Ludwigia (Ludwigia longifolia)

Present distribution

Scientific name:	Ludwigia longifolia (DC.) H.Hara
Common name(s):	ludwigia

This weed is not known to be naturalised in Victoria

Habitat:

“Marginal aquatic perennial” Frost tender. May be damaged by temperatures below 5ºC. (Brickell 1999). “Ecosystems most at risk include wetlands and riparian communities” (Regional Weeds Advisory Committee 2003). “Naturalised in swamps and marshes” (Australian Weeds Committee Date unknown). “Edges of creeks, ponds and dams” (Hornsby Shire Council 2008). May invade tropical and sub-tropical wetlands and riparian vegetation (Csurhes & Edwards 1998). “Potential to infiltrate irrigation and drainage channels” (McCall 2004). “Non-native Ludwigia spp. pose a serious threat to…wetland based farming throughout Eastern Australia” (Pritchard 2004). “Ludwigia species grow in sun to part shade in moist soil or water to varying depths” (Speichert G. & S. 2004).

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:
Water

Ecological Vegetation Divisions
Swampy scrub; freshwater wetland (permanent); treed swampy wetland; riparian; riverine woodland/forest; freshwater wetland (ephemeral); saline wetland; chenopod shrubland; chenopod mallee; hummock-grass mallee; lowan mallee; broombush whipstick

Colours indicate possibility of Ludwigia longifolia infesting these areas.

In the non-coloured areas the plant is unlikely to establish as the climate, soil or landuse is not presently suitable.

