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Humans and Nile crocodiles along the Kunene River, Namibia: population dynamics and socio-ecological interactions
Thesis (MScConEcol)--Stellenbosch University, 2023.
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| Language: | English |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867614139893940224 |
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| access_status_str | Open Access |
| author | Le Roux, Johannes Lucas |
| author2 | Leslie, Alison |
| author_browse | Le Roux, Johannes Lucas Leslie, Alison |
| author_facet | Leslie, Alison Le Roux, Johannes Lucas |
| author_sort | Le Roux, Johannes Lucas |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScConEcol)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/129421 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:47:17.937Z |
| 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:10019.1/129421 Humans and Nile crocodiles along the Kunene River, Namibia: population dynamics and socio-ecological interactions Le Roux, Johannes Lucas Leslie, Alison Naude, Vincent Stellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology & Entomology. Nile crocodile -- Ecology --Namibia -- Kunene River Human–animal relationships -- Namibia -- Kunene River Nile crocodile -- Effect of human beings on Crocodile populations Wildlife conservation -- Namibia UCTD Thesis (MScConEcol)--Stellenbosch University, 2023. Le Roux, J. L. 2023. Humans and Nile crocodiles along the Kunene River, Namibia: Population dynamics and socio-ecological interactions. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/fe644160-95f0-4b4e-ab83-ca5f0166e7f9 ENGLISH ABSTRACT: Human crocodile conflict is widespread throughout Africa and occurs at higher frequencies than in most other parts of the world. In spite of this, data on the distribution and scale of the conflict remains limited with conservationists and policy makers often relying on limited data to make management decisions. To make informed choices on how to mitigate these conflicts, an understanding of both the human dimensions, such as the frequency and distribution of conflict, as well as the biological dimensions, such as the distribution and abundance of crocodiles, is required. In the context of the lower Kunene River of north-western Namibia, one aerial survey of crocodiles was undertaken in 2012, while no previous research on the nature of human crocodile interactions had been undertaken before this study. Considering the above, this study aimed to estimate, as accurately as possible, the distribution and abundance of Nile crocodiles along the lower Kunene River, with the intention of comparing the current population estimate to that of 2012. In addition, the study set out to produce the first comprehensive data set on the scale, drivers, and distribution of human crocodile conflict (HCC) along the river. To estimate of the abundance and distribution of Nile crocodiles along the lower Kunene River, an aerial survey was undertaken over three days in April 2021. The data collected during the survey were plotted on a map and analysed using both the direct count and modelled estimate of the crocodile population. These results were compared to those of the 2012 survey. To understand the interactions between humans and crocodiles along the lower Kunene River, a social survey was undertaken during which a questionnaire was administered to 155 households living along the Namibian bank of the river. These social ecological data were collected over two months in early 2022 and interpreted using both spatial and statistical analysis. Regarding the Nile crocodile population along the lower Kunene River, a population estimate of between 287 (0.81 crocodiles per km), and 597 (1.7 crocodiles per km) was determined. These results suggest a decrease in the crocodile population of between 28 and 49% from 2012 to 2021. Additionally, a demographic shift seems to be underway with the numbers of crocodiles under 2 m in length appearing to remain relatively stable between 2012 and 2021, whereas the number of crocodiles > 2 m have decreased dramatically. Importantly, human population density appeared to be negatively correlated with crocodile abundance suggesting that as the number of humans