Coastal yucca (Yucca aloifolia)

Present distribution

Scientific name:	Yucca aloifolia L.
Common name(s):	Coastal yucca

This weed is not known to be naturalised in Victoria

Habitat:

Coastal areas (Christman 2004), sand dunes (Szuchy and Kutz 2000), shell mounds (Flora of Pakistan), woodlands, cultivated beds and sunny edges. Tolerant of many soil types, including rocky soils, must be well drained. Can grow on nutrient poor soil (Plants For A Future).Will flourish in full sun, but does well in partial sun (Christman 2004). Can tolerate almost full shade (Gilman 1999). High Salt tolerance (Gilman 1999; Christman 2004)). Tolerates temperatures down to -10°C (Plants for a Future). Established plants are very drought resistant (Plants for a Future).

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; pasture dryland

Ecological Vegetation Divisions
Coastal; heathland; grassy/heathy dry forest; lowland forest; foothills forest; forby forest; wet forest; granitic hillslopes; rocky outcrop shrubland; western plains woodland; alluvial plains grassland; semi-arid woodland; alluvial plains woodland; ironbark/box; chenopod shrubland; chenopod mallee; hummockgrass
mallee; lowan mallee; broombush whipstick

Colours indicate possibility of Yucca aloifolia 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 showing the potential distrbution of coastal yucca

