西双版纳热带雨林下砂仁拔除后的生态恢复

 种植砂仁（Amomum villosum）对西双版纳热带雨林植物多样性的影响引起了人们的关注。通过西双版纳热带雨林下种植的砂仁拔除后的生态恢复两年的研究工作，结果表明砂仁排除后：1）林下植物数量显著增加，超过同等类型的没种过砂仁的原始热带雨林；植物种类、物种多样性和均匀度都有大幅度增加，与原始热带雨林差别不大；群落组成成分仍向着热带雨林演替，优势种不明显，其中，草本和蕨类植物增加显著；2）林下植物生长速率在旱季与原始林差别不大，但在雨季可有较快生长；生物量在两年内可达到(636.1±43.4) g·m-2，超过原始林，特别是草本和蕨类植物生长较快；3）土壤含水量得到提高，与原始林相比差异不显著，并且，涵养水源的能力有所增加；深层土壤有机质的含量增加显著，速效磷含量需要更长时间的植被恢复才能有所提高，速效钾受淋洗作用的影响，地表有大量损失。文中最后讨论指出，热带林下砂仁实现斑块式的轮歇种植是协调保护与发展的较好方法，这在偏远少数民族地区有着较好的可行性。

Restoration of Tropical Rainforest After Removing Amomum villosum in Xishuangbanna

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.