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The impacts of invasive fish on ghost frog tadpoles
Thesis (MSc)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867613769628123136 |
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| access_status_str | Open Access |
| author | Van Blerk, Daniel |
| author2 | Measey, John |
| author_browse | Measey, John Van Blerk, Daniel |
| author_facet | Measey, John Van Blerk, Daniel |
| author_sort | Van Blerk, Daniel |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MSc)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/126978 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:41:24.431Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/126978 The impacts of invasive fish on ghost frog tadpoles Van Blerk, Daniel Measey, John Pegg, Josephine Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology. Frogs Predation (Biology) Tadpoles -- Behavior Fishes -- Habitat -- Environmental aspects Ghost frog -- Conservation -- South Africa Invasive fish -- Conservation -- South Africa Trout -- Behavior UCTD Thesis (MSc)--Stellenbosch University, 2023. ENGLISH ABSTRACT: The global impacts of invasive fish on native amphibians are diverse and ongoing, with documented negative impacts. The severity of impacts is expected to differ based on shared evolutionary history of amphibians with fish. Lotic systems are characterised by fast flowing water, which historically have limited upstream fish dispersal and ensured the lack of co- evolution between amphibians and fish. Water bodies associated with little to no flow are lentic systems and are often inhabited by both fish and amphibians. To date, there is a lack of comparison between the impacts of invasive fish on native amphibians between lotic and lentic systems. A comparison of the literature using a meta-analysis is conducted followed by a field-based study. A global meta-analysis was conducted to answer the question: Are the impacts of invasive fish on native amphibians are more severe in lotic than in lentic systems? Due to a paucity of data on other amphibian response variables, only amphibian behaviour could be compared between these systems. Behavioural responses show identical directions of effect between the two systems, with larger effect sizes for lotic amphibians. This does not support the expected more severe impacts on lotic systems, instead indicating a potential enhanced response to invasive fish by native lotic amphibians. The results identify a paucity of impact data in Africa and South America, with a general lack of suitable data for lotic systems. This is partly attributed due to the design of studies in most lotic systems. I recommend the use of control treatments for future lotic impact studies. I conducted a field-based study to quantify the impacts of invasive fish on ghost frog tadpoles (Family Heleophrynidae) in streams of South Africa. I used extensive field sampling of tadpole abundance, invasive fish, environmental and habitat variables to achieve the aim of investigating whether the preliminary negative effects of invasive fish on ghost frog tadpoles are reflected across a broader scale. Generalised linear-mixed models highlight a significant negative effect of invasive fish on ghost frog tadpoles, with further water quality parameters and physical habitat features playing significant roles impacting tadpole abundance. This thesis is the first to compare lentic and lotic amphibian responses to invasive fish and answers the question of whether there is a differential effect on amphibian behaviour in response to invasive fish, whilst elucidating the global lack of adequate lotic data. The second chapter not only represents the type of study needed to contribute towards lotic amphibian data but is also the largest scale at which the impacts of invasive fish on ghost frog tadpoles have been quantified. The results reported in this thesis contribute towards the motivation for global studies on the impact of invasive fish on native amphibians; and will aid in future conservation decisions regarding South Africa’s endemic lotic amphibians. The results of this thesis will likely have implication towards lotic amphibian conservation in South Africa and the world. AFRIKAANSE OPSOMMING: Indringer vis spesies het ‘n verskeidenheid negatiewe impakte op inheemse amfibieë Spesies regoor die wêreld. Hierdie impakte is beweer om meer skade te doen aan amfibieë spesies wat nie n evolusionêre geskiedenis met n inheemse vis spesie deel nie. Water massas wat oor die algemeen nie inheemse vis spesies het is die boonste lope van lotiese sisteme, waar die steil helling en deurlopende vloei die stroom-op beweging van visse verhoed het. Lentiese sisteme word uitgeken deur die gebrek aan n deurlopende stroom en het histories beide inheemse visse en amfibieë. Tot op hede is daar geen vergelyking tussen die impakte van indringer visspesies op inheemse amfibieë in lotiese en lentiese sisteme gemaak nie. Ek het n meta-analise uitgevoer op n globale datastel om die vraag te beantwoord of impakte van indringer visspesies meer skade doen aan lotiese amfibieë in vergelyking met lentiese amfibieë. As gevolg van n gebrek aan voldoende data op ander amfibiese veranderlikes, kon ek net gedrag vergelyk tussen die twee sisteme. Gedrag reaksies toon identitiese rigtings van effek, met n groter effek in lotiese amfibieë gemerk. Hierdie uitslag stem nie ooreen met die verwagte meer skadelike impak op lotiese amfibieë nie. Die uitslae identifiseer ‘n gebrek aan voldoende impak data vir Afrika en Suid-Amerika, asook n algemene gebrek aan voldoende data vir lotiese sisteme. Dit is gedeeltelik as gevolg van die ontwerp van die studies wat in lotiese sisteme uitgevoer word. Ek beveel aan dat die toekomstige studies in lotiese sisteme n vergelyking tussen n kontrole en n impak ondersoek terwyl die effek van die omgewing aangemerk word. Ek het n veld-studie uitgevoer om die impak van indringer visspesies op spookpadda paddavisse (Familie: Heleophrynidae) te ondersoek in Suid Afrika. Ek het paddavis getalle gemeet in die teenwoordigheid en afwesigheid van indringer visspesies, asook van belangrike water en habitat veranderlikes rekord gehou. Veralgemeende lineêr-gemengde modelle toon dat indringer visspesies ‘n betekenisvolle negatiewe impak op paddavis getalle het. Verdere water kwaliteit en fisiese habitat eienskappe speel ook belangrike rolle in die invloed op paddavis getalle. Die uitslae van hierdie thesis het hoogswaarskynlik nagevolge tot die bewaring van amfibieë spesies in Suid-Afrika en die wêreld. Masters 2023-02-20T14:54:38Z 2023-05-18T06:58:29Z 2023-02-20T14:54:38Z 2023-05-18T06:58:29Z 2023-03 Thesis http://hdl.handle.net/10019.1/126978 en_ZA Stellenbosch University x, 49 pages : illustrations (some color), maps application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Frogs Predation (Biology) Tadpoles -- Behavior Fishes -- Habitat -- Environmental aspects Ghost frog -- Conservation -- South Africa Invasive fish -- Conservation -- South Africa Trout -- Behavior UCTD Van Blerk, Daniel The impacts of invasive fish on ghost frog tadpoles |
| title | The impacts of invasive fish on ghost frog tadpoles |
| title_full | The impacts of invasive fish on ghost frog tadpoles |
| title_fullStr | The impacts of invasive fish on ghost frog tadpoles |
| title_full_unstemmed | The impacts of invasive fish on ghost frog tadpoles |
| title_short | The impacts of invasive fish on ghost frog tadpoles |
| title_sort | impacts of invasive fish on ghost frog tadpoles |
| topic | Frogs Predation (Biology) Tadpoles -- Behavior Fishes -- Habitat -- Environmental aspects Ghost frog -- Conservation -- South Africa Invasive fish -- Conservation -- South Africa Trout -- Behavior UCTD |
| url | http://hdl.handle.net/10019.1/126978 |
| work_keys_str_mv | AT vanblerkdaniel theimpactsofinvasivefishonghostfrogtadpoles AT vanblerkdaniel impactsofinvasivefishonghostfrogtadpoles |