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

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	Y. aloifolia is a shrubby plant with stem 1-7.5m high (PIER), when mature produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004), spread of the plant can reach 3-5ft (Gilman 1999). Plants will eventually form multi-stemmed clumps (Gilman 1999). Although Y. aloifolia can grow to 7.5metres high, and to 3 metres wide, access of individual and vehicles would not be greatly affected. Low nuisance value. Impedes individual access; unable to walk to waterways	ML	MH
2. Reduce tourism?	Y. aloifolia is a shrubby plant with stem 1-7.5m high (PIER), when mature produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004), spread of the plant can reach 3-5ft (Gilman 1999). Plants will eventually form multi-stemmed clumps (Gilman 1999). Cream and purple flowers are powerfully fragrant at night (Flora of Pakistan; Plants for a Future Database). Inflorescences can be up to 12cm long (Christman 2004). Size of plant, spread, conspicuous foliage and large inflorescences make Y. aloifolia noticeable within the landscape, but the impact on tourism would be minimal. Minor effects to aesthetics and recreational uses (aware of but not bothered by weed)	ML	MH
3. Injurious to people?	The trunk of Y. aloifolia is armed with sharp pointed straplike leaves (Christman 2004). It has spikes of bright white blossoms with sharp needle tips appear in springtime (Gilman 1999). The roots contain saponins. Saponins can be quite toxic to people, they are poorly absorbed by the body and tend to pass straight through. The fruit is purgative (strongly laxative) (Plants for a Future Database). Y. aloifolia possesses structures (including sharp leaves and spines) which could potentially cause injuries to people. There is also evidence of mild toxicity in the roots and fruit. Spines, burrs or toxic properties at most times of the year.	MH	M
4. Damage to cultural sites?	Y. aloifolia is a shrubby plant with stem 1-7.5m high (PIER), when mature produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004), spread of the plant can reach 3-5ft (Gilman 1999). Y. aloifolia is occasionally persistent around old habitations (Harden 1993). Y. aloifolia is a medium sized plant with a wide spread. Clumps of this plant may be unsightly, but little structural damage will be caused to heritage/cultural sites. Large clumps of Y. aloifolia and may create a moderate visual effect	M	M
Abiotic
5. Impact flow?	Grows on sand dunes and the coast (Plants for a Future Database), beaches and mainland (Szuchy and Kutz 2000). Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket. Older leaves wither and turn brown, hanging around the lower trunk (Christman 2004). Y. aloifolia is a terrestrial weed, not growing in or around waterways. If it grew in closer proximity to waterways then it would cause little or negligible affect on water flow	L	M
6. Impact water quality?	Shrubby plant with stem 1-7.5m high (PIER). Spread of plant can reach 3-5ft (Gilman 1999). Grows on sand dunes and the coast (Plants for a Future Database), beaches and mainland (Szuchy and Kutz 2000). Terrestrial weed, not growing in or around waterways. Noticeable but minor effects on either dissolved O2 or light levels.	ML	MH
7. Increase soil erosion?	Contractile roots (CR) were described for Y. aloifolia. A function of CR is to improve plant anchorage (North et al. 2008). Dense root systems will effectively hold soils together and potentially reduce the chance/severity of erosion. Low probability of large scale soil movement, or decreases the probability of soil erosion	L	ML
8. Reduce biomass?	Spanish bayonet also produces new buds, or offshoots near the base of the trunk, forming a thicket (Christman 2004). Vigorous reproduction occurs via rhizomes (Groman and Pellmyr 2000) Biomass may increase.	L	M
9. Change fire regime?	Contractile roots (CR) were described for Yucca aloifolia. One broad function of CR is to protect apical buds from fire (North et al. 2008). Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket. Older leaves -wither and turn brown, hanging around the lower trunk (Christman 2004). Dry yucca has a low ignition temperature of any wood, making it desirable for fire-starting (Wikipedia) Dense thickets of dry dead wood of Yucca, could potentially create a fire risk, Minor change to either the frequency or intensity of fire risk.	ML	ML
Community Habitat
10. Impact on composition (a) high value EVC	EVC = Valley Grassy Forest (V); CMA = Goulburn Broken; Bioregion = Central Victorian Uplands; VH CLIMATE potential Y. aloifolia is a shrubby plant with stem 1-7.5m high (PIER). Spread of plant can reach 3-5ft (Gilman 1999). Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004).	ML	MH
(b) medium value EVC	EVC = Riparian Forest/ Swampy Riparian Woodland (D); CMA = North East; Bioregion = Highlands – Northern Fall; VH CLIMATE potential. Y. aloifolia is a shrubby plant with stem 1-7.5m high (PIER). Spread of plant can reach 3-5ft (Gilman 1999). Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004).	ML	MH
(c) low value EVC	EVC = Heathy Dry Forest (LC); CMA = Goulburn Broken; Bioregion = Central Victorian Uplands; VH CLIMATE potential. Y. aloifolia is a shrubby plant with stem 1-7.5m high (PIER). Spread of plant can reach 3-5ft (Gilman 1999). Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004).	ML	MH
11. Impact on structure?	Y. aloifolia is a shrubby plant with stem 1-7.5m high (PIER). Spread of plant can reach 3-5ft (Gilman 1999). Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004). The size Y. aloifolia plants individually and in thickets has the potential to adversely affect the floral strata. Thickets may shade out other species below the plant and compete for resources against the other existing flora. Minor effect on 20-60% of the floral strata.	ML	MH
12. Effect on threatened flora?	Y. aloifolia is a shrubby plant with stem 1-7.5m high (PIER). Spread of plant can reach 3-5ft (Gilman 1999). Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004). Specific information on the impact this species has on threatened flora has not been determined. Any population of Bioregional Priority 1A* species is reduced, or any population of a VROT species could be replaced.	MH	M
Fauna
13. Effect on threatened fauna?	Y. aloifolia is a shrubby plant with stem 1-7.5m high (PIER). Spread of plant can reach 3-5ft (Gilman 1999). Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004). No threatened fauna affected due to fauna not co-existing within infested area or strata.	L	M
14. Effect on non-threatened fauna?	Y. aloifolia is a shrubby plant with stem 1-7.5m high (PIER). Spread of plant can reach 3-5ft (Gilman 1999). Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004). Due to its size, Y. aloifolia has potential to compete with smaller species which might be important food, shelter or habitat. It may displace the important native species and result in a reduction of resources for non-threatened fauna. Minor effects on fauna species; minor hazard or reduction in habitat/food/shelter.	ML	M
15. Benefits fauna?	Y. aloifolia is a shrubby plant with stem 1-7.5m high (PIER). Spread of plant can reach 3-5ft (Gilman 1999). Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004). Due to its size, Y. aloifolia has potential to provide native fauna with some shelter, food or important habitat. Provides some assistance in either food or shelter to desirable species.	MH	M
16. Injurious to fauna?	Spikes of bright white blossoms with sharp needle tips appear in spring time (Gilman 1999). The trunk is armed with sharp pointed straplike leaves (Christman 2004). The roots contain saponins. Whilst saponins are quite toxic to people, they are poorly absorbed by the body and tend to pass straight through. (Plants for a Future Database) Sharp leaves and inflorescences on Y. aloifolia have potentially detrimental impact upon fauna. Large spines or burrs dangerous to fauna. Toxic, and causes allergies.	H	MH
Pest Animal
17. Food source to pests?	Members of this genus seem to be immune to the predations of rabbits (Plants for a Future Database). Spikes of bright white blossoms with sharp needle tips appear in spring time (Gilman 1999) The roots contain saponins (Plants for a Future Database). Chemical compounds in leaves are a defence against herbivores, and also morphological characteristics which would also deter pest animals from consuming Y. aloifolia Provides minimal food for pest animals	L	MH
18. Provides harbor?	Shrubby plant with stem 1-7.5m high (PIER). Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004). Spread of plant can reach 3-5ft (Gilman 1999). Capacity to provide harbour and permanent warrens for foxes and rabbits through out the year	H	MH
Agriculture
19. Impact yield?	Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004). Spread of plant can reach 3-5ft (Gilman 1999). Spanish bayonet does well on any well drained soil, and grows in full to partial sunlight (Gilman 1999). Minor impact on quantity of produce (<5% reduction)	ML	M
20. Impact quality?	Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004). Plants form multi-stemmed clumps and spread of plant can reach up to 3-5ft (Gilman 1999). The Global Compendium of Weeds states Yucca aloifolia to be an agricultural weed, but the extent of weediness is unknown. There is potential for Yucca aloifolia to have a minor impact on value of land. Decreases in land value <10%	ML	MH
21. Affect land value?	Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004) Plants form multi-stemmed clumps (Gilman 1999). Decreases land value <10%	ML	M
22. Change land use?	Spanish bayonet produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004). Spread of plant can reach 3-5ft (Gilman 1999). Plants form multi-stemmed clumps (Gilman 1999). Some change, but no serious alteration of either agricultural return. Affects more the visual rather than intrinsic agricultural value.	ML	M
23. Increase harvest costs?	Shrubby plant with stem 1-7.5m high (PIER). Spanish bayonet also produces new buds or offshoots near the base of the trunk, forming a thicket (Christman 2004). Spread of plant can reach 3-5ft (Gilman 1999). If yucca aloifolia Minor increase in cost of harvesting.	ML	MH
24. Disease host/vector?	No evidence to suggest that this species is a host/vector for disease. Little or no host.	L	L

