Impact Assessment - Chinese violet (Asystasia gangetica ssp. micrantha) in Victoria
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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.
| Each resource attribute, or criterion, is assessed relative to a list of intensity ratings. Depending upon information found in relation to each criterion, a rating of Low, Medium Low, Medium High or High is assigned. Descriptions of the impact criteria and intensity ratings used in this process can be viewed here. |
The following table provides information on the impact of Chinese violet
A more detailed description of the methodology of the Victorian Weed Risk Assessment (WRA) method can be viewed below:
Victorian Weed Risk Assessment (WRA) method (PDF - 630 KB)
Victorian Weed Risk Assessment (WRA) method (DOC - 1 MB)
To view the information PDF requires the use of a PDF reader. This can be installed for free from the Adobe website (external link).
Common Name: Chinese violet
Scientific name: Asystasia gangetica ssp. micrantha
| Question | Comments | Rating | Confidence |
| Recreation | |||
| 1. Restrict human access? | ‘A perennial creeper .. grows up to 0.5 m high alone but to 3 m high on supporting vegetation’. Due to the preferred sites the weed grows ‘on vacant residential land, along fencelines and in neglected garden beds’ (CRC for Australian Weed Management 2003), it is likely to have only a minimal or negligible impact on human access. | L | M |
| 2. Reduce tourism? | ‘Infestations have now been identified at .. Anna Bay and Fern Bay [NSW]. These infestations are spread over a distance of 9 km and range in size from 2 square metres to several hectares’ (CRC for Australian Weed Management 2003). Due to the smothering nature of the weed, it may have a minor effect on the aesthetics of the land. | ML | M |
| 3. Injurious to people? | No toxic principle or physical properties likely to cause injury. | L | MH |
| 4. Damage to cultural sites? | Not documented to occur in areas of cultural significance. | L | MH |
| Abiotic | |||
| 5. Impact flow? | Terrestrial species. | L | MH |
| 6. Impact water quality? | Terrestrial species. | L | MH |
| 7. Increase soil erosion? | ‘..makes a good ground cover, especially on slopes that need protection from erosion’ (Whistler 2000 (cited in PIER 2005)). Unlikely to contribute to large scale soil movement. | L | MH |
| 8. Reduce biomass? | ‘Smothers other ground plants and displaces vegetation’ (CRC for Australian Weed Management 2003). Likely that biomass may increase. | L | M |
| 9. Change fire regime? | Grows well in drought areas and the plant will die off (CRC for Australian Weed Management 2003). However no evidence to suggest that it would change the frequency or intensity of fire. Assume small or negligible effect on fire risk. | L | M |
| Community Habitat | |||
| 10. Impact on composition (a) high value EVC | EVC= Coastal Banksia Woodland (V); CMA=Port Phillip; Bioreg=Gippsland Plain; CLIMATE potential=H. ‘Can smother all vegetation in the herbaceous layer’ (PIER 2005). Monoculture within the groundcover layer. | H | MH |
| (b) medium value EVC | No EVC found. | M | L |
| (c) low value EVC | EVC= Coastal tussock grassland (LC.); CMA=Port Phillip; Bioreg=Gippsland Plain; CLIMATE potential=H. ‘Can smother all vegetation in the herbaceous layer’ (PIER 2005). Monoculture within the groundcover layer. | H | MH |
| 11. Impact on structure? | ‘Smothers other ground plants and displaces vegetation’ (CRC for Australian Weed Management 2003). ‘Can smother all vegetation in the herbaceous layer’ (PIER 2005). Would have a major effect on <60% of the floral strata. | MH | MH |
| 12. Effect on threatened flora? | The potential for Asystasia gangetica ssp. micrantha to establish and naturalise in Victoria is highly unlikely due to ecoclimatic limitations. No impact on threatened flora in Victoria. | L | MH |
| Fauna | |||
| 13. Effect on threatened fauna? | The potential for Asystasia gangetica ssp. micrantha to establish and naturalise in Victoria is highly unlikely due to ecoclimatic limitations. No impact on threatened fauna in Victoria. | L | MH |
| 14. Effect on non-threatened fauna? | As an environmental weed, ‘it smothers other ground plants and displaces vegetation, which reduces the availability of habitat for native plants and animals’ (CRC for Australian Weed Management 2003). May have a minor effect on fauna spp. | ML | M |
| 15. Benefits fauna? | No evidence that the weed benefits indigenous fauna. | H | MH |
| 16. Injurious to fauna? | Not known to be harmful. | L | MH |
| Pest Animal | |||
| 17. Food source to pests? | Not known as a food source to pest animals. | L | MH |
| 18. Provides harbor? | Not known to provide harbour to pest species. | L | MH |
| Agriculture | |||
| 19. Impact yield? | ‘It is a major weed overseas .. it infests plantations, particularly oil-palm crops, and competes effectively for soil nutrients, reducing productivity and increasing crop management costs’ (CRC for Australian Weed Management 2003). Has the potential to have a minor impact on quantity of produce. | ML | M |
| 20. Impact quality? | No evidence that the weed impacts on agricultural quality. | L | MH |
| 21. Affect land value? | No evidence to suggest that the weed will affect land value. | L | MH |
| 22. Change land use? | No evidence that the weed will cause a change in priority of land use. | L | MH |
| 23. Increase harvest costs? | ‘It is a major weed overseas .. it infests plantations, particularly oil-palm crops, and competes effectively for soil nutrients, reducing productivity and increasing crop management costs’ (CRC for Australian Weed Management 2003). Weed may lead to a minor increase in cost of harvesting. | M | M |
| 24. Disease host/vector? | The weed provides host to minor disease (Asystasia gangetica mottle – potyvirus). Diagnostically susceptible host species include Chenopodium amaranticolor, Nicotiana tabacum, Phaseolus vulgaris and Sesamum indicum (VIDE 1996). | M | MH |
This table can also be viewed as a PDF document (printer friendly).
Impact Assessment Record - Chinese violet (PDF - 25KB)
Impact Assessment Record - Chinese violet (DOC - 50KB)
To view the information PDF requires the use of a PDF reader. This can be installed for free from the Adobe website (external link).
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