État de conservation de la forêt naturelle de Pobè au sud-est Bénin

Romain Dadi a, ?, Sedami Igor Armand Yevide a, Romaric Vihotogbe a, b, Carolle MA Avocevou-Ayisso a

Abstract

After 25 years of co-management, the biological diversity of the natural forest of Pobè in Benin has not been updated. This study  aims to assess t he conservation status  of this protected ecosystem, which  is subject  to numerous anthropogenic pressures. The objectives are to re-evaluate the  current area  of the  forest  using  remote  sensing  to obtain  precise  forest  cover  measurements, to  conduct a comprehensive floristic  inventory to  describe  its current plant  compos ition  and  diversity, and  to  analyze  the ecological  and  structural characteristics of the  forest.  The surveys  were  carried out  in 56 square  plots  of 40 m*40  m, spaced  at le ast 100  m apart, installed in a nearly uniform  manner along  the South-North or West-East axes, covering  8.96  ha (7.17%  of the total  area).  Within  each  plot,  all tree  species  with  a diameter at breast  height (d.b.h.) ? 5 cm were recorded. The geographic coordinates of the center  of each plot were recorded using a GPS. Diversity ind ices were calculated using R software  version

4.0.2,  and the diameter distribution was fitted  to the 3-parameter Weibull distribution using MINITAB version  14. In total,  69 tree species belonging to 62 genera  and 26 families were inventoried, dominated by the Leguminosae family (including the subfamilies Caesalpinioideae, Mimosoideae and Papilionoidea). The stand  density  was 180 individuals/ha, with  a basal  area  of 35.26  m²/ha and  an average diameter of 39.11  cm. A socio -economic  survey  characterized the  uses of the  69 inventoried species, ensuring a fine analysis  of the importance of forest resources for local communities. The diameter distribution fitted  to the Weibull  law has a sh ape parameter c = 1.17, typical  of undisturbed natural forests.  The forest  area,  re-evaluated using ArcGIS, is 125.5  hectares, showing  a slight  increase compared to the 115 hectares estimated in

1995.