Present distribution
| This weed is not known to be naturalised in Victoria | ||||
Habitat: Wet sites, steambanks <1000m (Morgan 2007); Fresh soils, moderate dampness, open habitats (Schmitz & Derricks 2008), Disturbed grounds and wood margins (Tutin 1964). Fairly common in forests and partial shade 1500 – 3200 m (eFloras 2009). |
Map Overlays Used Land Use: Forestry; pasture irrigation; Ecological Vegetation Divisions Swampy scrub; lowland forest; high altitude shrubland/woodland; high altitude wetland; alpine treeless; riverine woodland/forest Colours indicate possibility of Impatiens balfourii infesting these areas. In the non-coloured areas the plant is unlikely to establish as the climate, soil or landuse is not presently suitable. |
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QUESTION | COMMENTS | RATING | CONFIDENCE |
Social | |||
1. Restrict human access? | “Prodigious weed”, Upright, branched annual plant, growing 50-70cm high, leaves 7.5-12 cm long (Morgan 2007). “In late spring ’07 I received one plant … in spring ’08 it looked like I had a million seedlings”. (DsGa 2009). May therefore form monocultures or patches which restrict access somewhat, but no reports of this. Low nuisance value. | ML | MH |
2. Reduce tourism? | Recorded in areas where indigenous vegetation had withdrawn due to anthropogenic activity. (Cigic et al. 2003). Spread quickly as an uncontrolled weed species (Cigic et al. 2003). Minor effects to aesthetics and/or recreational uses (ie. aware but not bothered or activity inhibited). | ML | MH |
3. Injurious to people? | “All Impatiens spp. taste bitter and seem to be slightly toxic upon ingestion – vomiting and diarrhoea”(Wiki 2009). | ML | MH |
4. Damage to cultural sites? | Recorded in areas where indigenous vegetation had withdrawn due to anthropogenic activity. (Cigiv et al. 2003). “easy to pull where you don’t want them” (DsGa 2009). Unlikely to cause structural effect. Moderate visual effect. | ML | MH |
Abiotic | |||
5. Impact flow? | Reported to grow near creeks in Croatia (Cigic et al. 2003). Branched upright plant (Morgan 2007) Therefore unlikely to be able to reduce flow, although does die back annually (DsGa 2009) and some wilt dead vegetative matter may fall into creeks etc. Minor impact on surface or subsurface flow. | ML | M |
6. Impact water quality? | Reported to grow near creeks in Croatia (Cigic et al. 2003). Taste bitter and seem to be slightly toxic”(Wiki 2009). May have some effects of light levels and/or water quality from toxins leaching… Noticeable but minor effects in either dissolved O2 or light levels. | ML | MH |
7. Increase soil erosion? | “easy to pull where you don’t want them” (DG 2009). Illustrates a lesser capacity to bind soil well. Moderate probability of large scale soil movement. | ML | MH |
8. Reduce biomass? | In late spring ’07 I received one plant … in spring ’08 it looked like I had a million seedlings”. (DsGa 2009). It reseeds like crazy (DG 2009). Seeds prolifically (Spencer 2002). Likely to have a negative impact on the natural vegetation of ruderal or semi-natural communities (SWIS 2009). Therefore is likely to replace simular species with little overall change in biomass. Direct replacement of biomass by invader. | ML | MH |
9. Change fire regime? | “Stems: watery to fleshy” (UC/JEP 2009). Does die back -“True annual, seeds survive winter and then germinates” (DG 2009). Therefore may add some dry vegetative matter for fuel – but unlikely to be significant. Minor change to either frequency or intensity of fire risk. | ML | MH |
Community Habitat | |||
10. Impact on composition (a) high value EVC | EVC = Damp forest (E/V); CMA = West Gippsland; Bioregion = Strzelecki Ranges; H CLIMATE potential. Fairly common in forests and partial shade (eFloras 2009). Likely to have a negative impact on the natural vegetation of ruderal or semi-natural communities (SWIS 2009). In VIC has shown tendency to naturalise” (Spencer 2002). Minor displacement of some dominant or indicator species within any one strata/layer (eg. Ground cover, forbs, shrubs & trees). | ML | M |
