Kyoga Research Articles

Distribution and Relative Abundance of Bean Leaf Beetles (Ootheca spp.) (Insecta: Coleoptera: Chrysomelidae) in Uganda

Simple SummaryBean leaf beetles (Ootheca spp.) (Insecta: Coleoptera: Chrysomelidae) were originally thought to be minor pests of the common bean in Uganda, with only reports coming from the north. The beetles have already expanded to other locations, prompting farmers to postpone bean planting in order to avoid their damaging effects. The species that do exist in Uganda, however, are poorly documented. Furthermore, little is known about the factors that influence bean leaf beetle population dynamics and dispersion across the country. We conducted surveys to determine the species and relative abundance of bean leaf beetles, as well as the factors that control their population dynamics. We recovered 12 genera of leaf beetles on common bean from the sampled agro-ecological zones in Uganda. Only three species belong to the genus Ootheca (O. mutabilis, O. proteus and O. orientalis) in the surveyed locations of Uganda. Ootheca mutabilis is the most common of the three species, accounting for 70% of the total. The most infested agro-ecological zone is the Northern Moist Farmlands, whereas the least infested is the Southwestern Highlands. Our findings provide a foundation for assessing the importance of Ootheca species as common bean pests in Uganda.Bean leaf beetles (Ootheca spp.) (Insecta: Coleoptera: Chrysomelidae) are one of Africa’s most destructive pests of common bean and other leguminous crops. The beetles are widely distributed in Africa where they are estimated to cause annual crop yield losses of 116,400 tons of crop yields in sub-Saharan Africa. Despite their importance, little is known about the distribution, relative abundance and damage caused by bean leaf beetles in Uganda. As a result, the development of effective management methods has been hampered. We conducted surveys in six key Ugandan agro-ecological zones to determine the species distribution and relative abundance of bean leaf beetles. Findings indicate that leaf beetles belonging to 12 genera are present, including members of the genera Afrophthalma Medvedev, 1980, Buphonella Jacoby, 1903, Chrysochrus Chevrolat in Dejean, 1836, Diacantha Dejean, 1845, Exosoma Jacoby, 1903, Lamprocopa Hincks, 1949, Lema Fabricius, 1798, Nisotra Baly, 1864, Neobarombiella Bolz and Wagner, 2012, Ootheca Dejean, 1935, Parasbecesta Laboissière, 1940, and Plagiodera Dejean, 1835. We identified only three species belonging to the genus Ootheca: O. mutabilis, O. proteus, and O. orientalis. Seventy percent of all the beetles collected were O. mutabilis and these were present in all agro-ecological zones studied. The Northern Moist Farmlands (21.9%), West Nile Farmlands (12.9%), Central Wooded Savanna (4.4%) and Southern and Eastern Lake Kyoga Basin (1.4%) were the only agro-ecological zones where O. proteus was found. Only one specimen of O. orientalis was found at a single site in the Central Wooded Savanna. The Northern Moist Farmlands had a significantly (p < 0.05) higher bean leaf beetle density than the West Nile Farmlands and Southwestern Highlands. Similarly, the Northern Moist Farmlands had the highest beetle foliar damage per plant (1.15 ± 0.05), while the Southwestern Highlands had the lowest (0.03 ± 0.02). We provide the first information on Ootheca species distribution, abundance and damage in Uganda. Our findings provide a foundation for assessing the importance of Ootheca spp. as common bean pests in Uganda.

Over a century evidence of historical and recent dryness/wetness in sub‐humid areas: A Uganda, East African case

AbstractMany regions globally are grappling with the challenge of recurrent extreme weather events. Whereas attempts are being undertaken to understand their characteristics as a first step to guide targeted mitigation measures, these are focused on dryness and not wetness, which is also a challenge in sub‐humid areas. This study investigates dryness and wetness characteristics using the standardized precipitation evaporation index (SPEI) at timescales of 3, 6, 12 and 24 months for a period of 1901–2018 across Uganda's drainage basins. Trends in the dryness and wetness evolutions were conducted using the Mann‐Kendall (MK) statistic to establish the effects of global warming on the study area. A step change analysis reveals 1961 as a change point year from cool to warm periods. Results also reveal that warming mainly occurred in the recent period (1962–2018), with a temperature rise of over 2οC being recorded in 2009. Severe dryness events occurred in the recent period as opposed to wetness events that dominated the earlier period (1901–1961). Dryness and wetness varied among drainage basins, with the Aswa basin being more susceptible to severe dryness while the Lake Kyoga basin to severe wetness. Lira and Kitgum were identified as drought hotspots at timescales of 3, 6 and 12 months. SPEI was able to reveal 60% of historical dryness events and 75% of wetness events on record, making it an adequate tool for monitoring humid events as opposed to droughts in sub‐humid climates. It is hoped that this evidence can guide targeted mitigation measures towards climatic shocks within the region.

