous.	ml	m
7. Increase soil erosion?	For the growing season, grows densely along edge of waterways and wetlands creating a vegetative buffer against floodwaters. Does however die back during winter leaving only rhizomes.	ml	m
8. Reduce biomass?	Can grow taller than Phragmites australis, which it is competitive with (Lenssen, Menting. & Van der Putten. 2004), replacement, would be an increase in biomass.	l	m
9. Change fire regime?	No reports of this, doesn’t inhabit a fire regulated system.	l	m
Community Habitat
10. Impact on composition (a) high value EVC	EVC= Swamp Scrub (E); CMA= Corangamite; Bioreg= Otway Ranges; H CLIMATE potential. Can form monotypic stands within understorey.	mh	mh
(b) medium value EVC	EVC= Lowland Forest (D); CMA= Corangamite; Bioreg= Otway Ranges; H CLIMATE potential. Can form monotypic stands within understorey.	mh	mh
(c) low value EVC	EVC= Riparian Forest (LC); CMA= Corangamite; Bioreg= Otway Ranges; H CLIMATE potential. Can form monotypic stands within understorey.	mh	mh
11. Impact on structure?	Invasion of an area by E.hirsutum has led to a reduction in spp. richness (Wheeler. 1983). Described as a high marsh species impact on low to medium height layers (Lenssen, Menting. & Van der Putten. 2004).	mh	mh
12. Effect on threatened flora?	Not specified, however its invasion leads to a reduction in species richness (Wheeler. 1983).	mh	m
Fauna
13. Effect on threatened fauna?	Impact not specified.	mh	l
14. Effect on non-threatened fauna?	A high marsh species, its invasion does alter species composition altering the habitat in minor degrees.	ml	m
15. Benefits fauna?	It is a palatable species (Wheeler. 1983).	mh	m
16. Injurious to fauna?	No toxins or prickles reported.	l	m
Pest Animal
17. Food source to pests?	It is a palatable species (Wheeler. 1983).	ml	m
18. Provides harbor?	Not significantly more then a species it might replace like Pragmites (Lenssen, Menting. & Van der Putten. 2004).	ml	m
Agriculture
19. Impact yield?	Species mostly confined closely to wetland habitat, it can spread to undisturbed pasture (WSDE). However it is still edible and would have little affect yield.	l	m
20. Impact quality?	Species confined closely to wetland habitat and is still edible would have little affect.	l	m
21. Affect land value?	Species confined closely to wetland habitat and is still edible would have little affect.	l	m
22. Change land use?	Species confined closely to wetland habitat and is still edible would have little affect.	l	m
23. Increase harvest costs?	Species confined closely to wetland habitat and is still edible would have little affect.	l	m
24. Disease host/vector?	Species confined closely to wetland habitat and is still edible would have little affect.	l	m

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Germinates in spring (Etherington 1983). - Requires natural seasonal disturbances such as seasonal rainfall, spring/summer temperatures for germination.	mh	h
2. Establishment requirements?	Has reduced growth, but has been found to be tolerant of shading (Lenssen et al. 2003). - Can establish under moderate canopy/litter cover	mh	h
3. How much disturbance is required?	Present in wetlands, riparian and riverine systems. - Establishes in relatively intact OR only minor disturbed natural ecosystems (e.g. wetlands, riparian, riverine, grasslands, open woodlands); in vigorously growing crops OR in well-established pastures.	mh	h
Growth/Competitive
4. Life form?	A pseudo-annual semi-aquatic species (Lenssen et al. 2000). - Aquatic (submerged, emergent, floating for ALL of life, inc. germination), and semi aquatic (some plant parts always in water).	h	h
5. Allelopathic properties?	None described. - None.	l	m
6. Tolerates herb pressure?	Invaded an enclosure of fen after grazing by cattle was prevented (Wheeler 1983). - Consumed and recovers slowly. Reproduction strongly inhibited by herbivory but still capable of vegetative propagule production (by rhizomes or tubers); weed may still persist.	ml	mh
7. Normal growth rate?	Growth rate (Production of dry weight) of seedlings is comparable with other wetland species (Lenssen et al. 2003). - Moderately rapid growth that will equal competitive species of the same life form.	mh	mh
8. Stress tolerance to frost, drought, w/logg, sal. etc?	Tolerant of waterlogging and flooding however growth is reduced (Lenssen et al. 2003). Response to waterlogging found to be correlated with soil iron content in base-rich wetlands (Wheeler et al. 1985). Susceptible to Iron Toxicity, concentration >50mg per L can cause death (Wheeler et al. 1985). Restricted to wet sites (Susceptible to drought) (Traba et al. 2004). Shoots die back at the end of growing season leaving only rhizomes to over-winter (Frost resistant) (Lenssen et al. 2000). - Tolerant to at least two and susceptible to at least one.	ml	mh
Reproduction
9. Reproductive system	Sets seed and can reproduce vegetatively through rhizomes (Lenssen et al. 2000; Lenssen et al. 2003). - Both vegetative and sexual reproduction (vegetative reproduction may be via cultivation, but not propagation).	h	h
10. Number of propagules produced?	Many seeds >1000 (USGS) - 1000-2000	mh	m
11. Propagule longevity?	Seeds remain viable in the soil for more than 5 years (USGS). - Greater than 25% of seeds survive 5-10 years in the soil, or lower viability but survives 10-20 years.	ml	m
12. Reproductive period?	Perennial species described as able to form monotypic stands (WSDE) - Mature plant produces viable propagules for 10 years or more, or species forms self-sustaining monocultures	h	m
13. Time to reproductive maturity?	Can reproduce vegetatively within first growing season (Lenssen et al. 2000). - Reaches maturity and produces viable propagules, or vegetative propagules become separate individuals, in under a year.	h	mh
Dispersal
14. Number of mechanisms?	Seeds have tuft of hairs which enable them to be wind and water dispersed (Boedeltje et al. 2003) - Propagules spread by wind, water, attachment (humans, animals, or vehicles), or accidental human dispersal (ploughing).	mh	h
15. How far do they disperse?	Water can disperse propagules kilometres (Boedeltje et al. 2003). -Very likely that at least one propagule will disperse greater one kilometre.	h	mh

