Land use/land cover and plant community dynamics in the Benin's forest reserves: The effectiveness of participatory forest management

Assessing Participatory Forest Management (PFM) is crucial to design sustainable conservation biodiversity policies. Such assessments often prioritize PFM's impact on livelihoods and deforestation, overlooking the spatial and biodiversity dimensions. Thus underscores the need for tools like Land Use/Land Cover Change (LULCC) overviews and forest diversity assessments. Here, we integrated LULCC of fours forests reserves (Wari-maro Mont-Kouffe<acute accent>, Agoua, Goungoun and Lama), taxonomic (alpha index) and temporal beta diversity index to provide insight into PFM effectiveness over thirty-five years (1986-2021). Landsat MSS (1986), SPOT (2005) and Sentinel 2b (2021) satellite images were used to assess the LULCC, via supervised classification and visual interpretation. Temporal dynamics of trees diversity was evaluated using forest inventory data from two years (2007 and 2023). A linear regression was performed to identify the anthropogenic factors (fire, grazing, distance from villages to forests) driving temporal changes in floristic composition. We found a decline in forests area which was more critical after the implementation of PFM (2005 and 2021), with a slight decline in species diversity (1.80 +/- 0.68 in 2007 and 1.65 +/- 0.56 in 2023). PFM efficiency was higher in larger forests, which have experienced less deforestation than smaller ones. Significant variations in forest land cover were observed among forests from 1986 to 2021, particularly in Agoua (26.76% and 52.13% between 1986 and 2005 and 2005-2021 respectively) and Wari-maro Mont-Kouffe<acute accent> (1.96% and 0.16% between 1986 and 2005 and 2005-2021 respectively). There was a significant decline in trees density from 2007 (252 trees/ha) to 2023 (155 trees/ha), while tree diameter (15 to 22 cm) and height (8 to 12 m) have increased between 2007 and 2023. The foristic composition of forests has changed, with an overall downward trend in diversity, affected by forest fires. The study provides valuable insights into the effectiveness of PFM as a conservation policy.