Hypericum canariense L.

Title: Hypericum canariense L.

Scientific Name:

Hypericum canariense L.

Common Names:

Canary Island St John's wort

Image via GBIF

Habitat:

In its native range it has been found growing in the wild in disturbed places, coastal sage scrub, and in xerophytic scrub or forested zones from 150 to 800 metres. In grassland habitats up to 100 metres in elevation in coastal areas of California (PIER 2005). Natural areas threatened by H. canariense include mid to high elevation shrubland, grassland, gulches, and mesic to xeric forests (Starr et al. 2003).

Distribution:

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? ‘Water is sufficient to break seed dormancy’ (Dlugosch 2004). Opportunistic germinator.

2. Establishment requirements? ‘It seems to invade only disturbed or dry sites that have sufficient light’ (PIER 2005). Requires more specific requirements to establish.

3. How much disturbance is required? In Hawaii found ‘along roads, in yards, gulches, and pastures’ (Starr et al 2003). On Canary Islands it is found in dry scrub and laurel forests (Dlugosch 2004). Also found in coastal sage scrub and in grassland habitats (PIER 2005). Can establish in minor disturbed natural ecosystem.

GROWTH / COMPETITIVE

4. Life form? Shrub (Randall 2002). Life form – other.

5. Allelopathic properties? None described (PIER 2005).

6. Tolerates herb pressure? In Maui numerous insects were observed to be associated with H. canariense however ‘none of these insects were doing much damage to the plants’ (Starr et al 2003). Consumed but recovers quickly.

7. Normal growth rate? ‘Given favourable conditions, it may grow to over 1 m in its first year’ (Dlugosch 2004). In California it does out compete dominant native shrubs (Randall 2002). Rapid growth rate that will exceed most other species of same life form.

8. Stress tolerance to frost, drought, w/logg, sal. etc? Found in xerophytic scrub (PIER 2005). Somewhat tolerant to drought. In its native range in Canary Islands, not subjected to frost. Occurs in places with salinity (Hansford & Laconis 2004). No evidence to suggest that plant is tolerant of fire or waterlogging.

REPRODUCTION

9. Reproductive system? Reproduces by both seeds and rhizomes (Hansford & Laconis 2004). Both vegetative and sexual reproduction.

10. Number of propagules produced? Seeds are numerous (Randall 2002). Each fruit ‘releases hundreds of tiny seeds’ (Dlugosch 2004). Produces greater than 2,000 seeds per flowering event.

11. Propagule longevity? ‘.. seed germination rate is approximately 50%’ (Dlugosch 2004). Longevity not documented but no evidence to suggest seed survival is greater than 5 years.

12. Reproductive period? Annual herb. ‘Left undisturbed it is very likely to develop dense monoculture infestations’ (Randall 2002).

13. Time to reproductive maturity? ‘Flowers and fruits may be produced in the first year of growth’ (Dlugosch 2004).

DISPERSAL

14. Number of mechanisms? ‘[H. canariense] light seeds are probably wind dispersed’. Plants are found along roads, which may be an indication that it is spread by light vehicular traffic. (Starr et al 2003).

15. How far do they disperse? ‘Local spread in California ranges from 45 to 90 metres a year, which is considerable distance for a perennial shrub with no outside assistance or any known dispersal mechanisms ’ (Randall 2002). Very few to none will disperse to 1 km, most 20-200 m.

Impact Assessment

RECREATION

1. Restrict human access? Many-branched shrub which can grow from one to 5 metres tall (Randall 2002). Species can be used in borders. Plant is likely to impede individual access.

2. Reduce tourism? Has ‘numerous bright yellow flowers and an attractive shrubby habit (Randall 2002). Most noticeable during its flowering period (spring ) (Starr et al. 2003). Weed would have minor effect on aesthetics.

3. Injurious to people? Weed not documented to be injurious in any way.

4. Damage to cultural sites? Has ‘numerous bright yellow flowers and an attractive shrubby habit (Randall 2002). Most noticeable during its flowering period (spring ) (Starr et al. 2003). Weed would have a moderate visual effect.

ABIOTIC

5. Impact flow? Terrestrial species.

6. Impact water quality? Terrestrial species.

7. Increase soil erosion? Shrub is dense and multi-stemmed. Although foliage drops, unlikely that soil would be exposed for any length of time. Low probability of large scale soil movement.

8. Reduce biomass? ‘Highly competitive plant which displaces virtually all lower storey species’ (Randall 2002). Biomass may increase.

9. Change fire regime? Multi-stemmed scrub with foliage dropping in late summer (Dlugosch 2004). ‘Dense growth in dry environments, carries few leaves’ (PIER 2005). Plant would have minor effect on fire risk.

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? EVC= Plains Grassy Woodland (E.); CMA=Glenelg Hopkins; Bioreg=Victorian Volcanic Plain; CLIMATE potential=VH. Major displacement of some dominant species within the lower storey.

10(b) Impact on medium value EVC? EVC= Grassy Woodland (D); CMA=West Gippsland; Bioreg=Highland Southern Fall; CLIMATE potential=VH. Major displacement of some dominant species within the lower storey.

10(c) Impact on low value EVC? EVC= Granitic Hills Woodland (LC); CMA=Goulburn Broken; Bioreg=Northern Inland Slopes; CLIMATE potential=VH. Major displacement of some dominant species within the lower storey.

11. Impact on structure? ‘Highly competitive plant which displaces virtually all lower storey species’ (Randall 2002). Major effect on less than 60% of floral strata.

12. Effect on threatened flora? This species is not documented as posing an additional risk to threatened flora.

FAUNA

13. Effect on threatened fauna? This species is not documented as posing an additional risk to threatened fauna.

14. Effect on non-threatened fauna? Plant not documented to have an effect on non-threatened fauna.

15. Benefits fauna? Plant not known to provide benefits to indigenous fauna.

16. Injurious to fauna? Plant doesn’t have burrs or spines (PIER 2005) and not known to be toxic.

PEST ANIMAL

17. Food source to pests? Weed not documented as a food source to pest animals.

18. Provides harbor? Weed not known to provide harbour for pest species.

AGRICULTURE

19. Impact yield? Not known as a weed of agriculture (Randall 2002).

20. Impact quality? Not a weed of cropping (Randall 2002).

21. Affect land values? Weed not documented to affect land value (PIER 2005).

22. Change land use? See above. Not documented to cause a change in priority of land use (PIER 2005).

23. Increase harvest costs? Not known as a weed of agriculture (Randall 2002).

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

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

The entry of this assessment was made possible through the generous support of Nature's Weeding Centre.

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Attachments:

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referenced by (1)

wra997: Common Name - C (via Canary Island St John's wort)

Article: wra8652 (permalink)
Categories: :wra:h, :wra:inv1, :wra:invh, :wra:inv2, :wra:invml, :wra:inv3, :wra:invmh, :wra:inv4, :wra:invl, :wra:inv5, :wra:inv6, :wra:inv7, :wra:inv8, :wra:inv9, :wra:inv10, :wra:inv11, :wra:inv12, :wra:inv13, :wra:inv14, :wra:inv15, :wra:imp1, :wra:impml, :wra:imp2, :wra:imp3, :wra:impl, :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:imph, :wra:imp16, :wra:imp17, :wra:imp18, :wra:imp19, :wra:imp20, :wra:imp21, :wra:imp22, :wra:imp23, :wra:imp24
Date: 18 February 2023; 8:06:56 PM AEDT

Author Name: David Low
Author ID: adminDavid