Department of Natural Resources

Permanent URI for this collectionhttp://localhost:4000/handle/20.500.12092/1949

Browse

Now showing 1 - 20 of 52

290IMPACTS OF COMMUNITY ACTIVITIES ON ENVIRONMENTAL RESOURCES: THE POTENTIAL FOR DEVELOPING PAYMENT SCHEMES FOR ENVIRONMENTAL SERVICES
(VDM Dr Muller Gmbh and co, 2011-01) Kiptum, Andrew; Kipkoech, Anderson; Omondi, Humhprey; Adano, Wario R.; Osano, Odipo; iryahwaho, Byamukama B; Agasha, Annah
Natural resources have continued to be degraded largely because of lack of well-defined property rights, population pressure, high levels of poverty and the lack of proper understanding of deleterious impacts of human activities on forest and watershed resources depletion. The social cost of exploiting the resources is larger than the private benefits and individuals have incentives to excessively extract natural resources at an expense of conservation. This study considers the socio-economic aspect, farm size and activities, water availability, the distance of the agricultural activities to the edge of the forest and riverbank and agricultural management practices employed by the population in Mt. Elgon District of Western Kenya. A proxy price was obtained using hypothetical structured question on willingness to pay and willingness to accept. The sample of 236 households was used to obtain data. Field surveys, structured questionnaires, interviews with key informants, and review of secondary sources were the main tools used for data collection. Statistical package for social science (SPSS) and Excel was the main software for data analysis. The results reveal average household of 8 persons, with most households living below poverty threshold (one dollar per person per day) and on average farm size holdings of 3.105 acres per household. The results also show that most farms are within the edge of the forest and riverbank at a distance ranging about 8 km and 1 km, respectively. More than 50% of the sample population do not practice water and soil management, resulting in reduced physical properties of the water such as volume of water, turbidity, taste and smell to undesired state. The contingent value of ecosystem pricing from willingness to pay (WTP) and willingness to accept (WTA) exercise yield mean prices of the responses Ksh. 728.82 and Ksh. 6,631.44, respectively. In conclusion, the household activities of the community in Mt Elgon landscape encourage resource depletion. Therefore, adoption of sustainable agriculture and ecosystem management that consider conservation of natural resource in order to have desired qualities of the ecosystem products and to reduce the costs to the population living downstream and around are recommended. There is need to educate the local population living around the forest and watershed areas to practice sound farming practices.
Seed dispersal by Tana River mangabeys in fragmented gallery forests
(SciRes, 2012) Kimuyu, Duncan M.; Wahungu, Geoffrey M.; Otieno, Dennis O.
POPULATION ECOLOGY, DIET AND MOVEMENT OF STRAW-COLOURED FRUIT BATS (Eidolon helvum), WESTERN KENYA
(research gate, 2012-07) Webala, Paul W.; Musila, Simon; Makau, Rogers
The population status, movement, roost-site selection and diet of straw-coloured fruit bats (Eidolon helvum) were studied over a seven-month period in western Kenya. Overall, the bat population fluctuated markedly from as low as 7,000 to as high as >25,000 bats, and the bats shifted from one roosting camp to the other within the same general area, perhaps reflecting the seasonal variation in the availability of preferred foods. Preliminary results suggested that tree density was an important factor in roosting-camp selection for E. helvum in western Kenya, and the removal of roost trees could have serious ramifications on their conservation in the region. Germination experiments and direct observations indicated that E. helvum helped to disperse seeds of >32 plant species belonging to 18 families. Further monitoring is needed to provide a complete picture of the status and migration patterns of E. helvum in Kenya. Additionally, because the bats were viewed negatively with attendant persecution through roost-tree clearance and eradication programmes, a robust education and community outreach programme in local schools and local communities should be continued for the long-term conservation of viable populations of E. helvum in western Kenya.
The challenges of wild game on forest plantations management objectives in forest ecosystems in kenya
(Emerging Academy Resources, 2013) Mugo, Mware J.; Mutiso, Festus M.; Cheboiwo, Joshua K.; Sang, Francis; Tarus, George K.; Chemitei, Gideon K.