Population collapse in viviparid gastropods of the Lake Victoria ecoregion started before the Last Glacial Maximum.

Ecosystems of Lake Victoria and riparian communities have been strongly disrupted by the introduction of the invasive Nile perch and its fishing industry. Beyond this invasion and other recent anthropogenic stressors, the Lake Victoria ecoregion also underwent phases of pronounced aridity over the Late Pleistocene, lastly during the Last Glacial Maximum (LGM). The consequences of recent and historic environmental change have been canvassed for the adaptive radiation of haplochromine cichlids occupying the ecoregion, but their effect on freshwater invertebrate diversity remains largely unknown. Here, we use 15 microsatellite loci and approximate Bayesian computation to test whether viviparid gastropods experienced a population bottleneck during the LGM, as did cichlids. Clustering analyses support three viviparid gene pools in the Lake Victoria ecoregion, gathering specimens from 1) Lake Albert and the White Nile, 2) the Victoria Nile and Lake Kyoga and 3) Lake Victoria and tributaries. The last group contains the highest genetic diversity, but all groups have a considerable number of private alleles and are inferred to predate the LGM. Examinations of demographic history reveal a 190- to 500-fold population decline that started~125-150ka ago, thus substantially before the LGM bottleneck documented in haplochromine cichlids. Population collapses in viviparids are an order of magnitude more severe than declines in cichlids and have not been halted by the re-establishment of freshwater ecosystems since the LGM. Recent anthropogenic ecosystem deterioration is causing homogenization of previously diversified microhabitats, which may contribute to (local) extinction and enhanced gene flow among species within gene pools.

Genetic diversity of aflatoxin-producing Aspergillus flavus isolated from selected groundnut growing agro-ecological zones of Uganda

BackgroundGroundnut pre- and post-harvest contamination is commonly caused by fungi from the Genus Aspergillus. Aspergillus flavus is the most important of these fungi. It belongs to section Flavi; a group consisting of aflatoxigenic (A. flavus, A. parasiticus and A. nomius) and non-aflatoxigenic (A. oryzae, A. sojae and A. tamarii) fungi. Aflatoxins are food-borne toxic secondary metabolites of Aspergillus species associated with severe hepatic carcinoma and children stuntedness. Despite the well-known public health significance of aflatoxicosis, there is a paucity of information about the prevalence, genetic diversity and population structure of A. flavus in different groundnut growing agro-ecological zones of Uganda. This cross-sectional study was therefore conducted to fill this knowledge gap.ResultsThe overall pre- and post-harvest groundnut contamination rates with A. flavus were 30.0 and 39.2% respectively. Pre- and post-harvest groundnut contamination rates with A. flavus across AEZs were; 2.5 and 50.0%; (West Nile), 55.0 and 35.0% (Lake Kyoga Basin) and 32.5 and 32.5% (Lake Victoria Basin) respectively. There was no significant difference (χ2 = 2, p = 0.157) in overall pre- and post-harvest groundnut contamination rates with A. flavus and similarly no significant difference (χ2 = 6, p = 0.199) was observed in the pre- and post-harvest contamination of groundnut with A. flavus across the three AEZs. The LKB had the highest incidence of aflatoxin-producing Aspergillus isolates while WN had no single Aspergillus isolate with aflatoxin-producing potential. Aspergillus isolates from the pre-harvest groundnut samples had insignificantly higher incidence of aflatoxin production (χ2 = 2.667, p = 0.264) than those from the post-harvest groundnut samples. Overall, A. flavus isolates exhibited moderate level (92%, p = 0.02) of genetic diversity across the three AEZs and low level (8%, p = 0.05) of genetic diversity within the individual AEZs. There was a weak positive correlation (r = 0.1241, p = 0.045) between genetic distance and geographic distance among A. flavus populations in the LKB, suggesting that genetic differentiation in the LKB population might be associated to geographic distance. A very weak positive correlation existed between genetic variation and geographic location in the entire study area (r = 0.01, p = 0.471), LVB farming system (r = 0.0141, p = 0.412) and WN farming system (r = 0.02, p = 0.478). Hierarchical clustering using the unweighted pair group method with arithmetic means (UPGMA) revealed two main clusters of genetically similar A. flavus isolates.ConclusionsThese findings provide evidence that genetic differentiation in A. flavus populations is independent of geographic distance. This information can be valuable in the development of a suitable biocontrol management strategy of aflatoxin-producing A. flavus.