(b) medium value EVC | EVC = Riparian forest (D); CMA = East Gippsland; Bioregion = East Gippsland Lowlands; VH CLIMATE potential. Wet sites, streambanks (Morgan 2007). Fairly common in forests and partial shade. (eFloras 2009). Likely to have a negative impact on the natural vegetation of ruderal or semi-natural communities (SWIS 2009). In VIC has shown tendency to naturalise” (Spencer 2002). Minor displacement of some dominant or indicator species within any one strata/layer (eg. Ground cover, forbs, shrubs & trees). | ML | M |
(c) low value EVC | EVC = Damp forest (LC); CMA = East Gippsland; Bioregion = East Gippsland Lowlands; VH CLIMATE potential. Wet sites, streambanks (Morgan 2007). Fairly common in forests and partial shade. (eFloras 2009). Likely to have a negative impact on the natural vegetation of ruderal or semi-natural communities (SWIS 2009). In VIC has shown tendency to naturalise” (Spencer 2002). Minor displacement of some dominant or indicator species within any one strata/layer (eg. Ground cover, forbs, shrubs & trees). | ML | M |
11. Impact on structure? | Reseeds prolifically, (numerous reports in blogs/comments pers. Obs). “I wouldn’t call them invasive though. They don’t crowd out other plants and are easy to pull where you don’t want them” (DG 2009). “In VIC has shown tendency to naturalise” (Spencer 2002). Waste sites and abandoned gardens (SWIS 2009). Likely to have a negative impact on the natural vegetation of ruderal or semi-natural communities (SWIS 2009). Of ruderal or semi natural community minor effect on >60% of the layers or major effect on <60% of the floral strata. | MH | M |
12. Effect on threatened flora? | Light forests or damp places (Phillips & Rix 1999). Likely to have a negative impact on the natural vegetation of ruderal or semi-natural communities (SWIS 2009). May affect threatened flora within these community types but no specific reports in the literature. | M | M |
Fauna | |||
13. Effect on threatened fauna? | No information on impacts of I. balfourii on threatened flora. | M | L |
14. Effect on non-threatened fauna? | I. balfourii is able to colonise open habitats with high light intensities (NEOBIOTA 2008). “All Impatiens spp. taste bitter and seem to be slightly toxic upon ingestion – vomiting and diarrhoea”(Wiki 2009). Therefore in these communities it is likely to reduce food availability and possibly cause some animals to lose condition. Minor effects on fauna spp.; minor hazard or reduction in habitat/food/ shelter. | ML | MH |
15. Benefits fauna? | Provides nectar to humming birds and other birds Strader, (1995). Provides some assistance in either food or shelter to desirable species. | MH | MH |
16. Injurious to fauna? | “All Impatiens spp. taste bitter and seem to be slightly toxic upon ingestion – vomiting and diarrhoea”(Wiki 2009). Mildly toxic, may cause fauna to lose condition. | ML | MH |
Pest Animal | |||
17. Food source to pests? | The big pests for impatiens are mites, aphids, thrips and, white flies (MRIM 2009). Supplies food for one or more minor pest spp. (eg. Blackbirds or environmental insect pests). | ML | MH |
18. Provides harbour? | Not enough information to determine whether it is likely to harbour significant pests. | M | L |
Agriculture | |||
19. Impact yield? | “Present as part of Nitro-philic vegetation, mostly near forest edges, creeks and roads” (Cigic et al. 2003). No signs of photoinhibition (too much sunlight)(NEOBIOTA 2008). Therefore the nitrogen addition to pastures and full sunlight tolerance means I. balfourii could grow in pastures, containing toxins ”(Wiki 2009) may be harmful to livestock or at least reduce food availability. Minor impact on quantity of produce (eg <5% reduction). | ML | MH |
20. Impact quality? | “Present as part of Nitro-philic vegetation, mostly near forest edges, creeks and roads” (Cigic et al. 2003). No signs of photoinhibition (too much sunlight)(NEOBIOTA 2008). Therefore the nitrogen addition to pastures and full sunlight tolerance means I. balfourii could grow in pastures, containing toxins ”(Wiki 2009) may be harmful to livestock or at least reduce food availability. Minor impact on quality of produce (eg < 5% reduction). | ML | MH |
