Frank Onderi Masese

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• Doctor of Philosophy
• Senior Lecturer at University of Eldoret

Phytoplankton and macroinvertebrate assemblages were used to assess the impact of a kraft pulp and paper mill effl uent in Kenya, on River Nzoia downstream of the discharge point in relation to changes in water quality during May to June and November 2008 (rainy and dry seasons, respectively). Total phosphorus concentration increased from 0.027 mg·...

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 intens...

Primary production and ecosystem respiration are fundamental aspects of stream ecosystem functioning. Descriptions of Afrotropical primary producer communities and their response to various natural and anthropogenic drivers appeared early in the literature, with the construction of some of the world’s largest dams on the African continent in the 19...

The Afrotropical Streams and Rivers: Structure, Ecological Processes and Management is a comprehensive guide that provides assessment of major rivers and tributaries in Africa. Unlike other books available, the editors present a thorough study of geomorphological, hydrological, biological, and ecological processes incorporating a range of plant and...

Decomposition of plant litter is a key ecological process in streams, whose contribution to the global carbon cycle is large relative to their extent on Earth. We examined the mechanisms underlying the temperature sensitivity (TS) of instream decomposition and forecast effects of climate warming on this process. Comparing data from 41 globally dist...

Wildlife, people, and livestock rely on riverine ecosystems in arid and semi-arid areas as primary water sources. Studies on the influence of human activities and livestock on the ecological health of these seasonal systems are thus necessary. This is more relevant given the increasing demand for water as human populations grow, which leads to over...

This book offers the first comprehensive pan–African assessment of the characteristics, status, and management of African streams and rivers. Until now, there has been missing an authoritative reference book on the structure and functioning of these water systems, the challenges they face, and the management options available. Most existing literat...

Organic matter drives the cycling of carbon and nutrients and is the primary source of energy fuelling both terrestrial and aquatic ecosystems. Different from other river systems, Afromontane-savanna rivers are unique in their own respect regarding the drivers of OM and nutrient dynamics. Most large river systems experience rapid transitions from t...

The physicochemical conditions observed in streams and rivers result from intricate interactions among various factors, including underlying geology, soil composition, hydro-climatic characteristics (such as rainfall amount and duration), vegetation cover, and human activities. Although streams and rivers exhibit common traits globally, the distinc...

Although Lake Kanyaboli provides a sanctuary for fish species that are considered extinct (e.g., Oreochromis esculentus, Oreochromis variabilis and Haplochromis spp.) in Lake Victoria, comprehensive data on species diversity and abundance are lacking. This study, conducted over a year (February 2020 to February 2021), addressed this gap by assessin...

Macrophytes are an important component of freshwater ecosystems, including rivers and streams, where they play various roles, such as providing food and habitat for other aquatic organisms and being involved in phytoremediation and nutrient cycling. Additionally, they play an important role as natural resources (i.e., food, medicine, and constructi...

Knowledge of the trophic structure and the major energy sources supporting metazoan production are important considerations for biodiversity conservation and ecosystem management. African streams and rivers face multiple stressors from agricultural intensification, deforestation, and municipal and industrial effluents coupled with uncontrolled wate...

The growing African human population poses threats to many of its rivers and streams by placing pressure on their resources, thereby affecting their biodiversity. While their drivers may vary across regions, many of these threats are consistent throughout the continent and include climate change, habitat loss and degradation, the introduction of al...

Afrotropical rivers are integral to the continent's socioeconomic development, environmental health, and cultural heritage. Research on these Afrotropical rivers is essential for informed decision-making, sustainable resource management, and safeguarding the ecological and social values of rivers for future generations. This chapter explores the cu...

Multiple stressors are increasingly recognized as major concerns in the sustainability of aquatic ecosystems in Africa and the myriad of ecosystem services deriving to millions of people on the continent. Stressors commonly interact to affect environmental conditions (e.g., habitat and water quality), individual species, communities, and ecological...

Motivation: Freshwater ecosystems have been heavily impacted by land-use changes, but data syntheses on these impacts are still limited. Here, we compiled a global database encompassing 241 studies with species abundance data (from multiplebiological groups and geographic locations) across sites with different land-use categories. This compilation...

Motivation: Freshwater ecosystems have been heavily impacted by land-use changes, but syntheses on the impacts on freshwater ecosystems are still limited. Here, we compiled a global database encompassing 248 studies with species abundance data (from multiple taxon groups and geographic locations) across sites with different land-use categories. Thi...

Estuarine ecosystems are classified as among the most productive systems on the planet earth supporting an array of biodiversity. However, due to the ever increasing human population, they experience environmental degradation originating from intensive anthropogenic activities hence the need for regular assessment and monitoring to inform its manag...

