Changes in land cover and land use from 2016 to 2019 in south-east côte d’ivoire: Impacts of cash crops on forests

Abstract

In Côte d’Ivoire, over half of all forest cover (57%) has been destroyed in a quarter of a century (1990-2015), with considerable loss of biodiversity. In order to support policies aiming to reduce forest losses and to better understand the dynamics at work, detailed and regular mapping of land cover and land use changes is essential. However, mapping studies are rarely conducted over large areas and can quickly become obsolete because of the rapidly evolving human processes under-lying changes. This study aims to assess changes in land cover and land use from 2016 to 2019 in three regions of sou-th-eastern Côte d’Ivoire, with a particular focus on the dynamics of deforestation and forest degradation. The methodo-logy is based on the use of images from Sentinel-2 with 10 to 20-metre resolution over a study area covering 22,014 km2. Data for training purposes were first mar-ked out according to a description of the zone identifying 16 land cover and land use categories. These were then analysed with the Random Forests algorithm to pro-duce maps of land use and land cover in 2016 and 2019 with an overall precision of 92% and 87% respectively. Finally, the maps were cross-analysed to describe forest transitions in the study zone. The results clearly show that the extension of cash crops (cacao and coffee, rubber and oil palm), undifferentiated crops, fallow lands and infrastructure (dwellings and roads) has caused deforestation at a rate of 4.95% per year over the period investi-gated. Our study thus provides a detailed and up-to-date picture of changes in land cover and land use and input for discus-sions on the introduction of a national land use surveillance system.