Populations migrantes, dynamique des forêts et des systèmes agraires dans le sud du mbam-et-kim (centre-Cameroun

Abstract

For several decades now, the southern agricultural basin of Mbam-et-Kim has been witnessing the increasing settlement of new people from other varieties. This situation has caused profound changes in land use and land cover, as forest space is increasingly being lost to farming activities. According to the pioneers of agriculture in this area, agroforests were grown on forest land and mixed crops on the savannah. Nowadays, agroforests are being planted on the savannah, resulting in a reduction in mixed farming areas, with a high level of environmental vulnerability and a potential food crisis. This study therefore aims to analyse the changes brought about by migrant populations on forests and agricultural practices in the south of Mbam-et-Kim. In order to reach our goal, we adopted a systemic and hypothetico-deductive approach based on diachronic analysis of Landsat satellite images from 1978, 2015 and 2024, socio- economic surveys of 80 households in 9 localities (Ntui, Bivouna, Natchigal, Kéla, Guette, Bétamba, Biakoa, Goura and Mbangassina), 7 interview guides, a floristic inventory of 4 plots (03 agroforestry plots and 01 forest plot) measuring 150*20 m and two 1 km transects. The data was processed using SPSS for socio-economic data and Excel for floristic data. These activities show that the phenomenon of migrant populations in the southern Mbam-et-Kim agricultural basin is linked to several factors: transmission and reception. These migrant populations are at the origin of the extension of agricultural activities in the sense that they contribute to the increase in agricultural assets through the availability of labour, but they are also the bearers of innovative practices and tools for the agrarian systems of the southern Mbam-et-Kim agricultural basin. Based on the floristic inventory, we identified 79 individuals, 23 species, 20 genera and 14 families for the forests, grouped into 5 IUCN status categories and for agroforests: 671 individuals, 32 species, 27 genera and 22 families for the agroforests, grouped into 7 IUCN status categories. This similarity between the species information for the two ecosystems reflects the installation of agroforests on forests, resulting in very marked degradation. Most of the loss of forest cover in this area is due to degradation, with 26074,75 ha (34,32% of forest area) or 86,86% of the loss recorded, and deforestation, with 3943,69 ha (5,19% of forest area) or 13,14% of the loss recorded between 1978 and 2024. In terms of farming systems, agroforestry is the staple crop in this locality, with a spatial spread of 45504,94 ha (3,6%) compared with only 6891,64 ha (4,63%), showing its strong dominance and faster annual growth than mixed cropping. This expansion of agroforests has resulted in the encroachment of 13187,12 ha (25,52%) of savannah, which is synonymous with a reduction in the area available for mixed crops (food crops and vegetables). To date, the contribution of migrant populations to the agrarian systems of this locality is undeniable, the most prominent being the adoption of improved seeds for cocoa cultivation. Given the expansion of agroforests, we believe that sustainable agriculture and certification schemes should make it possible to regulate spatial disparities and initiate a possible agricultural transition in order to produce for the local market first and foremost, in an attempt to achieve food sovereignty in our sub-region.