Analyses of Precipitation and Evapotranspiration Changes across the Lake Kyoga Basin in East Africa

This study analyzed changes in CenTrends gridded precipitation (1961–2015) and Potential Evapotranspiration (PET; 1961–2008) across the Lake Kyoga Basin (LKB). PET was computed from gridded temperature of the Princeton Global Forcings. Correlation between precipitation or PET and climate indices was analyzed. PET in the Eastern LKB exhibited an increase (p &gt; 0.05). March–April–May precipitation decreased (p &gt; 0.05) in most parts of the LKB. However, September–October–November (SON) precipitation generally exhibited a positive trend. Rates of increase in the SON precipitation were higher in the Eastern part where Mt. Elgon is located than at other locations. Record shows that Bududa district at the foot of Mt. Elgon experienced a total of 8, 5, and 6 landslides over the periods 1818–1959, 1960–2009, and 2010–2019, respectively. It is highly probable that these landslides have recently become more frequent than in the past due to the increasing precipitation. The largest amounts of variance in annual precipitation (38.9%) and PET (41.2%) were found to be explained by the Indian Ocean Dipole. These were followed by precipitation (17.9%) and PET (21.9%) variance explained by the Atlantic multidecadal oscillation, and North Atlantic oscillation, respectively. These findings are vital for predictive adaptation to the impacts of climate variability on water resources.

Developmental and Cellular Basis of Vertical Bar Color Patterns in the East African Cichlid Fish Haplochromis latifasciatus.

The East African adaptive radiations of cichlid fishes are renowned for their diversity in coloration. Yet, the developmental basis of pigment pattern formation remains largely unknown. One of the most common melanic patterns in cichlid fishes are vertical bar patterns. Here we describe the ontogeny of this conspicuous pattern in the Lake Kyoga species Haplochromis latifasciatus. Beginning with the larval stages we tracked the formation of this stereotypic color pattern and discovered that its macroscopic appearance is largely explained by an increase in melanophore density and accumulation of melanin during the first 3 weeks post-fertilization. The embryonal analysis is complemented with cytological quantifications of pigment cells in adult scales and the dermis beneath the scales. In adults, melanic bars are characterized by a two to threefold higher density of melanophores than in the intervening yellow interbars. We found no strong support for differences in other pigment cell types such as xanthophores. Quantitative PCRs for twelve known pigmentation genes showed that expression of melanin synthesis genes tyr and tyrp1a is increased five to sixfold in melanic bars, while xanthophore and iridophore marker genes are not differentially expressed. In summary, we provide novel insights on how vertical bars, one of the most widespread vertebrate color patterns, are formed through dynamic control of melanophore density, melanin synthesis and melanosome dispersal.

Comprehensive knowledge of HIV prevention among fishing communities of Lake Kyoga, Uganda, 2013

BackgroundCompared to the general population in Uganda, fishing communities suffer greater burden of HIV/AIDS. We determined the level of comprehensive knowledge on HIV prevention and its associated factors among fishing communities of Lake Kyoga.MethodsWe conducted secondary analysis of data from the Lake Kyoga Behavioral Survey, a population-based sample survey on behavioral risk factors for HIV, syphilis, and schistosomiasis among adults in fishing communities of Lake Kyoga in 2013. We defined comprehensive knowledge as having correct knowledge on HIV prevention (consistent condom use, faithfulness, a healthy-looking person can have HIV, and HIV cannot be transmitted through food-sharing, witchcraft or handshake). We used logistic regression to determined potential factors associated with comprehensive knowledge on HIV prevention and control for confounding.ResultsOf 1780 persons in the sample, 51% (911/1780) were females. The mean age was 32 (range: 15–97) years. Overall, 51% (899/1780) of persons had comprehensive knowledge on HIV prevention. Level of comprehensive knowledge on HIV prevention was similar between females (52%, 449/911) and males (49%, 450/869). Males (76%, 658/869) had lower knowledge on HIV transmission from mother to child during breast feeding compared to females (81%, 738/911) (p-value 0.019). Fishermen (46%,324/711) who lived > 5 km away from a health center compared to 54% (572/1066) who lived within 5 km radius were less likely to have comprehensive knowledge on HIV prevention (PRRadj = 0.8; 95%CI = 0.5–0.92). Those who had ever tested for HIV were more likely to have comprehensive knowledge of HIV transmission (PRRadj = 1.1; 95% 1.03–1.70).ConclusionHalf of the population of Lake Kyoga fishing community had comprehensive knowledge of HIV prevention. Long distances from health facilities reduced the level of comprehensive knowledge on HIV transmission. HIV testing increased the level of comprehensive knowledge on HIV transmission. Ministry of health should ensure that HIV/AIDS information; education and communication and HIV counseling and testing activities are intensified in fishing communities of Lake Kyoga, with more emphasis on communities living in distances of more than 5 km away from the health facility.

