Impact Assessment - Tutsan (Hypericum androsaemum) in Victoria (Nox)

Back | Table | Feedback

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?	“An erect shrub, commonly about 1 m high.” Occurs, “…on damp, shaded sites and forest edges.” “Infestations spread rapidly and often form dense closed stands.” Herbaceous species; may be a nuisance to humans.	P & C (2001) Muyt (2001)	ML
2. Reduce tourism?	“An erect shrub, commonly about 1 m high.” Occurs, “…on damp, shaded sites and forest edges.” “Infestations spread rapidly and often form dense closed stands.” Some recreational activities may be affected.	P & C (2001) Muyt (2001)	ML
3. Injurious to people?	Not considered injurious to humans.		L
4. Damage to cultural sites?	Dense stands would create a negative visual effect.		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?	A shrub with numerous shallow roots to 30 cm deep, a few deeper. Not likely to increase soil erosion.	P & C (2001)	L
8. Reduce biomass?	“Tutsan is a serious weed in moist forests, woodlands and riparian areas. Infestations…often form dense closed stands that smother ground-flora and smaller shrubs.” Biomass may increase slightly.	Muyt (2001)	L
9. Change fire regime?	Effect on fire regime not documented, however, as a semi-deciduous plant, it may have little impact on fire risk.		L
Community Habitat
10. Impact on composition (a) high value EVC	EVC=Cool temperate rainforest (V); CMA=West Gippsland; Bioreg=Highlands – Southern Fall; VH CLIMATE potential. Establishes in disturbed and undisturbed bushland. Tolerates deep shade and can establish in open, sunny locations. Smothers ground flora and smaller shrubs. Major displacement of species in lower strata.	Muyt (2001)	MH
(b) medium value EVC	EVC=Warm temperate rainforest (R); CMA=East Gippsland; Bioreg=East Gippsland Uplands; H to VH CLIMATE potential. Impact as in 10(a) above.	Muyt (2001)	MH
(c) low value EVC	EVC=Wet forest (LC); CMA=West Gippsland; Bioreg=Highlands – Southern Fall; VH CLIMATE potential. Impact as in 10(a) above.	Muyt (2001)	MH
11. Impact on structure?	“There is an area near Mansfield, in Victoria, where it extends as the dominant species from a roadside for several hundred metres into native bushland greatly reducing the density of native species.” Serious impact on lower strata.	P & C (2001)	ML
12. Effect on threatened flora?
Fauna
13. Effect on threatened fauna?
14. Effect on non-threatened fauna?	In Victoria, it is widely distributed in damp and wet sclerophyll forest, riparian vegetation, warm and temperate rainforest. As the plant is unpalatable and rarely eaten and it forms dense close stands, it may have a some impact on reducing fodder.	Carr et al (1992) P & C (2001) Muyt (2001)	ML
15. Benefits fauna?	No known benefits.		H
16. Injurious to fauna?	“It is suspected of poisoning cattle in New Zealand, and of causing skin ailments in sheep and cattle although this is not well documented.” However, the plant is unpalatable and rarely eaten.	P & C (2001)	ML
Pest Animal
17. Food source to pests?	Not known as a food source to pest animals.		L
18. Provides harbor?	Not known to provide harbor		L
Agriculture
19. Impact yield?	“…tutsan encroaches onto semi-improved areas or pastures which have been severely overgrazed when, in Victoria, whole hillsides may be covered to the exclusion of most other vegetation.” These infestations greatly reduce the pasture available to stock.	P & C (2001)	MH
20. Impact quality?	Not known as a weed of cropping or to contaminate agricultural produce greatly.		L
21. Affect land value?	Not considered a significant weed of agriculture. Little effect on land value.		L
22. Change land use?	Not considered a significant weed of agriculture. Where it occurs on steep hillsides or in the presence of other vegetation in pasture situations, herbicides provide some degree of control. Change in land use not required.	P & C (2001)	L
23. Increase harvest costs?	Not known as a weed of cropping.		L
24. Disease host/vector?	None evident.		L

Impact Assessment Record - Tutsan (PDF - 31KB)
Impact Assessment Record - Tutsan (DOC - 60KB)
This table can also be viewed as a PDF document (printer friendly). To view the information PDF requires the use of a PDF reader. This can be installed for free from the Adobe website (external link).

Feedback

Do you have additional information about this plant that will improve the quality of the assessment?
If so, we would value your contribution. Click on the link to go to the feedback form.