Factors influencing liana species richness and structure following anthropogenic disturbance in a tropical forest Ghana
Addo-Fordjour P; El Duah P; Agbesi DKK
Although a lot of studies have been conducted on the effects of human disturbance on liana success information on the indirect effects of human disturbance on liana assemblages mediated by changes in forest structure and soil physicochemical factors is scanty. Consequently the study was conducted to determine the factors that influenced liana species richness and structure in forests of different disturbance intensities in the Southern Scarp forest reserve Ghana. The study was conducted in three main forests namely high moderate and low disturbance forests. Within each forest lianas (dbh = 2 cm) were enumerated in 6 25 x 20 m2 plots located along transects. Soil physicochemical properties and structural characteristics of each plot were determined. Liana species richness and abundance were significantly lower in the high disturbance forest than the other forests (p < 0.001). Liana basal area was significantly higher in the low disturbance forest than the other forests (p = 0.014). Tree abundance and dbh significantly predicted liana species richness and structure in the study (p < 0.05). On the basis of importance value index of the species three main liana communities each corresponding with a forest type were obtained. Stepwise multiple regression analyses revealed that exchangeable magnesium and calcium and total exchangeable bases were the main soil variables that affected liana species richness. Liana structure was influenced by the above-mentioned soil variables as well as exchangeable potassium and sodium and pH. The present study has demonstrated that changes in liana species richness and diversity following human disturbance may be at least partly due to variations in forest structure and soil properties as a result of disturbance.