Department of Environmental Studies

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5. Absentee owners and overlapping home ranges in a territorial species
(2021-01-07) Isbell, Lynne A.; Bidner, Laura R.; Loftus, Carter; Kimuyu, Duncan M.; Young, Truman P.
Abstract Understanding animals’ use of space can shed valuable light on multiple other aspects of behavioral ecology, including social organization, dispersal, and foraging efficiency. Home ranges, territories, core areas, and home range overlaps have been widely studied, but unless animals are directly observed or are tracked remotely on a fine temporal scale, how they actually use the space available to them and how they share (or partition) this space with a community of conspecifics over time cannot be fully understood. Using GPS technology, we tracked three adjacent groups of vervet monkeys (Chlorocebus pygerythrus) in Laikipia, Kenya, for 1 year to better understand the processes involved in territoriality and home range overlaps. Home ranges overlapped with any one neighboring group by 12.7–34.7%, but intergroup encounters only occurred in restricted areas within these zones, which defined territorial boundaries. The resources closest to the territorial boundaries were nocturnal core areas with preferred sleeping sites adjacent to shortgrass areas offering fewer hiding places for ambush predators and greater visibility for predator detection. Home range overlaps were not neutral zones, the result of shifting home range boundaries over time, or based on intergroup encounters at boundaries, but resulted when groups made incursions beyond their territorial boundaries while the neighbor was far away and likely unaware of the intruders. Thus, territories can be non-exclusive but may still be perceived by the animals themselves as sole-owned, as neighbors only intrude when territory owners are absent from that area.
Analysis of Short-Term Drought Episodes Using Sentinel-3 SLSTR Data under a Semi-Arid Climate in Lower Eastern Kenya.
(2023-06) Musyimi, Peter K.; Sahbeni, Ghada; Timár, Gábor; Weidinger, Tamas
This study uses Sentinel-3 SLSTR data to analyze short-term drought events between 2019 and 2021. It investigates the crucial role of vegetation cover, land surface temperature, and water vapor amount associated with drought over Kenya’s lower eastern counties. Therefore, three essential climate variables (ECVs) of interest were derived, namely Land Surface Temperature (LST), Fractional Vegetation Cover (FVC), and Total Column Water Vapor (TCWV). These features were analyzed for four counties between the wettest and driest episodes in 2019 and 2021. The study showed that Makueni and Taita Taveta counties had the highest density of FVC values (60–80%) in April 2019 and 2021. Machakos and Kitui counties had the lowest FVC estimates of 0% to 20% in September for both periods and between 40% and 60% during wet seasons. As FVC is a crucial land parameter for sequestering carbon and detecting soil moisture and vegetation density losses, its variation is strongly related to drought magnitude. The land surface temperature has drastically changed over time, with Kitui and Taita Taveta counties having the highest estimates above 20 ◦C in 2019. A significant spatial variation of TCWV was observed across different counties, with values less than 26 mm in Machakos county during the dry season of 2019, while Kitui and Taita Taveta counties had the highest estimates, greater than 36 mm during the wet season in 2021. Land surface temperature variation is negatively proportional to vegetation density and soil moisture content, as non-vegetated areas are expected to have lower moisture content. Overall, Sentinel-3 SLSTR products provide an efficient and promising data source for short-term drought monitoring, especially in cases where in situ measurement data are scarce. ECVs-produced maps will assist decision-makers with a better understanding of short-term drought events as well as soil moisture loss episodes that influence agriculture under arid and semi-arid climates. Furthermore, Sentinel-3 data can be used to interpret hydrological, ecological, and environmental changes and their implications under different environmental conditions.
Assessing Climate Variability Adaptation and Coping Strategies Among Rural Households in Kenya
(Journal of Water Sciences & Environment Technologies, 2018-08) Nduru, Gilbert M.; Musyimi, Peter Kinyae; Huho, Julius M.; Opiyo, Francis E.