in an area increases, the number of crocodiles decreases. The results of the social survey showed that the large majority (92%) of households actively engage in subsistence farming and place a great deal of importance on growing crops and rearing livestock. Community members living along the lower Kunene River appear to be heavily reliant on water from the river with at least two thirds of households using the river for drinking, washing, and bathing water. Reliable records of 33 crocodile attacks on humans between 2010 and March 2022 were obtained with men appearing to be at the highest risk of attack. Fishing was found to be the activity with the highest risk, and afternoon/ evening appeared to be the time with the highest risk of experiencing a crocodile attack. Additionally, there seemed to be an increased risk of attack as households performed more activities at the river, and for households who used the river as a primary source of water. Crocodile attacks on livestock appeared to be substantial with 55% of cattle owners and 78% of small stock owners reporting losses to crocodiles in 2021. Most (82%) livestock owners felt crocodiles were the animal responsible for the most damage to their herds, and most attacks appeared to occur in the hot and dry (Okuni) season. Watering livestock in the afternoon/ evening emerged as the time of day with the highest risk of attack while morning was the lowest, as was the case with attacks on humans. Households with a higher dependence on the river demonstrated a higher risk of experiencing attacks on livestock. The Nile crocodile population along the lower Kunene River showed a positive correlation with attacks on small stock, while the human population correlated positively with attacks on livestock and humans. Retaliation against crocodiles was not widely reported, although there were reports of crocodiles being killed with firearms, poison, snares, and hook and lines. Most respondents cited attacks on livestock as the motive behind retaliating against crocodiles. Perceptions of crocodiles were generally negative, and most respondents failed to offer solutions to the conflict between humans and crocodiles along the lower Kunene River. AFRIKAANSE OPSOMMING: Mens krokodil-konflik is algemeen en wydverspreid regoor landelike Afrika. Ten spyte hiervan is data oor die verspreiding en omvang van die konflik beperk, en natuurbewaarders steun dikwels op beperkte data om bestuursbesluite te neem. Om ingeligte keuses te maak oor hoe om hierdie konflik te verminder, is 'n begrip van die menslike dimensies, sowel as die biologiese bevindinge, nodig. In die konteks van die laer Kunene-rivier in noordwestelike Namibië is daar in 2012 een lugopname van krokodille geneem, terwyl geen vorige navorsing oor die aard van mens krokodil-interaksies voor hierdie studie onderneem is nie. Met bogenoemde in ag geneem, het hierdie studie ten doel gehad om die verspreiding van krokodille langs die laer Kunene so akkuraat as moontlik te skat, met die bedoeling om die huidige bevolkingsskatting te vergelyk met die van 2012. Daarbenewens het die studie ten doel gehad om die eerste omvattende databank oor die omvang, moontlike motiewe en verspreiding van mens krokodil-konflik langs die rivier te produseer. Om 'n skatting van die getal en verspreiding van krokodille langs die laer Kunene te maak, is 'n lugopname oor drie dae in April 2021 onderneem. Die data wat tydens die opname ingesamel is gekaarteer en dan geanaliseer met behulp van beide die direkte telling en gemodelleerde skatting van die krokodilpopulasie. Hierdie resultate is vergelyk met die van die 2012-opname. Om die interaksies tussen mense en krokodille langs die laer Kunene te verstaan, is ook 'n sosiale opname onderneem waarin 'n vraelys aan 155 huishoudings wat langs die Namibiese oewer van die rivier woon, voorgehou is. Hierdie sosio-ekologiese data is oor twee maande vroeg in 2022 ingesamel en is deur middel van ruimtelike en statistiese analise geïnterpreteer. Met betrekking tot die krokodilpopulasie langs die laer Kunene, is 'n bevolkingsskatting van tussen 287 (0.81 krokodille per km) en 597 (1.7 krokodille per km) bepaal. Hierdie resultate dui op 'n afname in die krokodilpopulasie van tussen 28 en 49% vanaf 2012 tot 2021. Daarbenewens blyk dit