Forests in Africa and Asia host various wildlife populations that cause varying levels of damages to forest resources. The economic damage is more severe in forest plantations meant for timber production that require huge financial outlays. Like many countries most forest ecosystems in Kenya contain many forest plantations and wild game conservation units. Despite the heavy losses to plantation crops by wild game, the extent of the loss as well as existence of a balance between wild game conservation and plantation forestry remains unknown. The study therefore attempts to deepen the knowledge on the impacts of game damage on forest ecosystems in particular plantations and also provide some option to forest managers to counter minimize damage levels. To minimize wild game damages in Key ecosystems of Mt. Kenya and Aberdares in Kenya game moats were constructed. Recently, electric fences were introduced into parts of the Aberdares to keep away wild animals from plantations and farms. The use of physical structures has been successful in reducing damage from large game such as elephants and buffaloes but controlling smaller game mostly monkeys, porcupines, and moles remain a challenge. This paper focuses on the benefits and challenges of restricting wild game movement in forest plantations management as well as the ecological and economic impacts in Mt Kenya and Aberdare ecosystems. The study was carried out through assessments of the damage intensity of foliage, tree limb breakages and bark damages of major plantation species in the age cohorts 5-10, 11-20 and > 20 years old. Damage attribution by specific group of game was evaluated to establish their overall contribution to forest plantation damages. The study results show that individual site damages were statistically different (P < 0.05) but had a weak Pearson correlation (rs = 0.46, n = 8, P = 0.05). The Duncan Multiple Range Test (DMRT) showed significant statistical differences in the two ecosystems but exhibited a strong negative correlation (rs = 0.97, n = 8, p < 0.05) in the prevalence of the causative animals . The Spearman Correlation Analysis on the prevalence of damages across the species showed a strong positive correlation (rs = +0.88, n = 8, P < 0.05). The economic production of plantation forests was found not to be compatible with wild game conservation but degree differed within the two ecosystems. In Mt Kenya, where plantations are not well protected from wild game, damage was widely prevalent as compared to the well-protected Aberdares ecosystem where it was minimal. The fencing off approach significantly reduced elephant damage in the Aberdare ecosystem but the restriction caused an increase in pressure on other critical forest resources resulting in overgrazing. The electric fence has been successful in restricting large wild game in Aberdare forests and hence the need to replace nonfunctional game moats with electric fences in Mt Kenya. Concurrently, carrying out habitat enrichment with preferred diets and other fallback resources in buffer zones between production units will provide the muchneeded critical resource to destructive wild game. Other strategies explored include well-designed animals migration corridors and culling measures. The study was limited in scope to physical damage to plantation forests and hence there is need widen studies to cover economic losses and impacts on natural forests to enable development of best strategies of controlling destructive wild game in forest ecosystems.
Encroachment of open grasslands and Acacia drepanolobium Harms ex B.Y.Sjöstedt habitats by Euclea divinorum Hiern in Ol Pejeta Conservancy, Kenya
(African Journal of Ecology , Wiley online Library, 2013-03) Wahungu, Geoffrey M.; Gichohi, Nathan, W.; Onyangi, Irene, A.; Mureu, Lucy, K.; Kamaru, Douglas; Mutisya, Samuel; Mulama, Martin; Makau, Joseph, K.; Kimuyu, Duncan, M.
