Impact of land use changes on the habitat of the Crowned Crane (Balearica pavonina) in Lake Chad Basin

Abstract

Sahelian wetlands are undergoing rapid transformation under the combined effects of climate change and human pressures, leading to the progressive degradation of wildlife habitats. This study analyzes the impact of land-use dynamics on the habitat of the Crowned Crane (Balearica pavonina) in a transboundary area between 1986 and 2026. The methodological approach combines remote sensing, spatial analysis, and phytosociological surveys. Land cover maps were produced from Landsat TM, ETM+, and OLI/TIRS imagery using supervised classification based on the Maximum Likelihood algorithm. Vegetation analysis is based on 54 phytosociological surveys conducted in six land cover units using the Braun-Blanquet sigmatist method. The results show an overall classification accuracy of 83.2% with a Kappa index of 0.81, indicating high reliability of the maps produced. Between 1986 and 2026, shrub savannas (18.1% to 43.7%) and wooded savannas (8.6% to 24.8%) experienced significant expansion, while permanent ponds (24.9% to 1.4%) declined. Transition analyses reveal a progressive conversion of wetlands to savanna formations and human-modified areas. Spatial modeling highlights a concentration of hotspots and ecological corridors in the southwest sector along the Komadougou River. The abundance of the Crowned Crane is significantly linked to environmental variables, including NDVI, NDWI, and distance to water. Phytosociological analysis identifies four distinct plant communities, with wetlands exhibiting the highest floristic diversity. This study shows that wetland degradation and ecological fragmentation constitute major threats to the conservation of Balearica pavonina in the Sahelian landscapes.

Keywords: Spatio-temporal dynamics, Ecological corridors, Niger