Dry spells and probability of rainfall occurrence for Lake Kyoga Basin in Uganda, East Africa

The economy of Uganda depends heavily on rainfed agriculture. In this study, daily observed rainfall datasets from 9 weather stations with length varying within 1955 and 2017 were used to generate the probability of rainfall and dry spells occurrence using a Markov chain approach. The length of the maximum dry spell was obtained using the direct method based on the definition of a dry day that rainfall is less than 0.85 mm (R < 0.85 mm) and the length of a dry spell is the sum of the number of dry days in a sequence. Mann–Kendall’s statistics (MK) was used to assess the trends in the length of maximum dry spells and Sen’s slope test to estimate the magnitude of change (Q2) in days/per month. MK test results show increasing trends in the length of the maximum dry spells in March at 5 stations, while an insignificant decrease in the length of maximum dry spells is revealed for remaining stations. For the month of April and May, the length of a maximum dry spell is observed to be decreasing across most stations although not statistically significant at the 5% significance level during their respective study periods. The probability of 8 days dry spell is high across all the stations (38–69%) in March, April, and August. This could strongly be related to the changing climate in the region. Negative impacts due to increased length of dry spells could be mitigated through well-timed planting of crops, use of irrigation, and growing of heat-/drought-tolerant crop varieties to match the changing weather and climate patterns.

Ethno-varieties and Distribution of jackfruit tree (Artocarpus heterophyllus Lam.) in Uganda: implications for trade, food security and germplasm conservation

Artocarpus heterophyllus Lam. is a fruit tree crop largely grown in tropical regions for its edible fruits. Though listed among underutilized crops, the demand for jackfruit in Uganda has increased. Amidst the increase in demand, the crop faces strong selective pressure and yet there is no documentation of the varieties and distribution of the crop in the country. This study therefore aimed at determining the varieties and distribution of jackfruit in Uganda using folk knowledge to provide a baseline for its production, booming market and conservation. A cross-sectional survey involving 349 participants comprising of 205 jackfruit traders and 144 jackfruit farmers from three political regions and three agro-ecological zones was conducted. Data were collected through face to face interviews using a semi-structured questionnaire and direct observations. Classification of jackfruit varieties, geographical location of the source of jackfruits for traders and the time of harvest of the fruit by the farmers were investigated. Occurrence of varieties per household was determined through on-farm visits. Data analysis techniques involved descriptive, chi-square and Cramer’s V measure of association analyses. Traders mainly obtained jackfruit from Central (46.0%) and Eastern (37.6%) political regions, Lake Victoria Crescent and Mbale Farmlands (41.1%) and Southern and Eastern Lake Kyoga Basin (30.0%) agro-ecological zones. Jackfruit varieties were classified basing on fruit texture and pulp colour, revealing four ethno-varieties, soft (Serebera), firm yellow (Kanaanansi), firm red (Namusaayi) and firm white (Namata). Namata and Serebera registered the lowest occurrences political regions and agro-ecological zones. Farmers harvested jackfruit throughout the year with a peak season in December and January. Folk knowledge provided baseline information for jackfruit variety categorization. Selection pressure exerted on Serebera and Namata demands for germplasm conservation. Since jackfruit thrives in a wide range of climatic conditions, its cultivation should be encouraged to ensure food security and sustain the increasing demand.

Ecosystem productivity response to environmental forcing, prospect for improved rain-fed cropping productivity in lake Kyoga Basin

Current global environmental especially climate changes necessitate revisiting approaches to ecosystems management in order to improve productivity in agroecosystems. This study was conducted to identify influential biophysical factors controlling ecosystems productivity, their spatial heterogeneous effect and estimate suitability of the land for production in the tropical Lake Kyoga Basin in Eastern Uganda. The study spanned 15 years (2001–2015). We used a simplified integrated approach to model productivity as a function of climatic, topographic, vegetation, soil attributes (2001–2013, period) using statistical, and geospatial models implemented in a GIS environment. Soil data was obtained through a field survey coupled with secondary data. Climatic and vegetative data were obtained as imagery data from online repositories, while topographic parameters were extracted from a 30-m digital elevation model. MODIS NDVI data was used as proxy of productivity. We used geographical weighted regression to assess the spatial heterogeneity effect of soil, climate and topography on productivity and fuzzy approach to capture gradient of suitable land for production. The results revealed soil types and precipitation as the dominant biophysical factors controlling the productivity. The factors, explained 52% of the observed variation in productivity. Results on soil attributes indicate a fertility problem as OM, N and K levels were below the critical levels for good crop production, hence only 40% of the soils are productive. The results captured well the spatial heterogeneity of the factors influencing productivity and land suitability for production. Overall, 69% of the basin was found to be suitable for production. Thus, the results of this study will motivate planners, decision-makers and researchers to analyse critically the suitability of adopted production technologies such fertilizer applications in the basin. Moreover, the concern authorities to explore external sources of food for areas with less suitable land for production, given projected climate changes.

