Besom heath (Erica scoparia)

Present distribution

Scientific name:	Erica scoparia L.
Common name(s):	besom heath

This weed is not known to be naturalised in Victoria

Habitat:

In its invasive range (Tasmania) it is naturalised along roadsides and has spread into both grassland and bushland (Baker 2005). In its native range it occurs in heathland pasture, dry grasslands (Bartolomè et al 2005), dominant on mountain peaks (Arévalo, Fernández-Palacios 2001), damp hollows and interdunal valleys in coastal marshland (UNEP 2005), floodable depressions on dunes (García-Novo et al 2007), marsh lagoons (Sousa, Garcia-Murillo 2003). It is tolerant of summer drought (Retuerto, Carballeira 2004) and grows in deep sandstone (Ojeda et al 2000) and nutrient-poor soils. “Must have acid conditions” (Underhill 1971).

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 dryland; pasture irrigation

Ecological Vegetation Divisions
Coastal; heathland; grassy/heathy dry forest; swampy scrub; freshwater wetland (permanent); treed swampy wetland; lowland forest; forby forest; granitic hillslopes; basalt grassland; alluvial plains grassland; alluvial plains woodland; freshwater wetland (ephemeral)

Colours indicate possibility of Erica scoparia 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 about 2 m (Silva et al 2006) – low nuisance value. May impede individual access	ml	m
2. Reduce tourism?	Greenish-white flowers (Underhill 1971) – weed not obvious to the average visitor	l	mh
3. Injurious to people?	Produces “clouds of pollen” (O’God 2006) – mildly toxic; may cause hay fever and other allergies	ml	ml
4. Damage to cultural sites?	Although E. scoparia has a deep root system to about 2 m (Silva et al 2006), it is not noted to cause damage to cultural sites	l	m
Abiotic
5. Impact flow?	Occurs in heathland shrub and pasture (Bartolomè et al 2005) – terrestrial – little or negligible effect on water flow	l	h
6. Impact water quality?	Occurs in heathland shrub and pasture (Bartolomè et al 2005) – terrestrial – no noticeable effect on dissolved oxygen or light levels	l	h
7. Increase soil erosion?	Deep root system to about 2 m (Silva et al 2006) – low probability of large scale soil movement	l	h
8. Reduce biomass?	Invades grasslands (Bartolomè et al 2005) – biomass may increase	l	h
9. Change fire regime?	Invades grasslands (Bartolomè et al 2005) and produces a “slowly decaying litter” (Debussche et al 1980) – likely to greatly change the frequency and intensity of fire risk	h	h
Community Habitat
10. Impact on composition (a) high value EVC	EVC = Lateritic Woodland/Heathy Woodland Mosaic (E); CMA = Glenelg Hopkins; Bioregion = Greater Grampians; VH CLIMATE potential It is the dominant canopy species in its native range and invades grasslands (Bartolomè et al 2005) – monoculture within a specific layer; displaces all spp. within a strata/layer	h	h
(b) medium value EVC	EVC = Lowland Herb-rich Forest (D); CMA = East Gippsland; Bioregion = East Gippsland Lowlands; VH CLIMATE potential It is the dominant canopy species in its native range and invades grasslands (Bartolomè et al 2005) – monoculture within a specific layer; displaces all spp. within a strata/layer	h	h
(c) low value EVC	EVC = Shrubby Foothill Forest (LC); CMA = Port Phillip and Westernport; Bioregion = Central Victorian Uplands; VH CLIMATE potential It is the dominant canopy species in its native range and invades grasslands (Bartolomè et al 2005) – monoculture within a specific layer; displaces all spp. within a strata/layer	h	h
11. Impact on structure?	It is the dominant canopy species in its native range and invades grasslands (Bartolomè et al 2005) – likely to have a major effect on <60% of the floral strata	mh	h
12. Effect on threatened flora?	Although it invades grasslands (Bartolomè et al 2005) and is therefore likely to change vegetation communities completely, the effect on Priority 1A spp and VROT spp is not yet determined	mh	l
Fauna
13. Effect on threatened fauna?	Although it invades grasslands (Bartolomè et al 2005) and is therefore likely to change habitats dramatically, the effect on VROT or Bioregional Priority spp is not yet determined	mh	l
14. Effect on non-threatened fauna?	Invades grasslands (Bartolomè et al 2005) and is therefore likely to change habitats dramatically, leading to the possible extinction of non-threatened fauna	h	h
15. Benefits fauna?	E. scoparia is unpalatable (Bartolomè et al 2005), but is an evergreen shrub that grows to 2 m (Silva et al 2006) – may provide shelter for some desirable spp.	mh	h
16. Injurious to fauna?	Not noted to be toxic or injurious to fauna (Underhill 1971) – no effect	l	mh
Pest Animal
17. Food source to pests?	Rabbits sometimes feed on young Erica spp. plants (Underhill 1971) – may supply food to a serious pest, but at low levels	mh	mh
18. Provides harbor?	Rabbits sometimes burrow underneath Erica spp. plants (Underhill 1971) – capacity to provide harbor and permanent warrens for rabbits, and possibly foxes, throughout the year	h	mh
Agriculture
19. Impact yield?	Has been known to cause serious growth problems in crop plants, “particularly with various grass species” (Rice 1984) due to its allelopathic properties. It is also known to invade grasslands and is not palatable (Bartolomè et al 2005) – potential to have a major impact on the quantity of produce	mh	m
20. Impact quality?	Although it is also known to invade grasslands (Bartolomè et al 2005) and causes problems in crop growth (Rice 1984), it is not likely to impact the quality of yield	l	m
21. Affect land value?	Although E. scoparia has allelopathic properties (Rice 1984) and invades grasslands (Bartolomè et al 2005) it is likely to have little or no affect on land value	l	m
22. Change land use?	Has been known to cause serious growth problems in crop plants, “particularly with various grass species” (Rice 1984) due to its allelopathic properties – may not be able to grow certain crops affected by this – downgrading of the priority of land use	mh	m
23. Increase harvest costs?	Although E. scoparia has allelopathic properties (Rice 1984) and invades grasslands (Bartolomè et al 2005) it is likely to have little or no affect harvest costs	l	m
24. Disease host/vector?	Not known be a host or vector for diseases of agriculture (not noted as such in Underhill 1971; Bartolomè et al 2005) – little or no host	l	m

