Assessment of the conservation status of Borassus akeassii Bayt., Ouédr. & Guinko in Western Burkina Faso through local communities perceptions and the species stands structure

Abstract

Borassus akeassii is one of the most common fan palms in West and Central Africa. In Burkina Faso, the species regenerates in the wild and is kept on farms by local people because of its high usefulness. It is used mainly by local communities for palm wine production and basket-making. We investigated the population dynamics and the local conservation status of Borassus akeassii in order to provide tools for the sustainable management of the species. People (n = 233) from five different ethnic groups were interviewed and their perceptions and conservation practices of the species were determined and compared between socio-demographic groups. For field measurement of the species populations, 30 inventory plots of 50 × 50 m size were used to collect data on individual life stage, sex, and exploitation state. Data were used to estimate the densities, the sex ratio, the regeneration and mortality rates and to calculate the permutation index (P), the Simpson’s dominance index (S), and the quotient (Q) between consecutive life stages of populations. This information provides highly condensed indices of population dynamics acting over many years. The results showed that 53% of informants report a declining trend for Borassus akeassii . However, perceptions of the species dynamics varied among ethnic groups. Harvesting was the main reported cause of the species’ decline. Population densities varied among life stages, with a dominance of seedlings. The permutation index, the Simpson’s dominance index, and the quotient between consecutive life stages revealed an unstable population structure of Borassus akeassii . However, the high intensity of exploitation of individuals versus the low mortality rate suggests Borassus akeassii is being used sustainably by local people. People are aware of the species' vulnerability and adopt practices for its conservation (e.g. planting and natural assisted regeneration). Encouraging good local practices of conservation together with the high potential of regeneration could ensure sustainable use of the species in Burkina Faso. Future research should thus focus on documenting the expert knowledge on sustainable exploitation of the species as an example to be reinforced and implemented in other areas.