Recent trends in land-use and cover change and deforestation in south–west Nigeria

Abstract

Land-use and cover change reflects choices in natural resource governance. Despite heavy targets on the forest and woodland, the southwest Nigeria states have little quantitative information on the magnitude and direction of land-use change across the states. This drives unsustainable land management and deforestation. This study utilized vegetation sampling and enumeration, GIS mapping and analyses of base maps and multi-temporal Landsat imageries to generate current vegetation status and time-series land-use and cover change for the southwest Nigeria. The results suggest that the woody species density in the forest plots ranges from 512 to 1040/ha with mean density of about 770.67/ha and species diversity values range from 2.014 to 2.911. The woody species in the savanna woodland ranged from 624 to 1232/ha in density and species diversity varies between 1.189 and 2.737. Relatively fewer number of trees of larger diameter at breast height in forest and low number of species per family in savanna reflect the influence of selective forest logging and woodland degradation. The study area experienced a historical net deforestation rate of − 1.1% per annum between 1986 and 2016 with deforestation rate of the primary forest at − 3.3% between 1986 and 2016 and − 10% between 2006 and 2016. Savanna woodland grew 0.8% annually from 1986 to 2016. The states recorded net deforestation rate ranging from − 2.63 to − 7.41% between 2006 and 2016. Reforestation through exotic Teak and Gmelina plantation grew at 43% annually between 1986 and 2016.