Modeling Vegetation Lifeforms Abundance based on <i>Epigeal Termitaria</i>Physiography and Altitude in Tropical Savannah of Katolo Sub-Location, Kisumu County

Termite mounds are major sites of functional heterogeneity in the tropical ecosystems globally;through their prodigious influence on vegetation and soil perturbation. They aid soil aeration, water infiltration and catabolism of vegetative matter into nutrient rich humus. There is no documentation of a model for prediction of vegetation lifeforms with respect to mound basal radii, heights and altitude. Objective of this study was therefore to develop a model for rapid prediction of vegetation lifeforms (trees, shrubs, lianas and grass) abundance based on physiography (basal radii and heights) and altitude of the termite mounds. Study population of the mounds was unknown. Cross sectional research design was used. Saturated sampling was done where sixty accessible termite mounds were studied. Both basal radii and heights of termite mounds were measured using 50 m tape measure or hand-held inclinometer. Altitude data were captured by hand-held Global Positioning System (GPS). Trees, shrubs and lianas were identified visually and counted on the mounds while grass abundance was estimated using 0.3 m by 0.3 m quadrat on every termitarium. Multiple Linear Regressions were done to model vegetation lifeforms abundance based on termite mound basal radius, height and altitude. Results indicated that predicted MLR significantly (p ≤ 0.05) predicted trees, shrubs and lianas but not grass abundance. Predicted trees abundance = -89.2587 + 10.46157 (radius (m)) - 4.96989 (height (m)) + 0.074074 (altitude (m)), predicted shrubs abundance = 19.26065 + 6.780626 (radius (m)) - 6.09157 (height (m)) - 0.00822 (altitude (m)) and predicted lianas abundance = -24.9345 + 5.881659 (radius (m)) - 0.68423 (height (m)) + 0.020729 (altitude (m)). This study demonstrated significant effect of termite mound physiography on vegetation lifeforms abundance as well as developed a model for rapid prediction of their abundance on termite mounds.

Land Cover Change and Its Socio-Economic Impact on the Residents of the Mara River, Kenya

Anthropogenic activities are increasingly catalyzing natural climatic factors that drive land cover change at different spatial scales. Available land cover data of the Mara River basin however give a broader picture of the entire basin regardless of the heterogeneity that exists at the sub-catchment level. This study sought to establish sub-catchment specific information on land cover changes through examination of satellite images of four Mara River sub-catchments (Amala, Nyangores, Talek and Sand River) for the period 1987-2017. The relationship between temperature, rainfall and land cover was also computed. In addition, a household survey and focus group discussions were conducted in each sub-catchments to establish the socio-economic impacts of land cover change on the community’s wellbeing. Forest cover was dominant in Amala (39.8%) and Nyangores (43.7%) sub-catchments in 1987 but by 2017 crop lands had surpassed forest cover in the two sub-catchments, accounting for 53.2% and 45.7%, respectively. However, in Talek (52.8%) and Sand River (47.4%) sub-catchments, grassland was the dominant land cover type in 1987 and after the 30 year period, grasslands remained dominant in Sand River, while shrub land became dominant in Talek sub-catchment. A weak positive correlation was observed between rainfall and forest cover, shrub land and cropland, while a negative correlation was observed between rainfall and bare land. Average temperature showed a positive moderate correlation with bare land and built up areas. Analysis of survey data revealed that livestock keeping, temperature increase, type of trees, education level of household head and weak environmental laws were the main drivers of land cover change (P &#8722;0.587), beans (r = &#8722;0.5459), sorghum (r = &#8722;0.351), cow peas (r = &#8722;0.544), and pigeon peas (r = &#8722;0.337). Focus group discussions participants were supportive of environmental protective measures to reverse negative land cover changes, while planting drought resistant trees, crop diversification and awareness creation among community members were recommended as the most ideal environmental management strategies.

Effects of Land Use Change on Land Degradation Reflected by Soil Properties along Mara River, Kenya and Tanzania

Human-induced changes to natural landscapes have been identified as some of the greatest threats to freshwater resources. The change from natural forest cover to agricultural and pastoral activities is rampant especially in the upper Mara River catchment (water tower), as well as along the course of the Mara River. The objective of this study was to determine the effect of land use change on the physico-chemical properties of soil (bulk density, carbon, nitrogen, phosphorus and pH) along the course of the Mara River. Five major land uses (agricultural lands, livestock/pastoral lands, forested lands, conservancy/game reserves, and natural wetland) were explored. Results revealed that the mean soil bulk density was 0.956 g/cm3 and differed significantly between sites (p < 0.001). Live biomass values differed significantly between sampling sites (land use types) within the Mara River Basin (F(4, 147) = 8.57, p < 0.001). The mean infiltration over a period of 150 minutes differed, not only among sampling sites, but also between different sides of the river (left and right) within the same sampling site. Soil pH was generally acidic across the five sites and varied significantly (F(4, 63) = 19.26, p tween sites along the Mara River Basin. The mean percentage soil nitrogen across all sampling blocks was 4.87%, with significant differences observed in percentage soil nitrogen (F (4, 63) = 3.26, p < 0.006) between sampling sites. The results indicated that the five land use types affected land degradation differently along the Mara River, while adjacent land degradation affected water physico-chemical properties. These results point to the need to have focused policies on integrated land and water resource management strategies in the Mara River Basin.