Rivers and streams contribute to global carbon cycling by decomposing immense quantities of terrestrial plant matter. However, decomposition rates are highly variable, and large-scale patterns and drivers of this process remain poorly understood. Using a cellulose-based assay to reflect the primary constituent of plant detritus, we generated a pred...

Aims: To determine the spatial variation in physico-chemical water quality attributes in estuarine ecosystems of South Coast Kenya to inform its management. Study Design: We employed diagnostic research design where such factors as anthropogenic activities, hydrology, and accessibility were considered in choosing 12 sampling stations. A mixed sampl...

Environmental impacts of tilapia fish cage aquaculture on water physico-chemical parameters of Lake Kivu, Democratic Republic of the Congo

Low-order streams contribute to the abiotic and biotic character of large rivers and are renowned for harboring unique forms of aquatic flora and fauna. However, most studies on headwater streams mainly focus on the mainstems and overlook the contribution of the tributary systems. Moreover, low-order streams are generally overlooked in legislation...

Habitat quality and diversity strongly influence the composition of macroinvertebrate communities in lotic ecosystems. We evaluated the functional organization of macroinvertebrates in response to changes in habitat type and seasonality in the Afromontane Moiben River in western Kenya. In-stream substrate characteristics were evaluated at the reach...

Over 42 million people rely on Lake Victoria as their primary source of food, employment, and clean drinking water. The lake's fisheries have produced around one million tonnes in recent years, but the lake's growing population has resulted in a lower catch rate per capita. And the lake and its catchment have been negatively impacted by a wide vari...

Human activities and global climate change affect ecosystems, species, and human services and resources (Dudgeon et al., 2006; Reid et al., 2019). Freshwater ecosystems are the most fragile habitats, hosting roughly 7% of the world’s biodiversity on 1% of land and 0.01% of water (Gleick, 1996; Reid et al., 2019). Human population growth exacerbates...

Africa is experiencing extensive biodiversity loss due to rapid changes in the environment, where natural resources constitute the main instrument for socioeconomic development and a mainstay source of livelihoods for an increasing population. Lack of data and information deficiency on biodiversity, but also budget constraints and insufficient fina...

Lake Victoria is the second largest freshwater lake in the world that was once a biodiversity hotspot hosting over 500 endemic haplochromine cichlids that were later decimated by exotic introductions and anthropogenically driven environmental and ecological changes. The environmental and ecological changes in the lake over the years have been attri...

Africa is experiencing extensive biodiversity loss due to rapid changes in the environment, where natural resources constitute the main instrument for socioeconomic development and a mainstay source of livelihoods for an increasing population. Lack of data and information deficiency on biodiversity, but also budget constraints and insufficient fina...

Many streams and rivers outside conservation areas across the Afrotropics face multiple stressors from land use change, urbanization, and excessive water withdrawals. Thus, there is a need to develop cost-effective tools for assessing and monitoring ecological changes to inform management decisions. Studies utilizing macroinvertebrate communities a...

Lake Victoria is the second largest freshwater lake in the world that was once a biodiversity hotspot hosting over 500 endemic haplochromine cichlids that were later decimated by exotic introductions and anthropogenically driven environmental and ecological changes. The environmental and ecological changes in the lake over the years have been attri...

Small streams constitute the majority of the water courses in a catchment and have specific characteristics that distinguish them from larger streams and rivers. Despite their small size and frequently remote locations, small streams contribute to ecosystem services that are important for humans. Here, we have identified 27 ecosystem services that...

Although several studies have investigated the relationships between water quality in rivers and the types of land use within their catchments, many aspects of these relationships remain unclear in Afromontane-savanna rivers, especially the interactions between catchment land use, seasonality and stream size. Afromontane-savanna catchments present...

Aquaponics incorporates aquaculture with hydroponics, whose principles and operations largely remain untested. Currently, there is a knowledge gap on the performance of aquaponic systems used for fish production under different stocking densities. This may hinder adoption and generally retard the development of aquaponic culture systems for fish an...

Most of the rivers in the Afrotropics emerge from forested uplands that are prime for human activities, including crop farming, grazing and settlement. However, streams draining these areas have a low diversity of fishes, which limits their use as indicators of water quality and ecological status. Here, we developed macroinvertebrate‐ and fish‐base...

Factors influencing the spatio-temporal dynamics of plankton communities in small tropical lakes are not well-understood. This study assessed plankton communities in response to spatial (six sampling sites) and seasonal (wet vs. dry seasons) changes in environmental variables in Lake Kanyaboli, a small satellite lake on the northern shores of Lake...

Microbes play a critical role in plant litter decomposition and influence the fate of carbon in rivers and riparian zones. When decomposing low‐nutrient plant litter, microbes acquire nitrogen (N) and phosphorus (P) from the environment (i.e., nutrient immobilization), and this process is potentially sensitive to nutrient loading and changing clima...