References

Boedeltje. G., Bakker. J.P., Bekker. R.M., Van Groenendael. J.M. & Soesbergen. M. (2003) Plant dispersal in a lowland stream in relation to occurrence and three specific life-history traits of the species in the species pool. Journal of Ecology. 91: 855-866.

Etherington. J.R. (1983) Control of germination and seedling morphology by ethene: differential responses, related to habitat of Epilobium hirsutum L. and Chamerion angustifolium (L.) J. Holub. Annals of Botany. 52: 653-658.

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., Menting. F.B.J. & Van der Putten. W.H. (2004) Do competition and selective herbivory cause replacement of Phragmites australis by tall forbs? Aquatic Botany. 78: 217-232

Lenssen. J.P.M., Menting. F.B.J., Van der Putten. W.H. & Blom. C.W.P.M. (2000) Vegetative reproduction by species with different adaptation to shallow-flooded habitats. New Phytologist. 145: 61-70

Traba. C., Wolanski.P. & Oklejewicz. K. (2004) Plant communities of abandoned meadows and files in the San valley. Grassland Science in Poland. 7: 207-238.

United States Geological Survey, U.S. Department of Interior, Southwest Exotic Plant Information Clearinghouse. viewed 25 Aug 2003, http://www.usgs.nau.swepic/asp/aprs/question.asp?Location=INDU&Symbol=EPHI

Washington State Department of Ecology: Water Quality Home. Non-native Freshwater Plants Hairy Willow-herb. Viewed 13 Oct 2006, http://www.ecy.wa.gov/programs/wq/plants/weeds/willoherb.html

Wheeler.B.D., Al-Farraj. M.M. & Cook. R.E.D. (1985) Iron toxicity to plants in base-rich wetlands: Comparative effects on the distribution and growth of Epilobium hirsutum L. and Juncus subnodulosus Schrank. New Phytologist. 100: 653-669.

Wheeler.B.D. (1983) Vegetation, nutrients and agricultural land use in a north Buckinghamshire valley fen. Journal of Ecology. 71: 529-544.

Global present distribution data references

Australian National Herbarium (ANH) 2006, Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, viewed 11 Sep 2006 , http://www.anbg.gov.au/avh/

Boedeltje. G., Bakker. J.P., Bekker. R.M., Van Groenendael. J.M. & Soesbergen. M. (2003) Plant dispersal in a lowland stream in relation to occurrence and three specific life-history traits of the species in the species pool. Journal of Ecology. 91: 855-866.

Den virtuella floran 2006, Naturhistoriska riksmuseet, viewed 11 Sep 2006, http://linnaeus.nrm.se/flora/

Global Biodiversity Information Facility (GBIF) 2006, Global biodiversity information facility: Prototype data portal, viewed 11 Sep 2006, http://www.gbif.org/

Integrated Pest Management System (IPMS) 2006, Department of Primary Industries, viewed Apr 2006.

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., Menting. F.B.J. & Van der Putten. W.H. (2004) Do competition and selective herbivory cause replacement of Phragmites australis by tall forbs? Aquatic Botany. 78: 217-232

Lenssen. J.P.M., Menting. F.B.J., Van der Putten. W.H. & Blom. C.W.P.M. (1999) Affects of sediment type and water level on biomass production of wetland plant species. Aquatic Botany. 64: 151-165.

Lenssen. J.P.M., Menting. F.B.J., Van der Putten. W.H. & Blom. C.W.P.M. (2000) Vegetative reproduction by species with different adaptation to shallow-flooded habitats. New Phytologist. 145: 61-70

Missouri Botanical Gardens (MBG) 2006, w3TROPICOS, Missouri Botanical Gardens Database, viewed 10 Sep 2006, http://mobot.mobot.org/W3T/Search/vast.html

The Victorian Flora Information System on CD (2005) Viridian's Biological Databases.

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