A bioindicator protocol for sustainable agribusiness in South Africa, using new crops as case studies

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Date
2014-11
Authors
Swart, Vaughn Richmond
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University of the Free State
Abstract
English: This study is innovative in that it proposes an Index determined by the functional qualities of arthropods and relates a monetary value to these qualities, based on new crop case studies conducted at two contrasting agroecosystem sites in South Africa. The sustainability of an agribusiness depends on the conservation of its biodiversity. The development of a robust methodology that can be used in an Environmental Management System (EMS) is thus necessary by (i) implementing measures of arthropod and general vegetation biodiversity and (ii) incorporating a monetary value to functional diversity, as mechanisms to indicate the degree of disturbance within the agro-ecosystem. The main objectives were to determine the relationship between arthropod diversity indices (species richness, abundance and evenness) and arthropod assemblages; to determine the relationship between the edge effect reaction of arthropods and the resistance and resilience of an agroecosystem; to determine the relationship between agricultural practices (such as pesticides and fertilizers), surrounding vegetation and arthropod richness and abundance; and to determine the relationship between arthropod species richness and abundance, and the proposed AFI (Agroecosystem Function Index), which is based upon the economic value of ecosystem services. Case studies were conducted to pinpoint potential indices of an ecological nature, with specific reference to the diversity indices of arthropods, as part of the methodology. Arthropods were used as an indicator community since they are prevalent, have high species diversity, are easy to sample, are important in ecosystem function, provide early detection of ecological changes and respond to environmental changes faster than vertebrates. The influence of agricultural management practices on this diversity is also taken into consideration. Quantitative and qualitative analysis revealed distinct patterns within the biodiversity at all the locations, relative to the frequency and diversity of vegetation sampled. Thus aspects of ecology (edge-effect, guild structure and functional diversity) should indicate a relationship between communities, which in turn would indicate the level of ecosystem integrity. The level of ecological integrity could be taken into consideration when adopting a quality Environmental Management System (EMS). Possibilities of incorporating a monetary value model, such as the Agroecosystem Function Index (AFI), to biodiversity analysis, that in turn has a bearing on ecosystem services and agribusiness, is also addressed. An EMS bio-indicator protocol is important as an aid to reduce the impact of agricultural management practices on the agro-ecosystem and to increase its functional efficiency.
Afrikaans: Hierdie studie is innoverend deurdat dit ‘n indeks daar stel wat deur die funksionele eienskappe van geleedpotiges bepaal word en ‘n geldwaarde daaraan koppel. Dit is op nuwe gewas gevallestudies wat by twee kontrasterende agroekostelsel studieareas in Suid Afrika uitgevoer is, gebasseer. Die volhoubaarheid van ‘n agribesigheid, hang van die bewaring van die biodiversiteit af. Die ontwikkeling van ‘n robuuste metode wat in ‘n Omgewing Bestuurstelsel gebruik kan word, vereis dat (i) maatstawwe van geleedpotige en algemene plantegroei biodiversiteit geïmplementeer word en dat (ii) ‘n geldwaarde vir funksionele diversiteit geïnkorporeer word, om as meganismes wat die vlak van versteuring binne die ekostelsel aandui, te dien. Die vernaamste doelwitte was om die verhouding tussen geleedpotige diversiteitsindekse (spesiesrykheid, volopheid en gelykheid) en geleedpotige samestelling te bepaal; die verhouding tussen die randeffek reaksie van geleedpotiges en die weerstand en veerkragtigheid van ‘n agroekostelsel te bepaal; die verhouding tussen landboupraktyke (soos plaagdoders en kunsmis), omliggende plantegroei en geleedpotige spesiesrykheid en volopheid te bepaal; en die verhouding tussen die geleedpotige spesiesrykheid en oorvloed, en die voorgestelde Agroekostelsel Funksionering Indeks, wat op die ekonomiese waarde van die ekostelsel dienste gebasseer is, te bepaal. Gevallestudies is uitgevoer om potensiële indekse van ‘n ekologiese aard vas te stel, met spesifieke verwysing na diversiteitsindekse van geleedpotiges, as deel van die metode. Geleedpotiges is as ‘n aanwyser-gemeenskap gebruik aangesien hulle volop voorkom, ‘n hoë spesies-diversiteit het, maklik is om te versamel, belangrik is in ekostelsel funksionering, geleenthede vir vroeë opsporing van ekologiese veranderinge bied en vinniger as gewerweldes op veranderinge in die omgewing reageer. Die invloed van landbou-praktyke op hierdie diversiteit word ook in ag geneem. Kwantitatiewe en kwalitatiewe analise het duidelike patrone in die biodiversiteit uitgewys en word, relatief tot die frekwensie en verskeidenheid van plantegroei-diversiteit wat ingesamel is, by die verskillende studiepunte waargeneem. Dus behoort aspekte van ekologie (randeffek, gildestruktuur en funksionele diversiteit) ‘n verhouding tussen gemeenskappe aan te dui, wat om die beurt die vlak van ekostelsel-integriteit aandui. Die vlak van ekologiese integriteit kan in ag geneem word wanneer ‘n kwaliteit Omgewing Bestuurstelsel aangeneem word. Moontlikhede om ‘n geldwaarde model, soos die Agroekostelsel Funksionering Indeks, vir biodiversiteit daar te stel, wat op sy beurt ‘n invloed op ekostelsel- dienste en agrobesigheid het, word ook aangespreek. ‘n Omgewing Bestuurstelsel bio-aanwyser protokol is belangrik as ‘n hulpmiddel om die impak van landbou-praktyke op die ekostelsel te verminder en die funksionele doeltreffendheid daarvan te verhoog.
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Agroecosystem indicators, New crops, Arthropods, Vegetation, Biodiversity, Functional diversity, Agribusiness, Agroecosystem Function Index, Biotic and abiotic factors, Environmental Management System, Thesis (Ph.D. (Environmental Business))--University of the Free State, 2014
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