Landscape characteristics and honeybee colony integrity: A case study of Mwingi, eastern Kenya
| dc.contributor.advisor | Veldtman, Ruan | en_ZA |
| dc.contributor.advisor | Abdel-Rahman, Elfatih | en_ZA |
| dc.contributor.advisor | Landmann, Tobias | en_ZA |
| dc.contributor.advisor | Muli, Eliud | en_ZA |
| dc.contributor.author | Ochungo, Pamela Aor | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology. | en_ZA |
| dc.date.accessioned | 2020-11-24T08:28:07Z | |
| dc.date.accessioned | 2021-01-31T19:40:52Z | |
| dc.date.available | 2020-11-24T08:28:07Z | |
| dc.date.available | 2021-01-31T19:40:52Z | |
| dc.date.issued | 2020-12 | |
| dc.description | Thesis (PhDConsEcol)--Stellenbosch University, 2020. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Honeybees (Apis mellifera) are highly efficient crop pollinators, providing valuable ecosystem services through pollination in diverse environments globally. However, honeybee populations are in decline and habitat loss and fragmentation, pests and parasites and nutritional deficiencies are emerging as some of the most important factors contributing to this decline, consequently threatening food security and rural communities’ livelihoods. Therefore, monitoring the interconnected effects of landscape fragmentation, pollen diversity, honeybee pests’ and honeybees’ colony strength is a fundamental component of their conservation as well as safeguarding continued ecosystem services. In Kenya, where the study is carried , there have been no investigations specifically addressing these linkages mainly because until recently, there has been unavailability of freely available moderate to high resolution landscape fragmentation maps. As such, the overall goal of this study was to quantify landscape fragmentation, and to investigate its effect on honeybee colony strength, pollen diversity and protein content and Varroa destructor mite occurrence in a semi-arid region located in the eastern part of Kenya. Using Sentinel-1A SAR and Sentinel-2A optical remote sensing systems, the first part of this study examined the use of a random forest machine learning algorithm to map fine-scaled and under-represented landscape elements representing honeybee habitats in six study sites (apiaries) specifically selected based on varying landscape degradation levels. The results indicated that the fused SAR and optical imagery had the highest overall accuracy for mapping the spatially explicit honeybee habitats and thereafter, fragmentation metrics relating to landscape composition and configuration were derived from this fused combination, within a 3 km buffer radius of each apiary. Landscape fragmentation metrics derived from the fused SAR and optical imageries were thereafter linked with honeybee colony strength parameters. Results of zero inflated negative binomial regression with mixed effects indicated that lower complexity of patch geometries represented by Fractal Dimension and reduced proportions of croplands were most influential at local foraging scales (1 km) from the apiary, while higher proportions of woody vegetation and hedges resulted in higher colony strength at longer distances from the apiary (2.5 km). Moreover, honeybees in moderately degraded landscapes displayed the most consistently strong colonies throughout the study period. In the third part of the study, pollen diversity and protein content were examined across the six apiaries. Results showed that pollen diversity was highest in moderately degraded landscapes while protein content in pollen did not vary by location but varied by seasonality. In the final part of the study, Varroa destructor mite did not have any effect on honeybee colony strength parameters, except for eggs. However, lower complexity of patch shapes and greater landscape homogeneity represented by the Shannon diversity index were highly influential on Varroa destructor mite occurrence. The overall study shows that landscape fragmentation influences honeybee colony strength, pollen diversity and Varroa destructor mite occurrence. These results can be used to inform hive placement for maximal colony strength and hive productivity. However, the study was conducted in only six apiaries and recommendations regarding validation at larger numbers of replicates are made. