Butterfly bush (Buddleja davidii)

Present distribution

Scientific name:	Buddleja davidii Franch.
Common name(s):	Butterfly bush

Map showing the present distribution of this weed.

Habitat:

A primary coloniser buddleja is described in its native range of China to from thickets mountain slopes (ed. Wu et al 1994). There is some variation in what habitats the species invades. The species has been shown to have a preference for areas of regular disturbance, light to no shade and rocky or gravel soils, with the greatest densities of the species in areas that share all three (Ream 2006). In New Zealand the largest infestations are associated with riparian areas including rocky beaches, sand bars and flood plains and areas of new pine plantations (Richardson et al 1999; Smale 1990). Other habitats that may be invaded to a lesser extent include; grassland, damp sclerophyll forest, coastal forest, forest edges, roadsides, abandoned quarries and disturbed areas (Blood 2001; Carr, Yugovic and Robinson 1992; Sullivan et al 2005; Weber 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; horticulture

Broad vegetation types
Coastal scrubs and grassland; coastal grassy woodland; box ironbark forest; inland slopes woodland; sedge rich woodland; dry foothills forest; moist foothills forest; montane dry woodland; 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; rainshadow woodland; mallee woodland; wimmera / mallee woodland

Colours indicate possibility of Buddleja davidii 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 distriburion of butterfly bush

