Cryptostegia grandiflora R. Br.

Title: Cryptostegia grandiflora R. Br.

Scientific Name:

Cryptostegia grandiflora R. Br.

Common Name:

rubber vine

Source & more images (via ALA)

Habitat: Semi-arid tropics. Found in areas receiving between 400 and 1400 mm of mainly summer rain. Grows on all soil types but germinates on soils retaining moisture. (CRC for Australian Weed Management 2003). Dry forest, roadsides, moist forest, rainforest openings at low elevations. Common in disturbed situations where there is temporary or permanent water, such as along gullies, rivers, creeks, waterholes and in saltmarsh areas. (ISSG 2005)

Distribution:

Original source via CABI

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? Seeds need between 5 and 15 days exposure to moist, warm (20-30°C) conditions before they will germinate. Germination occurs following good rain (CRC for Australian Weed Management 2003).

2. Establishment requirements? Establishment is enhanced by the presence of mulch on the soil surface (Parsons & Cuthbertson 2001). Plants tolerate shade and grow in a wide range of temperatures but are well adapted to a monsoonal climate (DNRME 2004). Wet shaded areas that protect the seeds from drying out are ideal with seeds readily germinating on riverbanks and other moist areas (CRC for Australian Weed Management 2003). However, the plant can also establish in dry forest (ISSG 2005).

3. How much disturbance is required? Plants are common in disturbed situations where there is temporary or permanent water, such as gullies, rivers, creeks, waterholes (IPIF 1999).

GROWTH / COMPETITIVE

4. Life form? It is a woody perennial vine (DNRME 2004). Climber

5. Allelopathic properties? None described in Parsons & Cuthbertson 2001.

6. Tolerates herb pressure? It is poisonous to stock, however, if animal is stressed or other feed is scarce, they may eat it. Biological control agents are being used (DNRME 2004).

7. Normal growth rate? This plant aggressively colonises areas and forms thickets which can smother other vegetation (DNRME 2004). No evidence to suggest that it can exceed other species of the same life form but assumed that the growth rate will equal competitive species of same life form.

8. Stress tolerance to frost, drought, w/logg, sal. etc? Does not occur in areas with more than 100 days frost per annum, and from 50-100 days frost per annum being a less suitable habitat. Needs absence of frequent fires to survive (Mackay 1996). Tolerant to water logging and drought tolerant up to 80 days. Survives in saltmarsh areas (ISSG 2005).

REPRODUCTION

9. Reproductive system? Propagates by seeds – known to be insect-pollinated. Cannot vegetatively reproduce (Starr , Starr & Loope 2003).

10. Number of propagules produced? Rigid seed pods (mostly grow in pairs) mature about 6 months after flowering and each contain an average of 350 brown seeds but can contain up to 450 seeds (DNRME 2004). Can produce more than 8000 seeds in a single reproductive episode and can set seed at least twice per year (Starr , Starr & Loope 2003).

11. Propagule longevity? Approximately 95% of seeds are viable (DNRME 2004). Seeds remain viable for approximately 12 months (Starr , Starr & Loope 2003).

12. Reproductive period? Individual plants have been known to live for more than 80 years (DNRME 2004).

13. Time to reproductive maturity? Plants can begin to reproduce after about 200 days although dependent on soil moisture, it can take more than four years to flower (Starr , Starr & Loope 2003).

DISPERSAL

14. Number of mechanisms? As each seed has a tuft of long white silky hair, wind and water easily disperse them (via both fresh and salt-water courses) (DNRME 2004). Animals, especially birds, also spread the seed. Seeds can spread in mud sticking to machinery and in the hooves of animals – spreading along watercourses then to pastures and open country (Starr , Starr & Loope 2003).

15. How far do they disperse? As seeds are very light with the tuft to aid dispersal, it is assumed that it is very likely that some propagules will disperse greater than one kilometre. Also bird dispersed (DNRME 2004).

Impact Assessment

RECREATION

1. Restrict human access? “The important properties of rubber vine are its ability to climb over and smother tall trees and to extend into rundown pastures. In such situations it forms dense thickets, particularly along waterways which, being impenetrable to man and beast, restrict access to water” (Parsons & Cuthbertson 2001). Major impediment to access waterways.

2. Reduce tourism? “…it is a twining vine, smothering vegetation. The Undarra Volcanic National Park in Queensland was affected when rubber vine covered the entrance of the volcanic lava tubes, thus decreasing the appeal of this attraction” (ARMCANZ 2001).

3. Injurious to people? “Extracts of the stems are…toxic and the plant has been implicated in human as well as animal deaths. Fortunately rubber vine is unpalatable and seldom eaten, so deaths are few” (Tomley 1998). Potentially fatal for humans.

4. Damage to cultural sites? “In thickets or supported by other vegetation it forms a dense tangled mass, smothering vegetation up to 40 m above the ground” (Tomley 1998). With the smothering habit of rubber vine, infestations on culturally significant vegetation (e.g. historical trees) could have a major impact.

