Impact Assessment - Pampas lily-of-the-valley (Salpichroa origanifolia) in Victoria (Nox)

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Assessment of plant invasiveness is done by evaluating biological and ecological characteristics such as germination requirements, growth rate, competitive ability, reproduction methods and dispersal mechanisms. Assessment of plant impacts, however, is determined by the extent to which a plant affects a land manager’s environmental, economic and social resources.

The relative importance of these resources varies depending upon the value people place on them and, as such, the assessment process is subjective. For example, a farmer is likely to place a higher emphasis on the impact of a plant on production (economic resource) than its impact on areas of natural vegetation occurring on the farm. Conversely, a Landcare or Friends group would value environmental or social resources more than economic resources.

Recognising that the value of resources vary between different land tenures, plant impact assessments allow a prioritisation of resources by land managers. Assessments can apply at a local, regional or state level, and the relative values of each resource identified may differ at each level.

The impact assessment method used in the Victorian Pest Plant Prioritisation Process uses three broad resource categories: social, environmental and agricultural, each with a number of related attributes. For example, social resources include such attributes as how the plant affects human access for recreation, or if it creates a health risk due to toxicity or by producing allergens.

Question	Comments	Reference	Rating
Recreation
1. Restrict human access?	A semi-erect, semi-prostrate perennial herb, with stems to 3 metres in length. Unlikely to impeded individual access.	P & C (2001)	L
2. Reduce tourism?	Infestations occur in medium to large populations and would be noticeable to visitors. Not likely to inhibit recreational activities.	Carr et al (1992)	ML
3. Injurious to people?	“It is claimed to be poisonous to stock but no losses have been reported in Australia. The fruit is sometimes used in preserves and is sold I the markets of Argentina and Paraguay for this purpose.” Consider harmless	P & C (2001)	L
4. Damage to cultural sites?	“Once firmly established pampas lily-of-the-valley smothers all other vegetation, killing large shrubs and fruit trees.” On cultural sites it would have a moderate visual effect.	P & C (2001)	ML
Abiotic
5. Impact flow?	Terrestrial species.	P & C (2001)	L
6. Impact water quality?	Terrestrial species.	P & C (2001)	L
7. Increase soil erosion?	Extensive perennial root system to 1 metre deep. Not likely to contribute to soil erosion.	P & C (2001)	L
8. Reduce biomass?	“…grows on home sites and neglected areas, trailing over fences, low bushes etc.” Biomass may increase.	P & C (2001)	L
9. Change fire regime?	No evidence to suggest the plant would support fire or its establishment. Increase in biomass may result in a minor change to the frequency of fire.		ML
Community Habitat
10. Impact on composition (a) high value EVC	EVC=Grassy woodland (E); CMA=Corangamite; Bioreg=Otway Plain; VH CLIMATE potential “Once firmly established, pampas lily-of-the-valley smothers all other vegetation, [and] killing large shrubs.” Current distribution is limited. High impact on low and mid strata.	P & C (2001) Carr et al (1992)	MH
(b) medium value EVC	EVC=Coastal dune scrub (D); CMA=Port Phillip; Bioreg=Victorian Volcanic Plain; VH CLIMATE potential Impact as in 10(a) above.	P & C (2001) Carr et al (1992)	MH
(c) low value EVC	EVC=Heathy woodland (LC); CMA=Port Phillip; Bioreg=Gippsland Plain; H CLIMATE potential Impact as in 10(a) above.	P & C (2001) Carr et al (1992)	MH
11. Impact on structure?	“Once firmly established, pampas lily-of-the-valley smothers all other vegetation, killing large shrubs and fruit trees, and making vegetable and flower culture difficult.” Serious impact on all strata. Possibly monoculture.	P & C (2001)	H
12. Effect on threatened flora?
Fauna
13. Effect on threatened fauna?
14. Effect on non-threatened fauna?	While limited in distribution, it does occur in medium to large populations. Would limit food source for native species.	Carr et al (1992)	ML
15. Benefits fauna?	No benefits.		H
16. Injurious to fauna?	Claimed to be poisonous but no evidence of this in Australia.	P & C (2001)	L
Pest Animal
17. Food source to pests?	“Rats, mice and ants are known to disperse seed in urban areas.” Possible limited food source to pests.	P & C (2001)	ML
18. Provides harbour?	Growth habit may provide limited harbour for rodents.		ML
Agriculture
19. Impact yield?	No evidence; not a weed of agriculture.		L
20. Impact quality?	Not a weed of cropping. No evidence of stock eating the plant.		L
21. Affect land value?	Not a weed of agriculture.		L
22. Change land use?	No		L
23. Increase harvest costs?	No evidence.		L
24. Disease host/vector?	None evident.		L

impact_pampas_lily_valley.doc