Title: Foeniculum vulgare Miller

Scientific Name:

Foeniculum vulgare Miller

Common Names:

fennel, dill, aniseed



Source & more images (via ALA)

Habitat: Humid-temperate regions, growing on a wide range of soil types (Parsons and Cuthbertson 1992). It is restricted to areas of moderate rainfall or where irrigation run-off water is available, or to low-lying areas subject to flooding (Parsons and Cuthbertson 1992). It occurs as a weed on roadsides, railway easements, channels and drains, rubbish dumps and neglected areas from which it occasionally encroaches onto more productive land (Parsons and Cuthbertson, 1992). Fennel invades dry coastal vegetation, lowland grassland and grassy woodland, riparian vegetation and rock outcrop vegetation (Carr et al. 1992).

Distribution:



Original source via CABI


Invasiveness Assessment

ESTABLISHMENT


1. Germination requirements? “Seeds germinate at almost any time of the year”, (Parsons and Cuthbertson, 1992).

2. Establishment requirements? “It grows best in open, un shaded situations”, (Parsons and Cuthbertson, 1992).

3. How much disturbance is required? Establishes in minor disturbed natural ecosystems (e.g. riparian vegetation and grasslands), crops and pastures, (Carr et al, 1992; Blood (n.d.)).

GROWTH / COMPETITIVE


4. Life form? Perennial herb – above ground material dies and re grows from crown each spring, therefore geophyte, (Parsons and Cuthbertson, 1992).

5. Allelopathic properties? Possible allepathic properties as many vegetables and herbs do not grow in association with fennel, (Parsons and Cuthbertson, 1992).

6. Tolerates herb pressure? Consumed: still assumed to be capable of vegetative propagule production (crown/root fragments), so may persist, (Parsons and Cuthbertson, 1992).

7. Normal growth rate? Fennel excludes almost all other vegetation. “Able to out compete small native understorey shrubs and groundcover plants”, (Northcote City Council; Parsons and Cuthbertson, 1992).

8. Stress tolerance to frost, drought, w/logg, sal. etc? Tolerant of frost, water logging, semi aridity, (Parsons and Cuthbertson, 1992).

REPRODUCTION


9. Reproductive system? Reproducing by seed, from the crown and pieces of crown and root, (Parsons and Cuthbertson, 1992).

10. Number of propagules produced? (Estimate based on pic. in Butcher 1961). ∼ 10 inflorescence x 16 umbels x 100 seeds/umbel = 16,000 seeds/plant, (Butcher, 1961).

11. Propagule longevity?

12. Reproductive period? May form dense monocultures (see pic. Parsons and Cuthbertson (1992) p. 171), (Parsons and Cuthbertson, 1992).

13. Time to reproductive maturity? “Plants generally do not flower until 18 months to 2 years old", (Parsons and Cuthbertson, 1992).

DISPERSAL


14. Number of mechanisms? Crown and root dragged by equipment and machinery. Seeds spread by vehicles, machinery, animals (external), clothing, water, etc. also wind, (Parsons and Cuthbertson, 1992; Blood (n.d.)).

15. How far do they disperse? Many will disperse > 200 m, especially through earth movement, stock, water and wind, (Parsons and Cuthbertson, 1992; Blood (n.d.)).


Impact Assessment

RECREATION


1. Restrict human access? An erect multi-stemmed perennial herb commonly 1.5 to 2.0 metres high. It is found along waterways, drainage lines and in seasonally moist locations within grasslands and woodlands. Dense infestations may restrict access to waterways. A soft, herbaceous plant the high growth of the plant may be a nuisance to people, (Muyt, 2001).

2. Reduce tourism? Dense infestations along waterways may restrict some recreational activities, (Muyt, 2001).

3. Injurious to people? The National Occupational Health and Safety Commission documents F. vulgare as causing photosensitivity through skin contact with the plant or its juices, (National Occupational Health and Safety Commission, 2003).

