Geography
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Item Hydrological responses to climate and land use changes: the paradox of regional and local climate effect in the Pra River Basin of Ghana(Elsevier Ltd., 2020) Bessah, E.; Raji, A. O.; Taiwo, O. J.; Agodzo, S. K.; Ololade, O. O.; Strapasson, A.Study Region: Pra River Basin, Ghana. Study Focus: The study modelled the changes in water yield using regional, sub-regional and local climate conditions from modelling outputs at spatial resolutions of 44 km, 12 km and 0.002 km respectively to drive the Integrated Valuation of Ecosystem Services and Trade-offs model at three time periods of land use land cover (LULC). Changes in historical water yield (simulated for 1986, 2002 & 2018 LULC using the mean climatic parameters from 1981-2010) and future scenario (simulated for 2018 LULC using the mean climatic parameters from 2020-2049) for annual, seasonal and monthly periods were assessed. New Hydrological Insights for the Region: The results show that future annual water yield could change by -46%, -48%, +44% and -35% under the regional, sub-regional, local and ensemble mean of the climate scenarios respectively. Seasonal water yield from the ensemble mean of the future climate scenario was projected to decrease between 2-16 mm, with a mean decrease of 33.39% during the December–February season. There was no directional effect of spatial resolution on water yield. The future period could be impacted by both drought and flood. We recommend that re/afforestation should be encouraged to improve infiltration and reduce deforestation which was 2.27% per annum in the assessed period to prevent flood causing runoffs, while irrigation technology will help to improve resilience to drought.Item An exploratory spatial analysis of household size from 2006 to 2010 in Nigeria(2019) Taiwo, O. J.Large household size of more than 5 persons per household (POPFACT, 2017) can hinder the attainment of Sustainable Development Goals (SDGs) by creating an unnecessary burden on family and the nation. Existing studies on household size have focused more on its consequences with limited attention to its pattern and causes. In addition, the smaller spatial units have mostly been the focus of such analysis and where a national data was used, the set of predictors often identified were assumed to explain the variations in household size across the component units. Due to differences in socioeconomic characteristics of residents and government policies, one expects differential predictors of household size in a multi-ethnic and multicultural country like Nigeria. Using the 2011 household survey data from the National Demographic and Health Surveys (NDHS, 2011), Moran-I, spatial regression, and Pearson Product Moment Correlation were used to analyse the spatial dependency in household size with a view to identifying its spatiotemporal correlates and predictors. The Moran-I showed that states that are contiguous have similar or near similar household sizes. Polygamy (r = 0.723, P<0.05), food poverty (r = 0.478, P<0.05), absolute poverty (r = 0.506, P<0.05) and a dollar-per-day poverty (r = 0.503, P<0.05) had a positive relationship with household size. Conversely, percentage of people using family planning (r = -0.687, P<0.05), unemployment (r = -0.434, P<0.05), percentage of the literate (r = -0.537, P<0.05), and number of higher institutions (r = -0.558, P<0.05) had negative significant relationship with household size. Improved use of family planning, access to education and encouraging monogamy will help in reducing large family size in Nigeria.Item Quantitative review of ecosystem services and disservices studies in the tropics(Scientific Research Publishing Inc., 2019-04) Rutebuka, E.; Olorunnisola, A. O.; Taiwo, O. J.; Mwaru, F.; Asamoah, E. F.; Rukundo, E.The tropics host about 80% of the planet’s terrestrial species and over 95% of its corals. A well-known tropical forest ecosystem to provide significant global regulating services has declined at a rate of 5.5 M ha per year from 1990-2015, while another region noted an increase per year. There is evidence that tropical region ecosystem services and disservices are the least studied in the world. This study quantified peer-review papers in the tropics, then explored the neglected ecosystem type, service category, assessment mode, applied techniques and choice dependence between ecosystem type, service category, assessment mode and applied techniques. The Google Scholar and Web of Science database were used to collect all ES & ED studies available online from 1960 to December 2017. This review covered 102 countries with 578 articles. The study showed dramatic articles increase in the last three years as more than 50% of articles were published after the year of 2014. The top countries in high articles were Mexico (n = 53), India (n = 43), and Brazil (n = 35). The ES & ED assessment tools/techniques are barely applied in tropics as only social based techniques such as interviews and questionnaire take over 45%, while biophysical tools like remote sensing and GIS appeared only in 20%, InVEST only in 3% while the rest tools are less than 1% even none such as ARIES model. Urban and marine ecosystem types, disservices category and trade-off assessment mode were the least studied. The review concluded that policy analysis ES & ED studies do not reflect the trade-offs and synergy analysis between different services which hinder the development of