Browsing by Author "Mwabumba, Mohamed"

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Analysis of land use and land-cover pattern to monitor dynamics of Ngorongoro world heritage site (Tanzania) using hybrid cellular automata-Markov model
(Elsevier, 2022) Mwabumba, Mohamed; Yadav, Brijesh; Rwiza, Mwemezi; Larbi, Isaac; Twisa, Sekela
Assessment of land-use and land-cover (LULC) change of any region is one of the prominent features used in environmental resource management and its overall sustainable development. This study analyzed the LULC changes of Ngorongoro Conservation Area (NCA) and its surroundings using Remote Sensing and Geographical Information System integrated with Cellular Automata-Markov model. The LULC maps for the years 1995, 2005, and 2016 were classified using unsupervised and supervised classification procedure, and projected for 2025 and 2035 under business-as-usual scenario using the CA–Markov model. The results indicated maximum gains and losses in cultivated land and woodland in the study duration, respectively. The projected LULC for the period 2025 to 2035 showed a reduction in bushland, forest, water, and woodland, but an intensification in cultivated land, grassland, bare land, and the built-up area. The natural forests with high environmental values were found to be continuously declining under the current land management trend, causing the loss in the NCA’s ecological values. For sustainable management, the authorities must reach conciliation between the existing LULC patterns change and ecosystem services monitoring. A rational land use plan must be made to control the increase of cultivated land and built-up area counting a rational land use plan and ecosystem services protection guidelines. Decision makers should involve stakeholder to support improved land use management practices for balanced and sustainable ecosystem services strategies.
Assessing Land Use/Cover dynamics of the Ngorongoro world heritage site in Tanzania using a hybrid CA–Markov model
(Authorea, 2020-10) Mwabumba, Mohamed; Yadav, BK; Rwiza, Mwemezi; Twisa, Sekela; Larbi, Isaac
In this study, land-use/cover pattern of the UNESCO world heritage site, Ngorongoro Conservation Area; is analyzed using the CA–Markov model with the help of RS and GIS. Hybrid classification techniques ware used to monitor land use/cover changes, using Landsat images for 1995, 2005 and 2016. The CA-Markov model is then used to predict the land use /cover maps for 2025 and 2035. The highest net gain from 1995-2016 observed in cultivated land (6.55%), grassland (2.68%), bare land (1.82%), bushland (0.48%) and built-up area (0.01%), and the net loss found in woodland (8.38%), forest (1.52%), wetland (1.41%), and water cover area (0.24%). However, reduction is expected in bushland (4.88%), forest (0.82%), water (0.77%) and woodland (0.07%) during 2025-2035 with increase in cultivated land (2.73%), grassland (1.19%), bare land (1.79%) and built-up area (0.14%). As per the current trend in land use management, forest cover is significantly declining; leading to the loss in the ecological values of the Ngorongoro Conservation Area and its surroundings. The results of this study can be used directly by the policymakers to plan appropriate conservation schemes to endorse improved land use management practices for ecological protection of the heritage site.
Assessment of Groundwater Quality under Changing Climate in Ngorongoro Conservation Area, Tanzania
(American Society of Civil Engineers, 2022-07) Mwabumba, Mohamed; Jahangeer, Jahangeer; Beegum, Sahila; Yadav, Brijesh; Rwiza, Mwemezi
Understanding the hydrochemical composition of water resources in the Ngorongoro Conservation Area (NCA, Dodoma, Tanzania) related to climate variability is essential for sustainable development. Thus, the current study used the HYDRUS-1D model to assess the groundwater quality change due to the leaching of hydrochemicals from surface water under the climate variability of the NCA. This study observed that the area’s surface water had varying hydrochemical contaminants, whereas the groundwater is currently most suitable for drinking and domestic purposes. However, it is predicted that two anions (Cl−1 and PO4−3) and two cations (Na+ and K+) are expected to exceed the permissible limits from 2036 to 2050, considering the anticipated climatic conditions. Changes in groundwater quality for cations and anions are significantly correlated to evapotranspiration and temperature, with Pearson’s coefficient of determinations r between 0.35 and 0.66. The findings of this study are necessary to benchmark better water resources management planning.