dat daar tans 'n demografiese verandering aan die gang is, met die aantal krokodille onder 2 m in lengte wat redelik stabiel bly tussen 2012 en 2021, terwyl die aantal krokodille >2 m drasties afgeneem het. Dit lyk asof die menslike bevolkingsdigtheid 'n negatiewe korrelasie met die getal krokodille toon, wat aandui dat die aantal krokodille afneem namate die aantal mense in 'n gebied toeneem. Die resultate van die sosiale opname het getoon dat die groot meerderheid (92%) van die huishoudings aktief aan bestaansboerdery deelneem. Gemeenskapslede wat langs die laer Kunene woon, is sterk afhanklik van water uit die rivier, en minstens twee derdes van die huishoudings gebruik die rivier vir drinkwater, was, en bad. Betroubare rekords van 33 krokodilaanvalle op mense tussen 2010 en Maart 2022 is verkry, en dit blyk dat mans die grootste risiko vir aanvalle inhou. Hengel is die aktiwiteit met die hoogste risiko, en die middag- /aandure blyk die tye met die hoogste risiko van 'n krokodilaanval. Daar was ook 'n verhoogde risiko van aanvalle wanneer huishoudings meer aktiwiteite by die rivier uitgevoer het, en vir huishoudings wat die rivier as hul primêre bron van water gebruik het. Krokodilaanvalle op vee blyk aansienlik te wees, met 55% van beesboere en 78% van kleinveeboere wat in 2021 verliese aan krokodille aangemeld het. Agt-en-tagtig persent van die vee-eienaars het gevoel dat krokodille die dier was wat die meeste skade aan hul kuddes aangerig het, en die meeste aanvalle blyk in die warm en droë (Okuni) seisoen voor te kom. Die middag- /aandure is die veedrinktyd met die hoogste risiko van aanvalle, terwyl dit in die oggend die laagste is. Soos met aanvalle op mense, het huishoudings wat meer afhanklik is van die rivier, 'n hoër risiko getoon om aanvalle op vee te ervaar. Die krokodilpopulasie langs die laer Kunene het 'n positiewe korrelasie met aanvalle op kleinvee getoon, terwyl die menslike bevolking 'n positiewe korrelasie met aanvalle op vee en mense getoon het. Vergelding teen krokodille is nie wydverspreid gerapporteer nie, maar daar was berugte van krokodille wat met gewere, gif, strikke en hoek- en lyn gevang is. Die meeste respondente het aangedui dat aanvalle op vee die motief was agter vergeldingsaksies teen krokodille. Persepsies van krokodille was oor die algemeen negatief, en die meeste respondente het nie oplossings vir die konflik tussen mense en krokodille langs die laer Kunene aangebied nie. Masters 2023-11-28T09:22:37Z 2024-02-20T11:00:52Z 2023-11-28T09:22:37Z 2024-02-20T11:00:52Z 2023-11-28 Thesis https://scholar.sun.ac.za/handle/10019.1/129421 en Stellenbosch University xx, 152 pages : illustrations, maps application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Nile crocodile -- Ecology --Namibia -- Kunene River Human–animal relationships -- Namibia -- Kunene River Nile crocodile -- Effect of human beings on Crocodile populations Wildlife conservation -- Namibia UCTD Le Roux, Johannes Lucas Humans and Nile crocodiles along the Kunene River, Namibia: population dynamics and socio-ecological interactions |
| title | Humans and Nile crocodiles along the Kunene River, Namibia: population dynamics and socio-ecological interactions |
| title_full | Humans and Nile crocodiles along the Kunene River, Namibia: population dynamics and socio-ecological interactions |
| title_fullStr | Humans and Nile crocodiles along the Kunene River, Namibia: population dynamics and socio-ecological interactions |
| title_full_unstemmed | Humans and Nile crocodiles along the Kunene River, Namibia: population dynamics and socio-ecological interactions |
| title_short | Humans and Nile crocodiles along the Kunene River, Namibia: population dynamics and socio-ecological interactions |
| title_sort | humans and nile crocodiles along the kunene river namibia population dynamics and socio ecological interactions |
| topic | Nile crocodile -- Ecology --Namibia -- Kunene River Human–animal relationships -- Namibia -- Kunene River Nile crocodile -- Effect of human beings on Crocodile populations Wildlife conservation -- Namibia UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/129421 |
| work_keys_str_mv | AT lerouxjohanneslucas humansandnilecrocodilesalongthekunenerivernamibiapopulationdynamicsandsocioecologicalinteractions |