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Vol. 12(1), pp. 22-32, January-March 2020 DOI: 10.5897/JENE2019.0810 Article Number: B5647BD63286 ISSN 2006-9847 Copyright © 2020 Author(s) retain the copyright of this article Journal of Ecology and The Natural Environment http://www.academicjournals.org/JENE Full Length Research Paper An assessment and local perception of sand deposits induced desertification in Sokoto State, Nigeria Ganiy Ishola Agbaje1, Bolarinwa Olutayo Balogun1*, Rufus Olakunle Oladosu1, Abdul-Rahman Adeniran Adegbite1, Olaleye Salu1, Felix Ndukson Buba1, Arinzechukwu Charles Owoh1 and Timothy Oyesode2 1African Regional Centre for Space Science and Technology Education in English, Nigeria. 2Surveying and Geoinformatics Department, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria. Received 10 December, 2019; Accepted 25 February, 2020 Sokoto State is one of the states in Nigeria that are prone to desertification. This study attempts to identify and delimit areas affected by desertification in the three northernmost Local Government Areas of Sokoto State, namely: Illela, Gada and Tangaza. Field study was carried out to verify the incident and occurrence of desertification and the menace of sand deposition. A simple random sampling method with questionnaire, combined with Focused Group Discussions and Key Informant Interviews was used to derive the local knowledge about sand transport and deposition, and, its socio-environmental impacts. The Digital Elevation Model of Tangaza, Gada, and Illela Local Government Areas for the year 2008 and 2014 were derived from ASTER images. The result indicated that the Gidan Kaura hill grew by about 30 m within the six-year period. This agreed with an overwhelming belief by 95% of the respondents that the area continues to suffer from sandstorms and sand deposition. This was visibly confirmed by the presence of sand dunes in most of the areas visited in the three local government areas. Normalized Difference Vegetation Index derived from Landsat images of the year 2013 and 2018 gave further insight into the current vegetation conditions. Key words: Northern Nigeria, desertification, sustainability, geospatial analyses, environmental impacts. INTRODUCTION Desertification is a global environmental problem. It is process that intensifies or extends desert conditions, defined as land degradation in arid, semi-arid, and dry leading to reduction in biological yield, impacting biomass sub-humid areas resulting from various factors including production negatively, resulting in insufficient land area climatic variations and human activities (UN, 1992; for livestock management and reduced crop production to Olagunju, 2015). Similarly, from the point of view of satisfy human nutritional needs. Some of the climatic Jamala et al. (2013), desertification represents any variations that have been implicated in drought and *Corresponding author. E-mail: [email protected]. Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License Agbaje et al. 23 desertification include increased sea-surface temperature north as would have been expedient in this study became (Giannini et al., 2003), rainfall shortages or drought (Dai impossible. Consequently, Sokoto State, which is not et al., 2004) and sand transportation and deposition affected by the Boko Haram insurgency was selected as (Ikazaki, 2015); while the implicated human activities in the study area for the purpose of ease of accessibility to desertification include deforestation, over-grazing and the affected sites and safely carrying out field unsustainable fuel-wood harvesting that lead to reduced observations. Therefore, the aim of this study was to vegetation cover (Tucker et al., 1991). carry out assessment of desertification or desert Desertification was first addressed as a global encroachment in northernmost part of Sokoto State of environmental menace with profound socio-economic Nigeria. and environmental impacts in the United Nations Studies on the Sahel region of Africa (Eklundh and Conference (UNCOD) on Desertification in 1977. The Sjolstrom, 2003; Aiguo et al., 2004) have focused on Conference led to the adoption of a Plan of Action to using time series medium resolution optical satellite Combat Desertification (PACD), to which Nigeria is a image to track variations in Normalized Difference signatory. This early global realization of the Vegetation Index (NDVI). The Earth observation satellite environmental menace of desertification and the images that were used in other studies (Martin and Saha, capability of its transboundary extension necessitated the 2009; Dasgupta et al., 2015) gave insight into call by the UN General Assembly in Rio de Janeiro, Brazil environmental conditions