Future Trade-Off for Water Resource Allocation: The Role of Land Cover/Land Use Change
(MDPI, 2024-02-02) Sigalla, Onesmo; Twisa, Sekela; Chilagane, Nyemo; Mwabumba, Mohamed; Selemani, Juma; Valimba, Patrick
Global croplands, pastures, and human settlements Have expanded in recent decades. This is accompanied by large increases in energy, water, and fertilizer consumption, along with considerable losses of biodiversity. In sub-Saharan Africa, policies are implemented without critical consideration; e.g., agricultural expansions impair ecosystem services. We studied land use/cover and the associated rate of change for four time epochs, i.e., 1991, 2001, 2011, and 2021. This employed remote sensing and GIS techniques for analysis, while future projections were modeled using cellular automata and the Markov chain. The kappa coefficient statistics were used to assess the accuracy of the final classified image, while reference images for accuracy assessment were developed based on ground truthing. Overall change between 1991 and 2021 showed that major percentage losses were experienced by water, forest, woodland, and wetland, which decreased by 8222 Ha (44.11%), 426,161 Ha (35.72%), 399,584 Ha (35.01%), and 105,186 Ha (34.82%), respectively. On the other Hand, a percentage increase during the same period was experienced in cultivated land, built-up areas, and grasslands, which increased by 659,346 Ha (205.28%), 11,894 Ha (159.93%), and 33,547 Ha (98.47%), respectively. However, this expansion of thirsty sectors Has not reversed the increasing amount of water discharged out of the Kilombero River catchment. We recommend the promotion of agroforests along with participatory law enforcement and capacity building of local communities’ institutions.
Hydrologic responses to climate and land use/cover changes in world heritage site of Ngorongoro conservation area and surrounding catchments, northern Tanzania
(NM-AIST, 2023-01) Mwabumba, Mohamed
In Tanzania, various studies have analyzed the impact of climate and land use/cover changes on water resources. However, information on the interactions between climate and land use/cover change, temporal and spatial variability of hydrological components and water quality at the local scale is insufficient. The objective of this study was to evaluate the hydrological response to climate and land use/cover changes in Ngorongoro Conservation Area (NCA) and surroundings. The study performed climate change analysis using outputs from a multi-model ensemble of Regional Climate Models (RCMs) and statistically downscaled Global Climate Models (GCMs). The CA–Markov model applied to project Land use/cover for the future 2025 and 2035. This study further used the Soil Water Assessment Tool (SWAT) modelling approaches to analyse the hydrological responses and HYDRUS 1D to determine the change in Groundwater quality due to climate and land use/cover changes. The analysis of climate change between historical period (1982-2011) and future period (2021-2050) indicated an increase in the mean annual rainfall and temperature, seasonal rainfall except June to September (JJAS) season which showed a decreasing trend. Spatially, rainfall and temperatures would increase over the entire area. The projected Land use/cover change for the period 2025 to 2035 compared to the baseline 2016, showed a reduction in bushland, forest, water, and woodland, but an intensification in cultivated land, grassland, bare land, and the built-up area. The surface runoff, evapotranspiration, lateral flow, and water yield would significantly increase in the future, while groundwater would decrease under combined climate and land use/cover change. It is predicted that two anions (Cl− and PO4 −3 ) and two cations (Na+ and K+ ) would exceed the permissible limits for the drinking water set by the World Health organisation (WHO) and Tanzania Bureau of Standards (TBS), from 2036 to 2050. Changes in groundwater quality due to major cations and anions is significantly correlated to evapotranspiration and temperature with Pearson correlation (r) between 0.35 and 0.85. Furthermore, correlate to the changes in all land use/ cover types with Pearson correlation (r) between 0.56 and 0.96. The results obtained provide further insight into future water resources management planning and adaptation strategie
Rainfall and temperature changes under different climate scenarios at the watersheds surrounding the Ngorongoro Conservation Area in Tanzania
(Elsevier, 2022-04) Mwabumba, Mohamed; Yadav, Brijesh; Rwiza, Mwemezi; Larbi, Isaac; Dotse, Sam-Quarcoo; Manoba, Andrew; Sarpong, Solomon; Kwawuvi, Daniel
Considering the high vulnerability of Northern Tanzania to climate change, an in-depth assessment at the local scale is required urgently to formulate sustainable adaptations measures. Therefore, this study analyzed the fu- ture (2021-2050) changes in rainfall and temperature under the representative concentration pathways (RCP4.5 and RCP8.5) for the watersheds surrounding the Ngorongoro Conservation Area (NCA) at a spatio-temporal scale relative to the observed historical (1982-2011) period. The climate change analysis was performed at monthly and annual scale using outputs from a multi-model ensemble of Regional Climate Models (RCMs) and statistically downscaled Global Climate Models (GCMs). The performance of the RCMs were evaluated, and the downscaling of the GCMs were performed using Statistical Downscaling System Model (SDSM) and LARS-WG, with all the models indicating a higher accuracy at monthly scale when evaluated using statistical indicators such as corre- lation (r), Nash-Sutcliff Efficiency (NSE) and percentage bias (PBIAS). The results show an increase in the mean annual rainfall and temperature in both RCPs. The percentage change in rainfall indicated an increase relative to historical data for all seasons under both RCPs, except for the June, July, August and September (JJAS) season, which showed a decrease in rainfall. Spatially, rainfall would increase over the entire basin under both RCPs with higher increase under RCP4.5. Similar spatial increase results are also projected for temperature under both RCPs. The results of this study provide vital information for the planning and management of the studied watershed under changing climatic conditions.