Pereskia aculeata Mill.

Title: Pereskia aculeata Mill.

Scientific name:

Pereskia aculeata Mill.

Common name(s):

leaf cactus, Barbados gooseberry

Source & more images (via ALA)

Habitat: Tropical and subtropical environments. Adapts to a wide variety of soil types but prefers well-drained, high-nutrient soils. Prefers light-shade environments. Invades forest margins and gaps and plantations (CRC for Australian Weed Management 2003) Rocky areas in mesophytic forest, from dry forest, restinga and dunes near the sea. Found on alluvial soils on diverse geological formations including igneous and calcareous rock (Leuenberger 1986).

Distribution:

Original source via CABI

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? “Germination generally occurs in the wetter winter and spring periods, providing there is not too much rain” (CRC Weed Management, 2003). Requires natural seasonal rainfall.

2. Establishment requirements? “Seedlings germinate readily in sunshine or in shade” (de Beer, 1988).

3. How much disturbance is required? “Forestry and conservation areas…amongst riparian vegetation along the banks of rivers…grows well in the subtropical eucalypt communities of southeastern Queensland” (CRC Weed Management, 2003). Invades forest margins and gaps, plantations (Henderson, 2001). Tends to establish in natural ecosystems that experience some disturbance.

GROWTH / COMPETITIVE

4. Life form? “Shrubby to clambering vine” (Henderson, 2001).

5. Allelopathic properties? Not noted in CRC Weed Management (2003), de Beer (1988) or Moran & Zimmerman (1991).

6. Tolerates herb pressure? “Heavily spined” (Moran & Zimmerman, 1991) in “closely spaced groups…make the infested area inaccessible” (de Beer, 1988) so this would prevent herbivory. Is subject to insect herbivory in South Africa through the introduction of biocontrol agents but these are South American species (Moran & Zimmerman, 1991).

7. Normal growth rate? “Grows quite vigorously in tropical and subtropical environments” (CRC Weed Management, 2003). “Reasonably vigorous…It overshadows all other vegetation and even big trees could collapse under the mass of the tangled branches” (de Beer, 1988). Growth rate has been observed to exceed most other species in the communities that it invades.

8. Stress tolerance to frost, drought, w/logg, sal. etc? “Drought tolerant…dislikes too much water.” Burning has been used to control this weed, but presumably it is not flammable because fresh material was burnt in oil drums (CRC Weed Management, 2003). Frost tolerant to –3°C (Faucon, 2005). Found in “dunes near the sea” (Leuenberger, 1986). Tolerant of at least 2 (drought, frost, salinity & fire) and susceptible to waterlogging.

REPRODUCTION

9. Reproductive system? Seeds and stem pieces (de Beer, 1988).

10. Number of propagules produced? A picture of approximately 1 m² of this plant shows about 400 flowers (Faucon, 2005). This plant can reach 12m and each fruit has a single seed (CRC Weed Management, 2003), so 12 x 400 = 4 800.

11. Propagule longevity? Reference to seed longevity was not found.

12. Reproductive period? Photographs of Pereskia from the Agricultural Research Council in South Africa (pers. comm.) show this plant forming dense monocultures.

13. Time to reproductive maturity? “Local experience is that is needs to grow to 6 metres long before it will flower” (Perrin, 2003). Being “reasonably vigorous” (de Beer, 1988), you would expect the plant to reach this height in 2-5 years.

DISPERSAL

14. Number of mechanisms? “The fruit are eaten by birds…that spread the seeds to other areas” de Beer (1988). Pieces of the plant may be washed downstream a considerable distance” (CRC Weed Management, 2003).

15. How far do they disperse? “Pieces of the plant may be washed downstream a considerable distance…Birds can move propagules…a long way from gardens” (CRC Weed Management, 2003). It is very likely that some propagules will disperse more than 1km.

Impact Assessment

RECREATION

1. Restrict human access? “The plant has a tendency to form large impenetrable clumps and its extreme thorniness makes control of large infestations difficult…Growing amongst riparian vegetation along the banks of rivers in Queensland and New South Wales” (CRC Weed Management, 2003). “Runners…also spread along the ground to make the whole area inaccessible” (de Beer, 1988).

2. Reduce tourism? Large, thorny, impenetrable thickets that are difficult to control and situated along riverbanks (see Q. 1) are likely to have a major impact on recreation in and around those rivers.

3. Injurious to people? The main shoots vigorously bear curved spines 4-8mm long and 2-5mm thick and straight spines 10-35mm long and 0.5-1.5mm thick and trichomes 1-2mm long (Leuenberger, 1982).

4. Damage to cultural sites? As a large, thorny climbing shrub that clambers over trees (Moran & Zimmermann, 1991) this plant has the capacity to detract visually from cultural sites.

ABIOTIC

5. Impact flow? Terrestrial species that “dislikes too much water” (CRC Weed Management, 2003).

6. Impact water quality? Terrestrial species that “dislikes too much water” (CRC Weed Management, 2003).

7. Increase soil erosion? This plant can smother vegetation (de beer, 1988) that might otherwise bind soil. In cool or drought conditions this plant loses its leaves (Leuenberger, 1986) and where it has killed the vegetation it has smothered, it will leave the soil bare and prone to erosion. It can form major infestations along riverbanks (pers. comm. photo from the Agricultural Research Council (ARC) in South Africa) making the likelihood of flooding, and large scale soil movement with major offsite effects highly likely.