Euclea divinorum, a fast establishing, unpalatable, and fire resistant bush is considered an invasive species in some parts of its range. In Ol Pejeta Conservancy (OPC), Kenya, E. divinorum bushes cover ˜27% of the total area (˜9470 ha.) and has been expanding in coverage and encroaching into A. drepanolobium woodlands, a key woody habitat for the endangered black rhino. Between 2006 and 2010, we assessed the spatial distribution, annual rates of spread and recruitment of E. divinorum in OPC. We used data from satellite imagery and belt transects laid at the transition between E. divinorum habitat and other habitats. Density of E. divinorum seedlings increased by 27% annually over five years, with more seedlings establishing in grassland habitat (56.6%) than in A. drepanolobium woodland (43.4%). Within the infection frontier, the number of seedlings was high at the ecotone and reduced predictably with an increase in distance into the infection zone. Increase in rainfall facilitated recruitment and survival of E. divinorum seedlings and also reduced damage on trees and seedlings by mega-herbivores, especially elephants. This study confirms the encroachment of E. divinorum bushland into other habitats. This has been accelerated by burning and damage to A. drepanolobium habitat thus opening it up to encroachment by E. divinorum.
Stand Composition, Floristic Affinities and Plant Formations in Mau Forests
(Academia, 2014) Mugo, Mware J.; Mutiso, Festus M.; Cheboiwo, Joshua; Sang, Francis; Tarus, George K.
The Mau ecosystem post-disturbance recovery process, integrity retention and resilience to future disturbances and sustainability remain unknown. In this paper, the ecosystem floristic composition, richness, diversity and affinities are evaluated. Diameter at breast height (dbh) of mature trees was measured and disturbances recorded in plots, dbh of saplings measured in subplots and seedlings count in microplots. To obtain the floristic composition and richness, we categorized species based on their families, development stages and life forms. Species density and quantity-measured diversity index (H’) were used to evaluate the species diversity. Jaccard (JIA) and Sorensen(S) similarity indices were used to calculate the species similarity between survey sites. Trees, Shrubs and climbers recorded belonged to 52 species, 45 genera and 31 families for seedlings; 43 species, 38 genera and 29 families for saplings and 55 species, 48 genera and 31 families for mature stems. The most species-rich family was rutaceae with six species followed by moraceae and flacourtiaceae with five. Anacardiaceae had 4 while rubiaceae and euphorbiaceae had 3 species each. Western Kedowa had the highest species diversity. Eastern Mt. Blackett had the lowest species diversity. Northern and Western Kedowa were the most similar pairs followed by Eastern and Western Mt Blackett and Western Kedowa and Southern Mt. Blackett. Past and present disturbance are the main cause of low number of species per family. We attribute the low diversity observed in Mt Blackett sites to aggressive proliferation of the invasive; Trichocladus ellipticus, which has modified natural regeneration patterns resulting close to an individualistic successional pathway. In conclusion, the sites represent different plant formations and thus floristically, they are dissimilar but at varying degrees. The postdisturbance recovery on different sites is following different trajectory successional pathways. There is lack of species co-existence under natural environment due to the presence of invasive species. We recommend that the on-going disturbances should be curtailed to promote regeneration and successful The Mau ecosystem post-disturbance recovery process, integrity retention and resilience to future disturbances and sustainability remain unknown. In this paper, the ecosystem floristic composition, richness, diversity and affinities are evaluated. Diameter at breast height (dbh) of mature trees was measured and disturbances recorded in plots, dbh of saplings measured in subplots and seedlings count in microplots. To obtain the floristic composition and richness, we categorized species based on their families, development stages and life forms. Species density and quantity-measured diversity index (H’) were used to evaluate the species diversity. Jaccard (JIA) and Sorensen(S) similarity were used to calculate the species similarity between survey sites. Trees, Shrubs and climbers recorded belonged to 52 species, 45 genera and 31 families for seedlings; 43 species, 38 genera and 29 families for saplings and 55 species, 48 genera and 31 families for mature stems. The most species-rich family was rutaceae with six species followed by moraceae and flacourtiaceae with five. Anacardiaceae had 4 while rubiaceae and euphorbiaceae had 3 species each. Western Kedowa had the highest species diversity. Eastern Mt. Blackett had the lowest species diversity. Northern and Western Kedowa were the most similar pairs followed by Eastern and Western Mt Blackett and Western Kedowa and Southern Mt. Blackett. Past and present disturbance are the main cause of low number of species per