Present distribution
| This weed is not known to be naturalised in Victoria | ||||
Habitat: Native to Nigeria & Zaire, tropical West Africa (Hutchinson & Dalziel 1931, USDA 2006). In Queensland, it occurs in urban bushland, dry sclerophyll forest, riparian vegetation, (Csurches & Edwards 1998) woodland and in coastal communities (pers.com.) including Allocasuarina and ‘beach scrub’ vegetation along the entire QLD coast (Batianoff & Franks 1997). Infestations are generally localised and patchy (pers.com.). In Hawaii & New Caledonia, it has spread vegetatively from cultivation, and naturalised in some areas (McKee 1994, Wagner et al 1999). |
Map Overlays Used Land Use: Broad vegetation types Colours indicate possibility of Sansevieria trifasciata 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? | Listed as one of the most abundant invasive ornamental weeds of Queensland beachfronts (Batianoff & Franks 1997). Occurring in popular beach localities and forming dense clumps to 1 m high (GCCC 2006), there is potential for this species to have some nuisance value and impede individual access for beach goers. | ML | ML |
2. Reduce tourism? | Listed as one of the most abundant invasive ornamental weeds of Queensland beachfronts (Batianoff & Franks 1997). Occurring in popular beach localities and forming dense clumps to 1 m high (GCCC 2006), it is likely to be noticeable to visitors and affect the aesthetics of a site. No information was found to suggest it would specifically affect recreational uses. | ML | M |
3. Injurious to people? | The presence of saponins and organic acids in all parts of the plant can lead to minor toxic affects if eaten such as excessive salivation, or minor skin irritation (Russell 1997). Mildly toxic. | ML | M |
4. Damage to cultural sites? | Likely to have little or negligible affect on the aesthetics or structure of a site. | L | M |
Abiotic | |||
5. Impact flow? | A terrestrial species, not likely to have an impact on water flow | L | M |
6. Impact water quality? | A terrestrial species, not likely to have an impact on water quality | L | M |
7. Increase soil erosion? | As a strongly rhizomatous species (George 1986) growing in dense clumps (GCCC 2006) it is unlikely to increase soil erosion, and may decrease the probability of soil erosion in some circumstances. | L | M |
8. Reduce biomass? | As a strongly rhizomatous species (George 1986) growing in dense clumps (GCCC 2006), it may cause an increase in community biomass, particularly in some of the more sparsely vegetated coastal areas that it occupies (Batianoff & Franks 1997). | L | ML |
9. Change fire regime? | Being a succulent, the foliage of S. trifasciata has a high moisture content. This combined with its capacity to form dense clumps (GCCC 2006, Obermeyer et al 1992) and invade fire prone communities, gives it the potential to decrease the intensity of fire by reducing fuel flammability. Minor change to intensity of fire risk. | ML | M |
Community Habitat | |||
10. Impact on composition (a) high value EVC | Climate modelling shows that this species is not likely to occur as an invasive plant in Victoria. | L | H |
(b) medium value EVC | Climate modelling shows that this species is not likely to occur as an invasive plant in Victoria. | L | H |
(c) low value EVC | Climate modelling shows that this species is not likely to occur as an invasive plant in Victoria. | L | H |
11. Impact on structure? | Described as an environmental weed (ICC 2007, PIER 2004) invading dry sclerophyll forest, riparian vegetation, (Csurches & Edwards 1998) woodland, and coastal communities (pers.com.) including Allocasuarina and beach scrub vegetation (Batianoff & Franks 1997). Being a strongly rhizomatous and (George 1986) growing in dense clumps (GCCC 2006), it is likely to have some impact on the structure of these vegetation communities, however, no information on its affects were found documented. | M | L |
12. Effect on threatened flora? | Climate modelling shows that this species is not likely to occur as an invasive plant in Victoria. | L | H |
Fauna | |||
13. Effect on threatened fauna? | Climate modelling shows that this species is not likely to occur as an invasive plant in Victoria. | L | H |
14. Effect on non-threatened fauna? | No information was found documented in relation to the impact this species might have on the habitat or food sources of indigenous fauna. | M | L |
15. Benefits fauna? | Caterpillars of Opogona sacchari are documented as feeding on S. trifasciata (Clercq & Luchene 1977 & Suss 1975) but it is not known if native species would also feed on it. It has been suggested that the fleshy orange fruits, may be attractive to birds and other vertebrates (PIER 2004, pers. com.). However, no information was documented on any observed consumption of the fruits or any other utilisation of the plant by animals, therefore its potential benefit to fauna is unknown. | M | L |
16. Injurious to fauna? | Information suggests that the foliage of this species could be toxic to some domestic pets with the potential to cause vomiting, salivation and diarrhoea (Merck 1991). It is unknown if these potentially toxic properties would affect native fauna. | M | L |
Pest Animal | |||
17. Food source to pests? | Information suggests that the foliage of this species could be toxic to some domestic animals with the potential to cause vomiting, salivation and diarrhoea (Merck 1991). The fleshy orange fruits are documented as being potentially attractive to birds and other vertebrates (PIER 2004, pers. com.), however, no information was found of any observed consumption of the fruits by animals, therefore, its potential as a food source to pest species is unknown. | M | L |
18. Provides harbour? | No information was found documented to suggest that S. trifasciata provides harbour to pest animals, and it appears to be unsuitable as harbour due to its dense clumping nature and stiff upright habit. | L | ML |
Agriculture | |||
19. Impact yield? | Not known as a weed of agriculture. | L | L |
20. Impact quality? | Not known as a weed of agriculture. | L | L |
