Hedge heath (Erica caffra)

Present distribution

Scientific name:	Erica caffra L.
Common name(s):	hedge heath

This weed is not known to be naturalised in Victoria

Habitat:

Naturalised in hillside scrub in NZ (Webb et al 1988), “in ravines and on cliffs, usually along streams or in damp places” (Van Wyk, Van Wyk 1997)
also occur on the margins of woodlands (Elliot 1999). In its native range it is dominant in riparian scrub in open and closed habitats (Galatowitsch,
Richardson 2005). Mixed sands and clays (Helme 2007), in soils that are seasonally waterlogged and very dry in the summer (Helme 2007).

Potential distribution

Potential distribution produced from CLIMATE modelling refined by applying suitable landuse and vegetation type overlays with CMA boundaries

Map Overlays Used

Land Use:
Forestry; horticulture perennial; pasture irrigation

Ecological Vegetation Divisions
Coastal; heathland; swampy scrub; freshwater wetland (permanent); treed swampy wetland; lowland forest; foothills forest; forby forest; damp forest; riparian; high altitude wetland; granitic hillslopes; western plains woodland; basalt grassland; alluvial plains grassland; alluvial plains woodland; ironbark/box; riverine woodland/forest; freshwater wetland (ephemeral)

Colours indicate possibility of Erica caffra infesting these areas.

In the non-coloured areas the plant is unlikely to establish as the climate, soil or landuse is not presently suitable.

Red= Very high	Orange = Medium
Yellow = High	Green = Likely

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	Grows to 3m (New Zealand Plant Conservation Network 2005) in riparian areas (Galatowitsch, Richardson 2005) – high nuisance value. People and/or vehicles access with difficulty	mh	mh
2. Reduce tourism?	Grows to 3m and has white, occasionally pink flowers (New Zealand Plant Conservation Network 2005) and is dominant in riparian areas (Galatowitsch, Richardson 2005) – some recreation uses could be affected	mh	mh
3. Injurious to people?	No mention of injurious properties (Van Wyk, Van Wyk 1997) – no effect	l	mh
4. Damage to cultural sites?	Grows to 3m and has white, occasionally pink flowers (New Zealand Plant Conservation Network 2005) – may have moderate visual effects	ml	m
Abiotic
5. Impact flow?	Riparian pioneer (Galatowitsch, Richardson 2005), but does not grow in the water – little or negligible affect on water flow	l	h
6. Impact water quality?	Riparian pioneer (Galatowitsch, Richardson 2005) and grows to 3m (New Zealand Plant Conservation Network 2005) – may have noticeable effects on light levels	ml	mh
7. Increase soil erosion?	As it is an evergreen shrub (New Zealand Plant Conservation Network 2005) there is low probability of large scale soil movement	l	m
8. Reduce biomass?	“tolerate open habitats favoured by alien trees, eventually forming closed canopies required by shade-tolerant species” (Galatowitsch, Richardson 2005) – increase biomass	l	h
9. Change fire regime?	“Tolerate open habitats favoured by alien trees, eventually forming closed canopies required by shade-tolerant species” (Galatowitsch, Richardson 2005). It is also dominant in a vegetation community that survives fire (Vogelgat Private Nature Reserve 2005) – greatly changes the frequency and intensity of fire risk	h	mh
Community Habitat
10. Impact on composition (a) high value EVC	EVC = Redgum Wetland (V); CMA = Wimmera; Bioregion = Wimmera; VH CLIMATE potential “tolerate open habitats favoured by alien trees, eventually forming closed canopies required by shade-tolerant species” (Galatowitsch, Richardson 2005) -Monoculture within a specific layer; displaces all spp. within a strata/layer	h	h
(b) medium value EVC	EVC = Valley Grassy Forest (D); CMA = East Gippsland; Bioregion = East Gippsland Lowlands; VH CLIMATE potential “tolerate open habitats favoured by alien trees, eventually forming closed canopies required by shade-tolerant species” (Galatowitsch, Richardson 2005) – Monoculture within a specific layer; displaces all spp. within a strata/layer	h	h
(c) low value EVC	EVC = Wet Heathland (LC); CMA = Glenelg Hopkins; Bioregion = Glenelg Plain; VH CLIMATE potential “tolerate open habitats favoured by alien trees, eventually forming closed canopies required by shade-tolerant species” (Galatowitsch, Richardson 2005)- Monoculture within a specific layer; displaces all spp. within a strata/layer	h	h
11. Impact on structure?	“tolerate open habitats favoured by alien trees, eventually forming closed canopies required by shade-tolerant species” (Galatowitsch, Richardson 2005) – may invade open areas, therefore may effect all layers	h	h
12. Effect on threatened flora?	Not known to threaten Priority 1A spp. or VROT spp.	mh	l
Fauna
13. Effect on threatened fauna?	Not known to threaten VROT or Bioregional Priority spp.	mh	l
14. Effect on non-threatened fauna?	“tolerate open habitats favoured by alien trees, eventually forming closed canopies required by shade-tolerant species” (Galatowitsch, Richardson 2005) – capacity to change habitat dramatically, leading to the possible extinction of non-threatened fauna	h	h
15. Benefits fauna?	No information on palatability, however it is a shrub to 3 m (New Zealand Plant Conservation Network 2005), therefore is likely to provide some assistance in shelter to desirable species	mh	m
16. Injurious to fauna?	No mention of injurious properties (Van Wyk, Van Wyk 1997) – no effect	l	mh
Pest Animal
17. Food source to pests?	Rabbits sometimes feed on young Erica spp. plants (Underhill 1971) – likely to supply food for a serious pest	mh	mh
18. Provides harbor?	Rabbits sometimes burrow underneath Erica spp. plants (Underhill 1971) – capacity to provide harbour and permanent warrens for foxes and rabbits throughout the year	h	mh
Agriculture
19. Impact yield?	Not listed as a weed of agriculture (Randall 2007) – impact on yield unknown	m	l
20. Impact quality?	Not listed as a weed of agriculture (Randall 2007) – impact on quality unknown	m	l
21. Affect land value?	Not listed as a weed of agriculture (Randall 2007) – impact on land value unknown	m	l
22. Change land use?	Not listed as a weed of agriculture (Randall 2007) – impact on priority of land use unknown	m	l
23. Increase harvest costs?	“tolerate open habitats favoured by alien trees, eventually forming closed canopies required by shade-tolerant species” (Galatowitsch, Richardson 2005) – if this invades pastureland and forestry plantations, clearing may be required before harvest – minor increase in cost of harvesting	m	m
24. Disease host/vector?	Plants belonging to the Erica genus “are eaten by the larvae of some Lepidoptera species” (Art Immersion 2008) – provides host to common pests	m	ml

