Present distribution
| This weed is not known to be naturalised in Victoria | ||||
Habitat: Grows on a grassland, alluvial plains (Medina et al 1989), coastal hardwood shrubland (Rutchey et al 2006), coastal Sand Sheet Woodlands (NatureServe 2002), agricultural areas, rural/disturbed land (ISSG 2008), “dry shores, and upland of mangrove swamps, open sites, second growth in wet to seasonally dry lowlands”… 200m a.s.l. (Gargiullo et al 2008). Sandy soils. Naturalised in Hawaii in dry secondary scrubland (PIER 2006). |
Map Overlays Used Land Use: No climate match Broad vegetation types No climate match Colours indicate possibility of Acanthocereus tetragonus 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? | 1-3 m tall… spines 0.5-7 cm long (Gargiullo et al 2008), sometimes 7 m high (PIER 2006), “can form impenetrable thickets” (ISSG 2008) – major impediment – tracks may be closed or impassable | h | m |
2. Reduce tourism? | 1-3 m tall… spines 0.5-7 cm long (Gargiullo et al 2008) and “can form impenetrable thickets” (ISSG 2008). It occurs in “ agricultural areas, coastland, rural/disturbed, scrub/shrublands” (ISSG 2008) – a cactus would be obvious to most visitors | h | m |
3. Injurious to people? | “heavily armed with spines” (Desert Feast 2008) | h | ml |
4. Damage to cultural sites? | “Can form impenetrable thickets” (ISSG 2008). It occurs in “ agricultural areas, coastland, rural/disturbed, scrub/shrublands” (ISSG 2008) – moderate visual effect | ml | m |
Abiotic | |||
5. Impact flow? | “terrestrial” (Gargiullo et al 2008) – little or negligible affect on water flow | l | mh |
6. Impact water quality? | “terrestrial” (Gargiullo et al 2008) – no noticeable affect on dissolved oxygen or light levels | l | mh |
7. Increase soil erosion? | “This cactus can form impenetrable thickets threatening native plants” (ISSG 2008) – low probability of large scale soil movement | l | m |
8. Reduce biomass? | “This cactus can form impenetrable thickets threatening native plants” (ISSG 2008) and occurs in “agricultural areas, coastland, rural/disturbed, scrub/shrublands” (ISSG 2008), is naturalised in dry secondary scrubland. Can grow to 7m (PIER 2006) – direct replacement of biomass | ml | m |
9. Change fire regime? | “This cactus can form impenetrable thickets threatening native plants” (ISSG 2008) and occurs in “agricultural areas, coastland, rural/disturbed, scrub/shrublands” (ISSG 2008), is naturalised in dry secondary scrubland. Can grow to 7m (PIER 2006) – the change in plant matter is likely to cause a moderate change to both frequency and intensity of fire risk | mh | ml |
Community Habitat | |||
10. Impact on composition (a) high value EVC | No climate match in Victoria | l | h |
(b) medium value EVC | No climate match in Victoria | l | h |
(c) low value EVC | No climate match in Victoria | l | h |
11. Impact on structure? | “semierect or erect cactus that leans or grows over other plants… forms thickets by the arching 3-to-5 angled stems that root where they touch the ground” (Everitt et al 2002). “This cactus can form impenetrable thickets threatening native plants” (ISSG 2008) – major effect on all layers. Forms monoculture | h | m |
12. Effect on threatened flora? | “This cactus can form impenetrable thickets threatening native plants” (ISSG 2008) – therefore it would have the potential to replace vegetation, however the effect on threatened flora is not yet identified | mh | l |
Fauna | |||
13. Effect on threatened fauna? | “Can form impenetrable thickets threatening native plants” (ISSG 2008) – has the potential to change habitat dramatically, however to the effect on threatened fauna spp is not yet identified | mh | l |
14. Effect on non-threatened fauna? | “This cactus can form impenetrable thickets threatening native plants” (ISSG 2008) – habitat changed dramatically, leading to the possible extinction of non-threatened fauna | h | m |
15. Benefits fauna? | Under the general heading of prickly pear, it is said that birds and animals eat the fruit (Jordan 2007). It also flowers at night (Mann 1970), so it may be a food source for nocturnal nectar feeders – may provide some assistance | mh | m |
16. Injurious to fauna? | spines 0.5-7 cm long (Gargiullo et al 2008) – large spines or burrs dangerous to fauna | h | mh |
Pest Animal | |||
17. Food source to pests? | Under the general heading of prickly pear, it is said that birds and animals eat the fruit (Jordan 2007) – may be a food source to pest birds and insects | ml | m |