family. We attribute the low diversity observed in Mt Blackett sites to aggressive proliferation of the invasive; Trichocladus ellipticus, which has modified natural regeneration patterns resulting close to an individualistic successional pathway. In conclusion, the sites represent different plant formations and thus floristically, they are dissimilar but at varying degrees. The postdisturbance recovery on different sites is following different trajectory successional pathways. There is lack of species co-existence under natural environment due to the presence of invasive species. We recommend that the on-going disturbances should be curtailed to promote regeneration and successful The Mau ecosystem post-disturbance recovery process, integrity retention and resilience to future disturbances and sustainability remain unknown. In this paper, the ecosystem floristic composition, richness, diversity and affinities are evaluated. Diameter at breast height (dbh) of mature trees was measured and disturbances recorded in plots, dbh of saplings measured in subplots and seedlings count in microplots. To obtain the floristic composition and richness, we categorized species based on their families, development stages and life forms. Species density and quantity-measured diversity index (H’) were used to evaluate the species diversity. Jaccard (JIA) and Sorensen(S) similarity indices were used to calculate the species similarity between survey sites. Trees, Shrubs and climbers recorded belonged to 52 species, 45 genera and 31 families for seedlings; 43 species, 38 genera and 29 families for saplings and 55 species, 48 genera and 31 families for mature stems. The most species-rich family was rutaceae with six species followed by moraceae and flacourtiaceae with five. Anacardiaceae had 4 while rubiaceae and euphorbiaceae had 3 species each. Western Kedowa had the highest species diversity. Eastern Mt. Blackett had the lowest species diversity. Northern and Western Kedowa were the most similar pairs followed by Eastern and Western Mt Blackett and Western Kedowa and Southern Mt. Blackett. Past and present disturbance are the main cause of low number of species per family. We attribute the low diversity observed in Mt Blackett sites to aggressive proliferation of the invasive; Trichocladus ellipticus, which has modified natural regeneration patterns resulting close to an individualistic successional pathway. In conclusion, the sites represent different plant formations and thus floristically, they are dissimilar but at varying degrees. The post disturbance recovery on different sites is following different trajectory successional pathways. There is lack of species co-existence under natural environment due to the presence of invasive species. We recommend that the on-going disturbances should be curtailed to promote regeneration and successful recruitment of non-pioneer species. Rehabilitation efforts should be based on the understanding of post disturbance floristic affinities and species mosaics.
Are stingless bees the primary vector in spread of banana Xanthomonas wilt in Central Uganda?
(International Journal of Ecology and Ecosolution, 2014-09) Namu, Flora, N.; Wittmann, Dieter
Stingless bees were speculated to be the primary vectors in the spread of the bacterial agent responsible for banana Xanthomonas wilt (BXW) in Uganda. It was hypothesized that the vector entered the banana plant through the male flowers. We therefore determined the likely role of the bees in spread of Xanthomonas campestris pv. musacearum that causes BXW. We first documented species of stingless bees present in the banana farms, their nesting sites and foraging behavior. Then we documented the foraging behavior of Hypotrigona gribodoi - Magretti and Plebeina hildebrandti Friese reared in wooden observation hives where we offered banana sap, bacterial ooze and nectar. We then measured sugar concentration in Pisang Awak, the banana variety reported to be most susceptible to Xanthomonas. We tested how far stingless bees would fly to collect banana nectar through indirect recruitment experiments to experimental feeders with 11, 33, 48 and 54% sugar solutions. Our findings were: four species of stingless bees, Hypotrigona gribodoi, Plebeina hildebrandti, Meliponula ferruginea Lepeletier and Meliponula sp. foraged and nested within the banana farms. They collected nectar from both male and female banana flowers but spent more time on female flowers than on male flowers. They did not collect banana sap and bacterial ooze from scars of recently dehisced male flowers and at the nest entrance of the observation hives. The foraging distance of workers of P. hildebrandti was 1050 and 1215 m when sugar solutions 11 and 33% were offered, respectively. The foragers would therefore fly less than 1215 m from the nest to collect Pisang Awak nectar which had an average sugar concentration of 12.5%. Thus stingless bees were likely to get accidental contamination with Xanthomonas campestris pv. musacearum just like any other moving object or insects. If the bees got accidentally contaminated with Xanthomonas, saps and resins within the nest would decontaminate them.
