IMPACTS OF BAMBUSA BAMBOS SPREAD ON SEEDLING RECRUITMENT, MORTALITY AND REGENERATION POTENTIAL OF NATIVE SPECIES IN TROPICAL MOIST EVERGREEN FORESTS OF SRI LANKA

Some native plants expand their populations rapidly in their home ranges, altering their structure and composition. Bambusa bambos, a native bamboo species, shows a rapid population expansion in tropical moist evergreen forests in the intermediate climatic zone, Sri Lanka. The present study was conducted to evaluate its impacts on the regeneration potential of other native forest species. The seedling emergence, survival and mortality were observed for a period of one year using quadrats laid along 18 transects marked from the forest edge towards the forest interior in forest patches with and without bamboo (+Bb and –Bb, respectively). The results revealed a higher abundance, richness and diversity of seedlings in +Bb than in -Bb, with lianas and herbs contributing more to these differences. However, tree seedlings showed higher turnover rates (recruitment and mortality) in -Bb, indicating their preference for undisturbed habitats. Tree and shrub seedlings survived better in -Bb forests while liana and herbaceous seedlings displaying the opposite. The results indicate that B. bambos spread showed an ability to alter the regeneration potential of native forests probably resulting bamboo-driven changes to micro-environmental conditions in the forest floor.