Asparagus declinatus L.

Title: Asparagus declinatus L.

Scientific Name:

Asparagus declinatus L.

Common Name:

pale-berry asparagus-fern, pale fruited asparagus, bridal veil

Source & more images

Habitat: Native to South Africa. In South Africa, ‘found in fynbos or coastal scrub, predominantly on rocky outcrops’ (Obermeyer, 1984 cited in Bass & Lawrie, 2003).‘ Potential to inhabit a range of vegetation communities including closed forests and open woodlands’ (Lethbridge, 2005). In Australia, has been found in low open forest (Bass & Lawrie, 2003).

Distribution:

Present Distribution - Australia (source: ALA)

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? The above ground shoots act as annuals, emerging in autumn from rhizomes, to then senesce with increasing temperatures from November to January (Lawrie 2006a). Germination can occur during the cooler months from march to august (Dept. Water, Land & Biodiversity Conservation 2006). Therefore germination is restricted by seasonal conditions.

2. Establishment requirements? In Australia, has been found in low open forest (Bass & Lawrie 2003). Under experimental conditions it has been reported to grow well under 70-90% shade and open sun (Bass et al 2006). The species has not been reported to establish under such conditions and therefore its known establishment under moderate canopy conditions is all that can be gone by at this stage.

3. How much disturbance is required? In South Africa, ‘found in fybros or coastal scrub, predominantly on rocky outcrops’ (Obermeyer 1984 cited in Bass & Lawrie 2003).‘Potential to inhabit a range of vegetation communities including closed forests and open woodlands’ (Lethbridge 2005). In Australia, has been found in low open forest (Bass & Lawrie 2003). Can establish in healthy natural ecosystems.

GROWTH / COMPETITIVE

4. Life form? Climbing perennial. Geophyte (Bass & Lawrie 2003).

5. Allelopathic properties? None described.

6. Tolerates herb pressure? Grazing by sheep and cattle has been tried as a control method, however it is not preferred by either species sheep mainly eating the new shoots, at high stocking rates can reduce the plant and restrict flowering and therefore sexual reproduction (Lawrie 2006b). In summery the species is not preferred and high stocking rates are required to prevent sexual reproduction.

7. Normal growth rate? The little is known about the growth rate of this species, however for management purposes it is presumed to be similar to A. asparragoides (Dept. Water, Land & Biodiversity Conservation 2006).

8. Stress tolerance to frost, drought, w/logg, sal. etc? Drought tolerant, the species senesces during the summer months to regrow from rhizomes in autumn (Lawrie 2006a). A. asparagoides ‘is frost tolerant and its root system allows it to survive summer droughts’ (Weeds CRC 2003). Fire is still being experimented with as a control method, however at this stage it has been unsuccessful due to the difficulty of maintaining a high intensity fire so as to cook the tubers (Lawrie 2006b). Susceptible to waterlogging. Found along coast (Lawrie 2006a ). Therefore likely to be salt tolerant.

REPRODUCTION

9. Reproductive system? Capable of both sexual and vegetative reproduction, by flowering and producing fruit and having an extensive branching rhizomatous root system (Lawrie 2006a).

10. Number of propagules produced? Normally have 5-8 seeds per fruit but can range from 2-14, fruit production can vary from 100-800 fruit m-2 therefore average seed production can be 4800 seeds m-2 (Lawrie 2006a). This species can form extensive root systems of branching rhizomes, with many of the rhizomes producing tubers and shoots (Lawrie 2006a). Therefore multiple stems may be considered the same plant and therefore it is possible that the number of propagules produced by one plant exceeds 2000.

11. Propagule longevity? For A. asparagoides ‘buried seed .. rots within two years, while seed on the soil surface may be viable for at least three years’ (Weeds CRC 2003). Studies currently being done to determine propagule longevity for A. declinatus.

12. Reproductive period? Insufficient information to determine reproductive period for A. declinatus.

13. Time to reproductive maturity? Unknown, A. asparagoides takes three years to flower, vegetative reproduction may occur faster.

