Insights from analyzing local ecological knowledge and stand structure for guiding conservation actions for the endangered tropical tree Pterocarpus erinaceus. Poir

Abstract

Sustainable management and conservation of multipurpose tree species in their natural habitats is crucial, given their vulnerability to climate change and increasing human activities. This can be achieved by harnessing in sights from local ecological knowledge (LEK) and classical ecological approaches to support biodiversity con servation efforts. Using forest inventory data from 126 plots and information from a semi-structured survey of 234 households, we investigated LEK (perception on population trend, causes, and conservation attitudes toward the species) and population ecology (tree density, size class distribution – SCD, structural diversity, and stability) of the endangered rosewood Pterocarpus erinaceus Poir. along a climate gradient in Benin (Sudanian (SZ), Sudano-Guinean (SGZ) and Guinean (GZ)). The results indicated that local communities were aware of the decline of P. erinaceus populations, although variations were observed with respect to ethnicity and age. The protection of the species regeneration by the communities in the GZ (63 %) probably led to the high regeneration rate (90 %) of P. erinaceus in this zone. Tree density declined from the SZ to GZ (2 and 1.23 times lower in SGZ and GZ compared to SZ), but variation in the mean diameter at breast height showed the opposite pattern (1.98 and 1.90 times lower in SGZ and SZ than in GZ). The SCD in the SGZ exhibited a bell-shaped pattern, while the populations in the SZ and GZ showed an inverted J-shaped distribution. Pruning intensity was 6.60 to 35.25 times higher in the SZ than in the SGZ and GZ, respectively, where regeneration rates were low, reflecting the potential negative effects of pruning on regeneration. Furthermore, P. erinaceus demonstrated tolerance for mixed-species stands (mingling of 40 % to 75 %), indicating an opportunity to integrate it into agroforestry systems with other species. This research highlights the impacts of human activity and climate conditions on P. erinaceus populations and informs on potential management actions needed for the conservation of the species.