of physically inaccessible in 1992, for an inter-governmental committee to prepare terrains and large landscape that could not have been for a legally binding instruction that addresses the done through conventional ground-based survey problem of desertification (UN, 1992). According to methods. Given that desertification occurs over a long- UNCCD (2013), desertification and drought are term period, the accurate identification of affected areas responsible for rapid increase in price indices of food stuff will necessarily require time-series data rather than single and other commodities. The impact of desertification on datasets. The specific objectives are to carry out in-situ the socio-economic life of rural households leads to observations to identify specific areas of occurrence; and reduction in crop and animal production, as well as examine the local socio-environmental factors that are causing livestock deaths and rise in the prices of responsible for its occurrence. This study combined in- foodstuffs. People migrate as a consequence of drought situ surveys with the Earth observation approaches and desertification to urban areas or to other rural areas, adopted in the aforementioned previous studies to in order to engage in economic activities such as farming, attempt to understand the local socio-cultural, economic grazing and fishing (Olagunju, 2015). Migration impact on and environmental impacts of desertification in the study family life leads to disruption of family ties. Viewed over a area. broad spectrum, other identified factors causing desertification include excessive wood extraction (Jamala et al., 2013) for fuel exacerbated by increasing population Study area and urbanization, and over-cultivation of marginal land. The northernmost States of Nigeria, with an annual Sokoto lies on the north-west zone of Nigeria and shares mean rainfall of less than 600 mm per year (Folaji, 2007) its borders with Niger Republic to the north, Katsina State have been described as susceptible to desertification to the East, Niger State to the South-east, Kwara State to (Mohammed, 2015). In response to the menace of the South and Benin Republic to the west. The zone is desertification, one of the Nigerian Government’s efforts found between latitudes 10°N and 13°58’ N; and in combating desertification was through the Global Tree longitudes 4° 8’E and 60 54’ E. The area so defined Planting Project, which started in 2005. The project was covers a land area of approximately 62,000 km2 (Ekpoh aimed at halting desert encroachment in 46 LGAs in the and Nsa, 2011). The climate of the zone is controlled country’s desertification frontline States. A 5 km tree largely by the dry, dusty, tropical- continental air mass planting in each LGA of Sokoto State was initiated under originating from the Sahara desert, and the warm, the oil Subsidy Reinvestment and Empowerment tropical-maritime air mass originating from the Atlantic Programme (Sure-P). The Sure-P was a programme of Ocean. The influence of both air masses on the region is the Federal Government of Nigeria, to ameliorate youth determined largely by the movement of the Inter-Tropical unemployment (Ugwu, 2012). Expectedly, all the efforts Convergence Zone (ITCZ), a zone representing the were confined to the northernmost part of Nigeria, where surface demarcation between the two air masses (Ekpoh the menace is most prevalent (Olagunju, 2015). and Nsa, 2011). The interplay of these two air masses However, studies (Linacre and Geerts, 2002; Geist and gives rise to the wet season associated with the tropical Lambin, 2004) generally attempted to denounce this fact, maritime air mass, and the dry season, associated with by describing desertification as a succession of cycles of the tropical continental air mass. The temperature ranges drought interspersed with high rainfall periods. However, between 35 and 40°C, while the warmest months are with the rampaging ethno-religious insurgency prevailing February, March and April when daytime temperatures in the most part of northern Nigeria, covering of the whole can exceed 45°C. The combined effects of temperature, 24 J. Ecol. Nat. Environ. Figure 1. Gada, Illela and Tangaza Local Government Areas in Sokoto State. humidity, rainfall, and other climatic variation, determine were affected by sand transport and deposition, with a the different types of vegetation belts in the zones and massive presence of sand dunes. the types of the indigenous or exotic crops that are and can be grown in Nigeria (Adetiloye et al., 2006). Three northernmost Local Government Areas of Illela, METHODOLOGY Gada and Tangaza of Sokoto State (Figure 1) were selected to gather information on desertification; and, its In order to gain access