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

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	“Nearly 4m in height” (McCall 2004). “Marginal aquatic” (Brickell 1999). “Shrubby multi-stemmed plant” (Hornsby Shire Council 2008). “Rapid and dense growth habit of plants” (Pritchard 2004). Limiting “usefulness for recreational and navigational purposes” (Regional Weeds Advisory Committee 2003). Major impediment to access of waterways. Significant works to provide reasonable access.	H	M
2. Reduce tourism?	“Limiting their usefulness for recreational and navigational purposes” (Regional Weeds Advisory Committee 2003). May cause a major impact on recreation. Weeds obvious to most visitors, with visitor response complaints and a major reduction in visitors.	H	M
3. Injurious to people?	Not found to be injurious.	L	ML
4. Damage to cultural sites?	No information found	M	L
Abiotic
5. Impact flow?	“Clogging wetlands, slow moving watercourses and waterways... Reducing the rate of flow in streams” (Regional Weeds Advisory Committee 2003). Serious impacts to both surface and subsurface water flow (e.g. attached emergent aquatics).	H	M
6. Impact water quality?	“Often form pneumatophores [that] help the plant absorb oxygen from the water” (Speichert G. & S. 2004). “Reducing the rate of flow in streams causes wide ecological damage through increased sedimentation ad accumulation of additional organic material resulting in the deoxygenation of the water column… Can intercept almost all incident light, dominate all other water plants and in some cases lead to the loss of native plants and animals” (Regional Weeds Advisory Committee 2003). High effects in either dissolved O2 and light; causing eutrophication.	H	M
7. Increase soil erosion?	“Ludwigia acts as a bank/ stream bed stabiliser” (Regional Weeds Advisory Committee 2003). Decreases the probability of soil erosion.	L	L
8. Reduce biomass?	Non-native Ludwigia spp have a “dense growth habit of plants” (Pritchard 2004). Can “dominate all other water plants and in some cases lead to the loss of native plants” (Regional Weeds Advisory Committee 2003). “Nearly 4m in height” (McCall 2004). Biomass may increase.	L	ML
9. Change fire regime?	Non-native Ludwigia spp have a “dense growth habit of plants” (Pritchard 2004). Can “dominate all other water plants and in some cases lead to the loss of native plants” (Regional Weeds Advisory Committee 2003). “Nearly 4m in height” (McCall 2004). May cause a minor change to either frequency or intensity of fire risk.	ML	ML
Community Habitat
10. Impact on composition (a) high value EVC	EVC = Montane Riparian Woodland (V); CMA =East Gippsland; Bioregion = Monaro Tablelands; VH CLIMATE potential. “Can intercept almost all incident light, dominate all other water plants and in some cases lead to the loss of native plants and animals… L. longifolia plants can form dominant colonies that result in reduced biodiversity and habitat, threatening native species” (Regional Weeds Advisory Committee 2003). Major displacement of some dominant spp. within a strata/layer (or some dominant spp. within different layers).	MH	H
(b) medium value EVC	Aquatic weed, all water bodies in Victoria are given a high value EVC.	L	H
(c) low value EVC	Aquatic weed, all water bodies in Victoria are given a high value EVC.	L	H
11. Impact on structure?	“Can intercept almost all incident light, dominate all other water plants and in some cases lead to the loss of native plants and animals… L. longifolia plants can form dominant colonies that result in reduced biodiversity and habitat, threatening native species” (Regional Weeds Advisory Committee 2003). Major displacement of some dominant spp. within a strata/layer (or some dominant spp. with in different layers).	MH	M
12. Effect on threatened flora?	“Can intercept almost all incident light, dominate all other water plants and in some cases lead to the loss of native plants and animals… Control of Ludwigia will also ensure the protection of rare or threatened species, for example the rare plant Grevillea longifolia in the Sutherland LCA” (Regional Weeds Advisory Committee 2003). Unknown affect on Victorian rare or threatened species.	MH	L
Fauna
13. Effect on threatened fauna?	“Can intercept almost all incident light, dominate all other water plants and in some cases lead to the loss of native plants and animals” Control of Ludwigia will also ensure the protection of rare or threatened species such as in the Sutherland LCA, many of the wetlands on the Kurnell Peninsula are potential habitat of the (respectively) endangered and vulnerable amphibian species- Litorea aurea (Green and Golden Bell Frog) and Crinia tinnula (Wallum Froglet) (Regional Weeds Advisory Committee 2003). Unknown affect on Victorian rare or threatened species.	MH	L
14. Effect on non-threatened fauna?	“Can intercept almost all incident light, dominate all other water plants and in some cases lead to the loss of native plants and animals” (Regional Weeds Advisory Committee 2003). Habitat may change dramatically, leading to the possible extinction of non-threatened species.	H	ML
15. Benefits fauna?	No benefits for fauna found.	M	L
16. Injurious to fauna?	Not found to be injurious.	L	ML
Pest Animal
17. Food source to pests?	No information found.	M	L
18. Provides harbour?	No information found.	M	L
Agriculture
19. Impact yield?	No information found.	M	L
20. Impact quality?	Readily adhere to moist surfaces and feathers, birds (especially ducks), machinery, footwear, clothing and mud. Machinery used to clean out drains, four wheel drive vehicles (Regional Weeds Advisory Committee 2003). “Seed capsules develop after flowering and contain thousands of tiny seeds” (Hornsby Shire Council 2008). Potential to cause major contamination of wool. (e.g. 5-20%).	MH	ML
21. Affect land value?	“Non-native Ludwigia spp. pose a serious threat to both the environment and wetland based farming throughout Eastern Australia due to uncontrollable seed dispersal and the rapid and dense growth habit of plants” (Pritchard 2004). “Potential to infiltrate irrigation and drainage channels” (McCall 2004). Readily adhere to moist surfaces and feathers, birds (especially ducks), footwear, clothing and mud. Machinery used to clean out drains, four wheel drive vehicles and boats can easily spread the minute seeds (Regional Weeds Advisory Committee 2003). “Seed capsules develop after flowering and contain thousands of tiny seeds… Edges of creeks, ponds and dams” (Hornsby Shire Council 2008). As this species is a potential threat to wetland based farming and a contaminant of wool, it could potentially affect land value but unknown how significantly.	M	L
22. Change land use?	“Non-native Ludwigia spp. pose a serious threat to both the environment and wetland based farming throughout Eastern Australia due to uncontrollable seed dispersal and the rapid and dense growth habit of plants” (Pritchard 2004). “Potential to infiltrate irrigation and drainage channels” (McCall 2004). Readily adhere to moist surfaces and feathers, birds (especially ducks), footwear, clothing and mud. Machinery used to clean out drains, four wheel drive vehicles and boats can easily spread the minute seeds (Regional Weeds Advisory Committee 2003). “Seed capsules develop after flowering and contain thousands of tiny seeds… Edges of creeks, ponds and dams” (Hornsby Shire Council 2008). Could be enough of a nuisance to warrant a change in land use due to the high production of seeds and rapid, dense growth and the need to control it. This may mean a detrimental change and significant loss for agricultural usage.	H	ML
23. Increase harvest costs?	“Non-native Ludwigia spp. pose a serious threat to both the environment and wetland based farming throughout Eastern Australia due to uncontrollable seed dispersal and the rapid and dense growth habit of plants” (Pritchard 2004). “Potential to infiltrate irrigation and drainage channels, swamps and wetlands” (McCall 2004). Readily adhere to moist surfaces, machinery, footwear, clothing and mud. Machinery used to clean out drains, four wheel drive vehicles and boats can easily spread the minute seeds” A combination of control methods is proposed for controlling Ludwigia including cut and paint, scrape and paint, manual slashing and repeated spraying of regrowth (Regional Weeds Advisory Committee 2003). “Seed capsules develop after flowering and contain thousands of tiny seeds… Edges of creeks, ponds and dams” (Hornsby Shire Council 2008). As this species produces copious amounts of seed that can grow rapidly into dense stands and is easily transported, it is likely to need significant control works. This may mean a major increase in time or labour, or machinery in harvesting.	H	ML
24. Disease host/vector?	No information found.	M	L