21. Affect land value? | Not enough information to determine the likelihood of affecting land value. No reports of this. | M | L |
22. Change land use? | Not enough information to determine the likelihood of affecting land use. No reports of this. | M | L |
23. Increase harvest costs? | Not enough information to determine the likelihood of increasing land use. No reports of this. | M | L |
24. Disease host/vector? | No information on I. balfourii being host to diseases | M | L |
QUESTION | COMMENTS | RATING | CONFIDENCE |
Establishment | |||
1. Germination requirements? | I. balfourii seeds require a cold stratification to break their dormancy but are still able to germinate after a period of drying (Tabak 2008). Seeds may be damaged by frost (Phillips & Rix 1999). Requires natural seasonal disturbances such as seasonal rainfall, spring/summer temperatures for germination. | MH | MH |
2. Establishment requirements? | Wet sites stream banks <1000m (UC/JEPS 2000). Genus prefers moist rich soils, like roadside ditches, reed beds, fens, riverbanks, & forest edges, and many are able to colonise disturbed ruderal locations. (WEPE 2009). “Locally naturalised on disturbed ground and at wood margins” (Tutin 1964). 1500 to 2500 m in the Himalayas (Neobiota 2008). Requires more specific requirements to establish (eg. open space or bare ground with access to light and direct rainfall). | ML | MH |
3. How much disturbance is required? | “Locally naturalised on disturbed ground and at wood margins” (Tutin 1964). Disturbed habitats (Tabak 2008). Recorded in areas where indigenous vegetation had withdrawn due to anthropogenic activity. (Cigiv et al. 2003). Establishes in highly disturbed natural ecosystems (eg. roadsides, wildlife corridors, or areas which have a greater impact by humans such as tourist areas or campsites) or in overgrazed pastures/poorly growing or patchy crops. | ML | MH |
Growth/Competitive | |||
4. Life form? | Dicot (ITIS 2009). Other. | L | MH |
5. Allelopathic properties? | No information in literature (pers. Obs). | M | L |
6. Tolerates herb pressure? | No information (pers. Obs). | M | L |
7. Normal growth rate? | Annual (Morgan 2007), “True annual, seeds survive winter and then germinates” (DG 2009). Growth rate is likely to be simular to other annuals. Moderately rapid growth that will equal competitive species of the same life form. | MH | MH |
8. Stress tolerance to frost, drought, w/logg, sal. etc? | Recovers from drought induced wilt (GABL 2009). Soil pH requirements 5.6-6.0 (acidic). 6.1-6.5 (mildly acidic). Light shade, partial to full shade. Low frost tolerance (Tabak 2008). “Not good in deep shade” (Phillips & Rix 1999). Can tolerate some drought and seeds survive winter germinate again. Tolerant to at least two and susceptible to at least one. | ML | MH |
Reproduction | |||
9. Reproductive system | Self-sows freely, outcrosses and hybridizes (Morgan 2007). Sexual (self and cross-pollination). | ML | MH |
10. Number of propagules produced? | “In late spring ’07 I received one plant … in spring ’08 it looked like I had a million seedlings”. (DsGa 2009). It reseeds like crazy (DsGa 2009). Seeds prolifically (Spencer 2002). No information on number of seeds produced but likely to be high seed production. | MH | MH |
11. Propagule longevity? | No information on seed longevity. | M | L |
12. Reproductive period? | Annual (Morgan 2007). “True annual, seeds survive winter and then germinates” (DG 2009). Mature plant produces viable propagules for only 1–2 years. | ML | MH |
13. Time to reproductive maturity? | Annual – between 1 and 2 years. | MH | MH |
Dispersal | |||
14. Number of mechanisms? | “…has seed pods that, when ripe, explode when touched”. Sold commercially for horticultural purposes (Tabak 2008). Disperses by seeds (SWIS 2009). Accidental human dispersal. | MH | MH |
15. How far do they disperse? | “…has seed pods that, when ripe, explode when touched” (Tabak 2008). Very few to none will disperse to one kilometre, most 20-200 metres. | ML | MH |