The aim of this study is to assess the adopted water scarcity adaptation and coping strategies of rural households to climate variability. It also identifies suitable strategies that minimize the impact of climate variability on water sources in arid and semi-arid (ASALs) in Kenya. The study was carried out in Makindu Sub-county, Makueni County, Kenya. Data collection techniques such as questionnaires and in-depth interview with 370 households, key informants interviews were used to assess the adaptation and coping strategies of rural households and identify the most suitable strategies for the study area. Rainfall data was collected from Makindu Meteorological station and used for meteorological drought characteristics analysis. Standardized Precipitation Index (SPI) was used to analyze drought severity in the study area between 1980 and 2011. SPI was used to quantify precipitation deficit for various time scales. Drought Intensity (DI) was used to determine decadal drought intensities. SPI results showed that 18 years out of 31 with negative SPI values an indication of drought severity occurrence. The year 2005 was the driest in the area with an SPI of -1.76. The study also showed increasing drought intensities from 1990s to 2000s. The study showed that the rural households had adopted varied adaptation and coping strategies to cope with impact of drought extremes on water sources. However, increase in drought characteristics occurrences minimized their resilience and adaptive capacities. The study observed that the strategies employed are unlikely to enable them cope with recent climate change and variability regimes, therefore need for most suitable and viable ones. The study identified viable strategies such as rainwater harvesting and sinking boreholes as long term measures that can enhance rural households’ resilience to climate change extremes in ASALs of Kenya.
Assessing Climate Variability Adaptation and Coping Strategies Among Rural Households in Kenya.
(Journal of Water Sciences & Environment Technologies, 2018) Musyimi, Peter Kinyae; Nduru, Gilbert M; Huho, Julius M; Opiyo, Francis E
The aim of this study is to assess the adopted water scarcity adaptation and coping strategies of rural households to climate variability. It also identifies suitable strategies that minimize the impact of climate variability on water sources in arid and semi-arid (ASALs) in Kenya. The study was carried out in Makindu Sub-county, Makueni County, Kenya. Data collection techniques such as questionnaires and in-depth interview with 370 households, key informants interviews were used to assess the adaptation and coping strategies of rural households and identify the most suitable strategies for the study area. Rainfall data was collected from Makindu Meteorological station and used for meteorological drought characteristics analysis. Standardized Precipitation Index (SPI) was used to analyze drought severity in the study area between 1980 and 2011. SPI was used to quantify precipitation deficit for various time scales. Drought Intensity (DI) was used to determine decadal drought intensities. SPI results showed that 18 years out of 31 with negative SPI values an indication of drought severity occurrence. The year 2005 was the driest in the area with an SPI of -1.76. The study also showed increasing drought intensities from 1990s to 2000s. The study showed that the rural households had adopted varied adaptation and coping strategies to cope with impact of drought extremes on water sources. However, increase in drought characteristics occurrences minimized their resilience and adaptive capacities. The study observed that the strategies employed are unlikely to enable them cope with recent climate change and variability regimes, therefore need for most suitable and viable ones. The study identified viable strategies such as rainwater harvesting and sinking boreholes as long term measures that can enhance rural households’ resilience to climate change extremes in ASALs of Kenya.
Assessment of Solid waste generation and composition in Bungoma County Urban Centres for appropriate waste management approaches
(2024-08-02) Wafula, Godfrey Wekesa; Kamiri, Hellen; Ouna, Tom
The quantity and characteristics of urban solid waste are a result of the interconnectedness of diverse factors at play including social, economic, and environmental factors. These directly influence the choice of management practice at the household or community level. Understanding these relationships can help policymakers and urban planners develop more effective waste management strategies. This study aimed at assessing solid waste generation and composition in Bungoma county urban centers to inform on strategies for effective management of urban waste. The study was carried out in Bungoma County urban centers, specifically Bungoma town, Webuye, Kimilili, Kapsokwony, Chwele, and Sirisia townships. The study applied a stratified sampling technique to select the urban and peri-urban centers while random sampling was used to select respondents in residential dwellings, business people, urban residents, and officers from government institutions including public health and environment, water, and natural resources were interviewed. Ancillary data was collected using questionnaires and interview schedules while historical data was obtained from the Bungoma County Department of Environment and used to validate observed data. Data was analysed using descriptive and inferential statistics and summarized using tables, charts, and graphs. Our findings show that the highest waste was generated from residential homes, commercial, and municipal services. In terms of composition, biodegradable waste had the highest proportion, followed by plastics and glass waste. Population growth could be a key factor in the increased generation of the waste.