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	“Vigorously opportunistic plant…Ludwigia seedlings require high light levels for germination” (Regional Weeds Advisory Committee 2003). Opportunistic germinator, can germinate or strike/ set root at any time whenever water is available.	H	M
2. Establishment requirements?	“Ludwigia species grow in sun to part shade in moist soil or water to varying depths” (Speichert G. & S. 2004). “There is some evidence of ecological control by shading under dense planting” (Regional Weeds Advisory Committee 2003). Can establish under moderate canopy.	MH	M
3. How much disturbance is required?	“Ludwigia has the ability to invade both disturbed and near pristine wetlands” (Port Stephens Council 2005). Can establish in healthy and undisturbed natural ecosystems.	H	M
Growth/Competitive
4. Life form?	“Marginal aquatic” (Brickell 1999). “Ludwigia species grow in sun to part shade in moist soil or water to varying depths” (Speichert G. & S. 2004). Aquatic and semi aquatic.	H	M
5. Allelopathic properties?	No mention of allelopathic properties. (Harden 2002; Speichert G. & S. 2004; Regional Weeds Advisory Committee 2003; Brickell 1999).	L	L
6. Tolerates herb pressure?	No information could be found.	M	L
7. Normal growth rate?	“Vigorously opportunistic plant [that can] dominate all other water plants” (Regional Weeds Advisory Committee 2003). Rapid growth rate that can exceed most other species of the same life form.	H	M
8. Stress tolerance to frost, drought, w/logg, sal. etc?	“Ludwigia species grow in sun to part shade in moist soil or water to varying depths” (Speichert G. & S. 2004). “Ecosystems most at risk include wetlands and riparian communities” Burning dense stands is a mentioned as part of a control method (Regional Weeds Advisory Committee 2003). “Naturalized in swamps and marshes” (Australian Weeds Committee, Date unknown). “Edges of creeks, ponds and dams” (Hornsby Shire Council 2008). “Potential to infiltrate irrigation and drainage channels” (McCall 2004). Frost tender. May be damaged by temperatures below 5ºC. (Brickell 1999). May invade tropical and sub-tropical wetlands and riparian vegetation (Csurhes & Edwards 1998). Highly resistant of waterlogging. Susceptible to frost and drought. Probably susceptible to fire and salinity.	L	ML
Reproduction
9. Reproductive system	Spreading and rooting at the nodes. Fruit containing seeds (Harden 2002). “Ludwigias propagate easily from stem cuttings and may also be grown from seed” (Speichert G. & S. 2004). Both vegetative and sexual reproduction.	H	M
10. Number of propagules produced?	“Seed capsules develop after flowering and contain thousands of tiny seeds” (Hornsby Shire Council 2008). Likely to produce greater than 2,000 seeds.	H	M
11. Propagule longevity?	“The seeds are extremely viable” (Hornsby Shire Council 2008). Exact time of viability unknown.	M	L
12. Reproductive period?	“Marginal aquatic perennial” (Brickell 1999). “Glabrous annual to 3m high” (Harden 2002). “Annual herb” (Australian Weeds Committee Date unknown). Information is conflicting.	M	L
13. Time to reproductive maturity?	“Research has found it can produce 25 million seeds per square metre under two year old plants” (Port Stephens Council 2008). Produces propagules between 1-2 years after germination.	MH	M
Dispersal
14. Number of mechanisms?	“Readily adhere to moist surfaces and feathers, and are dispersed by water, wind, birds (especially ducks), machinery, footwear, clothing and mud. Machinery used to clean out drains, four wheel drive vehicles and boats can easily spread the minute seeds… Stem pieces can take root after dispersal by flood” (Regional Weeds Advisory Committee 2003). Seeds bird dispersed.	H	M
15. How far do they disperse?	“Readily adhere to moist surfaces and feathers, and are dispersed by water, wind, birds (especially ducks), machinery, footwear, clothing and mud. Machinery used to clean out drains, four wheel drive vehicles and boats can easily spread the minute seeds … Stem pieces can take root after dispersal by flood” (Regional Weeds Advisory Committee 2003). Very likely that at least one propagule will disperse greater than one kilometre.	H	M