Floristic Composition, Affinities and Plant Formations in Tropical Forests: A Case Study of Mau Forests in Kenya
(International Journal of Agriculture and Forestry, 2015) Mugo, Mware J.; Mutiso, Festus M.; Cheboiwo, Joshua; Sang, Francis; Tarus, George K.
In the past, Mau forest complex has faced a wide range of disturbances majorly anthropogenic in nature. In this paper, the ecosystem floristic composition, richness, diversity and affinities are evaluated. Diameter at breast height (dbh) was measured and types and levels of disturbances recorded in plots, dbh of saplings measured in subplots and seedlings counted in microplots. To obtain the floristic composition and richness, we categorized species based on their families, development stages and life forms. Shannon-Wiener information index (H’) and Jaccard (JIA) and Sorensen(S) similarity indices were used to evaluate the species diversity and similarity respectively Trees, recorded belonged to 52 species, 45 genera and 31 families for seedlings; 43 species, 38 genera and 29 families for saplings and 55 species, 48 genera and 31 families for mature trees. The most species-rich family was rutaceae with six species followed by moraceae and flacourtiaceae with five. Western Kedowa had the highest diversity. Northern and Western Kedowa were the most similar pairs. Past and present disturbances and aggressive proliferation of the invasive; Trichocladus ellipticus (Eckl. and Zeyh) are the main causes of low species diversity and richness. In conclusion, the sites are floristically dissimilar but at varying degrees. The post-disturbance recovery on different sites is following different trajectory successional pathways. We recommend that the on-going disturbances should be curtailed to promote regeneration and successful recruitment of non-pioneer species.
Comparing Tree Heights among Montane Forest Blocks of Kenya Using LiDAR Data from GLAS
(Scientific Research Publishing, 2015) Kinyanjui, Mwangi James; Kigomo, Ngugi John; Kamau, Miriam Wambui; Nderitu, Joel Kariuki; Nyanjui, Charles; Nganga, John Macharia; Ojijo, William Odidi; Ashiono, Fredrick; Owate, Augustine Omamo; Ndirangu, Monicah Katumbi
This study was designed to use LiDAR data to research tree heights in montane forest blocks of Kenya. It uses a completely randomised block design to asses if differences exist in forest heights: 1) among montane forest blocks, 2) among Agro ecological zones (AEZ) within each forest block and 3) between similar AEZ in different forest blocks. Forest height data from the Geoscience Laser Altimeter System (GLAS) on the Ice Cloud and Land Elevation Satellite (ICE- SAT) for the period 2003-2009 was used for 2146 circular plots, of 0.2 - 0.25 ha in size. Results indicate that, tree height is largely influenced by Agro ecological conditions and the wetter zones have taller trees in the upper, middle and lower highlands. In the upper highland zones of limited human activity, tree heights did not vary among forest blocks. Variations in height among forest blocks and within forest blocks were exaggerated in regions of active human intervention.
Synergistic effects of fire and elephants on arboreal animals in an African savanna
(British Ecological Society, 2015) Sensenig, Ryan L.; Pringle, Robert M.; Kimuyu, Duncan M.; Palmer, Todd M.; Corinna Riginos; Veblen, Kari E.; Young, Truman P.