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Germination of Yucca aloifolia seed is inhibited by light (Curtis 1996). Y. aloifolia is tolerant of many soil types (Horticulture unlimited). Seeds are sown in spring (Plants for a Future Database). Requires specific environmental factors that are not part of an annual cycle to germinate.	L	MH
2. Establishment requirements?	Spanish bayonet flourishes in full sun and can tolerate full shade with light sandy soil, or any well drained soil (Christman 2004; Gilman 1999). This plant can grow on nutritionally poor soil. (Plants for a Future Database). Evidence suggests that Yucca aloifolia can establish in various situations of light intensity and soil type. Can establish under moderate canopy/litter cover.	MH	MH
3. How much disturbance is required?	Occasionally persistent around old habitations (Harden 1993). Growing in full or partial sun (Gilman 1999) in woodland and cultivated beds, sand dunes and the coast, occasionally up to 60km inland. Can also be found on the margins of brackish marshes (Plants for a Future Database). Establishes in relatively intact or minor disturbed natural ecosystems and/or in well established pastures.	MH	M
Growth/Competitive
4. Life form?	Shrubby plant with stem 1-7.5m high. (PIER). Perennial tree like monocot (Spooner 1997). Other.	L	M
5. Allelopathic properties?	No evidence of allelopathic properties. None.	L	M
6. Tolerates herb pressure?	Members of this genus seem to be immune to the predations of rabbits, and tolerant of predations by deer (Plants for a Future Database). Scale insects can be a problem, weakening the plant (Gilman 1999). Contractile roots (CR) were described for yucca aloifolia. One broad function of CRs is to protect apical buds from herbivores (North et al 2008). Consumed and recovers slowly. Reproduction strongly inhibited by herbivory but still capable of vegetative propagule production (by rhizomes or tubers), weed may still persist.	ML	M
7. Normal growth rate?	An evergreen tree growing … at a slow rate (Plants for a Future Database). Slow growth rate (Gilman 1999). Slow growth, will be exceeded by many other species.	L	M
8. Stress tolerance to frost, drought, w/logg, sal. etc?	It is drought and Frost resistant (Bodkin 1991). High Salt tolerance, high drought tolerance (Gilman 1999; Christman 2004). Tolerating temperatures down to -10°C. Established plants are very drought resistant (Plants for a Future Database). Highly tolerant of at least two (salinity/drought) and may be susceptible to at least one other (water logging).	MH	MH
Reproduction
9. Reproductive system	Vigorous reproduction occurs via rhizomes (Groman and Pellmyr, 2000). Spanish bayonet also produces new buds, or shoots near the base of the trunk (Christman 2004). Propagation via seed (PIER). Both vegetative and sexual reproduction.	H	MH
10. Number of propagules produced?	There are many small seeds (Szuchy and Kutz 2000). Ovaries 3-locular or 6-locular, approximately 25-30 seeds per locule (Zipcode Zoo 2008). From picture supplied by Floridata there are approx 55-60 flowers per plant. (30 seeds x 3 locules)x60 flowers=5400 seeds Above 2000.	H	M
11. Propagule longevity?	Individual crowns are monocarpic (dying after flowering) however the crown will usually produce a number of side-shoots before it dies and these will grow on to flower in later years (Plants for a Future Database). Greater than 25% of seeds survive 5 years, and vegetative reproduction.	L	M
12. Reproductive period?	Perennial tree like monocot (Spooner 1997) Individual crowns are monocarpic (dying after flowering) however the crown will usually produce a number of side-shoots before it dies and these will grow on to flower in later years (Plants for a Future Database). Mature plant produces viable propagules for only 1-2 years.	ML	M
13. Time to reproductive maturity?	Perennial tree like monocot (Spooner 1997). Individual crowns are monocarpic (dying after flowering) however the crown will usually produce a number of side-shoots before it dies and these will grow on to flower in later years (Plants for a Future Database). Sown seeds usually germinate within 1-12months (Plants for a Future Database). Perennial habit means that a single Yucca aloifolia plant will reach maturity within 1-3 years. Individuals of this species only flower once Reaches maturity and produces viable propagules OR vegetative propagules become separate individuals in under a year.	H	MH
Dispersal
14. Number of mechanisms?	Fruits are indehiscent, not releasing seeds when they mature. (Flora of North America) Vigorous reproduction occurs via rhizomes (Groman and Pellmyr 2000). Dispersal mechanisms are unknown for Yucca aloifolia.	MH	M
15. How far do they disperse?	Dispersal mechanisms are unknown for Yucca aloifolia, so dispersal distances cannot be estimated.	MH	L

