Revisiting plant conservation on wooded shrines by a transversal approach : "Core" vs. "satellite" species and anthropological knowledge in Bwaba land, Burkina Faso
Résumé
Studies on plant conservation in sacred groves provide mixed results, with some showing their effectiveness
while others do not. We argue that beyond the variety of field cases, studies usually suffer from overrating rare
species and insufficient consideration of societal data. The sacred sites of Bondoukuy department in Bwaba
cultural area (Burkina Faso) were geo-referenced and measured; the most abundant ligneous species were
listed and their abundance recorded. Their conservation status and dynamics were assessed based on the core
vs. satellite species model of Hanski. Data interpretations relied on the phytogeographical affinities of
abundant species and on anthropological knowledge of the Bwaba society.
The vast majority of shrines were less than 1 ha, located in or near villages in specific landscape features,
and covered with trees. The most abundant species of shrines belonged mostly to local phytochories, but were
subject to rather high anthropisation. The results support the concept that wooded shrines preserve local
biodiversity, but indicate threats from an invasive alien species. The location and condition of shrines appeared
to be constitutive features: the Bwaba system of thought involves a series of sacred sites (with and without
trees) located in remarkable features of the landscape, and their way of life has resulted in the proximity of
these sites to the villages. The beliefs that promote plant cover conservation do so only to a certain extent and
regardless of the species content, which raises the concern that alien species may upset the established
communities. These beliefs have led the Bwaba to choose the most humid environments in which to set up
their wooded shrines, which is interesting from a conservation perspective. The study advocates for a better
consideration of social data to identify the key elements of the dynamics of the vegetation of sacred groves.