References

Australian Weeds Committee (Date unknown) Longleaf Ludwigia. Available at: http://www.weeds.org.au/cgi-bin/weedident.cgi?tpl=plant.tpl&state=&s=&ibra=all&card=W19 (verified on 01/04/09).

Brickell C. (Ed.) (1996) A-Z Encyclopedia of Garden Plants. The Royal Horticultural Society. Covent Garden Books, London.

Csurhes S and Edwards R. (1998) Potential Environmental Weeds in Australia, Candidate Species for Preventative Control. Biodiversity Group, Environment Australia, Canberra, ACT.

Ensbey R. & Johnson A. (2007) Noxious and Environmental Weed control Handbook: A guide to Weed Control in Non-crop, Aquatic and Bushland Situations. NSW Department of Primary Industries. Available at: http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0017/123317/noxious-and-environmental-weed-control-handbook-3rd-edn.pdf (verified 21 April 2009).

Harden GJ. (2002) Flora of New South Wales. (Revised edition): Volume 2. Royal Botanic Gardens Sydney, UNSW Press.

Hornsby Shire Council (2008) Ludwigia longifolia (Long-leaf Willow Primrose) & Ludwigia peruviana (Ludwigia, Water Primrose). Available at:
http://www.hornsby.nsw.gov.au/uploads/documents/Ludwigia_Water_Primrose2008.pdf (verified on 01/04/09).

McCall in Sindel B.M & Johson S.B (2004) 14th Australian Weeds Conference : Papers and Proceedings. Society of NSW, Wagga Wagga.

NSW Department of Primary Industries (2005) Noxious weed declarations: Long-leaf willow primrose. Available at: http://www.dpi.nsw.gov.au/agriculture/pestsweeds/weeds/noxweed/noxiousapp?sq_content_src=%252BdXJsPWh0dHAlM0ElMkYlMkZ3d3cuYWdyaWMubnN3Lmdvdi5hdSUyRnRvb2xzJTJGdmlld3dlZWQuaHRtbCZhbGw9MQ%253D%253D&weed_id=80 (verified 21 April 2009).

Port Stephens Council (2005) Mambo Wetlands Plan of Management: Section B- Management Plan. Available at: http://portstephens.locale.nsw.gov.au/files/43858/File/PoMMambo.pdf (verified on 01/04/09).

Pritchard G. in Hunter Flora (2004) Invasive Weed Discovered in Port Stephens; Hunter Catchment Management Trust. Iss. 12. (verified on 01/04/09).

Regional Weeds Advisory Committee (2003) Regional Weed Management Plan. Available at: http://www.sydneyweeds.org.au/docs/Sydney-Ludwigia-Plan-03-08.pdf (verified on 01/04/09).

Speichert G. & S.(2004) Encyclopedia of Water Garden Plants. Timber press, Portland.

Global present distribution data references

Australian National Herbarium (ANH) (2008) Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, Available at
http://www.anbg.gov.au/avh/ (verified 20 April 2009).

Global Biodiversity Information Facility (GBIF) (2008) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 17 April 2009).

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