Attributes of Urban Greenspaces and their Influence on Visitors’ Preferences in Nairobi City County, Kenya
(Eastern African Journal of Humanities and Social Sciences Vol. 3 No. 1, 2024-07-07) Mbugua, Martin Wandie; Kamiri, Hellen; Kamau, Peter
Urban green spaces refer to land covered with vegetation such as forests, street trees, parks, gardens, and water bodies in an urban setup. In this study, we sought to investigate the attributes of urban green spaces in Nairobi County and their relationships to visitor preferences. The Garden City Model advanced by Howard (1898) guided the study. Quantitative and qualitative methods were used to collect data while a cross sectional survey designs and stratified random sampling of the green spaces was employed, based on the location within the urban core and peri-urban of Nairobi County. Four green spaces (Karura Forest, Ngong Road Forest, Nairobi Arboretum, and City Park) with diverse characteristics and attributes was selected. A sample population of 384 visitors to the green spaces were surveyed for their perceptions of the functions, use, and benefits of the green spaces. Our findings showed that attributes of green spaces including location, accessibility, security, hygiene, and infrastructure could explain the interaction between green space provision factors and the frequency of visits, time spent in the green spaces and overall satisfaction of the visitors. Green space provision should be equitable in regard to distance to residents, quality of spaces, facilities and services and should be designed to meet the needs of diverse residents. Further, they should provide services and benefits such as shade, recreation, and health which are the main attractions to the green spaces. To achieve maximum benefits for visitors, green spaces need to be safe and physically accessible to all.
Biological diversity of the Yala Swamp lakes, with special emphasis on fish species composition, in relation to changes in the Lake Victoria Basin (Kenya): threats and conservation measures
(Biodiversity & Conservation, 2003-05) Aloo-Obudho, Peninah
During the second half of the last century, the Lake Victoria ecosystem has undergone drastic ecological changes. Most notable has been the decline in the populations of many endemic cichlid fishes. The lake has lost nearly 200 haplochromines and one tilapiine, Oreochromis esculentus. The above changes have been attributed to effects of species stocking and, in particular, from predation pressure by the introduced Nile perch, Lates niloticus. Other factors that have led to the decline of the endemic species include intensive non-selective fishing, extreme changes in the drainage basin, increased eutrophication, and the invasion of the lake by the water hyacinth, Eichhornia crassipes. However, the remnants of some species that had disappeared from Lake Victoria occur abundantly in the Yala Swamp lakes (Kanyaboli, Sare and Namboyo). This paper discusses the biodiversity of the swamp and the three lakes and gives suggestions for their conservation.
Biomass Energy Resource of the Highland Bamboo (Yushania alpina) and Its Potential for Sustainable Exploitation in Southern Aberdares Forest
(Scientific Research Publishing, 2017-08) Katumbi, Ndirangu Monicah; Kinyanjui, Mwangi James; JM, Kimondo; Mugo, Joseph Mware
Yushania alpina is the only bamboo species native to Kenya and covers about 150,000 ha growing in pure or mixed stands in the montane forests. The Aberdare forest is one of the natural habitats for Y. alpine occupying an area of 6419 ha mainly in the water catchment areas. The growing human population and depletion of other forest resources have necessitated the exploration of Y. alpine as a source of energy. This paper assessed the quantity of Y. alpine available for biomass energy and its potential for sustainable exploitation. Plots were laid on area maps to cater for altitude and distance from farms. The study area was stratified into three altitudinal zones: A (2220 - 2330 m), B (2331 - 2440 m) and C (2441 - 2550 m). The initial sampling plot of 10 m × 10 m was located randomly 500 m from the edge of the forest while the subsequent plots were laid out systematically at intervals of 500 m. In each plot, a total enumeration and biomass estimation of bamboo clumps were done using Muchiri and Muga (2013) [1] method. Bamboo samples and those of commonly used biomass energy sources were analysed for calorific value using bomb calorimeter. In addition, data for quantities of biomass energy used by some local industries were used to estimate the amount of bamboo required. The mean stocking was 19,981 (20,000) culms ha−1, and varied significantly among altitude strata and distance from adjacent farms. The mean biomass density and energy content were 86 tons/ha and 380,893 Kca/ha respectively with the higher altitudinal stratum (zone C) having the highest means (114 tons/ha) while the lower stratum (zone A) had the lowest (65 tons/ha). The energy needed by sampled local industries was 416,276,266 Kcal per year against 2.4 billion Kcal available in the bamboo forest. This implies that the bamboo forest in its present stocking can provide biomass energy for these local industries for more than five years. With bamboo maturing with less than five years, the forest can sustainably provide the required energy while still providing its environmental services.