DISPERSAL

14. Number of mechanisms? A. declinatus seeds may be dispersed by the grey currawong, Australian magpie, Australian raven, brush wattlebird and red wattlebird (Bass & Lawrie 2003; Lawrie 2006a). Mammal species are also reported as dispersal agents, including brush tailed and ring tailed possums, foxes and bush rats (Bass 2002; Lawrie 2006). Bird dispersed and eaten by highly mobile animals.

15. How far do they disperse? Dispersal varies with the species between <100m for the smaller bird species to 10km for the currawong (Lawrie 2006a). The dispersal range of various species has been reported as follows; the grey currawong , 20km, the Australian magpie 1km and fox, 5km (Spennemann & Allen 2000)

Impact Assessment

RECREATION

1. Restrict human access? Climbing perennial that grows up to 1m with recurved and zig-zag branches. Can form dense mats. (Bass & Lawrie 2003). Unlikely to restrict human access.

2. Reduce tourism? Introduced as an ornamental species (Lawrie 2004). Therefore may alter aesthetics; however at this stage there is no evidence to support this.

3. Injurious to people? Weed not known to be injurious to people.

4. Damage to cultural sites? Introduced as an ornamental species (Lawrie 2004). Therefore may alter aesthetics; however at this stage there is no evidence to support this.

ABIOTIC

5. Impact flow? Terrestrial species (Marchant et al 1987).

6. Impact water quality? Terrestrial species (Marchant et al 1987).

7. Increase soil erosion? Tuberous roots (Marchant et al 1987). ‘Large plants may have 20-50 tubers and often become entangled with neighbouring plants to produce tuber masses of a square metre consisting of hundreds of tubers’ (Bass 2002). Invasion reduces the area of bare ground (Lawrie 2006a). Plants die back during summer (Bass & Lawrie 2003). May have some soil erosion but low probability of large scale soil movement.

8. Reduce biomass? Root systems form dense mats and can account for up to 85% of mass in mature plants. Where established, there is a decline in litter, bare ground and other ground cover’ (Bass & Lawrie 2003). Long-term a woodland may be altered to an A.declinatus meadow (Leah 2001). However this would be due to prevention of regeneration and other processes would have to be involved to remove those other species (Lawrie 2006a). Therefore an increase in biomass will largely be observed, largely due to the dense root system.

9. Change fire regime? Plant dies back during summer. One study showed that litter in infested areas reduced from 67% to 7%. (Bass & Lawrie 2003). Plant can also establish on bare ground. May cause a minor change to intensity of fire.

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? EVC=Parilla Mallee (BCS = E); CMA=Mallee; Bioreg=Lowan Mallee; CLIMATE potential=VH. ‘A. declinatus reduces biodiversity between 8% and 71%, reduces the recruitment of woody species by 69% and may alter successional pathways’ ‘Correlates with woody canopies > 2 m high’ Where established, there is a decline in litter, bare ground and other ground cover’. ..’approximately 69% less woody plant seedlings in 90 infested quadrats’ (Bass & Lawrie 2003). Potential to cause major displacement of dominant species within the lower and middle strata.

10(b) Impact on medium value EVC? EVC=Grassy dry forest (BCS = D); CMA=Wimmera; Bioreg=Greater Grampians; CLIMATE potential=VH. ‘A. declinatus reduces biodiversity between 8% and 71%, reduces the recruitment of woody species by 69% and may alter successional pathways’ ‘Correlates with woody canopies > 2 m high’ Where established, there is a decline in litter, bare ground and other ground cover’. ..’approximately 69% less woody plant seedlings in 90 infested quadrats’ (Bass & Lawrie 2003). Potential to cause major displacement of dominant species within the lower and
middle strata.

10(c) Impact on low value EVC? EVC=Heathy woodland (BCS = LC); CMA=Glenelg Hopkins; Bioreg=Glenelg Plain; CLIMATE potential=VH. ‘A. declinatus reduces biodiversity between 8% and 71%, reduces the recruitment of woody species by 69% and may alter successional pathways’ ‘Correlates with woody canopies > 2 m high’ Where established, there is a decline in litter, bare ground and other ground cover’. ..’approximately 69% less woody plant seedlings in 90 infested quadrats’ (Bass & Lawrie 2003). Potential to cause major displacement of dominant species within the lower and middle strata.

