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Abstract

Boneseed, Chrysanthemoides monilifera ssp. monilifera (Asteraceae) is concentrated in and near cities and
towns on the north and east coasts ofTasmania. Its absence from intervening rural and bushland areas cannot be
attributed to environmental conditions or a lack of time for dispersal from introduction points. The hypothesis
tested in the present paper is that the range of boneseed in Tasmania is limited by biotic resistance through
herbivory. Cafeteria experiments and field observations showed that sheep (Ovis aries), cattle (Bos taurus),Tasmanian
pademelons (Thylogale billardierii ), Bennett’s wallabies (Macropus rufogriseus), garden weevils (Phlyctinus
callosus) and native invertebrates all consumed boneseed, while common brushtail possums (Trichosurus vulpecula)
did not. A boneseed population subjected to sheep grazing for 168 days suffered high mortality, while an adjacent
ungrazed population survived intact. A replicated exclosure experiment showed that 75 days of grazing by cattle
reduced the size of boneseed plants. Observations of a population subject to Bennett’s wallaby and Tasmanian
pademelon grazing over 1 year and 2 months showed consistently high leaf damage to foliage within pademelon
reach and a decline in population, with high mortality rates in the driest and coldest times. Leaf loss attributable
to invertebrates did not prevent a nearby population without wallabies from growing.The distributions of the taxa
were consistent with biotic resistance, with those demonstrating no severe effect on boneseed individuals widespread,
while those with evidence of severe effects more common in rural areas than in urban areas. Boneseed
seemed unlikely to survive for very long at normal stocking levels. Macropod grazing, particularly that of T.
billardierii, may also inhibit the invasion of boneseed. Thus, the recent introduction of foxes to Tasmania may not
only cause the extinction of species such as T. billardierii, but also may cause an expansion of the range of boneseed.

Item Type:	Article
Authors/Creators:	Scurr, GF and Kirkpatrick, JB and Daniels, GD and McQuillan, PB
Keywords:	biotic resistance, Chrysanthemoides monilifera, herbivory, invasion.
Journal or Publication Title:	Austral Ecology
ISSN:	1442-9985
DOI / ID Number:	https://doi.org/10.1111/j.1442-9993.2008.01865.x
Additional Information:	The definitive version is available at www.blackwell-synergy.com
Item Statistics:	View statistics for this item

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