English

The Lubigi wetland, which is located in the north-western part of Kampala, the capital city of Uganda has been severely strained from anthropogenic encroachment and activities. These activities include harvesting of Cyperus papyrus and other plants, land filling for reclamation, human settlements and disposal of wastewater into the wetland among others. As a result of these anthropogenic activities, the macrophytes diversity and biomass in the wetland have been affected, which in turn affects the effectiveness of wetland for removal of pollutants. It is therefore important to investigate the characteristics of wetland macrophytes in the Lubigi wetland. Pertinent field investigations, surveys, data collection and laboratory tests and analyses were carried out. The problem being addressed was the current lack of information and knowledge about the biomass and biodiversity of the Lubigi wetland to protect the downstream Mayanja River and Lake Kyoga. Three transects each of 1.0 m wide was cut across this zone at about 700 m downstream of the main wastewater inlet, the second at about 1,440 m downstream of the main wastewater inlet and the third at about 1,930 m downstream of the main wastewater inlet. In each of the 3 transects, 5 sampling points were established. Samples were analyzed in order to determine plant biomass, diversity, density and vegetation zonation. The determination of nitrogen content in the biomass parts and sediments was also carried out in accordance with standard methods for the examination of samples. The results show that there are 9 dominant native wetland plants species, which account for about 60% of all the plants species recorded. Of these dominant plant species, three exhibited the monotype form of dominance, one is ubiquitous, the other three were the compressed form of dominance, six are aberrant, two are diffuse and one is patchy. The most dominant species are C. papyrus, Echinochloa pyramidalis, Typha capensis, Rottboellia cochinchinensis and Oldenlandia lancifolia, with biomass production mean values of 1.52&plusmn;0.13, 0.16&plusmn;0.03, 0.26&plusmn;0.04, 0.03&plusmn;0.01 and 0.37&plusmn;0.05 kgDWm-2, respectively. However, there is no statistically significant difference between the biomass of the plant species in the three transects. Plant densities range from 5.0&plusmn;3.09 to 19.56&plusmn;15.29 plants/m2, with a mean value of 10.19&plusmn;4.69 plants/m2. The overall mean plants and sediments nitrogen content are 67.54&plusmn;37.9 and 157.5 g/m2, respectively. &nbsp; Key words: Lubigi wetland, plant biodiversity, plant biomass, plant density, vegetation zonation.

Land Use Change using Geospatial Techniques: The Case of AwojaWatershed in Ngora District in Eastern Uganda

This study used remote sensing and Geo-graphical Information System (GIS) to assess the status of Awoja watersheds in Ngora district of Eastern Uganda. Landsat ETM Images covering the whole of Ngora district and part of Lake Kyoga of two time periods was carried out in the period April to July 2015. This wasacquired using USGS Earth Explorer. The images were processed and enhanced with ERDAS 2014 software to aid information extraction and analysis. Land cover change analysis was performed using ENVI 5.3 software. Supervised classification method with maximum likelihood algorithm was performed to obtain land use/ cover types. Five land use/cover types were identified: open water, wetland, tree cover, agriculture and built up area. The findings indicate a fivefold increase in built up area by 154.27km2 (i.e. 375%) and open water increased by 8.7 km2 (i.e. 55.33%). Wetland, tree cover and agriculture reduced in area by -1.0km2 (i.e. 5.1%), - 48.07 km2 (i.e. 34.46%) and -114.0km2 (i.e. 51.05%), respectively. These changes mainly resulted from deforestation, wetland encroachment, poor attitude and over population. Unless, appropriate watershed restoration strategies are designed through afforestation, law enforcement on culprits, continuous sensitisation of the watershed community on the causes of degradation, the over 1,700,000 individuals whose livelihoods depend on Awojawill continue to suffer the effects of degradation. There is need to advocate for non-consumptive projects as alternative sources of income. Keywords: Remote sensing, GIS, Watersheds.