Sustainable Utilization of Wetlands Resources in Selected Areas of Nyamira County, Kenya
(Research journali’s Journal of Geography, 2015) Huho, Julius M.; Angawa, Francis O.; Nyaboga, John Oganda
Researches on wetland utilization in Kenya focus more on wetlands located in the ASALs and Lowland areas giving less emphasis to those in high agricultural potential highland areas. This paper examined the utilization of Sironga and Nyabomite wetlands resources in the high potential agricultural areas of Nyamira County. The specific objective established the resources and their uses. Purposive sampling was used in selecting study areas and key informants. Simple random sampling was used in selecting household heads. Data was obtained through the administration of 126 questionnaires of which 115 was used for analysis. Quantitative data was analyzed using descriptive statistics. Data was presented using statistical tables, percentages and photographs. The common wetland resources utilization practices in the area are brick making activities and crop production. Traditionally, the wetlands provided place for conducting rituals and ceremonies. The following recommendations ought to be prioritized: identification of key stakeholders and assessment of their interests; emphasis on afforestation of the wetlands with trees that are friendly to the environment and adoption of alternative sources of livelihoods. The recommendations of this paper are useful in the sustainable utilization of wetland resources in Nyamira County and other high agricultural potential areas. Keywords: Biodiversity, conservation, livelihoods, utilization, wetland resources
An African stingless bee Plebeina hildebrandti Friese nest size and design (Apidae, Meliponini
(2016 John Wiley & Sons Ltd,, 2016) Namu, Flora N.; Wittmann, Dieter
A Public-Private Partnership Scheme To Avert Desertification in the Drylands of Kenya: Lessons for Social Scientists
(University of Dar es Salaam, 2016) Mwenzwa, Ezekiel Mbitha
The drylands of Kenya make up about 80% of the total land area and are defined by aridity, thermal stress, soil moisture deficiency and general human want. The poverty bedevilling the drylands leave their inhabitants without a sustainable livelihood, compelling them to rely on physical environmental resources. Indeed, the exploitation of natural resources in these areas has led to the manifestation of the tragedy of commons hypothesis. Official documents show that about 80% of households in these areas use charcoal and firewood as fuel, leading to deforestation. This situation is not accompanied by re-forestation, leaving more land bare annually, and therefore risking desertification. This is compounded by overstocking and encroachment of human settlements, which further leads to the destruction of other natural resources, including wetlands. This paper analyzes literature and roots for a paradigm shift in the exploitation of dryland resources to avert possible desertification. As a panacea, it proposes a public-private partnership of social scientists to avert this trend and augment environmental management and livelihood in the drylands of Kenya.
PCBs in fish and their cestode parasites in Lake Victoria
(Environ Monit Assess, 2016) Okoth, E. Oyoo; Otiego, J. Oluoch; Chemoiwa, E. J.; Ngugi, C. C.; Omutange, E. S.; Ngure, V.; Opiyo, M. A.
Polychlorinatedbiphenyls(PCBs)areclassified as persistent organic pollutants (POPs) regulated by the Stockholm Convention (2001). Although their production and use was stopped almost three decades ago, PCBs are environmental persistent, toxic, and bioaccumulate in biota. We assessed the levels of 7 PCB congeners (IUPAC nos. 28, 52, 101, 118, 138, 153, and 180) in sediment and fish (Oreochromis niloticus, Lates niloticus, and Rastrineobola argentea) and evaluated the potential of cestode fish endoparasite (Monobothrioides sp., Proteocephalaus sp., and Ligula intestinalis) as biomonitorsofPCBsinLakeVictoria,Kenya.Themedian concentrationof Σ7PCBsinsedimentsandfishwere2.2– 96.3 μg/kg dw and 300–3,000 μg/kg lw, respectively. At all the sampling sites, CB138, CB153, and CB180 were the dominant PCB congeners in sediment and fish samples. Compared to the muscle of the piscine host, Proteocephalaus sp. (infecting L. niloticus) biomagnified PCBs ×6–14 while Monobothrioides sp. (infecting O. niloticus) biomagnified PCBs ×4–8. Meanwhile, L. intestinalis (infecting R. argentea) biomagnified PCBs ×8–16 compared to the muscle of unparasitized fish. We demonstrate the occurrence of moderate to high levels of PCB in sediments and fish in Lake Victoria. We also provide evidence that fish parasites bioaccumulate higher levels of PCBs than their piscine hosts and therefore provide apromising biomonitor of PCBs. Weurgefurther a long-term study to validate the use of the above cestode fish parasites as biomonitoring tools for PCBs.
