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Dive into the research topics where Phillip Okoth Raburu is active.

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Featured researches published by Phillip Okoth Raburu.


African Journal of Aquatic Science | 2009

A preliminary benthic macroinvertebrate index of biotic integrity (B-IBI) for monitoring the Moiben River, Lake Victoria Basin, Kenya

Frank O. Masese; Phillip Okoth Raburu; M Muchiri

A Benthic Index of Biotic Integrity (B-IBI) was developed for the Moiben River. The index assesses effects of human disturbance on the biotic condition of stream macroinvertebrate communities. Eight stations were selected to represent different land-use types including forestry, settlement, grassland and mixed farming, practiced at different intensities. A total of 22 metrics were correlated against habitat quality and water quality parameters to determine their interrelationships. Ten metrics were shown to be responsive to changes in water and habitat quality, so could be used to separate sites according to levels of degradation. These were taxa richness (of Ephemeroptera, Plecoptera, Trichoptera and intolerant taxa richness), assemblage composition (percentage Ephemeroptera + Plecoptera + Trichoptera [EPT] individuals, and percentage of individuals in dominant taxa), pollution tolerance (percentage of tolerant individuals) and three functional feeding group metrics (ratio of scraper:filterer individuals, percentage gatherer genera, and percentage predator individuals). We calculated B-IBIs by summing metrics for each site, after transforming them to a discrete 1, 3, 5 scale. Values for the final index correlated well with measures of human influence based on qualitative assessment of habitat quality (Pearsons r 2 = 0.88). This preliminary benthic macroinvertebrate B-IBI shows promise for developing biological standards, which would facilitate long-term monitoring of streams in the upper reaches of Lake Victoria Basin.


African Journal of Aquatic Science | 2009

Macroinvertebrate assemblages as biological indicators of water quality in the Moiben River, Kenya

Frank O. Masese; M Muchiri; Phillip Okoth Raburu

Benthic macroinvertebrate assemblages at eight stations in the Moiben River, corresponding to different catchment land uses, were assessed in 2006 as indicators of water quality. The relative abundance per taxon, diversity index, richness index, evenness, dominance, percentage of five dominant taxa and percentage Ephemeroptera + Plecoptera + Trichoptera (EPT) individuals were determined per sampling period per station. Significant spatio-temporal variation was observed in relative abundance, with Diptera dominating the study area. Ephemeroptera, Plecoptera and Trichoptera dominated the headwater stations, whereas Coleoptera, Oligochaeta and Chironomidae dominated further downstream. Significant relationships were recorded between physico-chemical parameters — conductivity, BOD, temperature, and discharge — and the occurrence of specific taxa, mainly Heptagenia, Caenis, Baetis, Branchiobdella, Potamon, Ilyocoris, Elmis and Chironomus. Significant changes in macroinvertebrate assemblages were primarily due to changes in water quality. As elsewhere, macroinvertebrate communities proved to be good indicators of water quality and should be used as bioindicators in long-term monitoring of this river.


Aquatic Ecosystem Health & Management | 2009

Macroinvertebrate Index of Biotic Integrity (M-IBI) for monitoring rivers in the upper catchment of Lake Victoria Basin, Kenya

Phillip Okoth Raburu; Frank O. Masese; Christopher Aura Mulanda

The water quality of many streams in Lake Victoria Basin, Kenya is affected by agricultural intensification, municipal and industrial effluent, as well as water abstraction, livestock and deforestation. Management efforts have been hampered by lack of clear standards against which to judge the degree of environmental degradation. To achieve this goal, a macroinvertebrate-based Index of Biotic Integrity was developed to monitor ecological integrity of selected rivers occurring in the same ecological zone in the upper reaches of the basin. Macroinvertebrates were sampled with a Surber sampler at 22 stations. The stations were grouped into three condition categories (reference, intermediate and impaired stations) according to the level of degradation. Twenty metrics representing the structural and functional organization of macroinvertebrates were computed using Mann-Whitney U tests. The separation power of the metrics was evaluated using box plots. Final metrics were evaluated for responsiveness by Pearsons correlations with physicochemical parameters. Of the 20 metrics, 9 met the test criteria, as they displayed variability across the stations, and were used to provide the final scores for Macroinvertebrate Index of Biotic Integrity (M-IBI). Metric values at both reference and impaired sites were used to establish the scoring criteria using inter-quartile ranges. This index provided preliminary evidence of response to changes in ecosystem integrity exhibited by resident macroinvertebtrate assemblages in rivers in the upper reaches of Lake Victoria Basin. It was recommended that the index developed be used to assess and monitor rivers in the upper catchments of Lake Victoria Basin in Kenya.


Journal of ecology and the natural environment | 2014

The impact of water quality on species diversity and richness of macroinvertebrates in small water bodies in Lake Victoria Basin, Kenya

