Restoration of Tropical Rainforest After Removing Amomum villosum in Xishuangbanna

Abstract

The effects of Amomum villosum cultivation on biodiversity in Xishuangbanna tropical rainforest attract much attention. This research, which lasted two years, was carried out to study ecological restoration after removal of Amomum villosum in the rainforest of Xishuangbanna. The results were as follows: 1) the number of plants in the rainforest increased significantly, compared with the number in primary rainforest, which has the same type of vegetation but has never been planted with Amomum villosum . However, there are no significant differences between the two kinds of rainforests as to the species richness, plant diversity and evenness, which have increased prominently in both kinds of rainforests. The flora develops to that of tropical rainforest. The dominant species is not prominent, but the number of herbs and ferns increases significantly. 2) in the wet season, the seedlings grow faster in removed Amomum villosum rainforests than in primary rainforests, but there is no difference in dry season growth. The biomass of seedlings reached (636.1±43.4) g·m -2 after two years, exceeding that of primary rainforest, especially due to the fast growing herbs and ferns; 3) water content of soil was improved, as was the water capacity, with no difference to that of primary rainforests. The organic matter content of deep soil increased significantly, while the available phosphorus content needed long_time vegetation restoration to increase. Much of the available phosphorus of the surface was lost by the stream_water of rain. A new pattern of Amomum villosum rotation in tropical forests was recommended, which would be a good approach to the minority of mountain area in Xishuangbanna, because it could partly harmonize the contradiction between conservation and development.