Department of Biological Sciences

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Browsing Department of Biological Sciences by Subject "Free Living Nematodes"

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    Free Living Nematode Diversity in Polluted Soils: A Meta-Analysis
    (University of Embu, 2021-09) Tino, Lydia Seyialoi
    Soil disturbances affects the community structures of soil organisms and the deterioration of the soil environment can be evaluated by studying these changes. Many experimental results have been published on the effects of heavy metals on the diversity of soil free living nematodes. We used a meta-analysis to obtain comprehensive and multi-disciplinary information on the use of soil free living nematodes as tools for assessing soil quality. Our aim was to determine the effects of heavy metal pollution on the diversity of soil free living nematodes and evaluate their suitability in soil health assessment. Free living nematodes are found to respond quickly to environmental stress compared to higher organisms, as they have intimate relations with their surroundings due to their high surface to volume ratio. In effect the knowledge gained in relation to the effects of pollution on soil free living nematode diversity, showed that species more sensitive to the toxic substances contained in the polluted sites, can disappear while others which are more tolerant can dramatically increase. In fact, many trace elements contained in the organic waste were reported to reduce the abundance and diversity of soil free living nematode communities and influence the survival potential and the rate of growth of more sensitive species. These were the results of comparatively small number of field studies that tested the short term effects of low level contamination by heavy metals on the soil health examined by analyzing soil nematode communities. However, our analyses on the impacts of heavy metal contamination on soil free living nematode abundance have led to inconsistent results and maturity index showed no relationship with heavy metal pollution. This impacted our results and altered the expected outcome.
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    Free-Living Nematode Diversity in Organic and Conventional Farming Systems: A Meta-Analysis.
    (University of Embu, 2021-09) Wekesa, Emmanuel
    Research indicates that agricultural management practices affect the diversity of organic farms. Theoretically, organic farming should lead to a higher diversity of free living nematodes (FLNs) compared to conventional farming. However, it is not clear how these management practices affect the abundance and diversity of FLNs. This research synthesizes published literature reporting the diversity of FLNs in organic and conventional farms. Studies were identified through a comprehensive search in google scholar using the search string "free-living nematodes" AND "diversity" in "organic AND conventional farming". Which resulted to 56 articles and after considering an inclusion criterion only 8 articles were included in the study; one of which was a PhD dissertation. Throughout these articles, the abundance of FLNs was reported to be higher in organic farms than in conventional farms. The abundance of functional groups was also higher in organic farming systems than in conventional farming systems. Bacterivores had a higher abundance, followed by fungivores. While the omnivores and predators had some insignificant abundances. The findings from this study confirms that organic farming is a more sustainable agricultural management system as compared to conventional farming. This research also shows that soils in organic farms are much healthier and of a higher quality that those of conventional farms due to the high abundance of FLNs in organic farms.