References

Christman S (2004) Yucca aloifolia, available at http://www.floridata.com/ref/Y/yucc_alo.cfm

Curtis PN (1996) Germination and seedling survival studies of Xanthorrhoea australis in the Warby Range state park, north eastern Victoria, Australia. Australian Journal of Botany 44 pp 635-647

Dave’s Garden, available at, http://davesgarden.com/guides/pf/go/2090/

Flora of Pakistan, available via e-floras.org at http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=220014440

Flora of North America, available via e-floras.org at http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=220014440

Gilman E (1999) Fact Sheet FPS-614 from the University of Florida, Institute of Food and Agricultural Sciences, available at http://edis.ifas.ufl.edu/pdffiles/FP/FP61400.pdf

Harden GJ (1993) from PlantNet New South Wales Flora Online, available at http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Yucca~aloifolia

Global Compendium of Weeds www.hear.org/gcw/species.yucca_aloifolia/

Groman JD and Pelmyr O (2000) Rapid evolution and specialisation following host colonisation in a yucca moth. Journal of Evolutionary Biology 13 223-236

North BG, Brinton EK and Garrett TY (2007) Contractile roots in succulent monocots: convergence, divergence and adaptation to limited rainfall. Plant, Cell and Environment 31 1179-1189

Pacific Island Ecosystems at Risk (PIER), available at http://www.hear.org/Pier/species/yucca_aloifolia.htm

Plants for a Future Database, available at http://www.pfaf.org/database/plants.php?Yucca+aloifolia

Spooner A (1997) Yucca aloifolia, available at http://florabase.calm.wa.gov.au/browse/profile/16992

Szuchy E and Kutz DH (2000) Edible plants of Central Florida available at, http://www.nbbd.com/godo/ef/edibles/index.html

Wikipedia Database, available at http://en.wikipedia.org/wiki/Yucca

Zipcode Zoo, available at http://zipcodezoo.com/Plants/Y/Yucca_aloifolia/

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 12/12/08)

Department of Sustainability and Environment (DSE) (2006) Flora information system [CD-ROM], Biodiversity and Natural Resources Section, Viridans Pty Ltd, Bentleigh.

Department of the Environment and Heritage (Commonwealth of Australia). (1993 – On-going) Australian Plant Name Index (APNI) http://www.cpbr.gov.au/apni/index.html (verified 12/12/08)

Global Biodiversity Information Facility (GBIF) (2008) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 12/12/08)

IPMS: Integrated Pest Management System (2006) Department of Primary Industries.

Integrated Taxonomic Information System. (2008) Available at http://www.itis.gov/ (verified 12/12/08)

International Plant Names. (2005) International Plant Names Index Plant Name Search. Available at http://www.ipni.org/ipni/plantnamesearchpage.do (verified 12/12/08)

Missouri Botanical Gardens (MBG) (2008) w³TROPICOS, Missouri Botanical Gardens Database, Available at http://mobot.mobot.org/W3T/Search/vast.html (verified 12/12/08)

National Biodiversity Network (2004) NBN Gateway, National Biodiversity Network, UK, Available at http://www.searchnbn.net/index_homepage/index.jsp (verified 12/12/08)

United States Department of Agriculture. Agricultural Research Service, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. Taxonomy Query. (2008) Available at http://www.ars-grin.gov/cgi-bin/npgs/html/taxgenform.pl (verified 12/12/08)

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