Re-greening of agrosystems in the Burkina Faso Sahel: greater drought resilience but falling woody plant diversity

摘要

Droughts and land degradation result in biodiversity and ecosystem service losses with serious implications for human wellbeing. The Sahel region has seen increased plant cover since the end of 1970s-1980s droughts, but understanding the nature and implications of this change remains a priority. This study aimed to assess changes in the woody floristic composition of re-greened agrosystems since the droughts in Burkina Faso. In 148 vegetation survey plots distributed across areas with increasing woody plant cover and those to some extent protected from exploitation, a total of 71 species from 51 genera and 23 families were identified. Compared to pre-drought flora, our measurements show a decline in the diversity and density of woody species. Combretaceae species and thorny species of the genera Acacia and Balanites, which are more tolerant of drought, were the most dominant, indicating a post-drought woody vegetation that is more resistant to water stress. The increased presence of food-producing species in agroforestry parks (cultivated fields with woody plants) seems to reflect the growing needs of the human population.