Ile-Ife, Nigeria
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Ethiopian Journal of Environmental Studies & Management 9(6): 780 – 792, 2016. ISSN:1998-0507 doi: http://dx.doi.org/10.4314/ejesm.v9i6.10 Submitted: August 22, 2016 Accepted: November 10, 2016 SPATIO-TEMPORAL ANALYSIS OF LANDUSE DYNAMICS IN UPPER OPA CATCHMENT, SOUTHWEST NIGERIA *IBITOYE, M.O., 1 ABOYEJI, O.S. 2 AND ADEKEMI, S.O.A. 2 1Department of Remote Sensing and Geoscience Information System, Federal University of Technology, Akure, Nigeria 2Regional Centre for Training in Aerospace Surveys (RECTAS), Ile-Ife, Nigeria Abstract This study explored the use of geospatial techniques to assess land use change within upper Opa catchment area in Ile-Ife, Osun State, Nigeria for a period of 28 years between 1986 and 2014. To accomplish this, Landsat TM 1986, ETM 2002 and OLI 2014 were acquired from the USGS Earth Explorer in Global Land Cover Facility (GLCF) web site and subjected to supervised classification using the Anderson classification Scheme. Six land use/landcover classes were identified: Built-up, Bareland, Riparian, Forest Vegetation, Rock Outcrop and Water body using ENVI 5.1 Software. A change detection analysis of LULC was carried out to provide the necessary understanding of changes over the period and prediction for expected change in future was carried out. Result showed remarkable changes in all the land uses. For instance, Built-up increased from 7.01 km 2 (6.4%) in 1986 to 11.92 km 2 (10.8%) and 20.86km 2 (18.8%) in 2002 and 2014, respectively while vegetation reduced from 61.72km 2 (61.30%) in 1986 to 55.41km 2 (50.2%) in 2014. The study further confirmed that if the current rate of reduction in the vegetation cover is allowed to continue unabated, there may be no vegetation again in the area in the next 30 years, thus, jeopardizing the need of the future generation and causing greater harm to the environment. In view of the above, efforts should be made to control land use activities within upper Opa catchment by enforcing the “Green Policy” of the Environment Act of the Federal Government of Nigeria which will check the indiscriminate land uses particular the encroachment of other uses into vegetation land. Key words: Opa Catchment, LULC, Anthropogenic activities, Southwestern Nigeria Introduction about gross entry into areas which was Many developing countries of the previously occupied by natural forests. world today could be said to be suffering People are now concern about the raising from serious environmental degradation problem as a result of deforestation, resulting from human and natural causes. which is the temporary or permanent An important human factor is rapid clearing of forest either for agriculture growth in population which has brought purpose or any other purposes. Since *Corresponding Author: Ibitoye, M.O. 780 Email: [email protected] Spatio -Temporal Analysis of Landuse Dynamics ................ IBITOYE et al. prehistoric times, forest serves various such as Osun state. It is a problem purposes and will continue to do so as because of the present experience in long as life continues on this planet climate change, biodiversity loss and (Abbiw, 1990). The forest houses and pollution. Knowing that forest protects game, stabilizes the communities have a vital role to play in environment, prevents soil erosion and maintaining balanced eco-system of the serves as a source of medicinal plants for world, still pressures from the exploding curing diseases. Forests also provide the population and the subsequent growing greatest diversity of plant life, yet they needs of industries, food, fuel wood, continue to be felled through logging and fodder, timber activities etc., depletion faming activities and at times through and degradation of forests and burning and they are seldom replaced. In subsequently severe negative changes in many parts of Nigeria, the forestry sector ecosystem (Andreas and Hugh, 2009; contributes significantly to the internally Omiyale, 2001). Omiyale (2001) was of generated revenue (IGR) in some state the opinion that if 6.1 million hectares of (Akindele, 2001). Ajayi (2001) opined tropical forests are destroyed annually in that between 1996 and 2001, this sector 170 years, the total tropic forest would generated N608, 460,455.78 from the have completely wiped out. sales of timber alone. Uncontrolled human (anthropogenic) Nigeria is about 923,770 km 2, and activities has led to significant forests accounted for only 9.61%, while modification of the natural biodiversity in grassland 48.53%, fresh and inland Southwestern Nigeria as in the case of wetlands 1.05%, tree crop plantations upper Opa catchment, which has led to 0.3% and farmlands 20.33% (Omiyale, abrupt change in land use and land type 2001). He observed that an estimate of without adequate consideration for 43.48% of the total forest ecosystem in sustainable developments. Monitoring Nigeria has been destroyed by human and assessing the effect of anthropogenic activities between the period of 1980 and activities