城市绿地外来物种风险分析体系构建及其在上海世博会管理中的应用

外来物种风险分析是防止生物入侵的有效手段之一。本文按照风险识别、风险评估和风险管理3个阶段,构建了城市绿地外来物种风险分析体系。文中提出了4个层次、26个指标构成风险评估指标体系,此体系囊括了城市绿地外来物种的传入、定殖、扩散、危害等入侵风险形成的基本要素,并规范了风险指数的计算方法。以2010年上海世博会引进日本景观苗木可能携带的外来物种为对象,对该体系在生产实践中进行了应用。结果表明:高风险物种共7种,涉及害虫4种、植物病原微生物2种、植物线虫1种;中风险物种共10种,涉及害虫3种、植物病原微生物4种、植物线虫3种;低、极低风险物种各1种。根据风险分析结果,对以上物种提出了有针对性的风险管理措施。实践表明,该风险分析体系实用性强,在上海世博会植物引种过程中为防止外来物种入侵起到了较好的预警效果,为管理者提供了有价值的决策参考,有力保障了上海世博会期间的生态安全。

A risk analysis system for alien species in urban green spaces and application to the 2010 Expo, Shanghai

Invasive species pose risks to regional economies and public health as well as imposing serious damage to natural ecosystems.Urban ecosystems are more susceptible to biological invasions than other ecosystems because they are subjected to more frequent human disturbances.Green space acts as important channels for the spread of alien species into urban ecosystems.Risk analysis can be an effective tool used for preventing invasion of alien species.Although various risk analysis systems have been developed for agricultural and forest ecosystems or nature reserves,the domestic effort to manage risks associated with invasive species in urban green spaces has been limited in China.Therefore,there is a pressing need for formulating scientifically sound methods and approaches for risk analysis in this emerging field.Here,we presented a risk analysis system including risk identification,assessment and management for biological invasions in urban green spaces.Based on risk identification for alien species,we established a risk assessment index that consisted of 4 different layers,i.e.object,item,factor,index layers.A total of 26 index parameters were proposed to assess the risk level,which originated from the risks involved in introduction,colonization,spread and damage of alien species in urban green spaces.In addition,methods for index quantification,weight setting,modeling and risk grading were presented.Applying this system,we analyzed the risks of alien pest species potentially attached to trees brought from Japan to China to green landscapes for the 2010 Expo in Shanghai.Our results showed that 7 species posed a high risk(4 insects,2 plant pathogens,and 1 plant nematode),10 species a moderate risk(3 insects,4 plant pathogens and 3 plant nematodes),and other 2 species(1 insect and 1 nematode) a low or extremely low risk.Based on this analysis,risk management measures were suggested to help local policy-makers set priorities for the management of these alien pests.Monitoring did not reveal the presence of any invasive pests during or after the Expo,suggesting that the risk analysis system may have provided an effective tool for preventing the introduction of invasive alien species and effectively ensuring the ecological security of the 2010 Expo,Shanghai,China.