Subtle Impacts of Temperature and Rainfall Patterns on Land Cover Change Overtime and Future Projections in the Mara River Basin, Kenya

The interactive and cumulative effect of temperature and rainfall on land cover change is a priority at global, regional and local scale. This study examined changes in six land cover categories (forestland, grasslands, shrub land, bare land, built-up areas and agricultural lands) in four sub-catchments (Amala, Nyangores, Talek and Sand River), of the Mara River basin over a 30-year period (1987-2017) and made predictions of future land cover change patterns. Landsat Imageries of 90 m resolution were retrieved and analyzed using ArcGIS 10.0 software. Relationship between NDVI, temperature and precipitation was determined using Pearson’s correlation coefficient, while Markov chains analyses were performed on different land cover categories to project future trends. Results showed low to moderate (R2 = 0.002 to 0.6) trends of change in NDVI of different land cover categories across all sub-catchments. The greatest change (R2 0.34 to 0.5) was recorded in bare land in three of the four sub-catchments studied. Precipitation showed a strong positive correlation with built-up areas, forestlands, croplands, bare land, grasslands and shrub lands, while temperature correlated strongly but negatively with the same land cover categories. The change detection matrix projected significant but varying changes in land cover categories across the four sub-catchments by 2027. This study underscores the impact of changing climatic factors on various land cover categories in the Mara River basin sub-catchments, with different land cover categories exhibiting strong positive sensitivity to high precipitation and low temperature and vice-versa.

Validated Method for the Detection of Three Phthalates Derived from Marine Invertebrates

This study represents, detailly, the validated method for the extraction and quantification of widespread phthalic acid esters (PAEs) bis(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP) and di-n-octyl phthalate (DnOP) from solitary ascidians collected from a marine environment. The extraction was based on a pressurized liquid extraction method, using n-hexane as the solvent to extract the target PAEs from dry biological tissues, and was performed in an accelerated solvent extraction instrument. The average recovery of 89.2% was obtained from samples subjected to a pressure of ~1500 psi and 120°C in two 10-min cycles. GC-MS was used for quantification, conducted in single-ion monitoring mode. Following careful and rigorous cleanup procedures to prevent cross-contamination from laboratory glassware, PAE standards showed signals with good specificity. The obtained limits of detection were 130, 122 and 89 ng/g for DEHP, DBP and DnOP, respectively. Accordingly, the calculated limits of quantification were 394, 370 and 270 ng/g for DEHP, DBP and DnOP, respectively. The obtained linearity ranged from 5.4 to 269 ng/ml (equivalent to 135 - 6725 ng/g dry weight), with R2 ≥ 0.998. Concentrations in the range of 200 to 9000 and 400 to 5000 ng/g sample dry weight, for DEHP and DBP, respectively, were obtained from the ascidians. No DnOP was detected in any of the samples. These results indicate that the method presented in this study is applicable for detection of low and trace concentrations of the target PAEs in samples collected from a marine organism, which can serve as a bioindicator of plastic contamination.

Analysis of the Effects of Ill Human Health on the Health of Kakamega Forest in Western Kenya

Tropical rainforests face serious threats of land-use conversion and increasing pressure of resource use and Kakamega forest was no exception.The forest was a biodiversity-rich unique ecosystem and supports high population.Poverty,prevalence of diseases and rising modern healthcare costs had increased dependence on herbal medicines from the forest.However,the effect of collecting medicinal plant materials and the related disturbances that contributed to habitat and biodiversity loss remained a little investigated.This paper examined the effect of ill human health on health of and Kakamega forest,western Kenya.A sample of 250 out of 2,100 households within 5-km distance around the forest was studied.A household questionnaire,observation schedule,digital camera and secondary literature were used to gather information.The study found a weak inverse relationship between usage of herbal medicine and health of and Kakamega forest.Also,binary logistic regression revealed that the health of the forest worsened with increased use of herbal medicine(at p<0.01 level)as demonstrated by debarking ceteris paribus.Thus,herbal therapy reduced the forest biodiversity population size and density.Understanding effects of harvesting herbal materials on the forest was critical for drawing up conservation priorities,and incentives which balance human and forest ecosystem health.