Effects of dietary levels of essential oil (EO) extract from bitter lemon (Citrus limon) fruit peels on growth, biochemical, haemato-immunological parameters and disease resistance in Juvenile Labeo victorianus ﬁngerlings challenged with Aeromonas hydrophila
(John Wiley & Sons Ltd, 2016-04) Okoth, Elijah Oyoo; Muchiri, Mucai; Ngugi, Charles C.
Essential oils (EOs) are used in the food industry because of their biological activity. We evaluated the effects of administration of essential oil (EO) extracted from bitter lemon (Citrus limon) fruit peels on the growth performance, biochemical, haemato-immunological parameters and possible disease resistance in ﬁngerlings (4 weeks old) Labeo victorianus challenged with Aeromonas hydrophila. Fish were divided into ﬁve groups and fed diets supplemented with C. limon fruit peels EO extract at 1%, 2%, 5% and 8% [as fed basis] and treatment compared with control group fed diet without C. limon fruit peels EO extract. The experiment was executed in triplicate. Concentration of plasma cortisol, glucose, triglyceride and cholesterol decreased while that of total protein and albumin increased as dietary inclusion of the EO extract of C. limon fruit peels was increased from 2% to 5%. Meanwhile haemato-immunological parameters including red blood cell (RBC), white blood cell (WBC) counts, haematocrit (Htc), mean cell haemoglobin (MCH), mean cell haemoglobin concentration (MCHC) and neutrophiles increased with increasing dietary inclusion from 1% to 5% inclusion of C. limon fruit peels EO extract. Serum immunoglobulins, lysozyme activity and respiratory burst increased with increasing dietary levels up to 5% inclusion of EO extract of C. limon fruit peels. We demonstrate that formulation of feeds by incorporating upto 5% the EO extract from C. limon fruit peels signiﬁcantly improved biochemical, haematological and immunological response in juvenile ﬁsh resulting to lower mortality than the untreated groups and appear to be effective antibacterial against A. hydrophila.
Influence of cattle on browsing and grazing wildlife varies with rainfall and presence of megaherbivores
(The Ecological Society of America, 2017) Kimuyu, Duncan M.; Kari, E. Vebien; Corinna, Riginos; Chira, Robert M.; Githaiga, John M.; Young, Truman P.
In many savanna ecosystems worldwide, livestock share the landscape and its resources with wildlife. The nature of interactions between livestock and wildlife is a subject of considerable interest and speculation, yet little controlled experimental research has been carried out. Since 1995, we have been manipulating the presence and absence of cattle and large mammalian herbivore wildlife in a Kenyan savanna in order to better understand how different herbivore guilds influence habitat use by specific wildlife species. Using dung counts as a relative assay of herbivore use of the different experimental plots, we found that cattle had a range of effects, mostly negative, on common mesoherbivore species, including both grazers and mixed feeders, but did not have significant effects on megaherbivores. The effect of cattle on most of the mesoherbivore species was contingent on both the presence of megaherbivores and rainfall. In the absence of megaherbivores, wild mesoherbivore dung density was 36% lower in plots that they shared with cattle than in plots they used exclusively, whereas in the presence of megaherbivores, wild mesoherbivore dung density was only 9% lower in plots shared with cattle than plots used exclusively. Cattle appeared to have a positive effect on habitat use by zebra (a grazer) and steinbuck (a browser) during wetter periods of the year but a negative effect during drier periods. Plots to which cattle had access had lower grass and forb cover than plots from which they were excluded, while plots to which megaherbivores had access had more grass cover but less forb cover. Grass cover was positively correlated with zebra and oryx dung density while forb cover was positively correlated with eland dung density. Overall these results suggest that interactions between livestock and wildlife are contingent on rainfall and herbivore assemblage and represent a more richly nuanced set of interactions than the longstanding assertion that cattle simply compete with (grazing) wildlife. Specifically, rainfall and megaherbivores seemed to moderate the negative effects of cattle on some mesoherbivore species. Even if cattle tend to reduce wildlife use of the landscape, managing simultaneously for livestock production (at moderate levels) and biodiversity conservation is possible
