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The effects of landscape transformation, isolation, and habitat quality on plant-pollinator interactions in conservation corridors
Thesis (MScConsEcol)--Stellenbosch University, 2024.
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| Format: | Thesis |
| Language: | en_ZA en_ZA |
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Stellenbosch : Stellenbosch University
2024
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| _version_ | 1867613940409696256 |
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| access_status_str | Open Access |
| author | Khan, Zahra |
| author2 | Pryke, James |
| author_browse | Khan, Zahra Pryke, James |
| author_facet | Pryke, James Khan, Zahra |
| author_sort | Khan, Zahra |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScConsEcol)--Stellenbosch University, 2024. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/130402 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA en_ZA |
| last_indexed | 2026-06-10T12:44:07.837Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2024 |
| publishDateRange | 2024 |
| publishDateSort | 2024 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/130402 The effects of landscape transformation, isolation, and habitat quality on plant-pollinator interactions in conservation corridors Khan, Zahra Pryke, James Gaigher, Rene Van Schalkwyk, Julia Stellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology. Plant-pollinator relationships Natural areas -- South Africa -- KwaZulu-Natal -- Midland Protected areas -- Ecology Corridors (Ecology) Habitat corridors Landscape transformation Forests and forestry -- Effect of habitat modification on Climatic changes -- South Africa -- KwaZulu-Natal Forests and forestry -- Environmental aspects -- South Africa -- KwaZulu-Natal UCTD Thesis (MScConsEcol)--Stellenbosch University, 2024. ENGLISH ABSTRACT: The KwaZulu Natal Midland’s natural areas are comprised mainly of grasslands, wetlands, and indigenous forest which are highly threatened by agricultural expansion and commercial forestry. Many endemic plant and animal taxa occur in this region and require protection due to competing land uses. To mitigate biodiversity loss in these rich landscapes, conservation corridors have been implemented creating habitat and conduits for dispersal across the harsh matrix of alien trees. While corridors fulfil the functions of habitat and conduits for dispersal, there is significant fragmentation and habitat loss to forestry which are known to be the drivers of biodiversity loss worldwide. In light of this, my study explores plant-pollinator interactions to determine whether corridors are effectively preserving biodiversity and its function. I first explored the differences in plant-pollinator interaction networks between four different landscape contexts within conservation corridors. Interactions between flowering plants and flower visitors were observed in each landscape context and local environmental variables measuring habitat quality, (provision of food for the pollinators) and landscape variables measuring isolation (the amount of natural/semi-natural habitat in the broader landscape) and landscape transformation (the amount of habitat loss to afforestation in the immediate surroundings) were measured. Habitat quality was found to be the most important for the presence of flower visitors and facilitating plant-pollinator interactions. Isolation and landscape transformation played smaller roles and often had interactive effects on plant-pollinator biodiversity. I also investigated the functional traits of flowering plants and flower visitors to understand the traits that underpin the interactions observed. Flower visitor functional dispersion and dissimilarity were most affected by environmental conditions and the interactions between seasonality and landscape variables. However, again local environmental conditions were the main variable affecting flower visitor presence and functional dispersion and dissimilarity. Season, isolation, and landscape transformation also had individual and interactive effects on flower visitor and flowering plant assemblage composition along with environmental variables. Although landscape transformation and season had limited effects on flower visitor functional dissimilarity and dispersion, flower visitor traits differed distinctly between high and low levels of landscape transformation and season. Flowering plant traits also displayed some differences between season and landscape transformation, but these were not as distinct as with flower visitors. Low levels of isolation were found to be beneficial to plant- pollinator biodiversity even under high landscape transformation. In conclusion, landscape transformation had negative effects on flowering plant and flower visitor biodiversity, but conservation corridors helped ameliorate these effects. Habitat quality and condition (here vegetation height was used as a proxy for grassland condition) were most important for the presence of flower visitors and facilitating interactions between flower visitors and flowering plants. Results suggest that corridors are providing connectivity and habitat for flower visitors due to the diverse flower visitor traits found in different landscape contexts, however, isolation still negatively impacts biodiversity in some areas. Conservation efforts should focus mainly on improving habitat quality for flower visitors. This entails the effective control of invasive plants within corridors, the introduction of appropriate indigenous flora, and establishing appropriate disturbance regimes. Achieving connectivity should still be a focus of management to allow for rescue effects in the event of species loss, however, this should not overshadow habitat quality management. AFRIKAANSE OPSOMMING: Die KwaZulu Natalse Middelland se natuurlike gebiede bestaan hoofsaaklik uit grasvelde, vleilande en inheemse woude wat hoogs bedreig word deur landbou-uitbreiding en kommersiële bosbou. Baie