8. Reduce biomass? “Clambers over…trees…and may eventually kill them (Moran & Zimmermann, 1991).

9. Change fire regime? Burning is used to control this weed in South Africa (CRC Weed Management, 2003) however this appears to have been by dropping plant pieces into oil drums. This indicates that it is not very flammable. In subtropical eucalypt communities it has the potential to reduce the incidence and intensity of fires.

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? EVC= Foothill Box Ironbark Forest (V); CMA=East Gippsland; Bioreg= East Gippsland Upland; CLIMATE potential=H. . “Listed as a noxious weed in conservation areas in South Africa due to its formation of dense infestations” (CRC Weed Management, 2003). “It overshadows all other vegetation and even big trees could collapse under the mass of the tangled branches” (de Beer, 1988). Monoculture within the canopy layer.

10(b) Impact on medium value EVC? EVC= Riparian Forest (D); CMA=East Gippsland; Bioreg= East Gippsland Lowland; CLIMATE potential=H. “Listed as a noxious weed in conservation areas in South Africa due to its formation of dense infestations” (CRC Weed Management, 2003). “It overshadows all other vegetation and even big trees could collapse under the mass of the tangled branches” (de Beer, 1988). Monoculture within the canopy layer.

10(c) Impact on low value EVC? EVC= Lowland Forest (Lc); CMA=East Gippsland; Bioreg= East Gippsland Lowland; CLIMATE potential=H “Listed as a noxious weed in conservation areas in South Africa due to its formation of dense infestations” (CRC Weed Management, 2003). “It overshadows all other vegetation and even big trees could collapse under the mass of the tangled branches” (de Beer, 1988). Monoculture within the canopy layer.

11. Impact on structure? “Listed as a noxious weed in conservation areas in South Africa due to its formation of dense infestations” (CRC Weed Management, 2003). “It overshadows all other vegetation and even big trees could collapse under the mass of the tangled branches” (de Beer, 1988). This vine has the capacity to form monocultures affecting all layers.

12. Effect on threatened flora? No information found.

FAUNA

13. Effect on threatened fauna? No information found.

14. Effect on non-threatened fauna? Dense infestations that smother native trees (CRC Weed Management, 2003) could reduce habitat and food for native fauna.

15. Benefits fauna? “It bears …edible fruits 25-45mm in diameter, which are popular with birds” (CRC Weed Management, 2003). Its thorny branches may also protect small birds from predation.

16. Injurious to fauna? “Heavily spined” (Moran & Zimmermann, 1991).

PEST ANIMAL

17. Food source to pests? May provide habitat and a food source for pest bird species (see Q. 15).

18. Provides harbor? May provide harbor for small birds (see Q. 15).

AGRICULTURE

19. Impact yield? “Listed as a noxious weed in forestry in South Africa due to its formation of dense infestations” (CRC Weed Management, 2003). It “clambers over…commercially planted forest trees…and may eventually kill them” (Moran & Zimmermann, 1991). Given how difficult this plant is to control (CRC Weed Management, 2003), this could have a major impact on quantity of produce.

20. Impact quality? This plant is not noted as a weed of other agricultural systems in CRC Weed Management, (2003) and is not likely to impact on the quality of forestry products.

21. Affect land values? The labor-intensive nature of controlling this species, due to dense infestations that are thorny and that can regrow from stumps, leaf and stem fragments (CRC Weed Management, 2003), would probably reduce the value of badly infested land. Photographs from ARC in South Africa (pers. comm.) show extensive infestations that have entirely smothered acres of land.

22. Change land use? Commercial forests may no longer be viable in the presence of this weed (see Q. 19).

23. Increase harvest costs? The South African experience has shown that infestations are difficult to remove, involve meticulous human labor, and require “a great deal of follow-up treatment” (CRC Weed Management, 2003).

24. Disease host/vector? Not noted as a host for agricultural diseases (CRC Weed Management, 2003).

Feedback:

Do you have additional information about this plant that will improve the quality of the assessment? If so, we would value your contribution.

Assessment ratings originally made by the Victorian Department of Primary Industries.

The entry of this assessment was made possible through the generous support of The Weed's Network.

Attachments:

barbados via ala.JPG
distribution_map (43).png

referenced by (2)

wra1008: Common Names - L (via leaf cactus)wra825: Common Name - B (via Barbados gooseberry)

Article: wra5613 (permalink)
Categories: :wra:p, :wra:inv1, :wra:invmh, :wra:inv2, :wra:inv3, :wra:inv4, :wra:invml, :wra:inv5, :wra:invl, :wra:inv6, :wra:invh, :wra:inv7, :wra:inv8, :wra:inv9, :wra:inv10, :wra:inv11, :wra:invm, :wra:inv12, :wra:inv13, :wra:inv14, :wra:inv15, :wra:imp1, :wra:imph, :wra:imp2, :wra:imp3, :wra:imp4, :wra:impml, :wra:imp5, :wra:impl, :wra:imp6, :wra:imp7, :wra:imp8, :wra:imp9, :wra:impmh, :wra:imp10a, :wra:imp10b, :wra:imp10c, :wra:imp11, :wra:imp12, :wra:imp13, :wra:imp14, :wra:imp15, :wra:imp16, :wra:imp17, :wra:imp18, :wra:imp19, :wra:imp20, :wra:imp21, :wra:imp22, :wra:imp23, :wra:imp24
Date: 27 November 2009; 2:58:44 PM AEDT

Author Name: Michelle Heitch
Author ID: heitchm