Understanding current and potential distribution of Australian acacia species in southern Africa

dc.contributor.advisorRobertson, Mark P.
dc.contributor.coadvisorRouget, M.
dc.contributor.coadvisorWilson, John R.U.
dc.contributor.emailmrobertson@zoology.up.ac.zaen_ZA
dc.contributor.postgraduateMotloung, Rethabile Frangenie
dc.date.accessioned2021-04-30T13:21:19Z
dc.date.available2021-04-30T13:21:19Z
dc.date.created2014
dc.date.issued2014-06
dc.descriptionDissertation (MSc)--University of Pretoria, 2014.en_ZA
dc.description.abstractThis dissertation presents research on the value of using different sources of data to explore the factors determining invasiveness of introduced species. The research draws upon the availability of data on the historical trial plantings of alien species and other sources. The focus of the study is on Australian Acacia species as a taxon introduced into southern Africa (Lesotho, South Africa and Swaziland). The first component of the study focused on understanding the factors determining introduction outcome of species in historical trial plantings and invasion success of Australian Acacia species using Species Distribution Models (SDMs) and classification tree techniques. SDMs were calibrated using the native range occurrence records (Australia) and were validated using results of 150 years of South African government forestry trial planting records and invaded range data from the Southern African Plant Invaders Atlas. To understand factors associated with survival (‘trial success’) or failure to survive (‘trial failure’) of species in historical trial plantings, classification and regression tree analysis was used. The results indicate climate as one of the factors that explains introduction and/or invasion success of Australian Acacia species in southern Africa. However, the results also indicate that for ‘trial failures’ there are factors other than climate that could have influenced the trial outcome. This study emphasizes the need to integrate data on whether the species has been recorded to be invasive elsewhere with climate matching for invasion risk assessment. The second component of the study focused on understanding the distribution patterns of Australian Acacia species that are not known as invasive in southern Africa. The specific aims were to determine which species still exist at previously recorded sites and determine the current invasion status. This was done by collating data from different sources that list species introduced into southern Africa and then conducting revisits. For the purpose of this study, revisits means conducting field surveys based on recorded occurrences of introduced species. The known occurrence data for species on the list were obtained from different data sources and various invasion biology experts. As it was not practical to do revisits for all species on the list, three ornamental species (Acacia floribunda, A. pendula and A. retinodes) were selected as part of the pilot study for the conducted revisits in this study. Acacia retinodes trees were not found during the revisits. The results provided data that could be used to characterize species based on the Blackburn et al., (2011) scheme. However, it is not clear whether observed Acacia pendula or A. floribunda trees will spread away from the sites hence the need to continuously monitor sites for spread. The methods used in this research establish a protocol for future work on conducting revisits at known localities of introduced species to determine their population dynamics and thereby characterize the species according to the scheme for management purposes.en_ZA
dc.description.availabilityUnrestricteden_ZA
dc.description.degreeMSc (Zoology)en_ZA
dc.description.departmentZoology and Entomologyen_ZA
dc.description.sponsorshipNational Research Foundation (NRF)en_ZA
dc.identifier.citationMotloung, RF 2014, Understanding current and potential distribution of Australian acacia species in southern Africa, MSc (Zoology) Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/79720>en_ZA
dc.identifier.otherM14/9/189en_ZA
dc.identifier.urihttp://hdl.handle.net/2263/79720
dc.language.isoenen_ZA
dc.publisherUniversity of Pretoria
dc.rights© 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
dc.subjectSpecies distribution modelsen_ZA
dc.subjectSouthern African Plant Invaders Atlasen_ZA
dc.subjectForestryen_ZA
dc.subjectClassification treeen_ZA
dc.subjectExpert knowledgeen_ZA
dc.subjectField visitsen_ZA
dc.subjectAlien treeen_ZA
dc.subjectUCTDen_ZA
dc.titleUnderstanding current and potential distribution of Australian acacia species in southern Africaen_ZA
dc.typeDissertationen_ZA

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