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Germination higher in the summer (Arévalo, Fernández-Palacios 2001) – requires natural seasonal disturbance	mh	h
2. Establishment requirements?	Colonization improves in, but is not limited to, bare soil (Bartolomè et al 2005) and it is shade intolerant (Arévalo, Fernández-Palacios 2003) – requires specific requirements to establish, i.e. light	ml	h
3. How much disturbance is required?	“In heathland pasture... the replacement of traditional burning by shrub harvesting has lead to encroachment on intermixed dry grasslands by Erica scoparia.” And its “micro-habitat preferences for colonization require canopy gaps in mature shrubland, such as grassland patches” (Bartolomè et al 2005). In Tasmania it occurs on roadsides, then spreads to encroach on native bushland (CRC 2007) – establishes in highly disturbed natural ecosystems	ml	h
Growth/Competitive
4. Life form?	Evergreen lignotuberous resprouter shrub (Bartolomè et al 2005) – geophyte	ml	h
5. Allelopathic properties?	Has been known to cause serious growth problems in crop plants, “particularly with various grass species” (Rice 1984). Ballester et al (1977) also found that toxins are present in intact fresh leaves and various concentrations will inhibit germination and growth of red clover – allelopathic properties seriously affecting some plants	mh	mh
6. Tolerates herb pressure?	Not eaten by sheep, but eaten only to a limited extent by goats, “not palatable” (Bartolomè et al 2005) – favoured by heavy grazing as not eaten	h	h
7. Normal growth rate?	Being a dominant sprouter after fire (Ojeda et al 1996), it is likely to have a rapid growth rate that will exceed most other species of the same life form	h	h
8. Stress tolerance to frost, drought, w/logg, sal. etc?	Dominant sprouter after fire, also comes back from seed (Ojeda et al 1996) Tolerance of summer drought (Retuerto, Carballeira 2004) Grows in damp hollows and interdunal valleys in a coastal marshland (UNEP 2005) - Highly resistant to fire and water logging, tolerant of drought and may be tolerant to salinity	h	mh
Reproduction
9. Reproductive system	Seeds are the main form of regeneration, but can also reproduce vegetatively (Bartolomè et al 2005)	h	h
10. Number of propagules produced?	Flowers are “very numerous” (Underhill 1971) and the fruit is a “globose capsule containing numerous, very fine seeds” (Baker 2005) – above 2000	h	mh
11. Propagule longevity?	“transient” seed bank, i.e. seed persists in the soil for less than one year (Cerabolini et al 2003)	l	h
12. Reproductive period?	Can live for 10 years (Bartolomè et al 2005) – mature plants produce viable propagules for 3-10 years	mh	h
13. Time to reproductive maturity?	Unknown	m	l
Dispersal
14. Number of mechanisms?	Colonization occurs mainly within 4 m, “probably a consequence of the limited capacity for dispersion of the seeds... and their movement is mainly due to gravity” and it has a higher vegetative performance after cutting (Bartolomè et al 2005). However the seed “would be easily transported by water and on road works equipment” (Baker 2005)	mh	mh
15. How far do they disperse?	If transported by water and road works equipment (Baker 2005) it is very likely that at least one propagule will disperse greater than one kilometre	h	mh

