Geostatistical Analysis of Population Density and the Change of Land Cover and Land Use in the Komadugu-Yobe River Basin in Nigeria

Abstract:

The Komadugu-Yobe River Basin in northeastern Nigeria is an important tributary of Lake Chad and has experienced significant changes in population density and land cover in recent decades. The present study focuses on the application of geostatistical methods to examine the land cover and population density dynamics in the river basin. The geostatistical methods include spatial autocorrelation, overlapping neighborhood statistics with Pearson’s correlation coefficient, Moran’s I index analysis, and indicator variogram analysis with rose diagram. The land cover and land use maps were constructed from USGS Landsat images and Globcover images from the European Space Agency. The target years of the analysis are 1970, 1986, 2000, 2005, and 2009. The calculation of net changes in land cover indicates significant variation in the changes of rainfed cropland, mosaic cropland, and grassland. Spatial autocorrelation analysis and Moran I index analysis showed that the distribution of land cover is highly clustered. A new GIS geostatistical tool was designed to calculate the overlapping neighborhood statistics with Pearson’s correlation coefficient between the land use/land cover and population density datasets. The 10x10 neighborhood cell unit showed a clear correlation between the variables in certain zones of the study area. The ranges calculated from the indicator variograms of land use and land cover and population density showed that the cropland and sparse vegetation are most closely related to the spatial change of population density.