Carbon Sequestration by the Above Ground Biomass Pool in the South West Mau Forest of Kenya, 1985 - 2015
(Journal of Environment and Earth Science, 2020) Kinyanjui, Mwangi James; Kigomo, Mathew Kiura; Mburu, David Mwehia; Thuo, Aggrey Daniel Maina; Mundia, Charles Ndegwa
Forests are important for regulation of the global carbon balance. Increase in forest biomass enhances atmospheric carbon sequestration while decrease in forest biomass contributes to carbon dioxide emissions. World over, forest biomass has been declining due to forest loss and degradation. The South West Mau has experienced significant forest loss since 1964. The decline is posited to have significant impacts on carbon sequestration, carbon storage, carbon dioxide emissions and status of atmospheric carbon dioxide. This study assessed interannual trend and variability as well as change point detection in carbon sequestration in South West Mau Forest, Kenya between 1985 and 2015. Above ground biomass carbon sequestration was quantified based on the Carnegie-Ames-Stanford Approach (CASA) and carbon fraction for tropical climate domain. Carbon sequestration dynamics were characterized by increase-decrease cycles of approximately 3 years and low interannual variability (CV= 9.13). It emerged that South West Mau Forest was a net carbon emitter with a carbon sequestration balance of -588.40 Kg/ha between 1985 and 2015
Causal Factors Responsible for Changes in the Attributes of Urban Green Spaces in Nairobi City County, Kenya
(2024-07-26) Mbugua, Martin Wandie; Kamiri, Hellen; Kamau, Peter
Urban green spaces are an important part of public open spaces and a common service provided by a city, town, or municipal council. In Nairobi City County, green spaces have been increasingly threatened by overcrowding, poor planning, weak management structures, and illegal alienation thus denying city residents access to the much-needed recreation and leisure facilities. As the population increases in urban areas, their activities impact the environment and therefore the ecosystem services. This study was done with the Principle of Intelligent Urbanism in mind, as the most prolific urban development theory developed by the International Congress of Modern Architecture. Quantitative and qualitative methods were used to collect data while a cross-sectional survey designs and stratified random sampling of the green spaces was employed, based on the location within the urban core and peri-urban of Nairobi County. Four green spaces (Karura Forest, Ngong Road Forest, Nairobi Arboretum, and City Park) with diverse characteristics and attributes were selected. A sample population of 384 visitors to the green spaces was surveyed for their perceptions of the functions, uses, and benefits of the green spaces. Our findings showed that management structures and population growth are the main causal factors responsible for changes in the attributes of urban green spaces.
Climate Change Perception Among the Pastoralist Women in Narok County
(Academic Research International, 2018-03) Mashara, Janet Naisoi
With regards to the effects of climate change, Kenya has identified its ASALs as the most vulnerable areas to climate change with huge impacts on livestock rearing, small-holder agriculture and tourism, which are the dominant sources of livelihoods in these areas. Despite their limited ownership, women control most of the productive livelihoods including land and livestock. Despite the role played by women in livelihood activities, the attention given to them is still insufficient. More importantly is their vulnerability to the adverse effects of climate change. For appropriate national and county climate change adaptation strategies to be formulated, it is imperative to establish already existing mechanisms which are likely to form basis for some entry points. This study was aimed at assessing the perception of climate change and the response strategies of the pastoralist women in Narok County. A sample of 51 respondents was used and data analyzed qualitatively through content analysis. The findings revealed that a majority of the women are aware of climate change and its effects. There are a number of livelihoods embraced by women as adaptation strategies.
Combined effects of photoperiod and temperature on growth and survival of African catfish (Clarias gariepinus, Burchell 1822) larvae under laboratory conditions
(Taylor and Francis, 2016) Okoth, Elijah Oyoo; Orina, Paul Sagwe; Rasowo, Joseph; Musa, Safina; Munguti, Jonathan M.; Karisa, Harrison Charo
The effect of photoperiod (24L:00D, 12L:12D, and 00L:24D) and temperature (22 ± 1°C and 28 ± 1°C) on performance of Clarias gariepinus larvae was tested. Larvae weighing 3.2 ± 0.24 mg were cultured in aquaria at a stocking density of 20 fish L−1 and fed twice a day on catfish starter diet (40% CP) at 10 % BW day−1. Highest mean weight gain (31.00 mg), SGR (7.56% day−1), and survival (83%) were achieved at photoperiod and temperature combination of 00L:24D and 28 ± 1°C. Percent survival of larvae differed significantly (p < .05) among treatments with optimal survival of (83%) in treatment combination of 28 ± 1°C and 00L:24D, while lowest survival (40%) in treatment combination of 22 ± 1°C and 24L:00D.
