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Arthropod assemblages in a savanna invaded by Opuntia stricta (Cactaceae) in the Kruger National Park, South Africa

Dissertation (MSc)--University of Pretoria, 2009.

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Other Authors: Robertson, Mark P.
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Published: University of Pretoria 2013
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access_status_str Open Access
author2 Robertson, Mark P.
author_browse Robertson, Mark P.
author_facet Robertson, Mark P.
collection Thesis
dc_rights_str_mv © 2009, 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 Dissertation (MSc)--University of Pretoria, 2009.
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institution University of Pretoria (South Africa)
last_indexed 2026-06-10T12:38:43.836Z
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provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2013
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publisher University of Pretoria
publisherStr University of Pretoria
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spelling oai:repository.up.ac.za:2263/29922 Arthropod assemblages in a savanna invaded by Opuntia stricta (Cactaceae) in the Kruger National Park, South Africa Robertson, Mark P. Janse Van Rensburg, Berndt Coetzee, Julie A. kyle@cic-int.co.za Harris, K.R. (Kyle Robert) Kruger National Park (South Africa) O. stricta UCTD Dissertation (MSc)--University of Pretoria, 2009. Invasive alien species are considered the second greatest threat to global biodiversity after habitat loss. South Africa is not immune from such threats and it is estimated that 10 million ha (8.28%) of land has been invaded to some extent by invasive alien species. Although South Africa has been invaded by several taxa, it is the effect of invasive trees and shrubs that has been environmentally and economically most damaging. The concerns raised due to the effects of biological invasion are not only restricted to off-reserve areas, but also protected areas where invasive alien organisms often pose a greater threat than habitat loss. Kruger National Park (KNP), South Africa’s flagship conservation area has been invaded by numerous plant taxa. The most damaging of these is Opuntia stricta (Cactaceae) and current sources estimate that the weed has invaded approximately 35 000 ha of conserved land, despite the initiation of a biological control programme against it. However, little is known about the effect of O. stricta on biodiversity in the KNP despite the large number of resources allocated to its eradication, including a successful biological control programme against it. In this study, I investigated the effect of O. stricta infestation on beetle (Order Coleoptera) and spider (Order Araneae) assemblages across four treatments of varying O. stricta infestation levels (heavy infestation, medium infestation, surrounded sites and pristine sites). Species characteristic of each treatment (indicator species) were identified using the indicator method. In addition, spiders were collected to gauge the effectiveness of three collecting methods (pitfall traps, leaf litter sifting and active searching) in a savanna characterized by O. stricta invasion. One hundred and thirty one spider species (1050 individuals) and 72 beetle species (2162 individuals) were collected in the treatments. I found no significant differences in species richness, species density and species assemblages for both beetles and spiders across the treatments. In addition, no beetle or spider species were found to be characteristic indicator species for a given treatment, which further indicates that arthropod assemblages are similar when compared across treatments. These results indicate that O. stricta does not appear to have a significant effect on beetle and spider assemblages at its current infestation level, possibly because of the similarity in vegetation structure across the treatments. Regarding spiders, different collecting methods captured different species and only 17% of the species were shared, indicating that the methods complement each other. Therefore, in order to sample the spider community, all three methods should be employed. Of the 131 spider species collected, 54 species (41%) are new records for the KNP. In light of the results, it is suggested that KNP’s successful biological control programme has played an important role in reducing the extent of the O. stricta infestation and should be continued to further mitigate the impacts of O. stricta. Zoology and Entomology unrestricted 2013-09-07T17:16:24Z 2009-12-08 2013-09-07T17:16:24Z 2009-09-02 2009-12-08 2009-11-29 Dissertation Harris, KR 2009, Arthropod assemblages in a savanna invaded by Opuntia stricta (Cactaceae) in the Kruger National Park, South Africa , MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/29922 > E1497/ag http://hdl.handle.net/2263/29922 http://upetd.up.ac.za/thesis/available/etd-11292009-211107/ © 2009, 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 Kruger National Park (South Africa)
O. stricta
UCTD
Arthropod assemblages in a savanna invaded by Opuntia stricta (Cactaceae) in the Kruger National Park, South Africa
title Arthropod assemblages in a savanna invaded by Opuntia stricta (Cactaceae) in the Kruger National Park, South Africa
title_full Arthropod assemblages in a savanna invaded by Opuntia stricta (Cactaceae) in the Kruger National Park, South Africa
title_fullStr Arthropod assemblages in a savanna invaded by Opuntia stricta (Cactaceae) in the Kruger National Park, South Africa
title_full_unstemmed Arthropod assemblages in a savanna invaded by Opuntia stricta (Cactaceae) in the Kruger National Park, South Africa
title_short Arthropod assemblages in a savanna invaded by Opuntia stricta (Cactaceae) in the Kruger National Park, South Africa
title_sort arthropod assemblages in a savanna invaded by opuntia stricta cactaceae in the kruger national park south africa
topic Kruger National Park (South Africa)
O. stricta
UCTD
url http://hdl.handle.net/2263/29922
http://upetd.up.ac.za/thesis/available/etd-11292009-211107/