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	“Smoke treatment is essential in the propagation of nearly all South African Ericas” (Garden Web 2008) – requires unseasonal or uncommon natural events for germination	ml	ml
2. Establishment requirements?	Dominant in riparian scrub in both open and closed habitats (Galatowitsch, Richardson 2005) – can establish without additional factors	h	h
3. How much disturbance is required?	Occurs “in ravines and on cliffs, usually along streams or in damp places” (Van Wyk, Van Wyk 1997) and “on the margins of woodlands on Bruny Island” (Elliot 1999). Dominant in riparian scrub in both open and closed habitats (Galatowitsch, Richardson 2005) – establishes in relatively natural ecosystems	mh	mh
Growth/Competitive
4. Life form?	Shrub (Elliot 1999)	l	h
5. Allelopathic properties?	No literature that identifies E. caffra as allelopathic, however other Erica spp., such as E. cinerea, E. mediterranea, and E. scoparia, have allelopathic properties affecting some crops (Rice 1984). Therefore there is a chance that the allelopathic properties are as yet unknown	m	l
6. Tolerates herb pressure?	Plants belonging to the Erica genus “are eaten by the larvae of some Lepidoptera species” (Art Immersion 2008), however no information on its recovery, or specific to the species	m	l
7. Normal growth rate?	Dominant species (Vogelgat Private Nature Reserve 2005) – rapid growth rate that will exceed most other species of the same life form	h	m
8. Stress tolerance to frost, drought, w/logg, sal. etc?	Grows where frosts “occur most nights from march to September” in South Africa (Scott et al 2005) Dominant in a vegetation community that survives fire (Vogelgat Private Nature Reserve 2005) Grows in soils that are seasonally waterlogged and very dry in the summer (Helme 2007) Tolerant to frost, fire, water logging and may be tolerant to drought.	h	m
Reproduction
9. Reproductive system	By seed (New Zealand Plant Conservation Network 2005) – sexual reproduction	ml	m
10. Number of propagules produced?	“many seeds are produced” (New Zealand Plant Conservation Network 2005) and large plants of Eric cinerea can produce tens of thousands of seeds per year (Soons, Bullock 2008), up to 1.2 million (Bullock, Moy 2004) – likely to produce over 2000 per flowering event	h	m
11. Propagule longevity?	Although seeds of Erica cinerea can survive for 30 – 40 years in the soil seed bank (Turner, Conran 2004), it the propagule longevity for E. caffra is unknown	m	L
12. Reproductive period?	Unknown	m	l
13. Time to reproductive maturity?	Unknown	m	l
Dispersal
14. Number of mechanisms?	Dispersed by people and gravity (New Zealand Plant Conservation Network 2005). The seeds are also very easily scattered by wind, as 50,000 E. caffra seeds weigh one gram (Marloth 1932) – very light wind dispersed	h	m
15. How far do they disperse?	Dispersal by people (New Zealand Plant Conservation Network 2005) may result in dispersal greater that 1 km	h	m