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

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	Very invasive shrub species in riparian areas especially those exposed to frequent flooding and alluviation (Smale 1990). Able to grow 2m a year, it is reported to from dense thickets (Blood 2001). Therefore to maintain access in areas invaded by buddleja effectively control measures would have to be taken to prevent re invasion, which would require significant works.	h	mh
2. Reduce tourism?	Ornamental species (Stuart 2006). Invasion by this species could therefore alter aesthetics of an area. Invades riparian areas including instream (Smale 1990). It may therefore alter areas used for fishing and impact on such recreations.	m	l
3. Injurious to people?	Translation of Buddleja from Chinese means “fish poison grass” and toxic compounds have been isolated from the plant, it is probably for this reason it is not grazed by most species (Kay & Smale 1990). No reported cases of people being injured by this species and it is a popular garden plant (Stuart 2006).	l	m
4. Damage to cultural sites?	Ornamental species (Stuart 2006). Invasion by this species could therefore alter aesthetics of an area. The plant has an extensive root system and has been known to establish in rock faces and walls, and can displace paving and brickwork which then leads to high control and repair costs (Sheppard, Shaw & Sforza, 2006).	h	h
Abiotic
5. Impact flow?	Can establish on river banks and within the stream bed at times of low water or on sand/gravel bars (Smale 1990). It can then alter waterflow, increasing silt accretion and causing flooding (Dept. Cons NZ 2005). Therefore can have major impact on water flow, particularly in high water events.	mh	mh
6. Impact water quality?	No evidence of this reported.	l	m
7. Increase soil erosion?	Invades bare ground including landslip scars and is used in some areas to stabilise scree slopes (Sheppard, Shaw & Sforza, 2006).	l	h
8. Reduce biomass?	Can form dense thickets and out compete other shrubby species, which would be direct replacement, however the species is known as a primary coloniser invading areas of newly exposed earth, which would be an increase in biomass (Sheppard, Shaw & Sforza, 2006; Smale 1990; Stuart 2006). The species also allows succession by forest species (Smale 1990).	l	h
9. Change fire regime?	Unknown relationship with fire, however by increasing biomass in shrub layer and therefore elevated fuels invasion by this species could alter fire intensity. It is unknown however to what extent.	m	l
Community Habitat
10. Impact on composition (a) high value EVC	EVC= Riparian Woodland (E); CMA= Port Phillip; Bioreg= Central Victorian Uplands; VH CLIMATE potential. Can form monocultures, as stands age however, they do allow overstorey species to establish and then shade out the buddleja (Smale 1990). Therefore while the species may form monocultures for a time, to then be replaced by native species would only constitute major displacement. In less preferred habitat may only be present at low densities and have less impact (Ream 2006).	mh	h
(b) medium value EVC	EVC= Rocky Outcrop Shrubland (R); CMA= North East; Bioreg= Highlands-Northern Fall; VH CLIMATE potential. Can form monocultures, as stands age however, they do allow overstorey species to establish and then shade out the buddleja (Smale 1990). Therefore while the species may form monocultures for a time, to then be replaced by native species would only constitute major displacement. In less preferred habitat may only be present at low densities and have less impact (Ream 2006).	mh	h
(c) low value EVC	EVC= Granitic Hills Woodland (LC); CMA= North East; Bioreg= Highlands-Northern Fall; VH CLIMATE potential. Can form monocultures, as stands age however, they do allow overstorey species to establish and then shade out the buddleja (Smale 1990). Therefore while the species may form monocultures for a time, to then be replaced by native species would only constitute major displacement. In less preferred habitat may only be present at low densities and have less impact (Ream 2006).	mh	h
11. Impact on structure?	Can form monocultures, as stands age however, they do allow overstorey species to establish and then shade out the buddleja (Smale 1990). In less preferred habitat may only be present at low densities and have less impact (Ream 2006). Therefore while the species may form monocultures for a time, to then be replaced by native species would be a major impact on the lower strata, but not impact on the taller strata from eventually developing.	mh	h
12. Effect on threatened flora?	No specific information. In New Zealand it out competes early successional species, but allows the next successional forest to develop earlier than the native species (Smale 1990). This speeding up of succession may aid in revegetation and the protection of the later successional forest species.	mh	l
Fauna
13. Effect on threatened fauna?	No specific information. In Britain buddleja has formed an associated fauna, which includes many butterfly species, which previously didn’t have the same stable food supply (Owen & Whiteway 1980). No information on the species impact on threatened species in Australia is available.	mh	l
14. Effect on non-threatened fauna?	Can alter habitat, able to out compete other shrub species and form monocultures (Smale 1990). These may not significantly alter the habitat structure, however may reduce diversity of shelter and food supply, no evidence to confirm this has been reported.	m	l
15. Benefits fauna?	In Britain buddleja has formed an associated fauna, which includes many butterfly species, which previously didn’t have the same stable food supply and a dense shrub layer could also provide some shelter (Owen & Whiteway 1980). There is no evidence that this is important to desirable Australian species.	mh	mh
16. Injurious to fauna?	Translation of Buddleja from Chinese means “fish poison grass” and toxic compounds have been isolated from the plant, it is probably for this reason it is not grazed by most species (Kay & Smale 1990). Unknown however to what impact it has on fauna.	m	l
Pest Animal
17. Food source to pests?	Visited by bees (Owen & Whiteway 1980).	ml	h
18. Provides harbor?	The species creates dense thickets, reported as habitat for leopards in China (Owen & Whiteway 1980). Could therefore shelter many different species, potentially also rabbits and foxes.	m	l
Agriculture
19. Impact yield?	Reported to suppress growth of plantations of pine seedlings, through competition for light and can increase seedling mortality (Brockerhoff et al 1999). Therefore with out control buddleja significant reductions in pine plantations have been observed including total failure.	h	h
20. Impact quality?	Unknown.	m	l
21. Affect land value?	Not reported, potentially for forestry areas.	m	l
22. Change land use?	Not reported, with out control may make some forestry areas less viable.	m	l
23. Increase harvest costs?	May alter maintenance requirements for plantations.	m	l
24. Disease host/vector?	None reported	l	m

