引种桉树对本地生物多样性的影响

桉树以速生和适应多种环境的特性成为世界著名的造林树种.但引种桉树对环境可能产生负面影响，如导致土地退化、地下水水位下降和多样性降低等，特别是对林下本地生物物种多样性的影响及其原因还存有争议.本文对此进行了综述，认为大部分桉树人工林本地物种数量低于天然林，一般不高于乡土树种人工林，但总体上好于其他外来树种人工林.导致桉树人工林生物多样性低的原因主要是桉树的生理生态特性、人类不合理的规划和砍伐等，其中人为因素起主导作用.若根据引种地的群落性质，通过严格的设计和科学管理，可以将这种负面影响最小化.应按照有利于群落正常发育和植被更新的方式栽种桉树人工林，保留天然植被，减少人为干扰，从而减轻引种桉树的负面影响.

Effects of introducing Eucalyptus on indigenous biodiversity

Eucalyptus is well-known as an effective reforestation tree species, due to its fast growth and high adaptability to various environments. However, the introduction of Eucalyptus could have negative effects on the local environment, e.g., inducing soil degradation, decline of groundwater level, and decrease of biodiversity, and especially, there still have controversies on the effects of introduced Eucalyptus on the understory biodiversity of indigenous plant communities and related mechanisms. Based on a detailed analysis of the literatures at home and abroad, it was considered that the indigenous plant species in the majority of introduced Eucalyptus plantations were lesser than those in natural forests and indigenous species plantations but more than those in other exotic species plantations, mainly due to the unique eco-physiological characteristics of Eucalyptus and the irrational plantation design and harvesting techniques, among which, anthropogenic factors played leading roles. Be that as it may, the negative effects of introducing Eucalyptus on local plant biodiversity could be minimized via more rigorous scientific plantation design and management based on local plant community characteristics. To mitigate the negative effects of Eucalyptus introduction, the native trees and understory vegetation in plantations should be kept intact during reforestation with Eucalyptus to favor the normal development of plant community and regeneration. At the same time, human disturbance should be minimized to facilitate the natural regeneration of native species.