Cape aloe (Aloe ferox)

Present distribution

Scientific name:	Aloe ferox Mill.
Common name(s):	Cape aloe, bitter aloe

This weed is not known to be naturalised in Victoria

Habitat:

Native to Southern Africa. Common on rocky hill slopes. Grows in grassy fynbos and on edges of the karoo. Grows in open and bushy areas and bush scrubs (Aubrey 2001). Found in altitudes from sea level to 700 m (Van Wyk & Smith 2003). Species not known as naturalised in Victoria (DSE 2004, ANH 2006).

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:
Horticulture; Pasture dryland

Broad vegetation types
Coastal scrubs and grassland; coastal grassy woodland; grassland; plains grassy woodland.

Colours indicate possibility of Aloe ferox infesting these areas.

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

Map of the potential distrubution of cape aloe

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

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	Grows 2-3 metres with leaves arranged in rosettes. Young plants are very spiny and older plants have spines along edge and on upper and lower surfaces of the leaves (Aubrey 2001). Tends to be found in open areas and doesn’t appear to grow in thickets so at the most would cause a low nuisance value.	ml	mh
2. Reduce tourism?	On rocky slopes ‘creates a stunning winter display’. Flower colour varies from yellowy-orange to bright red (Aubrey 2001). Weed would be noticeable and would have a minor effect on aesthetics.	ml	mh
3. Injurious to people?	Young plants are very spiny and older plants have spines along edge and on upper and lower surfaces of the leaves (Aubrey 2001). Spines at most times of the year.	mh	mh
4. Damage to cultural sites?	On rocky slopes ‘creates a stunning winter display’. Flower colour varies from yellowy-orange to bright red (Aubrey 2001). If the plant was to occur at a cultural site would have a moderate visual effect.	ml	mh
Abiotic
5. Impact flow?	Terrestrial species (Reynolds 1982).	l	mh
6. Impact water quality?	Terrestrial species (Reynolds 1982).	l	mh
7. Increase soil erosion?	Plant is often found on rocky slopes (Aubrey 2001). Likely that it will check soil erosion. Low probability of large scale soil movement.	l	mh
8. Reduce biomass?	‘The density of dying and dead Aloe plants was significantly greater than live plants’ (Breebart et al 2002). Plants not documented to replace other species and often found in open areas. Likely that biomass will increase.	l	mh
9. Change fire regime?	Old dried leaves persist on the stem. Juicy succulent leaves. (Christman 2003). ‘Field surveys demonstrated a significant negative relationship between mortality and degree of stem coverage and laboratory studies confirmed the insulating properties of dead leaves .. 96% of all individuals with stems bare for more than 0.25m were killed by the fire. In contrast 97.3% of aloes with stems completely protected by dead leaves or bare for less than 0.25m survived’. Dead aloe leaves were found very difficult to burn (Bond 1983). Tends to be found in open areas and on rocky slopes. Would not have a major impact on the frequency or intensity of fire risk.	l	mh
Community Habitat
10. Impact on composition (a) high value EVC	EVC= Grassy woodland (BCS = E); CMA=North Central; Bioreg= Goldfields; CLIMATE potential=VH. Not documented to form dense infestations. Plant can grow over 3m tall (Aubrey 2001). May cause a minor displacement of some dominant species within the lower layer.	ml	mh
(b) medium value EVC	EVC= Grassy woodland (BCS = D); CMA=North East; Bioreg= Highlands-northern fall; CLIMATE potential=L. Not documented to form dense infestations. Plant can grow over 3m tall (Aubrey 2001). May cause a minor displacement of some dominant species within the lower layer.	ml	mh
(c) low value EVC	EVC= Coastal tussock grassland (BCS = LC); CMA=Corangamite; Bioreg= Gippsland Plain; CLIMATE potential=M. Not documented to form dense infestations. Plant can grow over 3m tall (Aubrey 2001). May cause a minor displacement of some dominant species within the lower layer.	ml	mh
11. Impact on structure?	Common on rocky hill slopes. Grows in grassy fynbos and on edges of the karoo. Grows in open and bushy areas (Aubrey 2001). Not documented to form dense infestations. Plant can grow over 3m tall. Plant would have a minor effect on 20-60% of the floral strata.	ml	mh
12. Effect on threatened flora?	This species is not documented as posing an additional risk to threatened flora.	mh	l
Fauna
13. Effect on threatened fauna?	This species is not documented as posing an additional risk to threatened fauna.	mh	l
14. Effect on non-threatened fauna?	Plant not documented as posing additional risk to non-threatened fauna.	l	mh
15. Benefits fauna?	Plant provides very little support to desirable fauna species.	h	mh
16. Injurious to fauna?	Young plants are very spiny and older plants have spines along edge and on upper and lower surfaces of the leaves (Aubrey 2001). In South Africa the plants are browsed by a number of animals and it is not documented that the spines effect them although possible that they may. Therefore score as medium.	m	l
Pest Animal
17. Food source to pests?	In Africa ‘monkeys and baboons raid the aloes for nectar’ (Aubrey 2001). Also browsed by Boer goats. Possible that plant could supply food for one or more pest species but not documented.	ml	l
18. Provides harbor?	Plant not documented to provide harbour for pest species.	l	mh
Agriculture
19. Impact yield?	Not a weed of agriculture.	l	mh
20. Impact quality?	Not a weed of cropping.	l	mh
21. Affect land value?	Weed not documented to effect value of land.	l	mh
22. Change land use?	Weed not known to cause a change in priority of land use.	l	mh
23. Increase harvest costs?	Not a weed of cropping.	l	mh
24. Disease host/vector?	Weed not known as a host or vector of disease for agriculture.	l	mh

