Title: Crataegus monogyna Jacq.

Scientific name:

Crataegus monogyna Jacq.

Common name(s):

hawthorn



Source & more images (via ALA)

Habitat: Humid and subhumid temperate regions, growing well in most soils and colonising shallow stoney sites where annual rainfall is over 600 mm (Parsons and Cuthbertson 1992). Infestations are usually associated with its use in hedges from where it forms thickets along roadsides and forest margins and colonises poorly managed pastures (Parsons and Cuthbertson 1992). Hawthorn is a weed of lowland grassland and grassy woodland, dry sclerophyll forest and woodland, damp sclerophyll forest and riparian vegetation (Carr et al. 1992).

Distribution:



Original source via CABI


Invasiveness Assessment

ESTABLISHMENT


1. Germination requirements? Seeds germinate in autumn (Parsons and Cuthbertson, 1992).

2. Establishment requirements? Occurs along forest margins and woodland areas (e.g. damp sclerophyll forest), so can establish under moderate canopy (Parsons and Cuthbertson, 1992; Carr et al, 1992).

3. How much disturbance is required? Established in minor disturbed natural ecosystems (e.g. woodlands and wetlands) (Carr et al, 1992).

GROWTH / COMPETITIVE


4. Life form? An erect shrub. Other. (Parsons and Cuthbertson, 1992)

5. Allelopathic properties? None described.

6. Tolerates herb pressure? Consumed but not preferred due to spines. (Parsons and Cuthbertson, 1992)

7. Normal growth rate? “Slow early growth” (Robinson, 1996). “Competitive ability low at first then aggressive” (Ester et al, 1993).

8. Stress tolerance to frost, drought, w/logg, sal. etc? Tolerance to drought, cold (frost), salinity. (Parsons and Cuthbertson, 1992)

REPRODUCTION


9. Reproductive system? Reproducing by seed and suckers (Parsons and Cuthbertson, 1992).


10. Number of propagules produced? Produce large amounts of seed. Well over 2000 berries (1 seed per berry) would be produced on a mature tree. (Parsons and Cuthbertson, 1992)


11. Propagule longevity?

12. Reproductive period? Plants are long lived, possibly > 70 years (Parsons and Cuthbertson, 1992; Ester et al, 1993).

13. Time to reproductive maturity? Plants do not flower until the 2nd or 3rd year (Parsons and Cuthbertson, 1992).

DISPERSAL


14. Number of mechanisms? Contaminated machinery, vehicles, animals (including birds) agricultural produce, mud and other animals (foxes, possums and wallaroos) (Parsons and Cuthbertson, 1992).

15. How far do they disperse?“Seeds are not equipped in any special way to aid dispersal”. However, seeds consumed by mammals especially and also birds is likely to be dispersed > 200 m. ALSO, Cooke (1991) states that seeds are spread “far into the bush” by birds and possums that eat the fruit. (Parsons and Cuthbertson, 1992; Cooke, 1991)


Impact Assessment

RECREATION


1. Restrict human access? A deciduous, dense shrub or small tree to 7 metres high and wide. Forms dense thickets that seriously impede movement. It invades a broad range of vegetation communities including riparian and coastal areas. Infestations likely to be a major impediment to humans (Parsons and Cuthbertson, 2001; Muyt, 2001).

2. Reduce tourism? Dense infestations would have a major impact on tourism. It seriously impedes movement and has a major impact on bushland habitats (Muyt, 2001).

3. Injurious to people? “…many stout branchlets terminating in spines, armed with thorns 5 to 25 mm long.” Spines present all year. (Parsons and Cuthbertson, 2001).

4. Damage to cultural sites? C. monogyna forms dense thickets, which have a major impact on bushland habitats. It presence would create a moderate negative visual impact on the area. The root system is deep and spreading and may cause some structural damage (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? The deep spreading root system would effectively bind soil. Although deciduous, the dense growth habit of the plant still provides significant soil cover. Not likely to contribute to soil erosion (Parsons and Cuthbertson, 2001).

8. Reduce biomass? Where it occurs in thickets along roadsides, forest margins, and poorly managed pastures, the dense vegetative growth would increase biomass (Parsons and Cuthbertson, 2001).

9. Change fire regime? In forest margins dense infestations may create an increased risk to the frequency of fire risk. The flammability of the plant is not documented.

COMMUNITY HABITAT


10(a) Impact on composition of high value EVC? EVC=Plains grassy woodland (E); CMA=West Gippsland; Bioreg=Gippsland Plain; VH CLIMATE potential. “When climate and soil are suitable it…forms dense stands.” It shades out ground-flora, “affecting the growth and regeneration of overstorey plants. Major impact on species within different layers.(Parsons and Cuthbertson, 2001; Muyt, 2001).

10(b) Impact on medium value EVC? EVC=Montane grassy woodland (D); CMA=West Gippsland; Bioreg=Highlands – Southern Fall; VH CLIMATE potential. Similar impact as above (Parsons and Cuthbertson, 2001; Muyt, 2001).

10(c) Impact on low value EVC? EVC=Riparian forest (LC); CMA=West Gippsland; Bioreg=Gippsland Plain; VH CLIMATE potential. Similar impact as above (Parsons and Cuthbertson, 2001; Muyt, 2001).

11. Impact on structure? “Dense thickets…have a major impact on bushland habitats, shading out ground-flora and affecting the growth and regeneration of overstorey plants.” Has a major effect on the floral strata (Muyt, 2001).

12. Effect on threatened flora?

FAUNA


13. Effect on threatened fauna?

14. Effect on non-threatened fauna? It has a major impact on bushland habitat. Spines deter grazing animals. Dense stands would significantly reduce habitat of native fauna. (Parsons and Cuthbertson, 2001; Muyt, 2001)


15. Benefits fauna? Birds, possums and wallaroos are known to eat the fruit. Provides habitat and food for smaller native animals (Parsons and Cuthbertson, 2001).

16. Injurious to fauna? Spines all year round; may injure larger grazing animals. “Some species of Crataegus contain hydrocyanic acid [and] should be considered potentially hazardous.” (Parsons and Cuthbertson, 2001).

PEST ANIMAL


17. Food source to pests? Birds and foxes are known to eat the fruit of C. monogyna (Parsons and Cuthbertson, 2001).

18. Provides harbor? “Dense patches provide good cover for rabbits and other pests.” (Parsons and Cuthbertson, 2001).

AGRICULTURE


19. Impact yield? “Dense stands reduce grazing capacity by direct competition and because the spines deter grazing animals. It is known that milk yields are reduced in the British Isles when cows graze hawthorn foliage.” Potential to establish dense patches would have a major impact on yield. (Parsons and Cuthbertson, 2001)

20. Impact quality? Not a plant of cropping. No documented effect on animal produce (Parsons and Cuthbertson, 2001).

21. Affect land values? Removing large infestations demands a major effort. Likely to have an impact on land value (Muyt, 2001).

22. Change land use? It colonises poorly managed pastures. Depending upon the density of infestation, availability of land may be restricted until plant is controlled. (Parsons and Cuthbertson, 2001)

23. Increase harvest costs? Not a plant of cropping; would have no impact on harvesting costs. (Parsons and Cuthbertson, 2001)

24. Disease host/vector? “In the British Isles, hawthorn is an important reservoir of the fire blight bacterium which affects pears and apples.” “It hosts Mediterranean fruit fly and light brown apple moth.” (Parsons and Cuthbertson, 2001; Blood, 2001).




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.






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Date: 19 October 2009; 4:07:26 PM AEDT

Author Name: Jessica Mackay
Author ID: mackayj