Ecological Characteristics and Morphological Features of the Lubigi Wetland in Uganda

The Lubigi is one of the largest Lake Kyoga drainage basin wetlands located in the north-western part of Kampala, the capital city of Uganda. It receives stormwater and polluted water from Kampala city and discharges it into Mayanja River and finally Lake Kyoga. Unfortunately, there is lack of information and knowledge on the capacity of the Lubigi wetland to protect the downstream water bodies from pollution. In an effort to address this it was necessary to investigate ecological and morphological characteristics of the Lubigi wetland. Pertinent field investigations, surveys, data collection and field tests and analyses were carried out. The results revealed that the area of drainage basin feeding the wetland is about 40 km2. The width of wetland main study area varies from 250 m to 450 m and water depth varies up to a maximum of 2.5 m. The wetland study area has a total surface area and volume are 1.09 ha and 1,073,000 m3, respectively. The wetland soil is dominated by thick loose peat near the inlet, but thickness of loose peat decreased rapidly towards the downstream end. Nine plant species were dominant in Lubigi wetland, but the most dominant species are Echinochloa pyramidalis, Cyperus papyrus, Thelypteris acuminata and Paspalum crobiculatum.

Gene flow and genetic structure in Nile perch, Lates niloticus, from African freshwater rivers and lakes.

BackgroundGeological evolution of the African continent has been subject to complex processes including uplift, volcanism, desert formation and tectonic rifting. This complex geology has created substantial biogeographical barriers, and coupled with anthropogenic introductions of freshwater fishes, has influenced the genetic diversity, connectivity and sub-structuring of the teleost fauna. Nile perch, Lates niloticus, is an iconic fish in Africa and is of high commercial importance, both in the species’ native range and where it has been translocated. However, the species is in decline and there is a need to understand its population genetic structure to facilitate sustainable management of the fishery and aquaculture development.MethodologyNile perch tissue samples were acquired from two West and four East (Lakes; Albert, Kyoga, Victoria and Turkana) African locations. Nineteen polymorphic microsatellite loci were used to study the genetic variation among populations across regions (West and East Africa), as well as between native and introduced environments within East Africa.Principal findings and their significanceResults revealed strong and significant genetic structuring among populations across the sampled distribution (divergence across regions, FCT = 0.26, P = 0.000). STRUCTURE analysis at a broad scale revealed K = 2 clusters, the West African individuals were assigned to one cluster, while all individuals from the East African region, regardless of whether native or introduced, were assigned to another cluster. The distinct genetic clusters identified in the current study between the West and East African Nile perch, appear to have been maintained by presence of biogeographic barriers and restricted gene flow between the two regions. Therefore, any translocations of Nile perch should be carefully considered across the regions of West and East Africa. Further analysis at a regional scale revealed further structuring of up to K = 3 genetic clusters in East African Nile perch. Significantly (P < 0.05) lower genetic diversity based on analysis of allelic richness (AR) was obtained for the two translocated populations of Lake Kyoga (AR = 3.61) and Lake Victoria (AR = 3.52), compared to Nile perch populations from their putative origins of Lakes Albert (AR = 4.12) and Turkana (AR = 4.43). The lower genetic diversity in the translocated populations may be an indication of previous bottlenecks and may also indicate a difficulty for these populations to persist and adapt to climatic changes and anthropogenic pressures that are currently present in the East African region.

Assessing the Impacts of Climate Change on Streamflow in Malaba River Catchment, Uganda

Malaba River in Uganda a focal area to the Lake Kyoga basin is prone to climate change because of its heavy reliance on rainfall as its major flow contributor. The impacts of climate change on streamflow in Malaba River were assessed using LARS-WG downscaling model and Soil and Water Assessment Tool (SWAT) model. This was achieved by downscaling the future (2020-2050) precipitation and temperature variables for A1B and A2 scenarios and simulating the projected climate with calibrated LARS-WG and SWAT models for the two scenarios. The SWAT calibration (1992 - 1999) and validation (2000 - 2004) NSE results were respectively 0.55 and 0.35. Results indicated that the projected areal rainfall will increase by 0.34 mm per year for A1B which is averagely 1% less than the baseline period. Areal rainfall for A2 scenario will increase by 0.41 mm per year which is averagely 9% more than the baseline period. The Flow Duration Curve analyses indicated that the A2 scenario displayed higher flows for all the percentiles as compared to the baseline flows while A1B scenario has lower flows for percentiles less than 50, and equal or slightly higher flows for percentiles greater than 50 as compared to the baseline flows.