18. Provides harbour? | “forms thickets by the arching 3-to-5 angled stems that root where they touch the ground” (Everitt et al 2002) – capacity to provide harbour and permanent warrens for foxes and rabbits throughout the year | h | mh |
Agriculture | |||
19. Impact yield? | Identified as an “agricultural weed” (Randall 2007) however to what extent is not stated | m | l |
20. Impact quality? | Identified as an “agricultural weed” (Randall 2007) however to what extent is not stated | m | l |
21. Affect land value? | Identified as an “agricultural weed” (Randall 2007) however to what extent is not stated | m | l |
22. Change land use? | Identified as an “agricultural weed” (Randall 2007) however to what extent is not stated | m | l |
23. Increase harvest costs? | Identified as an “agricultural weed” (Randall 2007) however to what extent is not stated | m | l |
24. Disease host/vector? | The genus Acanthocereus is known to be a host of Pseudococcus jackbeardsleyi (Jack Beardsley mealy bug) which affects leaves and fruits of banana plants (DAFF 2002) – not known to a host for diseases of agriculture in Victoria | l | m |
QUESTION | COMMENTS | RATING | CONFIDENCE |
Establishment | |||
1. Germination requirements? | Although it can grow in shade (Faucon 2005) and has high drought tolerance (Desert Feast 2008) the germination requirements are unknown | m | l |
2. Establishment requirements? | Grows in “low deciduous forest” (Ortiz 2001) and can grow in “light shade to shade” (Faucon 2005) – can establish without additional factors | h | m |
3. How much disturbance is required? | It occurs in “ agricultural areas, coastland, rural/disturbed, scrub/shrublands” (ISSG 2008) and in Hawaii it is naturalised in dry secondary scrubland (PIER 2006) – establishes in relatively intact ecosystems | mh | m |
Growth/Competitive | |||
4. Life form? | Shrub (Ochoterena 2008), vine-like (Desert Feast 2008) – climber | mh | ml |
5. Allelopathic properties? | None mentioned in the literature | m | l |
6. Tolerates herb pressure? | “The fruit is eaten by several species of birds and mammals including the bob-white quail, white-tailed deer, javelina, and raccoon” (Everitt et al 2002). It is also under a biological control program (AWC 2008): “Not a candidate for eradication: reasonable control is achieved with the mealybug Hypogeococcus festerianus” (AWC 2003) – although biocontrols appear to be effective in Queensland, other animals that eat the fruit aid in spreading it, i.e. capable of flowering/seed production under moderate herbivory pressure | mh | mh |
7. Normal growth rate? | “Forms tangled thickets and dominates the shrub stratum” (NatureServe 2002) and can grow “200cm per season” (FNA 2008) – rapid growth rate that will exceed most other species of the same life form | h | m |
8. Stress tolerance to frost, drought, w/logg, sal. etc? | “Tolerates brackish water or occasional inundation by seawater… can tolerate moderate amounts of salt wind without injury.” High drought tolerance “does not require and supplemental water once established” (Desert Feast 2008) Hardy to at least -4˚C (Faucon 2005) Acanthocereus needs well drained soil to grow in order to prevent the roots rotting (Dryscapes 2008) – susceptible to waterlogging | mh | ml |
Reproduction | |||
9. Reproductive system | “forms thickets by the arching 3-to-5 angled stems that root where they touch the ground” and seed (Everitt et al 2002) – both sexual and vegetative reproduction | h | m |
10. Number of propagules produced? | “many seeded” (Everitt et al 2002); numerous small black seeds (Desert Feast 2008) – it is likely to produce over 2000 seeds | h | m |
11. Propagule longevity? | Not found in the literature | m | l |
12. Reproductive period? | Not found in the literature | m | l |
13. Time to reproductive maturity? | Not found in the literature | m | l |
Dispersal | |||
14. Number of mechanisms? | “Spread by seed and vegetative reproduction from broken plant parts” (GCCC 2002). Under the general heading of prickly pear, dispersal is said to be by “birds and animals eating the fruit and excreting viable seed” (Jordan 2007) | h | m |
15. How far do they disperse? | Under the general heading of prickly pear, dispersal is said to be by “birds and animals eating the fruit and excreting viable seed” (Jordan 2007) – very likely that at least one propagule will disperse greater than one kilometre | h | m |