Comparative performance of invasive alien Eichhornia crassipes and native Ludwigia stolonifera under non-limiting nutrient conditions in Lake Naivasha, Kenya
(Hydrobiologia, 2010-09) Njambuya, Josephine; Triest, Ludwig
The ability of Ludwigia stolonifera to thrive in the presence of Eichhornia crassipes was investigated in Lake Naivasha, Kenya. L. stolonifera (indigenous) and E. crassipes (invasive alien) were grown in outdoor experimental boxes in monocultures and mixtures under non-limiting nutrient conditions. An additive series design with eight combinations of planting densities and four replicates was used. Competitive interactions between the two species were determined by assessing the final total biomass and above–below-ground biomass allocation after 98 days of growth. Biomass accumulation and allocation were significantly affected by competition in relation to species, with L. stolonifera accumulating more biomass than E. crassipes. ANOVA analysis indicated that there was no significant difference in Relative Growth Rate (RGR) and root/shoot ratio between monocultures and mixtures with E. crassipes. However, significant differences in RGRs were observed between monocultures and mixtures of L. stolonifera. Multiple regressions on species RGRs revealed that increasing initial biomass of a conspecific neighbour resulted to a greater reduction in species RGR in relation to increasing initial biomass of a hetero-specific neighbour. Thus, a stronger intrathan inter-specific competition coupled with the significantly higher RGR of L. stolonifera relative to that of E. crassipes enabled L. stolonifera to outperform E. crassipes
Competition between Lemna minuta and Lemna minor at different nutrient concentrations
(Plant Biology and Nature Management (APNA) Elsevier, 2011-02) Njambuya, Josephine; Stiers, Iris; Triest, Ludwig
We investigated the differential responses of invasive alien Lemna minuta and native Lemna minor to nutrient loading as well as the mechanism of competition between the species. The role of nutrients, species identity, species influence in determining the outcome of competition between the species was estimated using the Relative Growth Rate Difference (RGRD) model. The two species differed in their response to nutrient loading. The native L. minor responded indifferently to nutrient loading. The species Relative Growth Rate (RGR) was 0.10 d−1, 0.11 d−1 and 0.09 d−1 in high,medium and low nutrients, respectively. On the other hand, the invasive L. minuta responded opportunistically to high nutrient availability and had an RGR of 0.13 d−1, 0.10 d−1 and 0.08 d−1 in high, medium and low nutrients, respectively. As a result, the invasive species was dominant in high nutrient availability but lost to the native species at low nutrient availability. The invader formed approximately 60% and less than 50% of the stand final total dry biomass in high and low nutrient availability, respectively. Species RGR were reduced by both intra- and interspecific competition but intraspecific effects were stronger than interspecific effects. On the overall, the species significantly differed in their constant RGR. These differences in RGR between the species (species identity) and the differential response to nutrient loading were the main determinant of change in final biomass composition of these species in mixture. Species influence (competition) only had a small influence on the outcome of competition between the species. The observed species response to nutrient loading could be targeted in management of the invasive species. Lowering nutrients can be proposed to reduce the impact of the invasive L. minuta.