Estimation of Above Ground Biomass in Forests Using Alos Palsar Data in Kericho and Aberdare Ranges
(Scientific Research Publishing, 2017) Kinyanjui, Mwangi James; Odera, Patroba Achola; Maina, Eunice Wamuyu
Above Ground Biomass is one of the six pools identified in the inventory of forest resources and estimation of greenhouse gas emissions and sinks from the forestry sector. The pool varies by management practices in different agro- ecological or agro-climatic zones in forests. The quantification of above ground biomass (AGB) hence carbon sequestration in forests has been very difficult due to the immense costs required. This research was done to estimate AGB using ALOS PALSAR L band data (HH, HV polarisation) acquired in 2009 in relation with ground measurements data in Kericho and Aberdares ranges in Kenya. Tree data information was obtained from ground measurement of DBH and tree heights in 100 circular plots of 15 m radius, by use of random sampling technique. ALOS PALSAR image is advantageous for its active microwave sensor using L-band frequency to achieve cloud free imageries, and the ability of long wavelength cross-polarization to estimate AGB accurately for tro- pical forests. The variations result between Natural and plantation forest for measured and estimated biomass in Kericho HV band regression value was 0.880 and HH band was 0.520. In Aberdare ranges HV regression value of 0.708 and HH band regression value of 0.511 for measured and estimated biomass respectively. The variations can be explained by the influence of different management regimes induced human disturbances, forest stand age, density, species composition, and trees diameter distribution. However, further research is required to investigate how strong these factors affect relationship between AGB and Alos Palsar backscatters.
Estimation of Above Ground Biomass in Forests Using Alos Palsar Data in Kericho and Aberdare Ranges
(Scientific Research Publishing, 2017) Kinyanjui, Mwangi James; Odera, Patroba Achola; Maina, Eunice Wamuyu
Above Ground Biomass is one of the six pools identified in the inventory of forest resources and estimation of greenhouse gas emissions and sinks from the forestry sector. The pool varies by management practices in different agro- ecological or agro-climatic zones in forests. The quantification of above ground biomass (AGB) hence carbon sequestration in forests has been very difficult due to the immense costs required. This research was done to estimate AGB using ALOS PALSAR L band data (HH, HV polarisation) acquired in 2009 in relation with ground measurements data in Kericho and Aberdares ranges in Kenya. Tree data information was obtained from ground measurement of DBH and tree heights in 100 circular plots of 15 m radius, by use of random sampling technique. ALOS PALSAR image is advantageous for its active microwave sensor using L-band frequency to achieve cloud free imageries, and the ability of long wavelength cross-polarization to estimate AGB accurately for tro- pical forests. The variations result between Natural and plantation forest for measured and estimated biomass in Kericho HV band regression value was 0.880 and HH band was 0.520. In Aberdare ranges HV regression value of 0.708 and HH band regression value of 0.511 for measured and estimated biomass respectively. The variations can be explained by the influence of different management regimes induced human disturbances, forest stand age, density, species composition, and trees diameter distribution. However, further research is required to investigate how strong these factors affect relationship between AGB and Alos Palsar backscatters.
Impacts of Bush Encroachment on Wildlife Species Diversity, Composition, and Habitat Preference in Ol Pejeta Conservancy, Laikipia, Kenya
(Hindawi, 2017) Kavwele, Cyrus M.; Kimanzi, Johnstone K.; Kinyanjui, Mwangi J.
Biomass Energy Resource of the Highland Bamboo (Yushania alpina) and Its Potential for Sustainable Exploitation in Southern Aberdares Forest
(Scientific Research Publishing Inc., 2017) Kinyanjui, Mwangi James; Katumbi, Ndirangu Monicah; Kimondo, JM; Mware, Mugo Joseph
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). Theenergy 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.