Small water bodies are the most threatened freshwater habitat types because of the large ratio between their size and the catchment they drain. In this study, we assessed the current and historical changes in the physical, chemical, and biological variables of Lake Kanyaboli, which is a satellite lake on the northern shores of Lake Victoria in west...

In many regions of the world, large populations of native wildlife have declined or been replaced by livestock grazing areas and farmlands, with consequences for terrestrial-aquatic ecosystem connectivity and trophic resources supporting food webs in aquatic ecosystems. The river continuum concept (RCC) and the riverine productivity model (RPM) pre...

Since recorded time, rivers have facilitated the establishment of human civilizations because of the myriad ecosystem goods and services they offer (Macklin and Lewin, 2015). Rivers provide transportation corridors, supply food in form of fisheries, and are major sources of water for irrigation, domestic use, renewable energy, and industrial develo...

Expansion of agriculture is particularly worrying in tropical regions of the world, where native forests have been replaced by croplands and grasslands, with severe consequences for biodiversity conservation and ecosystem functioning. However, limited data exist on the effects of agriculture on the functioning of tropical streams. We conducted a le...

Expansion of agriculture is particularly worrying in tropical regions of the world, where native forests have been replaced by croplands and grasslands, with severe consequences for biodiversity conservation and ecosystem functioning. However, limited data exist on the effects of agriculture on the functioning of tropical streams. We conducted a le...

Animals can impact freshwater ecosystem structure and function in ways that persist well beyond the animal’s active presence. These legacy effects can last for months, even decades, and often increase spatial and temporal heterogeneity within a system. Herein, we review examples of structural, biogeochemical, and trophic legacies from animals in st...

Labeo victorianus (Boulenger, 1901) is one of the endemic fishes in Lake Victoria Basin (LVB) but is now threatened by multiple stressors caused by human activities. We investigated spatial and temporal variability in food composition and condition of L. victorianus in influent rivers of Lake Victoria, Kenya. Sampling was done during the dry and we...

The composition of macroinvertebrate functional feeding groups (FFGs) has been used as surrogates of ecosystem attributes in aquatic ecosystems, but studies that utilize such knowledge are still limited in the tropics. This study investigated the suitability of abundance- vs. biomass-based metrics of macroinvertebrate FFGs as surrogates of ecosyste...

Supplementary data for the article: Abundance- and biomass-based metrics of functional composition of macroinvertebrates as surrogates of ecosystem attributes in Afrotropical streams

Populations of large wildlife have declined in many landscapes around the world, and have been replaced or displaced by livestock. The consequences of these changes on the transfer of organic matter (OM) and nutrients from terrestrial to aquatic ecosystems are not well understood. We used behavioural data, excretion and egestion rates and C: N: P s...

This presentation explores changes in land use and land cover changes in select landscapes and river basins in Kenya and relates the changes with the condition of water resources (water quality and quality), biodiversity (mainly invertebrates) and ecosystem processes.

Aquaponics is an innovative and sustainable fish and vegetable production system that has the potential to contribute to the food security and livelihoods of many people in sub-Saharan African (SSA) countries that are experiencing pervasive droughts, declining crop yields, soil pollution, and climate change. Although an emerging innovation in many...

The composition of macroinvertebrate functional feeding groups (FFGs) has been used as surrogates of ecosystem attributes in aquatic ecosystems but studies that utilize such knowledge are still limited in the tropics. This study investigated the suitability of abundance- vs. biomass-based metrics of macroinvertebrate FFGs as surrogates of ecosystem...

Changes in land use from forestry to urban settlement or agriculture are of great global concern because they are associated with soil degradation, enrichment of nutrients, sedimentation, input of harmful pollutants into aquatic ecosystems and alteration of ecological communities. Benthic macroinvertebrate assemblages at eight sites along the Nzoia...

We studied the length-weight relationship (LWR) and condition factor of Labeo victorianus (Boulanger, 1901) in four rivers (Awach, Mara, Nyando and Sondu-Miriu) in Lake Victoria Basin, Kenya. A total of 421 fish individuals of the species were measured for length and weighed. There was no significant variation in mean relative condition (Kn) of L....

In many regions around the world, large populations of native wildlife have declined or been replaced by livestock grazing areas and farmlands, with consequences on terrestrial-aquatic ecosystems connectivity and trophic resources supporting food webs in aquatic ecosystems. The river continuum concept (RCC) and the riverine productivity model (RPM)...

Expansion of agriculture is particularly worrying in tropical regions of the world, where native forests have been replaced by croplands and grasslands, with severe consequences for biodiversity conservation and ecosystem functioning. In this study, we used leaf litter decomposition and the composition of macroinvertebrate functional feeding groups...

This paper presents estimates of loading rates of organic matter, carbon, nitrogen and phosphorus by livestock (cattle) into aquatic ecosystems. These estimates have been compared with existing rates for the common hippopotamus in a river system where the distribution of the two (livestock and hippos) overlap.