ABIOTIC

5. Impact flow? Terrestrial species (Tomley 1998).

6. Impact water quality? ‘.. severely threatens riverine vegetation, and can potentially displace the plants and animals that inhabit riverbanks, thereby affecting the water quality of streams’ (CRC for Australian Weed Management 2003). Potential to have minor effects in dissolved O2.

7. Increase soil erosion? Rubber vine increases soil erosion due to, “…loss of grasses and other ground covers” (ARMCANZ 2001). It commonly occurs along watercourses (Parsons & Cuthbertson 2001), thus there is a high probability for large scale soil movement.

8. Reduce biomass? “Rubber vine invades and dominates…riverine forest, eucalypt woodland and vine thickets” (Tomley 1998). The smothering nature of rubber vine suggests biomass would increase.

9. Change fire regime? “Heavy grazing and drought reduced the amount of available fuel, and so reduced the frequency and intensity of fires” (Mackey 1996). Although the plant burns vigorously, it requires a significant dry fuel load to cause ignition (Parsons & Cuthbertson 2001). Minor change to frequency of fire.

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? The potential for C. grandiflora to establish and naturalise in Victoria is highly unlikely due to ecoclimatic limitations (Mackey 1996). No impact on EVCs in Victoria.

10(b) Impact on medium value EVC? The potential for C. grandiflora to establish and naturalise in Victoria is highly unlikely due to ecoclimatic limitations (Mackey 1996). No impact on EVCs in Victoria.

10(c) Impact on low value EVC? The potential for C. grandiflora to establish and naturalise in Victoria is highly unlikely due to ecoclimatic limitations (Mackey 1996). No impact on EVCs in Victoria.

11. Impact on structure? “Rubber vine invades and dominates…riverine forest, eucalypt woodland and vine thickets. As a result some of these communities could be largely degraded” (Tomley 1998). “It is a vigorous climber which will smother and kill plants and shade out the ground layer; potential to destroy all deciduous vine thickets in Queensland” (ARMCANZ 2001). Major impact on <60% of the floral strata.

12. Effect on threatened flora? The potential for C. grandiflora to establish and naturalise in Victoria is highly unlikely due to ecoclimatic limitations (Mackey 1996). No impact on threatened flora in Victoria.

FAUNA

13. Effect on threatened fauna? The potential for C. grandiflora to establish and naturalise in Victoria is highly unlikely due to ecoclimatic limitations (Mackey 1996). No impact on threatened fauna in Victoria.

14. Effect on non-threatened fauna? See comment in 11 above. “Fauna living in such communities are also threatened. Rubber vine destroys the habitat of the greater glider Petauroides volans Kerr and the squirrel glider Petaurus norfolcensis Kerr” (Tomley 1998). Reduction in habitat leading to reduced numbers but not local extinction.

15. Benefits fauna? No known benefits.

16. Injurious to fauna? “The plant is highly toxic to cattle, goats, sheep and, especially, horses” (Parsons & Cuthbertson 2001). Potentially injurious to native herbivores.

PEST ANIMAL

17. Food source to pests? Not known as a food source to pest animals.

18. Provides harbor? ‘Its effects include … harbouring feral animals such as wild pigs’ (DNRME 2004). Can provide harbour for minor pest spp.

AGRICULTURE

19. Impact yield? “…there is a direct loss of pasture on better soils where rubber vine competes directly with pasture grasses, [with] dense infestations reducing carrying capacity by nearly 100%” (Tomley 1998). Serious impact on yield.

20. Impact quality? Not a weed of cropping. Not known to affect the quality of other agricultural produce.

21. Affect land values? “Chippendale (1991) reported that landholders perceived that property values…had dropped …due to infestation by rubber vine. …landholders recognise that rubber vine is a serious enough problem to affect their capital investment” (Tomley 1998).

22. Change land use? Rubber vine is toxic, it seriously hinders day-to-day stock management of cattle and increases mustering costs (Tomley 1998). With such a serious impact on grazing activities, land may no longer be viable for grazing purposes.

23. Increase harvest costs? “Mustering costs are almost doubled” (Tomley 1998). Major increase in time and labour to muster animals.

24. Disease host/vector? None evident.

Feedback

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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:

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rubber vine via ala.JPG
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referenced by (1)

wra1032: Common Name - R (via rubber vine)

Article: wra5225 (permalink)
Categories: :wra:c, :wra:inv1, :wra:invmh, :wra:inv2, :wra:inv3, :wra:inv4, :wra:invml, :wra:inv5, :wra:invl, :wra:inv6, :wra:inv7, :wra:inv8, :wra:inv9, :wra:inv10, :wra:invh, :wra:inv11, :wra:inv12, :wra:inv13, :wra:inv14, :wra:inv15, :wra:imp1, :wra:imp2, :wra:imp3, :wra:imp4, :wra:imp5, :wra:imp6, :wra:imp7, :wra:imp8, :wra:imp9, :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: 23 November 2009; 4:02:12 PM AEDT

Author Name: Jessica Mackay
Author ID: mackayj