References

Art Immersion (2008) The Erica Resource. Available at http://www.artimmersion.com/Emot-to-Evil/erica.php (verified 10 November 2008)

Dave’s Garden (2008) Plant Files: Heath, Erica. Available at http://davesgarden.com/guides/pf/go/118720/ (verified 17 October 2008)

Elliot D (1999) Spanish heath. Meander Valley Weed Strategy. Available at http://www.microtech.com.au/mvws/spheath.htm (verified 1 October 2008)

Galatowitsch S, Richardson DM (2005) Riparian scrub recovery after clearing of invasive alien trees in headwater streams of the Western Cape, South Africa. Biological
Conservation, 122, 509-521

Garden Web (2006) How do I grow Erica caffra from seed? iVillage Inc. Available at http://forums.gardenweb.com/forums/load/safrplt/msg0308102022061.html (verified 24
October 2008)

Helme NA (2007) Botanical report: Fine scale vegetation mapping of the Bokkeveld Escarpment. Report for CapeNature, as part of the C.A.P.E. programme. Available at
http://bgis.sanbi.org/fsp/bokkeveldvegetationreport.pdf (verified 24 October 2008)

Marloth R (1932) The Flora of South Africa Vol III.

New Zealand Plant Conservation Network (2005) Erica caffra. Available at http://www.nzpcn.org.nz/exotic_plant_life_and_weeds/detail.asp?WeedID=1516 (verified 20 October
2008)

Rice EL (1984) Allelopathy: second edition. Academic Press, Inc.

Roy B, Popay I, Champion P, James T, Rahman A (2004) An illustrated guide to common weeds of New Zealand, 2nd Edition. New Zealand Plant Protection Society.

Scott L, Bousman CB, Nyakale M (2005) Halocene pollen from swamp, cave and hyrax dung deposits at Blydefontein (Kikvorsberge), Karoo, South Africa. Quaternary
International, 129, 49-59

Turner D, Conran JG (2004) The reproductive ecology of two naturalised Erica species (Ericaceae) in the Adelaide Hills: the rise and fall of two ‘would-be’ weeds? Transactions of the Royal Society of South Australia, 128(1), 23-31

Underhill TL (1971) Heaths and heathers; Calluna, Daboecia and Erica. David & Charles: Newton Abbot

Van Wyk B, Van Wyk P (1997) Field guide to Tress of Southern Africa. Struik.

Vogelgat Private Nature Reserve (2005) Vegetation; Indigenous plant species. Available at http://www.vogelgat.co.za/vegetation.htm (verified 24 October 2008)

Webb CJ, Sykes, WR, Garrock-Jones PJ (1988) Flora of New Zealand Vol 4. Botany Division, DSIR. Christchurch, NZ.

Global present distribution data references

Australian National Herbarium (ANH) (2008) Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, Available at
http://www.anbg.gov.au/avh/ (verified 10 November 2008).

Scott L, Bousman CB, Nyakale M (2005) Halocene pollen from swamp, cave and hyrax dung deposits at Blydefontein (Kikvorsberge), Karoo, South Africa. Quaternary
International, 129, 49-59

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