Open AccessReduction of tree cover in West African woodlands and promotion in semi-arid farmlands
Author(s) -
Martin Brandt,
Kjeld Rasmussen,
Pierre Hiernaux,
Stefanie M. Herrmann,
Compton J. Tucker,
Xiaoye Tong,
Feng Tian,
Ole Mertz,
Laurent Kergoat,
Cheikh Mbow,
John L. David,
K. A. Melocik,
Morgane Dendoncker,
Caroline Vincke,
Rasmus Fensholt
Publication year - 2018
Publication title -
nature geoscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.435
H-Index - 200
eISSN - 1752-0908
pISSN - 1752-0894
DOI - 10.1038/s41561-018-0092-x
Subject(s) - arid , agroforestry , geography , woody plant , woodland , tropical savanna climate , population , vegetation (pathology) , environmental science , forestry , ecosystem , ecology , biology , medicine , demography , pathology , sociology
Woody vegetation in farmland acts as a carbon sink and provides ecosystem services for local people, but no macro-scale assessments of the impact of management and climate on woody cover exists for drylands. Here we make use of very high spatial resolution satellite imagery to derive wall-to-wall woody cover patterns in tropical West African drylands. Our study reveals a consistently high woody cover in farmlands along all semi-arid and sub-humid rainfall zones (16%), on average only 6% lower than in savannas. In semi-arid Sahel, farmland management increases woody cover to a greater level (12%) than found in neighbouring savannas (6%), whereas farmlands in sub-humid zones have a reduced woody cover (20%) as compared to savannas (30%). In the region as a whole, rainfall, terrain and soil are the most important (80%) determinants of woody cover, while management factors play a smaller (20%) role. We conclude that agricultural expansion cannot generally be claimed to cause woody cover losses, and that observations in Sahel contradict simplistic ideas of a high negative correlation between population density and woody cover.