Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Insect pollinators play an important role in producing crops in global agriculture. Pollinatordependent
crops contribute to maintaining a healthy variety in the human diet and often have a
high market value, beneficial for local or regional economies. Insect crop pollinators can either
be from natural areas adjacent to orchards, or they can be brought into orchards by beekeepers
that manage them. Pollination by wild pollinators is an ecosystem service, while managed
pollinators (mostly honeybees) is a humanly managed service, considered not to be related to the
ecosystem. Ecosystem services and their economic value have often been used as an incentive
for conservation, although it is sometimes difficult to characterise and quantify them. Wild and
managed pollinators have been reported to be threatened in several regions around the world, and
there is concern about the effect a pollination deficit may have on crop production. Different
crops and cultivars have different levels of dependence on insect pollination due to a
combination of biological, physical and management factors. In this study, the pollination
dependence of the Granny Smith apple cultivar and the respective contributions of wild and
managed pollinators are investigated in the Western Cape province of South Africa. Granny
Smith apples show a significant increase in production with insect pollination (wild and
managed). Managed honeybees are more abundant in orchards than wild honeybees, and also
provide a better pollination service. This difference between the pollination service of wild and
managed honeybees are specifically noted in the quality, where managed honeybees pollination
result in significantly more seeds per fruit and consequently produce a better shaped apple. The
study goes further by quantifying the ecosystem services to the managed honeybee industry
through a questionnaire completed by beekeepers. It was found that 49% of the managed hives in
the Western Cape rely to some extent on natural vegetation as a forage source. Furthermore 18%
of honey produced is also from natural vegetation and the wild honeybee population replenish
managed honeybee stocks if they become depleted. Although managed honeybees are not
usually considered an ecosystem service, it is clear that they are still linked to the ecosystem via
these pathways. It is thus obvious that all pollination sources are linked to the environment, not
just wild pollinators. A further economic valuation of the ecosystem service studied, and to the
argument for conservation of pollinators and the resources they depend on. / AFRIKAANSE OPSOMMING: Insek bestuiwing speel ‘n belangrike rol in die produksie van gewasse in landbou wêreldwyd.
Gewasse wat bestuiwing-afhanklik is, dra by tot ‘n gesonde verskeidenheid in die mens se dieët
en hul hoë mark waarde is voordelig vir plaaslike en streeks ekonomieë. Insek bestuiwers kan of
van natuurlike areas langs boorde afkomstig wees, of bestuurde bestuiwers kan deur byeboere in
boorde ingebring word. Bestuiwing deur wilde bestuiwers is ‘n ekosisteem diens, maar die
byeboere verskaf ‘n bestuurde diens, wat nie altyd gereken word om aan die ekosisteem verwant
te wees nie. Ekosisteem dienste en hul ekonomiese waarde word gereeld gebruik as insentief vir
bewaring, alhoewel dit soms moeilik is om dit te karaktariseer en te kwantifiseer. In sekere
streke wêreldwyd is dit bewys dat wilde, asook bestuurde bestuiwers, bedreig is en daar heers
bekommernis dat ‘n tekort aan bestuiwers gewas produksie negatief sal beïnvloed. Verskillende
gewasse en kultivars het verskillende vlakke van bestuiwing-afhanklikheid as gevolg van
verskillende biologiese en fisiese faktore en bestuurspraktyke. In hierdie studie is die
bestuiwings-afhanklikheid van die Granny Smith appel kultivar ondersoek, asook die bydrae van
wilde en bestuurde heuningbye in die Wes-Kaap provinsie van Suid Afrika. Granny Smith appels
toon ‘n betekenisvolle produksie verbetering met insek bestuiwing (wilde en bestuurde bye).
Daar is ‘n groter hoeveelheid bestuurde bye in ‘n boord as wilde bye, en hulle verskaf ook dus ‘n
beter bestuiwingsdiens. Die voordeel van bestuurde bye bo wilde bye word veral in vrug
kwaliteit opgemerk. As bestuurde bye gebruik word, is daar betekenisvol meer sade per vrug en
gevolglik het die appels ook ‘n beter vorm. Verder fokus die studie ook op die kwantifisering
van ekosisteem dienste wat aan die bestuurde heuningby industrie verskaf word, deur inligting
van byeboere te gebruik. Daar is bevind dat 49% van die kolonies bestuurde bye in die Wes-
Kaap is tot ‘n mate afhanklik van natuurlike plantegroei vir voedsel. Verder is 18% van die
geproduseerde heuning ook afkomstig van natuurlike plantegroei se nektar en byeboere vang
wilde kolonies om uitgestorwe bestuurde kolonies te vervang. Dit is dus duidelik dat alle
bestuiwings bronne gekoppel is aan die omgewing, nie slegs wilde bestuiwers nie. ‘n Verdere
ekonomiese waardasie van die onderskeie ekosisteem dienste wat bestudeer is, voeg motivering
by tot die bewaring van bestuiwers en die hulpbronne waarvan hulle afhanklik is.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/6830 |
| Date | 03 1900 |
| Creators | Mouton, Madele |
| Contributors | Samways, Michael J., Veltman, Ruan, De Lange, Willem, University of Stellenbosch. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 92 p. : ill. |
| Rights | University of Stellenbosch |
Page generated in 0.0021 seconds