The Fate of Nitrogen and Faecal Coliform in the Lubigi Wetland in Uganda

The capacity of the Lubigi wetland to reduce nitrogen and faecal coliform pollution entering Lake Kyoga in Uganda was investigated. Three transects with 5 sampling points in each, were established in the wetland. Wetland plants samples were collected from the specific locations along the transects, and laboratory tests and analyses were carried out for plants biomass and nitrogen contents determination. Samples of wetland sediments were also collected, and laboratory tests and analyses were done for determination of nitrogen content in the sediments. Wetland water samples were taken from the main wetland inlet and the main outlet from the wetland main study area. At the same time, wetland water pH, dissolved oxygen and temperatures were measured in-situ. Laboratory tests and analyses for ammonia-nitrogen, nitrate-nitrogen, total Kjeldahl nitrogen, total nitrogen and faecal coliforms were carried out on the wetland water samples. The results indicate that the Lubigi wetland received about 16 to 173 mg/l of total nitrogen, largely in form of organic- nitrogen (64.7%) and ammonia-nitrogen (35.2%). Nitrate-nitrogen and Nitrite-nitrite accounted for only 0.1% of the total nitrogen in the inlet. The wetland removed about 24.9% of this nitrogen, which is equivalent to removal of about 1,672 tons of nitrogen annually. About 67.5 gN/m2 and 0.30 gN/kg of dry sediments were sequestered in the wetland plants biomass and the benthic layer respectively. The Lubigi wetland main study area also receives faecal coliform concentrations with the wetland inlet mean value of 653,509 CFU/100ml and its outlet mean value is 218,676 CFU/100ml. These values give a faecal coliform (FC) overall removal efficiency of approximately 66.5%. It was thus concluded that the Lubigi wetland has considerable capacity to buffer and protect Lake Kyoga, by reducing nitrogen and faecal coliform pollution entering the lake.

Assessment of Impacts of Climate Change on Hydro-meteorological Ecosystem Services and Water Stress in Lake Kyoga Catchment

Through review of several studies on climate change, an attempt was made to investigate the sensitivity of water resources to climate change over Lake Kyoga catchment. Climate change is predicted to increase the frequency of climatic extremes that can lead to loss of life and property. This study was mainly to analyze the water stress arising from the impacts of climate change on hydro-meteorological ecosystem services. The methodology of the study consists of analysis of available meteorological and hydrological observations, analysis of Global Weather Data for ArcGIS/SWAT output data and finally seasonal performance of precipitation and temperature using Climate Predictability Tool outputs. The Correlation Percentage change was used to estimate the rate of change of flow and water levels under a changed climate. The outputs for different stations showed that climate change has already affected water resources in Lake Kyoga catchment with continuous reduction in water levels of 6%. The results of the study revealed that climate change is likely to increase precipitation by 10-20% received during the wet seasons resulting in higher stream flow and a reduction of 20-40% of precipitation during the dry seasons. The GCMs also demonstrated an increase in maximum and minimum temperatures of 1 to 30C by 2065 with minimum temperatures increasing more rapidly compared to the maximum temperatures for the two scenarios (RCP4.5 and RCP8.5). The strategies for adaptation and mitigation measures have been identified.

Recent changes in terrestrial water storage in the Upper Nile Basin: an evaluation of commonly used gridded GRACE products

Abstract. GRACE (Gravity Recovery and Climate Experiment) satellite data monitor large-scale changes in total terrestrial water storage (ΔTWS), providing an invaluable tool where in situ observations are limited. Substantial uncertainty remains, however, in the amplitude of GRACE gravity signals and the disaggregation of TWS into individual terrestrial water stores (e.g. groundwater storage). Here, we test the phase and amplitude of three GRACE ΔTWS signals from five commonly used gridded products (i.e. NASA's GRCTellus: CSR, JPL, GFZ; JPL-Mascons; GRGS GRACE) using in situ data and modelled soil moisture from the Global Land Data Assimilation System (GLDAS) in two sub-basins (LVB: Lake Victoria Basin; LKB: Lake Kyoga Basin) of the Upper Nile Basin. The analysis extends from January 2003 to December 2012, but focuses on a large and accurately observed reduction in ΔTWS of 83 km3 from 2003 to 2006 in the Lake Victoria Basin. We reveal substantial variability in current GRACE products to quantify the reduction of ΔTWS in Lake Victoria that ranges from 80 km3 (JPL-Mascons) to 69 and 31 km3 for GRGS and GRCTellus respectively. Representation of the phase in TWS in the Upper Nile Basin by GRACE products varies but is generally robust with GRGS, JPL-Mascons, and GRCTellus (ensemble mean of CSR, JPL, and GFZ time-series data), explaining 90, 84, and 75 % of the variance respectively in "in situ" or "bottom-up" ΔTWS in the LVB. Resolution of changes in groundwater storage (ΔGWS) from GRACE ΔTWS is greatly constrained by both uncertainty in changes in soil-moisture storage (ΔSMS) modelled by GLDAS LSMs (CLM, NOAH, VIC) and the low annual amplitudes in ΔGWS (e.g. 1.8–4.9 cm) observed in deeply weathered crystalline rocks underlying the Upper Nile Basin. Our study highlights the substantial uncertainty in the amplitude of ΔTWS that can result from different data-processing strategies in commonly used, gridded GRACE products; this uncertainty is disregarded in analyses of ΔTWS and individual stores applying a single GRACE product.