Detritivorous invertebrates play major roles in organic matter processing and nutrient cycling in headwater streams. In this study, three common leaf species in upland Kenyan streams (Vernonia myriantha, Syzygium cordatum and the exotic Eucalyptus globulus) were used to determine the influence of deployment period (14 vs 28 days) on relative decomp...

Macroinvertebrates play a unique role in aquatic ecosystems by acting as processors of nutrients and organic energy from allochthonous and autochthonous sources. Within East Africa, and especially Kenya, anthropogenic influences on streams and rivers as a result of deforestation and the expansion of agricultural lands are pervasive. This study inve...

The relationship between detritivore diversity and decomposition can provide information on how biogeochemical cycles are affected by ongoing rates of extinction, but such evidence has come mostly from local studies and microcosm experiments. We conducted a globally distributed experiment (38 streams across 23 countries in 6 continents) using stand...

Studies investigating the effects of human activities on the functional organization of macroinvertebrate communities in tropical streams and rivers are very limited, despite these areas witnessing the greatest loss of natural forests globally. We investigated changes in taxon richness, numerical abundance and biomass of macroinvertebrate functiona...

Across the Afrotropical ecosystems human activities are increasingly modifying natural flow regimes, nutrient and organic matter loading and processing in streams and rivers with implications on ecosystem structure and functioning. The Mara River Basin has undergone extensive land-use change, but influences of these changes on water quality and aqu...

Aquaponics is a fish-plant recirculating system where nutrients received from the fish culture are absorbed by the plants for growth. The technology is relatively new for fish culture in Kenya, and the principles and operations remain largely untested for many fish species. This study determined how stocking density affects the growth performance a...

Running waters contribute substantially to global carbon fluxes through decomposition of terrestrial plant litter by aquatic microorganisms and detritivores. Diversity of this litter may influence instream decomposition globally in ways that are not yet understood. We investigated latitudinal differences in decomposition of litter mixtures of low a...

Running waters contribute substantially to global carbon fluxes through decomposition of terrestrial plant litter by aquatic microorganisms and detritivores. Diversity of this litter may influence instream decomposition globally in ways that are not yet understood. We investigated latitudinal differences in decomposition of litter mixtures of low a...

Streams and rivers are globally threatened ecosystems due to increasing levels of exploitation, habitat degradation and other anthropogenic pressures. In the Lake Victoria Basin (LVB) in East Africa, these threats are mostly caused by unsustainable land use, however, the monitoring of ecological integrity of river systems has been hampered by a lac...

Understanding the biotope requirements of the various aquatic biota is crucial for effective biomonitoring. Yet, the biotope preferences of macroinvertebrates in Afrotropical rivers have been poorly studied. In this study, we investigated the influence of human disturbance and flow-driven biotope changes on the β-diversity and biotope preferences o...

The use of socioeconomic and cultural parameters in the assessment and biomonitoring of ecological health of aquatic ecosystems is still in its nascent stages. Yet, degradation of aquatic ecosystems has elicited concerns because of its bearing on social and economic development of communities consisting of marginalized and vulnerable groups, as wel...

Lake Baringo is a Ramsar‐designated water body facing a myriad of environmental challenges attributable to anthropogenic activities. At the same time, however, it is an important aquatic resource not only to the local community but also to the international arena because of its rich biodiversity. It supports an artisanal fishery with four major fis...

Riverine ecosystems are some of the most biologically diverse on earth, but are also among the most threatened by anthropogenic actions. Lack of local-scale studies monitoring changes in riverine populations makes it difficult to determine how communities respond to region-specific anthropogenic threats. In this study, we compared fish assemblage s...

The Lake Victoria Basin (LVB) is a global hotspot of aquatic biodiversity, but aquatic ecosystems are under threat from multiple stressors. Most studies on fish have focused on Lake Victoria, while patterns of fish diversity, distribution, and assemblage structure in influent rivers remain poorly understood. To assess threats and conservation statu...

Many stream invertebrates consume substantial amounts of plant litter at some time during their life cycle and thus play a key role in plant litter decomposition. These litter-consuming invertebrates include mainly shredders, a functional feeding group defined by their ability to shred litter, but also some scrapers, leaf miners, wood borers, and g...

In many regions of the world, populations of large wildlife have been displaced by livestock, and this may change the functioning of aquatic ecosystems owing to significant differences in the quantity and quality of their dung. We developed a model for estimating loading rates of organic matter (dung) by cattle for comparison with estimated rates f...

Anthropogenic activities have led to increases in nitrous oxide (N2O) emissions from river systems, but there are large uncertainties in estimates due to lack of data in tropical rivers and rapid increase in human activity. We assessed the effects of land use and river size on N2O flux and concentration in 46 stream sites in the Mara River, Kenya,...