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dc.contributor.authorGravuer, Kelly L.en
dc.date.accessioned2008-03-13T22:55:00Z
dc.date.issued2004en
dc.identifier.urihttps://hdl.handle.net/10182/340
dc.description.abstractTwo conceptual approaches which offer promise for improved understanding of biological invasions are conceptualizing the invasion process as a series of distinct stages and explicitly incorporating human actions into analyses. This study explores the utility of these approaches for understanding the invasion of Trifolium (true clover) species in New Zealand. From the published literature, I collected a range of Trifolium species attributes, including aspects of global transport and use by humans, opportunistic association with humans in New Zealand, native range attributes, habitat characteristics, and biological traits. I also searched historical records to estimate the extent to which each species had been planted in New Zealand, a search facilitated by the enormous importance of Trifolium in New Zealand's pastoral agriculture system. Regression analysis and structural equation modelling were then used to relate these variables to success at each invasion stage. Fifty-four of the 228 species in the genus Trifolium were intentionally introduced to New Zealand. Species introduced for commercial agriculture were characterised by a large number of economic uses and presence in Britain, while species introduced for horticulture or experimental agriculture were characterised by a large native range area. Nine of these 54 intentionally introduced species subsequently naturalised in New Zealand. The species that successfully naturalised were those that had been planted extensively by humans and that were well-matched to the New Zealand climate. A further 16 species (from the pool of 174 species that were never intentionally introduced) arrived and naturalised in New Zealand without any recorded intentional aid of humans. Several attributes appeared to assist species in unintentional introduction-naturalisation, including a good match to the New Zealand climate, a large native range area, presence in human-influenced habitats, a widespread distribution in Britain, and self-pollination capability. The 25 total naturalised species varied greatly in their current distributions and in the rates at which they had spread to achieve those distributions. Species that had spread quickly and are currently more widespread had been frequent contaminants in the pasture seed supply and have a long flowering period in New Zealand. Other biological traits and native range attributes played supporting roles in the spread process. Attributes facilitating success clearly varied among invasion stages. Humans played a dominant role at all stages of this invasion, although biological traits had increasing importance as a species moved through the invasion sequence. My findings suggest that incorporation of human actions and the stage-based framework provide valuable insight into the invasion process. I discuss potential avenues by which these approaches might be integrated into predictive invasion models.en
dc.format.extent1-158en
dc.language.isoenen
dc.publisherLincoln Universityen
dc.subjectinvasiveen
dc.subjectalienen
dc.subjectexoticen
dc.subjectintroduced speciesen
dc.subjectnon-indigenousen
dc.subjectplanten
dc.subjectstageen
dc.subjecttransitionen
dc.subjectstage-specific frameworken
dc.subjectexperimental trialsen
dc.subjectintroductionen
dc.subjectnaturalisationen
dc.subjectspreaden
dc.subjectTrifoliumen
dc.subjectcloveren
dc.subjecthuman agencyen
dc.subjecthuman dispersalen
dc.subjectintroduction efforten
dc.subjectunintentionalen
dc.subjectdeliberateen
dc.titleDeterminants of the introduction, naturalisation, and spread of Trifolium species in New Zealanden
dc.typeThesis
thesis.degree.grantorLincoln Universityen
thesis.degree.levelMastersen
thesis.degree.nameMaster of Scienceen
dc.subject.marsdenFields of Research::300000 Agricultural, Veterinary and Environmental Sciences::300800 Environmental Scienceen
lu.contributor.unitLincoln Universityen
lu.contributor.unitFaculty of Agriculture and Life Sciencesen
lu.contributor.unitDepartment of Pest Management and Conservationen
lu.contributor.unitSoil, Plants and Ecological Sciencesen
pubs.organisational-group/LU
pubs.organisational-group/LU/Agriculture and Life Sciences
pubs.organisational-group/LU/Agriculture and Life Sciences/ECOL
pubs.organisational-group/LU/SPES
pubs.publication-statusPublisheden
dc.publisher.placeCanterburyen


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