endemiese plant- en dieretaksa kom in hierdie streek voor en vereis beskerming as gevolg van mededingende grondgebruike. Om biodiversiteitsverlies in hierdie ryk landskappe te versag, is bewaringskorridors geïmplementeer wat habitatte en verbindings skep vir verspreiding oor die harde matriks van uitheemse bome. Terwyl korridors die funksies van habitat en verbindings vir verspreiding vervul, is daar aansienlike fragmentasie en habitatverlies aan bosbou wat bekend is as die drywers van biodiversiteitsverlies wêreldwyd. In die lig hiervan ondersoek my studie plant- bestuiwer interaksies om te bepaal of korridors effektief biodiversiteit en die funksie daarvan bewaar. Ek het eers die verskille in plant-bestuiwer-interaksienetwerke tussen vier verskillende landskapkontekste binne bewaringskorridors ondersoek. Interaksies tussen blomplante en blombesoekers is in elke landskapkonteks waargeneem en plaaslike omgewingsveranderlikes wat habitatkwaliteit meet, (voorsiening van voedsel vir die bestuiwers) en landskapsveranderlikes wat isolasie meet (die hoeveelheid natuurlike/semi-natuurlike habitat in die breër landskap) en landskapstransformasie (die hoeveelheid habitatverlies aan bebossing in die onmiddellike omgewing) is gemeet. Daar is gevind dat habitatkwaliteit die belangrikste is vir die teenwoordigheid van blombesoekers en om plant-bestuiwer interaksies te fasiliteer. Isolasie en landskapstransformasie het kleiner rolle gespeel en het dikwels interaktiewe uitwerking op plantbestuiwer biodiversiteit gehad. Ek het ook die funksionele eienskappe van blomplante en blombesoekers ondersoek om die eienskappe te verstaan wat die interaksies wat waargeneem is, onderlê. Blombesoekers se funksionele verspreiding en verskille is die meeste beïnvloed deur omgewingstoestande en die interaksies tussen seisoenaliteit en landskapveranderlikes. Plaaslike omgewingstoestande was egter weer die hoofveranderlike wat die teenwoordigheid van blombesoekers en funksionele verspreiding en ongelykheid beïnvloed het. Seisoen, isolasie en landskaptransformasie het ook individuele en interaktiewe effekte gehad op die samestelling van blombesoekers en blomplante saam met omgewingsveranderlikes. Alhoewel landskaptransformasie en seisoen beperkte uitwerking op blombesoekers se funksionele ongelykheid en verspreiding gehad het, het blombesoekerseienskappe duidelik verskil tussen hoë en lae vlakke van landskaptransformasie en seisoen. Blomplanteienskappe het ook 'n paar verskille tussen seisoen- en landskaptransformasie getoon, maar dit was nie so duidelik soos by blombesoekers nie. Daar is gevind dat lae vlakke van isolasie voordelig is vir plantbestuiwer biodiversiteit selfs onder hoë landskap transformasie. Ter afsluiting, landskapstransformasie het negatiewe effekte op blomplante en blombesoekersbiodiversiteit gehad, maar bewaringskorridors het gehelp om hierdie effekte te verbeter. Habitatkwaliteit en toestand (hier is plantegroeihoogte gebruik as 'n maatstaf vir grasveldtoestand) was die belangrikste vir die teenwoordigheid van blombesoekers en fasilitering van interaksies tussen blombesoekers en blomplante. Resultate dui daarop dat korridors konnektiwiteit en habitat vir blombesoekers verskaf as gevolg van die diverse blombesoekerseienskappe wat in verskillende landskapkontekste gevind word, maar isolasie het steeds 'n negatiewe impak op biodiversiteit in sommige gebiede. Bewaringspogings moet hoofsaaklik fokus op die verbetering van habitatgehalte vir blombesoekers. Dit behels die effektiewe beheer van indringerplante binne korridors, die bekendstelling van toepaslike inheemse flora, en die vestiging van toepaslike versteuringsregimes. Die bereiking van konnektiwiteit moet steeds 'n fokus van bestuur wees om voorsiening te maak vir reddingseffekte in die geval van spesieverlies, maar dit behoort nie habitatkwaliteitbestuur te oorskadu nie. Masters 2024-03-04T18:13:00Z 2024-04-26T16:18:19Z 2024-03-04T18:13:00Z 2024-04-26T16:18:19Z 2024-03 Thesis https://scholar.sun.ac.za/handle/10019.1/130402 en_ZA en_ZA Stellenbosch University 118 pages : illustrations (some color), maps application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Plant-pollinator relationships Natural areas -- South Africa -- KwaZulu-Natal -- Midland Protected areas -- Ecology Corridors (Ecology) Habitat corridors Landscape transformation Forests and forestry -- Effect of habitat modification on Climatic changes -- South Africa -- KwaZulu-Natal Forests and forestry -- Environmental aspects -- South Africa -- KwaZulu-Natal UCTD Khan, Zahra The effects of landscape transformation, isolation, and habitat quality on plant-pollinator interactions in conservation corridors |
| title | The effects of landscape transformation, isolation, and habitat quality on plant-pollinator interactions in conservation corridors |
| title_full | The effects of landscape transformation, isolation, and habitat quality on plant-pollinator interactions in conservation corridors |
| title_fullStr | The effects of landscape transformation, isolation, and habitat quality on plant-pollinator interactions in conservation corridors |
| title_full_unstemmed | The effects of landscape transformation, isolation, and habitat quality on plant-pollinator interactions in conservation corridors |
| title_short | The effects of landscape transformation, isolation, and habitat quality on plant-pollinator interactions in conservation corridors |
| title_sort | effects of landscape transformation isolation and habitat quality on plant pollinator interactions in conservation corridors |
| topic | Plant-pollinator relationships Natural areas -- South Africa -- KwaZulu-Natal -- Midland Protected areas -- Ecology Corridors (Ecology) Habitat corridors Landscape transformation Forests and forestry -- Effect of habitat modification on Climatic changes -- South Africa -- KwaZulu-Natal Forests and forestry -- Environmental aspects -- South Africa -- KwaZulu-Natal UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/130402 |
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