References

Arévalo JR, Fernández-Palacios JM (2001) Seed bank analysis of tree species in two stands of the Tenerife laurel forest (Canary Islands). Forest Ecology and Management, 130,
177-185

Arévalo JR, Fernández-Palacios JM (2003) Spatial patterns of trees and juveniles in a laurel forest of Tenerife, Canary Islands. Plant Ecology 165, 1-10

Baker M (2005) Weed Alerts. Tasweeds incorporating Spotter 28, 10-11. Available at http://www.angelfire.com/nb/tasweeds/pdf/Tasweeds_Sept05.pdf (verified 12 November
2008)

Ballester A, Albo JM, Vieitez E (1977) The allelopathic potential of Erica scoparia L. Oecologia 30, 55-61

Bartolomè J, Lòpez ZG, Boncano MJ, Plaixats J (2005) Grassland colonization by Erica scoparia (L.) in the Montseny Biosphere Reserve (Spain) after land-use changes.
Agriculture, Ecosystems and Environment 111, 253-260

Cerabolini B, Ceriani RM, Caccianiga M, De Andreis R, Raimondi B (2003) Seed size, shape and persistence in soil: a test on Italian flora from Alps to Mediterranean coasts. Seed Science Research 13, 75-85

CRC for Australian Weed Management (2007) Weed management guide; Managing weeds for biodiversity. Spanish heath (Erica lusitanica) and other Erica species. Available at
http://weedscrc.org.au/documents/wmg_spanish%20heath.pdf (verified 13 October 2008)

Debussche M, Escarre J, Lepart J (1980) Changes in Mediterranean shrub communities with Cytisus purgans and Genesta scorpius. Vegetatio 43, 73-82

García-Novo F, Lo Faso RF, Sevilla DG (2007) Restoration of an ancient dune system enhancing landscape perception. In: Isermann M, Kiehl K (eds) Restoration of Coastal
Ecosystems. Coastline Reports 7, 61-67. Available at http://www.eucc-d.de/plugins/coastline_reports/files/CoastLine%20Reports7%20-%207%20-%20Garcia-Novo%20et%20al.pdf (verified 12 November 2008)

O’God (2006) Heather: Calluna vulgaris and the Ericas. Heather Society. Available at http://www.druidry.org/obod/trees/Heather.htm (verified 12 November 2008)

Ojeda F, Arroyo J, Maranon T (2000) Ecological distribution of four co-occurring Mediterranean heath species. Ecography, 23, 148-159

Ojeda F, Maranon T, Arroyo J (1996) Postfire regeneration of a Mediterranean heathland in southern Spain. International Journal of Wildland Fire 6(4), 191-198

Retuerto R, Carballeira A (2004) Estimating plant responses to climate by direct gradient analysis and geographic distribution analysis. Plant Ecology 170, 185-202

Rice EL (1984) Allelopathy, 2nd Edition. Academic Press, Inc.

Silva JS, Rego FC, Mazzoleni S (2006) Soil water dynamics after fire in a Portuguese shrubland. International Journal of Wildland Fire, 15, 99-111

Sousa A, García-Murillo P (2003) Changes in the wetlands of Andalusia (Doñana Natural Park, SW Spain) at the end of the Little Ice Age. Climatic Change 58, 193-217

Tutin TG, Heywood VH, Burges NA, Moore DM, Valentine DH, Walters SM, Webb DA (eds) (1972) Flora Europaea Vol 3. Cambridge University Press.

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

UNEP (2005) Donana National Park – Spain. Protected areas and world heritage. United Nations Environment Programme and World Conservation Monitoring Centre. Available
at http://www.unep-wcmc.org/sites/wh/donana.html (verified 13 October 2008)

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 11 November 2008).

Global Biodiversity Information Facility (GBIF) (2008) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 11 November 2008).

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