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Germinates from spring to late summer (Aubrey 2001). Plant requires natural seasonal temperatures for germination.	mh	mh
2. Establishment requirements?	Needs full sun (Christman 2003). Requires more specific requirements to establish.	ml	m
3. How much disturbance is required?	Common on rocky hill slopes. Grows in grassy fynbos and on edges of the karoo. Grows in open and bushy areas (Aubrey 2001). In dry rocky places and in scrubs (Christman 2003). Establishes in minor disturbed natural ecosystems.	mh	mh
Growth/Competitive
4. Life form?	Succulent tree (Aubrey 2001). Life-form – other	l	mh
5. Allelopathic properties?	None described.	l	mh
6. Tolerates herb pressure?	“monkeys and baboons raid the aloes for nectar’ (Aubrey 2001). ‘Mortality of Aloe ferox [in KwaZulu-Natal] was a result of extensive browsing by Boer goats’ (Breebart et al 2002). Unknown what herbivores would attack the plant in Victoria but in South Africa it is consumed and recovers slowly.	ml	h
7. Normal growth rate?	‘The growth rate of this aloe can be quite moderate and some would consider it a slow grower’ (TCSS (n.d.)). Slow growth – will be exceeded by many other species.	l	m
8. Stress tolerance to frost, drought, w/logg, sal. etc?	Seedling will rot if overwatered (Aubrey 2001). ‘Relatively tolerant of drought’ (Christman 2003). ‘Shows a remarkable adaptability in terms of rainfall, and flourishes in extremely dry areas of the Karoo, but also in relatively wet parts of the eastern part of the distribution’ (Van Wyk & Smith 2003). Frost hardy to -6C (Christman 2003). When clothed with a layer of dead leaves the plants are resistant to fire (Bond 1983). Resistant to drought. Tolerant of fire and frost. Susceptible to water logging. Possibly resistant to salinity. Highly tolerant of at least 2 susceptible to at least 1.	mh	mh
Reproduction
9. Reproductive system	Known to cross-pollinate (Hoffman 1998). ‘Propagation is by seed or separation of the offsetting plants’ (TCSS (n.d.)). Ability to produce both by seed and vegetatively.	h	h
10. Number of propagules produced?	By the images (Cactus Jungle 2002), it would appear that one raceme can have up to at least 200 seeds and 5-8 erect racemes per plant (Reynolds 1982). Between 1000-2000 propagules produced per flowering event.	mh	mh
11. Propagule longevity?	Insufficient information to determine propagule longevity.	m	l
12. Reproductive period?	Known to be ‘relatively long-lived’ (TCSS (n.d.)). Other species of aloe live greater than 40 years.	h	m
13. Time to reproductive maturity?	Insufficient information to determine time to reach reproductive maturity.	m	l
Dispersal
14. Number of mechanisms?	Attracts many birds (Aubrey 2001). Ovary 6-7 mm long, 4mm diameter (Reynolds 1982). Bird and wind dispersed.	h	mh
15. How far do they disperse?	Attracts many birds (Aubrey 2001). Ovary 6-7 mm long, 4mm diameter (Reynolds 1982). Most propagules would likely disperse less than 1000m but many greater than 200m.	mh	mh

References

Aubrey, A. 2001, ‘Aloe ferox Mill., Plantzafrica, South African National Biodiversity Institute, viewed 04 Aug 2006, http://www.plantzafrica.com/plantab/aloeferox.htm

Australian National Herbarium (ANH) 2006, Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, viewed, http://www.anbg.gov.au/avh/

Bond, W. 1983, ‘Dead leaves and fire survival in Southern African tree aloes’, Oecologia, vol. 58, no. 1, pp. 110-114.

Breebart, L., Bhikraj, R. and O’Connor, T.G. 2002, ‘Impact of goat browsing on Aloe ferox in a South African savanna’ African Journal of Range and Forage Science, vol. 19, no. 1, pp. 77-78. CAB Abstracts.

Christman, S. 2003, Aloe ferox, Floridata, viewed 04 August 2006, http://www.floridata.com/ref/A/aloe_fer.cfm

Cactus Jungle 2002, Aloe ferox, Cactus Jungle Garden and Nursery, viewed 25 Sep 2006, http://www.cactusjungle.com/blog/uploads/misc/ferox.jpg

Department of Sustainability and Environment (DSE) 2004, Flora information system [CD-ROM], Biodiversity and Natural Resources Section, Viridans Pty Ltd, Bentleigh.

Global Biodiversity Information Facility (GBIF) 2006, Global biodiversity information facility: Prototype data portal, viewed 2006, http://www.gbif.org/

Hoffman, M.T. 1988, ‘The pollination ecology of Aloe ferox Mill.’, South African Journal of Botany, vol. 54, no. 4, pp. 345-350, CAB Abstracts.

Palgrave, K.C. 1977, Trees of Southern Africa, C. Struik Publishers, Cape Town.

Reynolds, G.W. 1982, The aloes of South Africa, A.A. Balkema, Rotterdam.

Tuscan Cactus and Succulent Society (TCSS), n.d., Tuscan Cactus and Succulent Society Database, viewed 25 Aug 2006, http://tucsoncactus.org/cgi-bin/db/dbman/db.cgi?db=default&uid=default&view_records=1&ID=*&nh=5

Van Wyk, B-E. & Smith, G. 2003, Guide to the Aloes of South Africa, 2nd ed., Briza Publications, Pretoria

Global present distribution data references

Australian National Herbarium (ANH) 2006, Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, viewed, http://www.anbg.gov.au/avh/

Christman, S. 2003, Aloe ferox, Floridata, viewed 04 August 2006, http://www.floridata.com/ref/A/aloe_fer.cfm

Global Biodiversity Information Facility (GBIF) 2006, Global biodiversity information facility: Prototype data portal, viewed 2006, http://www.gbif.org/

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