生物多样性与植物生产力间具有密切的联系，但森林生态系统（尤其是人工林生态系统）下生物多样性与生产力的相互关系研究相对较少。桉树作为著名的三大速生树种，已被引种到世界近百个国家和地区。中国有超过360万hm2的桉树人工林，仅广西就达186万hm2，其中60-70%桉树人工林采取连栽体制。桉树连栽引起的生物多样性减少、地力衰退和生产力下降，已成为社会各界共同关注的焦点。本项目拟在对尾巨桉Ⅰ-Ⅲ代林分连续15年（已完成2个轮伐期）定位监测的基础上，继续对第3个轮伐期的尾巨桉林开展研究，通过长期的群落生态学调查、野外控制实验以及室内化学分析，探讨尾巨桉连栽的生物多样性（包括植物、土壤动物和微生物多样性）效应及其对长期生产力的影响机制，并与前15年的研究结合形成一较为完整的研究体系，将能给连栽尾巨桉人工林的生物多样性效应和长期生产力的可持续性一个公正合理的评价，为林业部门的相关决策提供理供理论指导。

Biological diversity is considered as having a close association with plant productivity, while the interrelation between them is rare studied in the forest ecological system. As one of three largest fast growing woods, eucalypt has been introduced to nearly 100 countries and regions. There are now in excess of 3.6 million ha of eucalypt plantations in China, about 1.86 million ha of which are in Guangxi province. About 60-70% of them is managed with continuous cropping system. There is a debate on negative effects of continuous cropping of eucalyptus plantation on biodiversity and productivity, such as biodiversity reduction and soil degradation. Based on our previous 15 years located research (including Ⅰ-Ⅲ generations and second rotation cycles) with Eucalyptus urophylla×E. grandis plantations, we plan to continuously monitor the effects of continuous cropping eucalypt plantations on the biodiversity (including plants, soil animals and soil microbe) with the third rotation cycles, and study the relationship between biodiversity and productivity under continuous cropping systems, through the long-term investigation, field control experiment, and biochemical analysis. Integrated with our previous 15 year studies, our study will provide fair and reasonable assessment on biodiversity effects and sustainability productivity in continuous cropping management of eucalypt plantations, and provide guidance for dispatching of forestry departments.