especially those that has to do 1990. Popoola and Akande (2001) argued with land use changes is helpful in order that the annual rate at which forest is to catalogue the diverse effects of this been destroyed for farming and other land use change on forested areas and anthropogenic activities averagely is other human endeavours. Hence, about 3.5% and forest area losses from information on land use and possibilities 14.9 million to 10.1 million hectares for their optimal use is essential for the annually. In 2001, about 5.34% of the selection, planning and implementation total land area of Nigeria was under of land use schemes to meet the forest as against the international increasing demands for basic human requirement where 25% of the total land needs and welfare without jeopardizing area of each country was mandated to be the need of future generation. under forest (Popoola and Akande, Several studies have been carried out 2001). on LULC in various parts of the world Land expansion and modernization (Adeoye, 2012; Aduah and Aabeyir, has become a major problem in Nigeria 2012; Fernandez and Dhorde, 2014; especially, in the tropical forest region Oyinloye and Oloukoi, 2012; Shiferaw, 781 Ethiopian Journal of Environmental Studies and Management Vol. 9 no.6 2016 2011; Tran et al ., 2015; Turan et al ., 7°35 ′N and Longitudes 4°31 ′E and 2010). As regards the study area, it has 4°39 ′E and falls under Koppen’s Af been a focus for many researches because humid tropical rainforest climates. The of its location within a university daily minimum temperature is 25 oC (Obafemi Awolowo University, Ile Ife) while the mean maximum is 33 oC environment. Apart from the work of (Adejuwon and Jeje, 1975). The mean Adediji and Jeje (2004) who worked on annual rainfall is about 1400mm, with the land use and sediment delivery ratio in rainy season between April and October. Opa basin and Adediji (2005) on The rainy season is marked by two reservoir sedimentation on Opa maxima, in June/July and catchment, there is no known research September/October. These two periods record on land use land cover dynamics are separated by a short dry spell in in Opa Catchment. Thus, this study aims August. The area is characterized by in providing the information (on LULC) natural vegetation of the tropical using the advancement in space rainforest of multiple canopies and lianas technology particularly in Remote (Adediji, 2005). However, the persistent sensing and GIS applications. The result removal of the natural vegetation for of the study is hoped to provide relevant cultivation of arable crops such as yam, information for effective monitoring, cocoyam, plantain, cassava, maize etc. planning and formulation of policies that and cash crops such as cocoa, kolanut etc. would support the conservation of the in a mixed faming pattern coupled with environment and nature in the area. logging activities has led to the Study Area destruction of the original vegetation. The study area which is As evident from the above activities, approximately 110km 2 in size extends the people are predominantly Yoruba from part of Ile Ife, capital of Ife Central farmers of Ile Ife with their farmsteads, Local Government including Obafemi camps and hamlets such as Mokuro, Awolowo University campus in Ile-Ife, to Amuta, Poju, Fadugbo, Itamerin and Osu town in Atakumosa West Local Alakowe located at different areas within Government Area (Figure 1). The study the catchment. area lies within Latitudes 7°27 ′N and 782 Spatio -Temporal Analysis of Landuse Dynamics ................ IBITOYE et al. Figure: The Study area Materials and Methods obtaining cloud-free images. The image The data used for the study consists data were used to generate the land of Landsat satellite images, ancillary data use/cover for the study period. In such as administrative and topographic addition, ancillary data consisting of maps, and GPS data collected from administrative and topographic maps fieldwork. Landsat image data are were used to derive the administrative popular data sources for documenting boundaries and topographic information spatio-temporal changes in land cover within and around the study area. and use due to their long history, Image Processing and Classification reliability, and availability and medium The Landsat satellite images data resolution (Lui and Coomes, 2015; which were delivered with UTM Zone Townsend et al ., 2009). Multi-date 31N projection using the WGS 1984 Landsat satellite image of 1986, 2002 and Datum, were pre-processed to correct for 2014 captured by the satellite during the radiometric and geometric errors. The dry season (months of November to corrections were conducted using March) were used for the study. Dry calibration tool and Fast Line-of-sight season image data were adopted in other Atmospheric Analysis of Hypercubes to avoid seasonal variations of (FLAASH) algorithm in ENVI 5.1 topographic details, particularly software environment (Hester et al ., vegetation cover, and the possibility of 2008; Lui and Coomes, 2015).