pragmatic policy and decisions toward ES sustainable management in the tropics. The rampant urbanization in the tropics is subjected to destroy existing ES. Thus, this review highly suggested a high concern of urbanization ecosystem. This study also calls for great academic research to give attention to the tropical rainforest region as most African countries to host such forest have not even a single article on ES & ED.Item The impact of varying spatial resolution of climate models on future rainfall simulations in the Pra River Basin (Ghana)(IWA Publishing, 2020) Bessah, E.; Raji, A. O.; Taiwo, O. J.; Agodzo, S. K.; Ololade, O. O.This work compares future projections of rainfall over the Pra River Basin (Ghana) using data from five climate models for the period 2020–2049, as referenced to the control period 1981–2010. Bias-correction methods were applied where necessary and models’ performances were evaluated with Nash–Sutcliffe Efficiency, root-mean-square error and coefficient of determination. Standardised Anomaly Index (SAI) was used to determine variability. The onset and cessation dates and length of the rainy season were determined by modifying the Walter–Olaniran method. The ensemble means of the models projected a 1.77% decrease in rainfall. The SAI showed that there would be drier than normal years with the likelihood of drought occurrence in 2021, 2023, 2031 and 2036. The findings showed that high-resolution models ( 25 km) were more capable of simulating rainfall at the basin scale than mid-resolution models (26–150 km) and projected a 20.13% increase. Therefore, the rainfall amount is expected to increase in the future. However, the projected increase in the length of the dry season by the ensemble of the models suggested that alternative sources of water would be necessary to supplement rainfed crop production for food security.Item Variable resolution modeling of near future mean temperature changes in the dry sub-humid region of Ghana(Springer, 2018-05) Bessah, E.; Raji, A. O.; Taiwo, O. J.; Agodzo, S. K.; Ololade, O. O.The study used two models from Rossby Centre Regional Atmospheric Model (RCA4) and two from Weather Research and Forecasting Model (WRF) plus the Statistical Downscaling Model—Decision Centric (SDSM-DC) at 44 km, 12 km and 2 m resolution respectively to project the impact of climate change on mean temperature in the Pra River Basin for the period 2020–2049. Results showed that the minimum temperature increased (+ 1.47 °C) faster than the increase (+ 1.11 °C) in maximum temperature for observed period 1981–2010. An evaluation of the performance of the models with time-series based metrics showed that SDSM-DC and RCA4 are better for projecting mean temperature in the study area compared to WRF despite its resolution. Analysis of variance (p < 0.05) indicated significant difference between the projected mean temperature of the five models but there was no significant difference between SDSM-DC and RCA4 models. Correlation between models was highest at R = 0.727 between SDSM-DC and RCA4. The years 2041, 2042 and 2047 were projected as hottest by minimum two different models. The mean temperature change was projected at + 1.36, + 1.42 and + 1.12 °C by SDSM-DC, RCA4 and WRF respectively. The ensemble of projection depicted same trend of February—April as the high mean temperature and July—September as the lowest as was for the observed period. However, January is projected to have the highest change in mean temperature of + 1.51 °C. The maximum temperature for observed period was found to be the mean temperature in the period 2020–2049. Future study will focus on the impact of projected temperature change on ecosystem services delivery in the region.Item Urban growth during civilian and military administrations in Osogbo, Nigeria(2018-06) Taiwo, O. J.Research on comparative analysis of urban growth and structure during military and civilian regimes most especially in Africa where coup d’etats is common and where land is mainly controlled by private individuals is limited. This study analysed the temporal patterns and morphological characteristics of urban growth during the military and civilian regimes as well as during different civilian administrations using eight landscape metrics. Landsat satellite images of 1984, 1991, 2000, 2003, 2010 and 2014 were used in the analysis. It was found that urban growth occurred primarily through expansion (annexation) of extant urban areas rather than spontaneous and detached development.Item Use of GIS to delineate site-specific management zone for precision agriculture(Taylor & Francis, 2017) Oshunsanya, S. O.; Oluwasemire, K. O.; Taiwo, O. J.Soil heterogeneity is one of the several factors that explain within-field variations in crop yielding. To overcome this problem, experiment was conducted within the University of Ibadan to identify the zones with similar soil properties that can be managed uniformly to optimize crop yield. A total of 62 soil samples were collected from 6.5 ha of farmland based on the differences in slope, soil moisture regime, land management and cropping pattern. The spatial distributions of soil properties were mapped out using Inverse Distance Weighing (IDW) interpolation technique and the results were subsequently reclassified into different soil management categories. The results showed that the farmland consists of four classes of total nitrogen (N), phosphorus (P) and soil bulk density (SBD); three classes of carbon © and oxygen (Ө); two classes of soil pH; one class of soil texture. Each of the soil management maps was subsequently overlaid on each other to produce four specific site management units (SSMU) for vegetable cultivation. The four SSMU consisted of highly suitable unit occupying 0.143 ha, marginally suitable unit occupying 0.971 ha, moderately suitable unit occupying 0.517 ha and unsuitable unit occupying 4.9 ha of land. The SSMU will alleviate problems of reduced yield due to over or under applications of agrochemicals.Item Analysis of urban agricultural characteristics along land use gradient in Lagos State, Nigeria(2016) Taiwo, O. J.The paper argued that land use diversity influenced urban agriculture and that understanding the characteristics of each land use type within which urban agriculture is situated will help to identify prospects and challenges confronting urban agriculture. Three hundred questionnaire coupled with personal interviews were used in collecting relevant information and data pertaining to socio-economic and demographic characteristics of urban farmers. Existing land use map of the LGA was updated with the 2010 high-resolution satellite (Quickbird) image of the LGA. Frequencies, cross-tabulation and analysis of variance were used in analysing variations in socio-economic factors across different land use types. The rapid disappearance of urban agricultural sites within the built-up areas is situated within the concept of the survival of the fittest.The results showed that the land use characteristics within which urban agriculture is located moderate its size, rental cost, profit, accessibility to roads network, while it exacts little or no influence on it with regard to distance from markets and water sources. The findings provide new insights into theoretical debates on the role of land use pattern in influencing pertinent factors of urban agriculture in and around cities. It brings to the fore the need to consider the spatial pattern of urban land use in the allocation of space for urban agriculture while emphasising the role of geographical distance in determining urban agricultural outcomes.Item Spatial association between environmental noise levels and occurrence of children hearing impairments in Ibadan metropolis, Nigeria(2015) Oguntoke, O.; Olatinwo, M.; Taiwo, O. J.Reports in the past few decades indicate that Nigerian cities have high noise levels that is claimed to impact the health of residents negatively. The present article therefore examine the relationship between levels of environmental noise in selected residential areas in Ibadan metropolis with varying reported cases of hearing impairments (HI). Data on cases of HI were collected from one hospital; noise monitoring was conducted with the aid of a noise level meter while copies of questionnaire were administered to residents to elicit information on public perception. The distribution of reported cases of HI among residential areas in Ibadan city showed varying magnitude (p < 0.001). About 75 % of children diagnosed with HI cases were within ages of 4-12 and female children suffered more (53.9 %). Sensorineural and conductive impairments accounted for 88.2 % of all reported HI cases. Monitored noise levels vary significantly among the selected residential area at each of morning, after-noon and evening (p < 0.05). Noise levels at morning and evening showed significant correlation with cases of HI reported at each of the 10 selected residential areas (r = 0.81; 0.82). Regression analysis showed that noise level explained 70.1 % of the spatial pattern of HI cases. Residents indicated that their neighbourhoods were noisy, that noise levels were on the increase and that ceremonies and generator use were major sources of noise. An integrated strategy for noise control is urgently required to stem the tide of noise pollution so as to safeguard human health in Nigerian cities.Item Environmental factors and population at risk of malaria in Nkomazi municipality, South Africa(2016-05) Adeola, A. M.; Botai, O. J.; Olwoch, J. M.; Rautenbach, C. J. de W.; Adisa, O. M.; Taiwo, O. J.; Kalumba, A. M.Objective: Nkomazi local municipality of South Africa is a high-risk malaria region with an incidence rate of about 500 cases per 100 000. We examined the influence of environmental factors on population (age group) at risk of malaria. Methods: R software was used to statistically analyse data. Using remote sensing technology, a Landsat 8 image of 4th October 2015 was classified using object-based classification and a 5-m resolution. Spot height data were used to generate a digital elevation model of the area. Results: A total of 60 718 malaria cases were notified across 48 health facilities in Nkomazi municipality between January 1997 and August 2015. Malaria incidence was highly associated with irrigated land (P = 0.001), water body (P = 0.011) and altitude ≤400 m (P = 0.001). The multivariate model showed that with 10% increase in the extent of irrigated areas, malaria risk increased by almost 39% in the entire study area and by almost 44% in the 2-km buffer zone of selected villages. Malaria incidence is more pronounced in the economically active population aged 15–64 and in males. Both incidence and case fatality rate drastically declined over the study period. Conclusion: A predictive model based on environmental factors would be useful in the effort towards malaria elimination by fostering appropriate targeting of control measures and allocating of resources.