21. Affect land value? | Not known as a weed of agriculture. | L | L |
22. Change land use? | Not known as a weed of agriculture. | L | L |
23. Increase harvest costs? | Not known as a weed of agriculture. | L | L |
24. Disease host/vector? | Recorded as a host of root-knot nematode (Meloidogyne incognita) (Sanyat Misra et al 2002, Esser 1990, Stokes & King 1973). Potential host to a common agricultural pest. | L | M |
QUESTION | COMMENTS | RATING | CONFIDENCE |
Establishment | |||
1. Germination requirements? | Little information was available in relation to germination requirements of Sansevieria trifasciata. There is some indication that natural seasonal disturbances, such as warmer temperatures, may be required for germination, but also that this species is largely spread vegetatively where it is naturalised (McKee 1994, Wagner et al 1999, Csurches & Edwards 1998), suggesting that seed germination may not occur readily. | M | L |
2. Establishment requirements? | Grows in low light conditions, needs some shading (Chahinian 1986) and has a preference for moist shady sites (GCCC 2006). Grown under 50 % shade as a cultivated crop (Conover & Poole 1976). Potential to establish under moderate canopy. | MH | M |
3. How much disturbance is required? | It has naturalised in urban bushland, dry sclerophyll forest and riparian vegetation around Brisbane (Csurches & Edwards 1998) and Allocasuarina and beach scrub along the entire Queensland Coast (Batianoff & Franks 1997). Invades coastal & woodland communities (pers.com). Can establish in minor disturbed natural ecosystems. | MH | M |
Growth/Competitive | |||
4. Life form? | Strongly rhizomatous (George 1986) herbaceous perennial succulent to 100 cm in height (Weeds Aust 2007, Chahinian 1986). Life form- Geophyte | ML | MH |
5. Allelopathic properties? | No reference to allelopathic properties was found (PIER 2004). | L | M |
6. Tolerates herb pressure? | The only references to herbivory found were of two insect species, a caterpillar and weevil beetle, feeding on S. trifasciata in a horticultural nursery environment (Clercq & Luchene 1977, Skadow & Karl 1967 & Suss 1975). It is documented as being potentially toxic to some domestic mammals causing vomiting, salivation and diarrhoea due to the Haemolytic saponin and organic acids found in the leaves and flowers (Merck 1991). It appears from available information that it is not readily consumed by many species in the natural environment. It is cultivated as a fibre crop in several countries (Hanelt & IPK 2001) with the regrowth being harvested every 2 to 3 months (Conover & Poole 1976). It must therefore have a good growth response to regular cutting which indicates it is also likely to recover well from herbivory. Consumed but not preferred and recovers quickly. | MH | ML |
7. Normal growth rate? | Under cultivation, S. trifasciata ‘Laurentii’ appears to be relatively fast growing, documented as growing to a height up to 37. 5 cm in 48 days (Marlatt 1975). However, due to lack of information regarding its growth under natural conditions, it is unclear how the growth rate of S. trifasciata compares to other species of the same lifeform. | M | L |
8. Stress tolerance to frost, drought, w/logg, sal. etc? | ‘…one of the ones at the top of the list of all known decorative plants in the world to tolerate abuse and neglect (Chahinian 1986)’. Drought resistant and frost tolerant only to –2 o C for short periods, rots easily if over watered (Desert Tropicals 2005, MBG 2007). Very drought-hardy perennials (Obermeyer et al 1992). Moderately tolerant of soil salinity and salt spray (Bezona et al 2001, Batianoff & Franks 1997). Potential to display some fire tolerance due to its rhizome system (George 1986) and high tissue moisture content (Brooks et al 2004), but not documented. Drought resistant and moderately tolerant of salinity (and maybe fire), susceptible to water-logging and most frosts. | M | M |
Reproduction | |||
9. Reproductive system | Although the spread of S. trifasciata in Australia appears to be largely by vegetative reproduction (Csurches & Edwards 1998) it is documented in the literature as spreading both vegetatively and via seed (Weeds Aust 2007, PIER 2004). | H | M |
10. Number of propagules produced? | It is documented as producing less than 1000 seeds/m2 (PIER 2004). However, determining how many plants in a given area would be hard, due to the difficulty in distinguishing between plants as a result of vegetative spread. Only an approximation of seed production can be made here due to lack of available information. Flowers occur in clusters of around 5, approx. 2. 5 cm apart along a spike up to 75 cm in length (Chahinian 1986). In the unlikely event that the maximum number of flowers is fertilised, there could be around 125 fruits produced, each containing 2 seeds (Weeds Aust 2007) equalling approximately 250 seeds/ inflorescence. Images sighted indicate that 1 or 2 inflorescence per plant is most common, so seed production is likely to fall within the category of ‘50-1000’ seeds per flowering event. | ML | ML |
11. Propagule longevity? | No information was found documented on the longevity of propagules. | M | L |
12. Reproductive period? | Being a strongly rhizomatous species (George 1986) spreading and growing into dense clumps (GCCC 2006), it is possible that colonies would persist and reproduce for many years, but no information on reproductive period for this species was found documented. | M | L |
13. Time to reproductive maturity? | No information was found documented on the time it takes for this species to reach reproductive maturity. | M | L |
Dispersal | |||
14. Number of mechanisms? | In Australia, current spread is mostly through vegetative expansion from gardens and dumping of garden waste (Csurches & Edwards 1998, pers. com.). However, it has been proposed that the fleshy orange fruits are likely to be attractive to birds and other vertebrates, with the potential to provide a seed dispersal mechanism (PIER 2004, pers. com.). | MH | L |
15. How far do they disperse? | Through bird dispersal many seeds could reach at least 200 m. | MH | L |