Analysis of the Dynamics of Forest Landscape Fragmentation in Western Madagascar under the Influence of Migration

Economic activities by migrant populations lead to changes in landscape structure and land use in non-forested areas. This article aims to analyse the spatial and temporal dynamics of forest fragmentation and to examine the influence of migration on the configuration of the forest landscape within the Menabe Antimena protected area between 2017 and 2022. The methods used include a diachronic analysis of satellite imagery using remote sensing. Following canopy classification, land-use classes were categorised as forest or non-forest. The results reveal that forest fragmentation shows a generalised increase of 13.94% within the protected area and 25.05% at its periphery, with an overall peak observed in 2022. Furthermore, the configuration of forest fragments is significantly correlated with migration inflows. The landscape is dominated by micro-fragments covering an area of less than 20 ha, which account for between 98.86% (16,197 out of 16,383 fragments) and 99.18% (20,622 out of 20,792 fragments) of the total within the protected area; and 99.08% (11,607 out of 11,715 fragments) to 99.30% (12,226 out of 12,312 fragments) outside the protected area. At the same time, fragment density increased from 2.32 to 3.92 fragments/ha, resulting in a significant change in the fragmentation index (from 0.60 to 0.87) for the 20-50 ha class. These results make a major contribution to the overhaul of national conservation strategies by demonstrating the need to incorporate internal population flows into protected area management plans.