Steve O. Ngodhe; Phillip Okoth Raburu; Boaz Kaunda-Arara; Alfred Otieno Achieng

This study was carried out in small water bodies (SWBs) within Uasin-Gishu and Siaya Counties of Kenya to investigate the effects of water quality on species diversity and richness of macroinvertebrates in these areas. The water quality of the SWBs was assessed in two dams in UasinGishu County (Kesses and Kerita) and the other two in Siaya County (Mauna and Yenga) within Lake Victoria Basin. Water samples for total phosphorus (TP) and total nitrogen (TN) were collected at each sampling station and analyzed using standard methods and procedures. Physico-chemical parameters such as dissolved oxygen (DO), pH and temperature were taken in situ using electronic meters while biological oxygen demand (BOD) was analyzed using Winkler method after 5-days incubation period. Macroinvertebrate samples were collected using a scoop net (500 µm mesh size) then transferred into a white tray for washing and sorting prior to identification. Preliminary tests of water quality parameters were evaluated by GLM analysis of variance of which very significant differences were observed for both spatial (p = 0.004) and temporal (p= 0.001) variability with the measured water quality parameters. The results showed that there is both negative and positive change of macroinvertebrate composition and abundance between SWBs over time due to spatio-temporal variation of water quality parameters. Principle Component Analysis (PCA) further confirms this. PCA described over 90% of variation at the stations. For both seasons, TN, TP, temperature, pH, DO and BOD were found to have a significant influence of the species diversity, dominance and richness of macroinvertebrates. Principle component analysis of TN, TP, DO, pH and BOD for the SWBs described 96% of their variation when they were compared at temporal and spatial scales. This trend leads to the variation in species diversity; dominance and richness of macroinvertebrates in these SWBs. Water quality and littoral invertebrate mean relative abundance were significantly different among the studied small water bodies during the study period. Overall, water quality seemed to have had effect on species diversity, dominance and richness of the invertebrate benthic community therefore can be used as a bio-monitor to aquatic health.


Archive | 2012

Effects of Deforestation on Water Resources: Integrating Science and Community Perspectives in the Sondu-Miriu River Basin, Kenya

Frank O. Masese; Phillip Okoth Raburu; Benjamin N. Mwasi; Lazare Etiegni

Rivers play a major role as sources of water for both domestic and industrial use in many parts around the world. In developing countries, where infrastructure for water supply has not been fully developed, rivers provide a direct source of water for domestic use with minimal or no treatment at all. For water scarce countries, including Kenya (WRI, 2007), this means that water catchment areas should be managed properly so as to retain their capacity to supply good quality water all year round. Thus, understanding the possible consequences of land use and land cover changes on water resources is a requisite for better water resources management. However, this is not to be as many river catchments are undergoing rapid change mediated by human encroachment.


Journal of ecology and the natural environment | 2013

Use of macroinvertebrate assemblage to assess the ecological integrity of Nyando Wetlands, Kenya

Patrick Oduor Orwa; Phillip Okoth Raburu; Julius Kipkemboi; Priscah Rongoei; Steve Omari

This study aimed to investigate changes in macroinvertebrate assemblage within Nyando wetlands and developed an index of biotic integrity for monitoring human disturbances. Triplicate macroinvertebrate samples were collected monthly for seven months using a scoop net. They were sorted live, counted and identified to genus level. Water samples for nutrients were collected and analyzed using standard methods. Physico-chemical parameters were taken in situ using electronic meters. Macroinvertebrates were analyzed for richness, diversity, dominance and abundance. Abundance was correlated with physico-chemical parameters. Kruskal-Wallis test was used to test spatial differences in macroinvertebrate community. Metrics for index of biotic integrity were chosen, tested, and a 5, 3, 1 scoring criteria was used. A total of 45 genera were identified and Kruskal-Wallis test analysis revealed significant spatial differences in macroinvertebrate abundance. Repeated measures ANOVA showed significant spatio-temporal differences. Tolerant macroinvertebrates were abundant at the disturbed sites whereas intolerant taxa showed a strong negative correlation with nutrient levels. Sites with higher disturbance recorded a total index score far below the reference site score. The results indicated that macroinvertebrates in Nyando wetlands can be used to monitor its ecological integrity. The IBI developed should be used to protect the lake from eutrophication.


Archive | 1999

Conservation and Rehabilitation of Lake Kanyaboli Wetland, Kenya

Phillip Okoth Raburu

The Kenya national wetlands standing committee of the interministerial committee on environment defines wetlands as “Areas of land that are permanently, seasonally, or occasionally waterlogged with fresh, saline, brackish or marine waters, including both natural and man-made areas that support characteristic biota” (NWSC 1994). Although the Ramsar definition is broad enough, the national definition was deemed necessary to minimize confusion that often arose while using definitions developed in temperate countries. The three East African countries (Kenya, Uganda, and Tanzania) have come up with the region’ s wetland classification system (RWBG 1996). The classification identifies five broad wetland types that occur in East Africa as marine, estuarine, sodic and/or saline waters, freshwater, and man-made wetlands. Each of these broad types has several classes. In this classification system, Lake Kanyaboli is classified as a freshwater lacustrine/palustrine wetland. This is because it is a shallow lake adjoined to a wide palustrine wetland, the Yala swamp.


Scientific Research and Essays | 2009

Macroinvertebrate-based Index of biotic integrity (M-IBI) for monitoring the Nyando River, Lake Victoria Basin, Kenya

Phillip Okoth Raburu; J. B. Okeyo-Owuor; Frank O. Masese


River Research and Applications | 2012

Development of a fish-based index of biotic integrity (FIBI) for monitoring riverine ecosystems in the Lake Victoria drainage Basin, Kenya

Phillip Okoth Raburu; Frank O. Masese


Lakes and Reservoirs: Research and Management | 2010

A preliminary macroinvertebrate Index of Biotic Integrity for bioassessment of the Kipkaren and Sosiani Rivers, Nzoia River basin, Kenya

Christopher Mulanda Aura; Phillip Okoth Raburu; Jan Herrmann

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John W Gichuki

Hong Kong Environmental Protection Department

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