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Die heuningby (Apis mellifera) is ‘n hoogs doeltrefende bestuiwer van gewasse en verskaf waardevolle ekosisteemdienste deur bestuiwing wêreld-wyd in diverse omgewings. Egter, heuningby populasies is aan die afneem as gevolg van fragmentasie, peste en siektes, en voedings tekorte, as sommige van die belangrikste faktore. As voortvloeisel hiervan word voedsel-sekuriteit en die lewensbestaan van plattelandse gemeenskappe bedreig. Daarom is die monitering van die tussen-verbintenis van landskapfragmentasie, stuifmeeldiversiteit, heuningbypeste en heuningbykoloniesterkte ‘n fundamentele komponent van hul bewaring en voorgesette ekositeemdienste. In Kenja, waar hierdie studie uitgevoer is, was daar nog nooit enige ondersoeke wat spesifiek hierdie verbintenisse aanspreek nie. Dit is hoofsaaklik as gevolg van die tot onlangse onbeskikbaarheid van vrylik bekombare, hoë-resolusie landskapfragementasiekaarte. Sodoende was die oorhoofse doel van hierdie studie om lanskapfragmentasie en om die uitwerking hiervan op heuningbykoloniesterkte, stuifmeeldiversiteit en proteïn-inhoud, en die voorkoms van die Varroa destructor myt, in ‘n semi-dorre streek in die Oostelike deel van Kenja te kwantifiseer. Met behulp van Sentinel-1A SAR en Sentinel-2A optiese afstandswaarnemingstelsels, het die eerste deel van hierdie studie 'n ewekansige ‘forest’-masjienleer algoritme gebruik om die fynskaalse en onderverteenwoordigde landskapselemente wat heuningbyhabitatte voor te stel in ses studiepersele (byekorf-staanplekke of ‘apiaries’), spesifiek gekies op grond van hul verskillende landskap-agteruitgangsvlakke. Die resultate het aangedui dat die versmelte SAR en optiese beelde die hoogste algehele akkuraatheid het vir die kartering van die ruimtelike eksplisiete heuningbyehabitatte. Hierna is fragmenteringsmetrieke afgelei van hierdie versmelte kombinasie, met betrekking tot landskapsamestelling en -konfigurasie binne 'n buffer-radius van 3 km van elke byekorf-staanplek. Landskapsfragmenteringsmetrieke afgelei van die versmelte SAR en optiese beelde is daarna gekoppel aan heuningbysterkte-parameters. Resultate van nul-opgeblase negatiewe binomiale regressie met gemengde effekte, het aangedui dat laer kompleksiteit van kol-geometrieë wat deur Fraktaledimensie voorgestel word, en die verminderde proporsies van gewaslande, die invloedrykste was op plaaslike voedingsbronne vanaf die byekorwe (1 km), terwyl hoër verhoudings in houtagtige plantegroei en heinings in hoër koloniesterkte op langer afstande vanaf die byekorwe (2,5 km) tot gevolg gehad het. Boonop het heuningbye in matig-agteruitgaande-landskappe die mees bestendigste sterk kolonies gedurende die studietydperk gehaad. In die derde deel van die studie is stuifmeeldiversiteit en proteïeninhoud oor die ses byestaanplekke ondersoek. Resultate het getoon dat stuifmeelverskeidenheid die hoogste was in matig-agteruitgaande-landskappe, terwyl die proteïeninhoud in stuifmeel nie volgens plek varieër het nie, maar wel volgens seisoenaliteit. In die laaste gedeelte van die studie het Varroa destructor myt geen effek gehad op die sterkteparameters van heuningbykolonies nie, behalwe vir eier telings. Laer kompleksiteit van kolvorms en groter landskaphomogeniteit wat deur die Shannon-diversiteitsindeks voorgestel word, het egter 'n groot invloed gehad op die voorkoms van die Varroa destructor myt. As ‘n geheel dui die studie dat die fragmentering van die landskap die sterkte van die heuningbykolonie, die stuifmeelverskeidenheid en die voorkoms van Varroa destructor myt beïnvloed. Hierdie resultate kan gebruik word om korfplasing in te lig vir maksimale koloniesterkte en korfproduktiwiteit. Die studie is egter in slegs ses byekorf-staanplekke uitgevoer en aanbevelings oor validering met groter getalle herhalings word gemaak. | af_ZA |
| dc.description.version | Doctoral | en_ZA |
| dc.format.extent | 145 pages : illustrations (some color) | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/109241 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Fragmented landscapes | en_ZA |
| dc.subject | Honeybee -- Kenya -- Mwingi | en_ZA |
| dc.subject | Bee pollen | en_ZA |
| dc.subject | Varroa destructor | en_ZA |
| dc.subject | Bee culture -- Effect of habitat modification on | en_ZA |
| dc.subject | Honeybee -- Diseases -- Control | en_ZA |
| dc.subject | Honeybee -- Ecology | en_ZA |
| dc.subject | UCTD | en_ZA |
| dc.title | Landscape characteristics and honeybee colony integrity: A case study of Mwingi, eastern Kenya | en_ZA |
| dc.type | Thesis | en_ZA |