Assessing the impacts of current and future changes of the planforms of river Brahmaputra on its land use-land cover

River bankline migration is a frequent phenomenon in the river of the floodplain region.Nowadays,channel dynamics-related changes in land use and land cover(LULC)are becoming a risk to the life and property of people living in the vicinity of rivers.A comprehensive evaluation of the causes and consequences of such changes is essential for better policy and decision-making for disaster risk reduction and management.The present study assesses the changes in the Brahmaputra River planform using the GIS-based Digital Shoreline Analysis System(DSAS)and relates it with the changing LULC of the floodplain evaluated using the CA-Markov model.In this study,the future channel of the Brahmaputra River and its flood plain’s future LULC were forecasted to pinpoint the erosion-vulnerable zone.Forty-eight years(1973–2021)of remotely sensed data were applied to estimate the rate of bankline migration.It was observed that the river’s erosion-accretion rate was higher in early times than in more recent ones.The left and right banks’average shifting rates between 1973 and 1988 were -55.44 m/y and -56.79 m/y,respectively,while they were-17.25 m/y and -48.49 m/y from 2011 to 2021.The left bank of the river Brahmaputra had more erosion than the right,which indicates that the river is shifting in the leftward direction(Southward).In this river course,zone A(Lower course)and zone B(Middle course)were more adversely affected than zone C(Upper course).According to the predicted result,the left bank is more susceptible to bank erosion than the right bank(where the average rate of erosion and deposition was -72.23 m/y and 79.50 m/y,respectively).The left bank’s average rate of erosion was -111.22 m/y.The research assesses the LULC study in conjunction with river channel dynamics in vulnerable areas where nearby infrastructure and settlements were at risk due to channel migration.The degree of accu-racy was verified using the actual bankline and predicted bankline,as well as the actual LULC map and anticipated LULC map.In more than 90% of cases,the bankline’s position and shape generally remain the same as the actual bankline.The overall,and kappa accuracy of all the LULC maps was more than 85%,which was suitable for the forecast.Moreover,chi-square(x^(2))result values for classified classes denoted the accuracy and acceptability of the CA-Markov model for predicting the LULC map.The results of this work aim to understand better the efficient hazard management strategy for the Brahmaputra River for hazard managers of the region using an automated prediction approach.

Spatial distribution and habitat characterization of mosquito species during the dry season along the Mara River and its tributaries,in Kenya and Tanzania

Background:Vector-borne diseases are increasingly becoming a major health problem among communities living along the major rivers of Africa.Although larger water bodies such as lakes and dams have been extensively researched,rivers and their tributaries have largely been ignored.This study sought to establish the spatial distribution of mosquito species during the dry season and further characterize their habitats along the Mara River and its tributaries.Methods:In this cross-sectional survey,mosquito larvae were sampled along the Mara River,its two perennial tributaries(Amala and Nyangores),drying streams,and adjacent aquatic habitats(e.g.swamps,puddles that receive direct sunlight[open sunlit puddles],rock pools,hippo and livestock hoof prints,and vegetated pools).Each habitat was dipped 20 times using a standard dipper.Distance between breeding sites and human habitation was determined using global positioning system coordinates.The collected mosquito larvae were identified using standard taxonomic keys.Water physico-chemical parameters were measured in situ using a multiparameter meter.Mean mosquito larvae per habitat type were compared using analysis of variance and chi-square tests,while the relationship between mosquito larvae and physicochemical parameters was evaluated using a generalized linear mixed model.The Cox-Stuart test was used to detect trends of mosquito larvae distribution.The test allowed for verification of monotonic tendency(rejection of null hypothesis of trend absence)and its variability.Results:A total of 4001 mosquito larvae were collected,of which 2712(67.8%)were collected from river/stream edge habitats and 1289(32.2%)were sampled from aquatic habitats located in the terrestrial ecosystem about 50 m away from the main river/streams.Anopheles gambiae s.s,An.arabiensis,and An.funestus group,the three most potent vectors of malaria in Sub-Saharan Africa,together with other anopheline mosquitoes,were the most dominant mosquito species(70.3%),followed by Culex quinquefasciatus and Cx.pipiens complex combined(29.5%).Drying streams accounted for the highest number of larvae captured compared to the other habitat types.A stronger relationship between mosquito larvae abundance and dissolved oxygen(Z=7.37,P≤0.001),temperature(Z=7.65,P≤0.001),turbidity(Z=−5.25,P≤0.001),and distance to the nearest human habitation(Z=4.57,P≤0.001),was observed.Conclusions:Presence of malaria and non-malaria mosquito larvae within the Mara River basin calls for immediate action to curtail the insurgence of vector-borne diseases within the basin.A vector control program should be conducted during the dry period,targeting drying streams shown to produce the highest number of larval mosquitoes.