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List of contents
1. General introduction and study rationale
2. Anthropogenic influences on the structure and functioning of riverine ecosystems in the Lake Victoria basin
3. Macroinvertebrate functional feeding groups in Kenyan highland streams: implications for organic matter processing
4. Litter processing and shredder distribution as indicators of riparian and catchment influences on ecological health of tropical streams
5. Linkage between DOM composition and whole-stream metabolism in headwater streams influenced by different land use
6. Partitioning the relative importance of different sources of energy for consumers on the longitudinal gradient of the Mara River, Kenya
7. Synthesis and conclusions
About the author
Frank Onderi Masese is currently lecturer in aquatic sciences at the University of Eldoret, Kenya. He is a member of various professional organizations, including the Ecological Society of Eastern Africa, East African Water Association, Nature Kenya and the Ecological Society of America.He is aquatic scientist with interest in the influence of anthropogenic activities on the structure and functioning of riverine ecosystems. This involves assessing ecosystem level responses to perturbations on catchments, riparian areas and in-stream habitats. He is also working on assessing the influence of discharge variation on organic matter processing, ecosystem connectivity and carbon flow among consumers in streams and rivers, and monitoring human-induced ecological changes in streams and rivers using multimetric and biotic indices. To achieve these objectives, he utilizes holistic and integrated approachesfor the assessment ofcatchment level influences, including land use change, livestock and wildlife populations on water quality and ecosystem functioning.
Summary
To properly conserve, restore and manage riverine ecosystems and the services they provide, it is pertinent to understand their functional dynamics. Growing human populations and high dependency on natural resources in developing countries have exerted pressure on land and water resources. However, there is a major knowledge gap concerning the influence of human activities on the functioning of tropical rivers in terms of organic matter processing and energy sources supporting riverine consumers.
This thesis explores the functioning of tropical upland streams and savanna rivers by assessing the spatial and temporal dynamics in organic processing under different land-use and discharge conditions and the resultant influence on energy sources for riverine consumers.
This thesis contributes to the theories of river functioning and has improved understanding of the functioning of African tropical streams by identifying a diverse macroinvertebrate shredder guild and determining its role in organic matter processing. This thesis also shows that large mammalian herbivores enhance terrestrial-aquatic food web linkages in African savanna rivers via the transfer of organic matter. The findings of this researcht are useful for defining future research needs and actions for sustainable management of agriculturally influenced streams and savanna rivers in landscapes witnessing declining wildlife populations and changing land uses.