11. Impact on structure? ‘A. declinatus reduces biodiversity between 8% and 71%, reduces the recruitment of woody species by 69% and may alter successional pathways’ ‘Correlates with woody canopies > 2 m high’ Where established, there is a decline in litter, bare ground and other ground cover’. ..’approximately 69% less woody plant seedlings in 90 infested quadrats’ (Bass & Lawrie 2003). A. asparagoides ‘is a major threat to most low shrubs and groundcover plants in mallee, dry sclerophyll forest and heath vegetation’ (Weeds CRC 2003). Major effect on lower and middle strata.

12. Effect on threatened flora? While no specific species are mentioned Winkler & Taylor (2006) report that the species has potential to impact of threatened flora species.

FAUNA

13. Effect on threatened fauna? Plant not documented as posing an additional risk to threatened fauna.

14. Effect on non-threatened fauna? Plant not documented as having an effect on non-threatened fauna species.

15. Benefits fauna? ‘Preliminary seed dispersal observations of A. declinatus in South Australia indicate the main dispersers are medium to large gregarious birds such as Strepera versicolor (Grey Currawong), Gymnorhina tibicen (Australian Magpie) and Anthochaera carunculata (Red Wattlebird). Arboreal mammals, such as Trichosurus vulpecula (Brush-tailed Possum) and Pseudocheirus peregrinus (Common Ringtail Possum) and small rodents’ (Bass & Lawrie 2003). Plant may provide some assistance in food to desirable species.

16. Injurious to fauna? Plant not documented as being injurious to fauna.

PEST ANIMAL

17. Food source to pests? Foxes have been reported to consume the species fruit (Lawrie 2006a).

18. Provides harbor? Not documented to provide harbor to pest species.

AGRICULTURE

19. Impact yield? May impact upon forestry and some horticulture however at this stage to what extent is unknown. Has ‘similar morphology, ecology and impacts as A. asparagoides (Lawrie 2002). A. asparagoides ‘causes losses to primary industries by shading citrus and avocado trees and interfering with picking’ ‘Grows well in citrus orchards and pine plantations’ (Weeds CRC 2003).

20. Impact quality? Not documented to impact upon quality.

21. Affect land values? ‘Appears to spread more rapidly and better withstand control activities than A. asparagoides’. Possible that land value may be affected if spreads to agricultural areas. Not documented at this stage.

22. Change land use? A. declinatus not documented to change priority of land use but if it spreads to agricultural areas has the potential to.

23. Increase harvest costs? A. declinatus not documented to increase harvest costs but if spreads to agricultural land may involve more time and labour.

24. Disease host/vector? Not documented as a host or vector for disease of agriculture.

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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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referenced by (1)

wra825: Common Name - B (via bridal veil)

Article: wra4347 (permalink)
Categories: :wra:a, :wra:inv1, :wra:invmh, :wra:inv2, :wra:inv3, :wra:invh, :wra:inv4, :wra:invml, :wra:inv5, :wra:invl, :wra:inv6, :wra:inv7, :wra:invm, :wra:inv8, :wra:inv9, :wra:inv10, :wra:inv11, :wra:inv12, :wra:inv13, :wra:inv14, :wra:inv15, :wra:imp1, :wra:impl, :wra:imp2, :wra:impml, :wra:imp3, :wra:imp4, :wra:imp5, :wra:imp6, :wra:imp7, :wra:imp8, :wra:imp9, :wra:imp10a, :wra:impmh, :wra:imp10b, :wra:imp10c, :wra:imp11, :wra:imp12, :wra:imp13, :wra:imp14, :wra:imp15, :wra:imp16, :wra:imp17, :wra:imp18, :wra:imp19, :wra:impm, :wra:imp20, :wra:imp21, :wra:imp22, :wra:imp23, :wra:imp24
Date: 10 November 2009; 3:54:15 PM AEDT

Author Name: Jessica Mackay
Author ID: mackayj