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Seeds of this species are reported to germinate freely (Blood 2001).	h	mh
2. Establishment requirements?	Can tolerate shade, may not perform well in deep shade, but as a pioneer coloniser is reported in many inhospitable places including old tarmac, almost raw lava and cracks in the walls of abandoned quarries (Blood 2001; Stuart 2006; Webb, Sykes & Garnock-Jones 1988).	mh	mh
3. How much disturbance is required?	Can invade riparian areas (Blood 2001; Weber 2003).	mh	mh
Growth/Competitive
4. Life form?	Shrub – Tree (Stuart 2006). Therefore other.	l	mh
5. Allelopathic properties?	None described.	l	m
6. Tolerates herb pressure?	A biocontrol program is being developed in New Zealand, in laboratory tests plants have died under high densities of Cleopus japonicus larva (Brockerhoff et al 1999). Responds well to pruning in autumn (Stuart 2006). Reported as unpalatable to grazing species (PIER 2007). Can re-sprout from the stump if damaged (Weber 2003). Therefore not preferred and can quickly recover if damaged.	mh	mh
7. Normal growth rate?	Fast growing, can grow up to 2 m in the first year, reaching sexual maturity (Owen & Whiteway 1980).	h	h
8. Stress tolerance to frost, drought, w/logg, sal. etc?	Tolerant of frost and can regenerate if damaged (Blood 2001). Tolerant of drought, can grow in cracks in cliffs and walls of abandoned quarries, even seedlings can tolerate a high degree of water stress (Humphries, Jordan & Guarino 1982). Tolerant of waterlogging; in New Zealand it has invaded in stream beds and after flooding events has recovered from being covered in up to 50cm of alluvium (Smale 1990). Stuart (2006) reports however Buddleja species are susceptible to waterlogging. Noted as not being tolerant of fire (Paterson 2000). However control actions require treating the stump to prevent regowth and the species is known as a primary coloniser of disturbed areas (Smale 1990; Weber 2003) Salinity unknown, it has not however been reported in areas exposed to saline conditions.	mh	mh
Reproduction
9. Reproductive system	Reproduces by seed (Blood 2001).	ml	mh
10. Number of propagules produced?	Reported to have an annual seed production of 3 million per plant (Miller 1984).	h	mh
11. Propagule longevity?	Seeds have been described as having a deep dormancy and can remain viable in the soil for many years (Paterson 2000). Control reported to be complicated by persistent seed banks (Sheppard, Shaw & Sforza 2006).	m	l
12. Reproductive period?	Can form monocultures (Sheppard, Shaw & Sforza 2006). While there is dispute as to age to maturity that is only between the 1^st and 2^nd year (Blood 2001; Owen & Whiteway 1980). The species has been described as short lived they can still live up to 40 years, therefore capable of a reproductive period greater than 10 years (Smale 1990).	h	h
13. Time to reproductive maturity?	There is dispute as to age to maturity that is only between the 1^st and 2^nd year (Blood 2001; Owen & Whiteway 1980).	h	mh
Dispersal
14. Number of mechanisms?	Natural dispersal is primarily through wind and water. The seeds are able to float and are very light and are winged (Smale 1990).	h	h
15. How far do they disperse?	It’s unknown specifically how far seeds can disperse, however Smale (1990) describes the plant as having efficient dispersal through wind and water. The seeds have also been described as being “blown far and wide, are capable of germinating wherever they settle” (Stuart 2006). With this evidence and records of very isolated buddleja infestations, it is presumed that a significant proportion of the seeds are capable of travelling distances of more than 1km (Ream 2006).	h	m

References

Blood K., 2001, Environmental Weeds. A field guide for SE Australia. CH Jerram & Associates – Science publishers. Mt Waverley.

Brockerhoff E.G., Withers T.M., Kay M. & Faulds W., 1999, Impact of the defoliator Cleopus japonicus (Coleoptera: Curculionidae) on Buddleja davidii in the laboratory. Proceedings of the 52nd NZ Plant Protection Conference. 113-118

Carr G.W., Yugovic J.V. and Robinson K.E., 1992, Environmental weed invasions in Victoria: conservation and management implications, Department of Conservation and Environment, Clifton Hill.

