Wind erosion response to past and future agro-pastoral trajectories in the Sahel (Niger)

• Published in: Landscape ecology Vol. 37; no. 2; pp. 529 - 550
• Main Authors: Pierre, C., Hiernaux, P., Rajot, J. L., Kergoat, L., Webb, N. P., Touré, A. Abdourhamane, Marticorena, B., Bouet, C.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.02.2022; Springer Nature B.V; Springer Verlag
• Subjects: Amplification; Arid regions; Biomedical and Life Sciences; Continental interfaces, environment; Ecology; Environmental impact; Environmental Management; Fluctuations; Land cover; Land degradation; Land management; Land use; Land use management; Land use planning; Landscape; Landscape Ecology; Landscape/Regional and Urban Planning; Life Sciences; Nature Conservation; Research Article; Sciences of the Universe; Sediments; Semi arid areas; Soil erosion; Soil fertility; Sustainable Development; Variability; Vegetation; Vegetation growth; Wind erosion; Niger; Land management scenarios; Agro-pastoral practices; Modelling; Wind erosion; Land use; Sahel; Modelling Sahel
• ISSN: 0921-2973; 1572-9761
• DOI: 10.1007/s10980-021-01359-8

Context Wind erosion plays a major role in land degradation in semi-arid areas, especially in the Sahel. There, wind erosion is as sensitive to land use and land management as to climate factors. Future land use intensification may increase wind erosion and induce regional land degradation. Objective We aimed to estimate wind erosion responses to changing land management in a Sahelian region. Methods We defined land use intensification scenarios for a study site in southwestern Niger for two historical situations (1950s and 1990s), and two alternative prospective scenarios (2030s: extensive or intensive). We simulated vegetation growth and horizontal sediment flux of wind erosion for the corresponding landscapes. Results Annual amounts of horizontal sediment flux increased with land management changes from 1950s (nil flux) to 1990s (176 kg m −1 yr −1 ) and 2030s (452 to 520 kg m −1 yr − 1), mostly because of differences in land use, declining soil fertility, and practices decreasing the dry vegetation. For 2030s, intensive scenario exhibited larger vegetation yields than extensive conditions, but similar large values of horizontal sediment flux, thus questioning the sustainability of both scenarios. Realistic sets of practices had as large an influence as the largest theoretical range of practices on the variability of annual horizontal sediment flux. This variability was as large as that due to meteorological conditions. Conclusions This study demonstrates that the environmental impact of land use and management practices, of which wind erosion is an aspect, must be assessed at the landscape scale to account for the variability in land cover and associated land management.