Ex-situ conservation and diversity index of greened ex-tin mine

Abstract

Abstract The greened ex-tin mine comprises planted timber species of Acacia mangium, Hopea odorata and Khaya ivorensis. The ex-tin mine was formerly a lowland dipterocarps mixed forest. The man-made forest was established at 4 x 5 m spacing or 500 stem/ha on slime tailings. However, high mortality of the timber species due to damages by wild pigs and farm animals have reduced the plantation of 3.2 ha to only 93 stems of Acacia mangium, 92 stems of Hopea odorata and 130 stems of Khaya ivorensis at 20 years after planting. The regeneration covering the planting line was kept and the planting spaces in-between the planting lines were cleared for planting of another 14 species of endemic, endangered and threatened tree species (EETS). The ex-situ conservation program of planting 1500 stems of EETS to the 3 ha site was sponsored by Asian Forest Cooperation Organization (AFoCO). The 100% vegetation survey was carried out 4 years after planting. The species richness, Shannon diversity index and species evenness were computed for the nurse stand, and the nurse stands with EETS. The results obtained for species richness, Shannon Index (H) and Shannon Evenness index (EH) of the nurse stand and nurse stand with EETS was 24, 1.46, 0.46 and 38, 2.30, 0.63, respectively. The nurse stand with EETS has increased in species richness, H and EH of nurse stand to 58%. and 36.9%, respectively. More importantly, none of the introduced EETS was found in the composition of the natural regeneration of the 20 years old nurse stand. The 21 species naturally regenerated in the nurse stand were an only pioneer and late pioneer species. This shows that ex-tin mine after the reclamation efforts of planting timber species and the natural regeneration will not be able to regain the initial species composition of a lowland dipterocarps forest. The domestication technology of EETS developed in this project is reproducible. The project has successfully preserved the 14 EETS and the site shall be a demonstration plot for the future seed production area.