Competitive abilities of invasive Lagarosiphon major and native Ceratophyllum demersum in monocultures and mixed cultures in relation to experimental sediment dredging
(Aquatic Botany, 2011-06) Steirs, Iris; Njambuya, Josephine; Triest, Ludwig
Competitive abilities of Lagarosiphon major (Ridley) Moss (invasive in Belgium) and native Ceratophyllum demersum L. were assessed experimentally in relation to sediment dredging. We mimicked these conditions by taking undisturbed sediment (‘before dredging’ treatment) and by using restored sediment where the uppermost nutrient rich top layer was removed (‘after dredging’ treatment). Both the species were allowed to grow for seven weeks in monocultures and mixed cultures at different planting densities. Overall, invasive L. major performed better than native C. demersum independent of the characteristics of the growth environment. L. major achieved a higher relative growth rate (RGR) in both treatments based on total length (0.17–0.21 week−1) and weight (0.10–0.19 week−1) compared to C. demersum (length: 0.04–0.07 week−1; weight: 0.03–0.17 week−1). The better performance of L. major was due to a high plasticity under stressful conditions of low free CO2 and high pH. Intraspecific competition and niche partitioning were observed between the two species indicating that species coexistence is favoured instead of competitive exclusion. L. major performed better in the ‘after dredging’ treatment. Consequently, we deduce that sediment dredging will not lead to a decline of the invasive L. major
Diversity and Altitudinal Distribution of Understorey Corticolous Lichens in a Tropical Montane Forest in Kenya (East Africa)
(research gate, 2018) Ndiritu, George G.; Kirika, Paul M.; Mugambi, George K.; Newton, Leonard E.; Lumbsch, H. Thorsten
Lichens constitute an important component of tropical forest biodiversity. This study inventoried corticolous lichens and examined their variation in various forest types with varying climatic conditions in Mt. Kenya, East Africa. Specifically we evaluated variation of lichen assemblages in relation to forest types and tree diversity along an altitudinal gradient (1800-3100m). Ten study sites were established on two contrasting sides of Mt. Kenya in the indigenous forest: six of them at Chogoria which is on the humid southeastern windward side of the mountain and four sites on the Sirimon side located on the drier northwestern leeward side. Overall 242 lichen taxa were documented; with Chogoria and Sirimon forests having 148 and 94 species that translated to an adequate sampling effort of 74 % and 68 %, respectively. The two contrasting forest types (Chogoria and Sirimon) supported slightly different lichens assemblages. Meanwhile lichen assemblages were found to significantly vary with elevation (or forest types) and with tree host. Posterior analyses showed that the differences were significant among sampling sites (or forest types) on the Chogoria side and insignificant on the Sirimon side. Similarly the number of lichens differed significantly among the host tree species. This study stresses the urgent need to upscale the sustainable management of the presently threatened tropical forests in order to preserve their structural heterogeneity.
Dryland Farming and Food Security in Kenya: Challenges and Research Priorities
(Elixir, 2011-06) Mwenzwa, Ezekiel
Agriculture is the backbone of Kenya and employs the highest proportion of the population, accounts for approximately a quarter of the country’s Gross Domestic Product (GDP) and close to two-thirds of total exports, hence its importance in poverty alleviation. Despite the importance of the sector, about four-fifths of the country’s land area is arid and semi-arid (ASAL), making rain fed agriculture largely enviable. As such, livestock and dry land farming are elevated to the highest among livelihood options for resident communities who are largely nomadic pastoralism and agro-pastoralists. While weather patterns are largely responsible for low crop yields and therefore food insecurity, there are other factors that come into play to escalate want in these areas including socio-cultural dynamics and institutional bottlenecks. This paper looks at the challenges of dryland farming in semi-arid areas of Kenya and henceforth points at possible research gaps that need to be bridged to alleviate food insecurity and enhance national development and the achievement of the UN Millennium Development Goal 1 of eradicating extreme poverty and hunger
Ecological, Recreational and Educational Potential of a Small Artificial Wetland in an Urban Environment
(African Journal of Aquatic Science, 2019-11) Ndiritu, GG; Gitau, PN; Gichuki, NN
Pertinent questions remain on whether small, artificial wetlands, such as abandoned quarries play any ecological or socio-economic role in the environment. To increase information on roles played by small-sized artificial wetlands in the environment, an assessment study was carried out in the Lily Wetland, an abandoned flooded quarry in Karura forest in Nairobi City, Kenya. This study was guided by the idea that artificial wetlands can develop over time to acquire ecological characteristics similar to those of natural wetlands. Ecological information was collected on water physico-chemical characteristics, vegetation, birds and macroinvertebrates, whereas questionnaires were administered to assess recreational and educational values of the Lily Wetland. Inspection of Google Earth maps showed that the pond has not dried in the past fifteen years, with its area remaining relatively constant between dry (0.29 ± 0.03 ha) and wet (0.36 ± 0.06 ha) seasons. Water quality of the wetland was good: pH of 7.5–7.8; dissolved oxygen = 8.73 ± 0.43 mg l−1; and clarity (Secchi disk reading) = 24.00 ± 0.43 cm. The biological component included 12 wetland plant species, 11 aquatic macroinvertebrate taxa, four species of wetland