4. Damage to cultural sites? Not an aggressive root system; structure not affected. Dense infestations would create have a moderate negative visual effect, (Muyt, 2001).

ABIOTIC


5. Impact flow? Terrestrial species, (Parsons and Cuthbertson, 2001).

6. Impact water quality? Terrestrial species, (Parsons and Cuthbertson, 2001).

7. Increase soil erosion? A perennial herb that in dense infestations eliminates most other ground flora, but retains good ground cover. It has a stout branched taproot to around 1 metre deep with many laterals. Not likely to contribute to soil erosion, (Parsons and Cuthbertson, 2001; Muyt, 2001).

8. Reduce biomass? Grows mostly in open, disturbed areas, such as roadside, railway easements, channels and drains. Minor effect on biomass. Dense infestations may increase biomass, (Parsons and Cuthbertson, 2001).

9. Change fire regime? Flower stems partly die back in winter. Images of dense infestations show increased dry matter. Possible minor increase to the frequency of fire risk, (Parsons and Cuthbertson, 2001; The Nature Conservancy, 2003).

COMMUNITY HABITAT


10(a) Impact on composition of high value EVC? EVC=Plains grassland (E); CMA=West Gippsland; Bioreg=Highlands – Southern Falls; VH CLIMATE potential “Grows best in open, unshaded situations. Once established, fennel excludes almost all other vegetation.” Major displacement of species within different strata, (Parsons and Cuthbertson, 2001).

10(b) Impact on medium value EVC? EVC=Shrubby woodland (R); CMA=Corangamite; Bioreg=Central Victorian Uplands; VH CLIMATE potential Impact as in 10(a) above. Population density may be limited due to overstorey cover, (Parsons and Cuthbertson, 2001).

10(c) Impact on low value EVC? EVC=Heathy woodland (LC); CMA=Port Phillip; Bioreg=Gippsland Plain; VH CLIMATE potential Impact as in 10(b) above, (Parsons and Cuthbertson, 2001).

11. Impact on structure? “Dense infestations eliminate most other ground-flora and severely impede overstorey regeneration.” Major effect on ground flora, (Muyt, 2001).

12. Effect on threatened flora?

FAUNA


13. Effect on threatened fauna?

14. Effect on non-threatened fauna? While livestock may find the plant palatable, its widespread distribution in medium to large populations suggests that native fauna do not significantly graze on it. With its dominant nature, it is likely to reduce habitat, (California Exotic Pest Plant Council, 2003; Carr et al., 1992).

15. Benefits fauna? No documented benefits.

16. Injurious to fauna? “Apparently animals graze the fennel stubble without ill effects.” Not known to cause injury to native fauna, (Parsons and Cuthbertson, 2001).

PEST ANIMAL


17. Food source to pests? No evidence of the plant providing food to pest species.

18. Provides harbor? Dense infestations may provide harbor for minor pests such as rodents.

AGRICULTURE


19. Impact yield? Not a serious weed of pasture or cropping. “It does not establish in grazed pastures or cultivated paddocks. Herb growers note that tomatoes and beans do not grow in association with fennel, suggesting possible allelopathic effect.” Likely to have some effect in those situations, (Parsons and Cuthbertson, 2001).

20. Impact quality? Not a serious weed of pasture or cropping. “When growing on headlands of arable crops, seedlings often occur in the crops.” Minor impact on quality through seed contamination, (Parsons and Cuthbertson, 2001).

21. Affect land values? Not a serious weed of pasture or cropping. Not likely to affect land value, (Parsons and Cuthbertson, 2001).

22. Change land use? Not a serious weed of pasture or cropping. Land use not affected, (Parsons and Cuthbertson, 2001).

23. Increase harvest costs? No increase in harvest costs.

24. Disease host/vector? None evident.




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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 an anonymous donor.






Attachments:
Fennel plant.jpg
tn_fennel_flower.jpg
dill via ala.JPG
distribution_map (27).png
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Date: 19 October 2009; 3:23:44 PM AEDT

Author Name: Jessica Mackay
Author ID: mackayj