DSpace Community: Geography

Hydrological responses to climate and land use changes: the paradox of regional and local climate effect in the Pra River Basin of Ghana

2020-01-01T00:00:00Z

Title: Hydrological responses to climate and land use changes: the paradox of regional and local climate effect in the Pra River Basin of Ghana Authors: Bessah, E.; Raji, A. O.; Taiwo, O. J.; Agodzo, S. K.; Ololade, O. O.; Strapasson, A. Abstract: 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.

An exploratory spatial analysis of household size from 2006 to 2010 in Nigeria

2019-01-01T00:00:00Z

Title: An exploratory spatial analysis of household size from 2006 to 2010 in Nigeria Authors: Taiwo, O. J. Abstract: 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.

Quantitative review of ecosystem services and disservices studies in the tropics

2019-04-01T00:00:00Z

Title: Quantitative review of ecosystem services and disservices studies in the tropics Authors: Rutebuka, E.; Olorunnisola, A. O.; Taiwo, O. J.; Mwaru, F.; Asamoah, E. F.; Rukundo, E. Abstract: 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.

The impact of varying spatial resolution of climate models on future rainfall simulations in the Pra River Basin (Ghana)

2020-01-01T00:00:00Z

Title: The impact of varying spatial resolution of climate models on future rainfall simulations in the Pra River Basin (Ghana) Authors: Bessah, E.; Raji, A. O.; Taiwo, O. J.; Agodzo, S. K.; Ololade, O. O. Abstract: 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.