Genetic diversity and population structure of the tsetse fly Glossina fuscipes fuscipes (Diptera: Glossinidae) in Northern Uganda: Implications for vector control.

Uganda is the only country where the chronic and acute forms of human African Trypanosomiasis (HAT) or sleeping sickness both occur and are separated by < 100 km in areas north of Lake Kyoga. In Uganda, Glossina fuscipes fuscipes is the main vector of the Trypanosoma parasites responsible for these diseases as well for the animal African Trypanosomiasis (AAT), or Nagana. We used highly polymorphic microsatellite loci and a mitochondrial DNA (mtDNA) marker to provide fine scale spatial resolution of genetic structure of G. f. fuscipes from 42 sampling sites from the northern region of Uganda where a merger of the two disease belts is feared. Based on microsatellite analyses, we found that G. f. fuscipes in northern Uganda are structured into three distinct genetic clusters with varying degrees of interconnectivity among them. Based on genetic assignment and spatial location, we grouped the sampling sites into four genetic units corresponding to northwestern Uganda in the Albert Nile drainage, northeastern Uganda in the Lake Kyoga drainage, western Uganda in the Victoria Nile drainage, and a transition zone between the two northern genetic clusters characterized by high level of genetic admixture. An analysis using HYBRIDLAB supported a hybrid swarm model as most consistent with tsetse genotypes in these admixed samples. Results of mtDNA analyses revealed the presence of 30 haplotypes representing three main haplogroups, whose location broadly overlaps with the microsatellite defined clusters. Migration analyses based on microsatellites point to moderate migration among the northern units located in the Albert Nile, Achwa River, Okole River, and Lake Kyoga drainages, but not between the northern units and the Victoria Nile drainage in the west. Effective population size estimates were variable with low to moderate sizes in most populations and with evidence of recent population bottlenecks, especially in the northeast unit of the Lake Kyoga drainage. Our microsatellite and mtDNA based analyses indicate that G. f. fuscipes movement along the Achwa and Okole rivers may facilitate northwest expansion of the Rhodesiense disease belt in Uganda. We identified tsetse migration corridors and recommend a rolling carpet approach from south of Lake Kyoga northward to minimize disease dispersal and prevent vector re-colonization. Additionally, our findings highlight the need for continuing tsetse monitoring efforts during and after control.

Proliferation of &amp;lt;i&amp;gt;Salvinia molesta&amp;lt;/i&amp;gt; at Lake Kyoga Landing Sites as a Result of Anthropogenic Influences

Salvinia molesta (native of south-eastern Brazil) is a free floating aquatic fern that has spread to several countries around the globe including Uganda. Under optimum growing conditions, the plant is capable of spreading rapidly where it can have immense environmental, economic and human health impacts. Thick mats of the weed have been recorded in some parts of Lake Kyoga, Uganda where it hinders the abstraction of water, docking and boat take-off, bathing and swimming activities. Therefore this study aimed to determine the extent of S. molesta at selected landing sites in Lake Kyoga and the influence of anthropogenic activities on the weed coverage as well as the effect of physico-chemical parameters of the water on the development of the weed. Quadrats were used to ascertain the coverage of S. molesta while the physico-chemical parameters were determined by standard methods. The results showed significant positive correlation of S. molesta weed coverage with phosphates (PO4-P) and negative correlations with pH, dissolved oxygen (DO) and water flow rate. Though statistically insignificant waste sites recorded the highest overall S. molesta coverage (82.61 ± 21.12 m2) per 400 m2 quadrat followed by boat docks (82.24 ± 19.45 m2), gardens (50.93 ± 11.82 m2) and finally fishing areas (27.94 ± 5.93 m2) respectively. The overall weed coverage was highest around the shoreline locations of Acholi inn landing site (101.72 ± 22.89 m2 per 400 m2) followed by Masindi port (60.39 ± 15.64 m2), Waitumba (41.89 ± 10.55 m2) and the least in the offshore location at Kayei landing site (39.71 ± 10.17 m2). Salvinia molesta distribution in Lake Kyoga is linked to nutrient (PO4-P) supply, proximity to the shoreline and the associated anthropogenic activities. Hence waste sites, gardens and boat docks enhance S. molesta invasion in Lake Kyoga. Therefore, sources of nutrients (phosphates) into Lake Kyoga that favour the proliferation of S. molesta should be minimized through adequate waste treatment and prohibition of cultivation close to the lake. Salvinia molesta coverage along the routes of moving boats should also be contained so as to reduce the spread of the weed in the lake through boat movements. Furthermore, eradication efforts of S. molesta weed in Lake Kyoga should be heightened at the shoreline areas of the lake in the various landing sites within the lake basin.