Population Status and Extinction Risk of Medicinal Plants in a Moist Closed Canopy Afromontane Forest: A Case of Prunus africana (Hook. f.) Kalkman in South West Mau Forest, Kenya
The exploitation of the medicinal Prunus africana trees from forests in Kenya has raised concerns. The effects of such exploitation on the regeneration trend or population structure in disturbed and undisturbed sites have not been documented for prescription of its sustainable management and conservation strategies. This study assessed exploitation level, regeneration trend and population structure of P.africana in South West Mau forest in Kenya. It was hypothesized that population of the species was unstable due to high exploitation. Diameters at Breast Height (DBH) of large trees were measured and regeneration counted in four sites with varying anthropogenic influence: undisturbed, low, moderate and high disturbance areas. Three transects of 100 m apart and running from forest edge up to 1 km inside the forest were established in each site. Four sample plots measuring 20 m x 50 m were laid at 250 m intervals along each transect. Each plot was divided into 10 equal square subplots of 100 m 2 and 25 m 2 sub-subplots nested in each and a quadrat of 1 m 2 at its centre. Trees >10 cm in DBH were measured in subplots while saplings and seedlings were counted in sub-subplots and quadrats respectively. The density of debarked P. africana stems was significant different between the sites (p < 0.012) and the least disturbed site had the highest debarking rate (90 %). Regenerations and adult trees densities was also significantly different (p = 0.043 and p = 0.005 respectively). The relatively undisturbed site provided the highest regeneration density and a balanced population structure for P. africana population (almost reverse-J curve) as compared to other sites where the species population was relatively unstable. The findings revealed need for strategic restoration measures for the species.