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Biogeographical insights from ecotones and phytogeographic regions in southern Africa : case studies on invertebrates and alien plants
Thesis (PhD)--University of Pretoria, 2012.
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University of Pretoria
2013
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| _version_ | 1867613536615661568 |
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| access_status_str | Open Access |
| author2 | Janse Van Rensburg, Berndt |
| author_browse | Janse Van Rensburg, Berndt |
| author_facet | Janse Van Rensburg, Berndt |
| collection | Thesis |
| dc_rights_str_mv | © 2012 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. |
| description | Thesis (PhD)--University of Pretoria, 2012. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/30790 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:37:42.843Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/30790 Biogeographical insights from ecotones and phytogeographic regions in southern Africa : case studies on invertebrates and alien plants Janse Van Rensburg, Berndt Robertson, Mark P. Hugo, Sanet UCTD Thesis (PhD)--University of Pretoria, 2012. This thesis addresses questions within the research fields of invasion biology and spatial ecology, with a focus on species distribution patterns, biogeographical regions and ecological transition zones, or ecotones. More specifically, species distribution patterns in alien plants at large spatial scales using atlas data, and invertebrate patterns making use of field data collected at a smaller scale (total extent ca. 30 km). First I show that alien plants form largescale geographically differentiated species assemblages in southern Africa (i.e. South Africa, Lesotho, Swaziland, Namibia and Botswana). I demonstrated this by mapping and describing several alien phytogeographic regions at a quarter-degree spatial resolution, and further suggest possible environmental and human-caused determinants of each of these regions. Second, at the same spatial resolution (for South Africa and Lesotho combined, and each of the plant biomes), I show that relatively higher levels of alien plant species richness occur at or near to ecotones, compared to areas that are spatially further away from these ecotones and that typically represent the core habitat of the ecoregions examined. This finding remained valid after taking into account the underlying positive relationships between alien plant richness and energy availability. I also suggest that it is the relatively higher environmental heterogeneity at ecotones (represented here by spatial variation in altitude, rainfall and geology) that promote high alien plant richness. Third, at a smaller spatial scale I report several examples of change in beetle and spider species composition across a savannagrassland ecotone in the west of South Africa’s Free State Province, with the ecotone itself supporting comparatively lower levels of species richness and abundance. This contrasts with a popular assumption that ecotones are characterised by high species richness. Data gained from long-term intensive sampling is preferable for ecological studies, but not always available or practical to acquire; however with the three studies in this thesis I show that data from existing species atlases and feasible short-term surveys can be successfully applied to answer a variety of ecological questions. Zoology and Entomology Unrestricted 2013-09-09T07:31:43Z 2013-05-20 2013-09-09T07:31:43Z 2013-04-12 2012 2013-05-02 Thesis Hugo, S 2012, Biogeographical insights from ecotones and phytogeographic regions in southern Africa : case studies on invertebrates and alien plants, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-05022013-171153/ > D13/4/482/ag http://hdl.handle.net/2263/30790 http://upetd.up.ac.za/thesis/available/etd-05022013-171153/ © 2012 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. application/pdf University of Pretoria |
| spellingShingle | UCTD Biogeographical insights from ecotones and phytogeographic regions in southern Africa : case studies on invertebrates and alien plants |
| title | Biogeographical insights from ecotones and phytogeographic regions in southern Africa : case studies on invertebrates and alien plants |
| title_full | Biogeographical insights from ecotones and phytogeographic regions in southern Africa : case studies on invertebrates and alien plants |
| title_fullStr | Biogeographical insights from ecotones and phytogeographic regions in southern Africa : case studies on invertebrates and alien plants |
| title_full_unstemmed | Biogeographical insights from ecotones and phytogeographic regions in southern Africa : case studies on invertebrates and alien plants |
| title_short | Biogeographical insights from ecotones and phytogeographic regions in southern Africa : case studies on invertebrates and alien plants |
| title_sort | biogeographical insights from ecotones and phytogeographic regions in southern africa case studies on invertebrates and alien plants |
| topic | UCTD |
| url | http://hdl.handle.net/2263/30790 http://upetd.up.ac.za/thesis/available/etd-05022013-171153/ |