Trend and Structure of Populations of Balanites aegyptiaca in Parkland Agroforestsin Western Niger

Current and future trends of the parklands and the population of Balanites aegyptiaca in western Niger were investigated through the analysis of the diversity, the regeneration status and the size class distributions of the woody plants. A total of 21 plots, measuring 2500 m2 (50 m x 50 m) each were randomly selected to represent the parklands of B. aegyptiaca in the study area. Across all plots 1180 individual plants were recorded, representing 13 species, 10 genera and 7 families. The most diverse family is Fabaceae and the most dominant family is Balanitaceae represented by only one species B. aegyptiaca. The density of the regeneration was 71.16 and 33.31 plants ha-1 for the entire parkland and the population of Balanites aegyptiaca, respectively, while the diversity and the evenness indices of B. aegyptiaca were 2.52 and 0.24, respectively. B. aegyptica, Faidherbia albida, Hyphaene thebeica and Acacia nilotica populations had the highest values for the importance value index (IVI). Results from the analysis of the size class distribution indicate that the parklands and the population of B. aegyptiaca appear to be healthy and stable with high regeneration rates. However, low recruitment of juveniles to adults was observed due to seedling and sapling mortality, and high disturbance regimes, which in the long term can affect the population turnover.Acacia tortilis, A. senegal, Azadirachta indica and Prosopis juliflora populations had the lowest IVI values and may be the most sensitive to the disturbance regimes in the study area. Therefore, we suggest designing and implementing a conservation programme in the study area, which will protect and facilitate the growth of the juveniles of both overexploited and underexploited populations.