birds, and viable populations of fish and frogs. An assessment of the recreational and educational importance of the Lily Wetland, based on 34 respondents showed that 24 of the respondents visited Karura forest for recreational purposes, whereas 10 were there for educational purposes. Further analyses between the different benefits showed that the value of the forest, walking trails and wetland were significantly ranked important, when compared with the value placed on playing in fields and visiting the restaurants. Specifically, the Lily Wetland was regarded as important, because of its scenery, nature and recreational attributes. This study concluded that the Lily Wetland and other small wetlands in the urban environments have potential for recreational and educational use as in situ laboratories and demonstration centers, where benefits of conserving urban biodiversity can be communicated
Environmental assessment of the East African Rift Valley lakes
(Aquatic Sciences, 2003) Odada, Eric, O.; Olago, Daniel, O.; Bugenyi, Fred; Kulindwa, Kassim; Karimumuryango, Jerome; West, Kelly; Ntiba, Micheni; Wandiga, Shem; Aloo-Obudho, Peninah; Achola, Pius
An assessment of the East African Rift Valley lakes was initiated by the United Nations Environment Programme (UNEP) with funding from Global Environment Facility as part of the Global International Waters Assessment (GIWA). The purpose of GIWA was to produce globally comparable assessments and examine stresses on international waters: marine, coastal and fresh; surface and groundwaters. The assessment of the East African Rift Valley lakes was undertaken from the perspective of water quality and quantity, associated biodiversity and habitats, their use by society and societal causes of the regionally identified issues and problems. Assuming intrinsic values of aquatic ecosystems, the assessment of social perspective focused on human use of water and considered the incremental costs of measures to encourage sustainable development. The assessment identified the major concerns facing the East African Rift Valley lakes. By and large, pollution and unsustainable exploitation of fisheries and other living resources emerged as critical concerns attributable to human activities. East Africa has a very high concentration of humans and economic activities. Pollution is from uncontrolled discharge of wastes directly into the lakes. Unsustainable exploitation of fisheries and other living resources is caused by over-fishing, destructive fishing practices, and introduction of non-native species that affect the composition of the native communities, resulting sometimes in the collapse of certain species and dominance by resilient ones. Loss of biodiversity also was identified as a major concern; and the issues of excessive by-catch and discards are also relevant. Trawling using undersized mesh-nets for target species and indiscriminate fishing gear or poison is serious, in most cases resulting in indiscriminate catches, including juvenile fish. Given the transboundary nature of the issues identified in this assessment, appropriate multilateral policy and institutional arrangements need to be established in East Africa to address the main concerns of these large lakes. Riparian countries must pay attention to the regional management of these transboundary water bodies, and appropriate planning of human population sizes and their settlement, land-use and waste disposal to control pollution. Although East African lakes contribute relatively little emission of greenhouse gases, there is a need to reduce the rate of deforestation and even restore cleared areas since forests serve as sinks of greenhouse gases towards mitigating adverse climatic changes.
Environmental Determinants of Choice of Sustainability Strategies Adopted by Group Ranches in Samburu County, Kenya
(2017) Kithumbu, Eustace N.; Huho, Julius M.; Omondi, Humphrey R.
The group ranch system is one of the best land ownership and livestock production strategies Page | 153 in the dry lands of the world where the potential for rain-fed agriculture is limited. This has resulted in numerous studies on the establishment of group ranches, their dissolution and coping strategies but with less focus on the sustainability of the group ranches. It is against this background that this study investigated environmental characteristics influencing choice of sustainability strategies adopted by group ranches in Samburu County, Kenya. The investigation adopted a descriptive survey research design employing use of Questionnaires, Key Informant Interviews, Focus Group Discussions and observation as primary data collection methods. The study used content validity and Cronbach’s alpha methods to measure validity and reliability of the research instruments, respectively. The target population for the study was the 16,611 registered members in 38 group ranches spread out in the County. The study sampled twelve group ranches with approximately 5,643 members from which 374 respondents were systematically sampled. Purposive sampling was used to select Key Informants and the participants in the Focus Group Discussions. The study employed Multi-linear Regression to analyse environmental characteristics determining choice of sustainability strategies. The Analysis of Variance (ANOVA) was used to test the hypothesis and p-value of 0.00 was obtained, indicating that environmental characteristics significantly determined choice of sustainability strategies adopted by group ranches in the County. Overall, rainfall patterns were the predominating environmental characteristic with a regression coefficient of 0.317 while diseases had the least influence on choice of sustainability strategies adopted by group ranches in Samburu County, with a regression coefficient of 0.029. The study recommended integration of environmental characteristics in formulating policies for sustainability of group ranches.