Abstract
Monitoring regeneration in woody communities and understanding the drivers of its success is crucial for gaining insight into the long-term persistence of trees in African drylands, where they play key socio-ecological roles. While fire, grazing and water availability are key factors for regeneration in these ecosystems, seed arrival, germination and seedling recruitment are still poorly documented under natural conditions in the West African Sahel. Tree planting is commonly carried out in West Africa to promote regeneration. The cost is considerable, the success is variable and its influence on spontaneous regeneration is unknown. We conducted a field inventory to ascertain the regeneration ability of woody communities in a Sahelian savanna in three land management types (plantations, communal grazing, old enclosures) to determine (i) the proportion of the different regeneration mechanisms; (ii) the influence of adult trees; (iii) the influence of management type and topography and (iv) their temporal dynamics. We first showed that regeneration diversity was poor, with half of the adult species not recorded in the regeneration phase. Secondly, regeneration mostly came from true seedlings compared to resprouting. Thirdly, adult communities were found to greatly influence regeneration density and composition. Fourthly, topography proved to influence regeneration density, whereas we observed little effect of the land management type. Lastly, historical data highlighted a steep decline in regeneration density over recent decades. These results raise questions about the persistence of woody vegetation in Sahelian savannas and highlight the need to protect large trees in suitable microsites, such as topographic depressions, to promote regeneration.
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Data availability
Inventory data from 2015 and 2021 are available on request.
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Acknowledgements
This research was financed by the Carbon Sequestration and Greenhouse Gas Emissions in (Agro) Sylvopastoral Ecosystems in the Sahelian CILSS States (CaSSECS) project, supported by the European Union under the Development Smart Innovation through Research in Agriculture (DeSIRA) initiative. Its content is the sole responsibility of the authors and can in no way be taken to reflect the position of the European Union. The authors would like to thank Ibrahima Diop and Babacar Sarr from the CSE, and Ahmadou Sow for their help during field work.
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Acquisition: Simon Taugourdeau, Caroline Vincke and Abdoul Aziz Diouf. Resources: Simon Taugourdeau and Abdoul Aziz Diouf. Supervision: Simon Taugourdeau and Caroline Vincke.
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Conceptualization: Morgane Dendoncker, Simon Taugourdeau and Caroline Vincke; Methodology: Morgane Dendoncker and Simon Taugourdeau. Formal analysis and investigation: Morgane Dendoncker, Simon Taugourdeau, Ramata Ndianor, Sabine Miehe. Writing - original draft preparation: Morgane Dendoncker. Writing - review and editing: Morgane Dendoncker, Caroline Vincke, Ramata Ndianor, Abdoul Aziz Diouf, Sabine Miehe, Daouda Ngom and Simon Taugourdeau.
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Dendoncker, M., Vincke, C., Ndianor, R. et al. Sahelian woody communities are endangered by regeneration impoverishment in three land management types. New Forests (2024). https://doi.org/10.1007/s11056-024-10041-1
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DOI: https://doi.org/10.1007/s11056-024-10041-1