Department of Conservation, 2005, Plant me instead, Department of Conservation. Wellington, New Zealand.

Humphries R.N., Jordan M.A. & Guarino L., 1982, The effect of water stress on the mortality of Betula pendula Roth. and Buddleia davidii Franch. seedlings. Plant and Soil. 64: 273-276

Kay M. & Smale M.C., 1990, The potential for biological control of Buddleja davidii Franchet in New Zealand. 29-33 in Bassett C., Whitehouse L.J. & Zabkiewicz J.A., (ed) Alternatives to the Chemical Control of Weeds. Proceedings of an International Conference. Ministry of Forestry, FRI Bulletin 155.

Miller A, 1984, The distribution and ecology of Buddleia davidii Franch in Britain, with particular reference to conditions supporting germination and the establishment of seedlings. Dphil thesis, Council for National Academic Awards, Oxford Polytechnic, Oxford, Uk. in Sheppard et al 2006.

Owen D.F. & Whiteway W.R., 1980, Buddleja davidii in Britain: History and development of an associated fauna. Biological Conservation. 17: 149-155

Paterson J.P.H., 2000, Buddleja davidii Franchet (Loganiaceae) Buddleia davidii.viewed 22 Jan 2007. http://members.lycos.co.uk/woodyplantecology/docs/web-bud.htm

Pacific Island Ecosystems at Risk (PIER) 2007, Buddleja davidii, Risk Assessment Results. viewed 12 Jan 2007, http://www.hear.org/Pier/wra/pacific/buddleja_davidii_htmlwra.htm

Ream J., 2006, Production and Invasion of Butterfly Bush (Buddleja davidii) in Oregon. A project submitted to the Oregon State University, University Honors College and Bioresource Research. viewed 23 Jan 2007 http://ir.library.oregonstate.edu/dspace/bitstream/1957/2233/1/final+draft.pdf

Sheppard A.W., Shaw R.H. & Sforza R., 2006, Top 20 environmental weeds for classical biological control in Europe: a review of opportunities, regulations and other barriers to adoption. Weed Research. 46: 93-117

Smale M.C., 1990, Ecological role of Buddleia (Buddleja davidii) in streambeds in the Te Urewera National Park. New Zealand Journal of Ecology. 14: 1-6

Stuart D.D., 2006, Buddlejas. Timber Press.

Sullivan J.J., Timmins S.M. & Williams P.A., 2005, Movement of exotic plants into coastal native forest from gardens in northern New Zealand. New Zealand Journal of Ecology. 29: 1-10

Webb C.J., Sykes W.R. & Garnock-Jones P.J., 1988, Flora of New Zealand, Vol 4, Botany Division, Department of Scientific & Industrial Research, New Zealand.

Weber E. 2003, Invasive plant species of the world: a reference guide to environmental weeds, CABI Publishing, Wallingford.

Wu Z., Raven P.H et al eds, 1994, Flora of China. 15: 334.

Global present distribution data references

Australian National Herbarium (ANH) 2007, Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, viewed 12 Jan 2007 , http://www.anbg.gov.au/avh/

Calflora: Information on California plants for education, research and conservation. [web application]. 2007. Berkeley, California: The Calflora Database [a non-profit organization] viewed 12 Jan 2007, http://www.calflora.org/ .

Department of Sustainability and Environment (DSE) 2006, Flora information system [CD-ROM], Biodiversity and Natural Resources Section, Viridans Pty Ltd, Bentleigh.

Global Biodiversity Information Facility (GBIF) 2007, Global biodiversity information facility: Prototype data portal, viewed 12 Jan 2007, http://www.gbif.org/

Missouri Botanical Gardens (MBG) 2007, w³TROPICOS, Missouri Botanical Gardens Database, viewed 11 Jan 2007, http://mobot.mobot.org/W3T/Search/vast.html

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