城市绿地生态评价研究进展

Research advances in ecological assessment of urban greenspace

城市绿地的科学评价为绿地的规划和管理提供了参考,对人们正确认识和改造绿地建设起着重要的作用,为城市绿地生态功能的发挥提供了重要的依据和保障。以绿地结构的评价为基础,总结了城市绿地生态功能、服务评价、健康评价的方法和研究进展;提出了城市绿地生态风险评价的基本方法并概括了城市绿地可持续评价的研究方向。结果显示:当前城市绿地的生态评价在范围上逐渐从微观尺度发展到宏观尺度,日益强调绿地的生态服务功能,重点关注于绿地的碳储量与降温增湿功能与效益评价以及价值化研究;城市绿地的健康评价和可持续性评价均尚处于初级的探索阶段。指出了城市绿地生态评价的关键在于评价结果在管理和规划中的应用,在评价内容上必须关注各部分的结合,在评价方法上应该借助基础研究的长期监测、评价的量化以及多学科交叉的渗透。

Land use change, including urbanization, has resulted in a series of environment problems. As the world continues to be urbanized at an increasing pace, our urban ecosystems and landscapes must be made more sustainable through improved management practices. To achieve this goal the structure, function, and sustainability of urban green spaces must be better understood because they provide a series of ecosystem functions and services. Urban greenspace and its functions are under increasing pressures induced by urbanization, including land conversion into impervious surfaces, soil pollution, air pollution, and intense disturbances. Ecological assessment of urban green space cans provides valuable information for urban planning and management, in order to protect and enhance ecosystem services of urban green spaces. Urban greenspace assessment includes several aspects. First, the structural assessment of greenspace can be carried out at multiple scales. On a local scale, structural evaluation focuses mainly on species composition and vegetation structure. With the use of GIS and remote sensing data, landscape pattern analysis of urban greenspace is often conducted at the regional scale. Here, we also review research methods and advances in the study of ecological functions, ecosystem services, and sustainability of urban greenspace. Our results show that an increasing number of methods have emerged in recent decades for assessing the ecosystem function and services of urban green spaces on both local and landscape/regional scales. Some of the methods are quantitative and economically oriented （ i. e. developed to valuate greenspace ecosystem services monetarily）. Among numerous ecosystem functions of urban greenspace, the carbon sequestration capacity, cooling effect, and humidifying effect have received greater attention from researchers. Despite its importance for urban sustainability, ecological risk assessment of urban green spaces has been rarely studied so far. Evaluation of urban ecosystem health and sustainability is challenging, and still in its infancy, demanding more emphasis in future research. Based on the review of previous work, we propose a conceptual framework for studying and assessing urban green spaces, with a particular emphasis on humans roles in the holistic urban ecosystems. Ecological assessment of urban greenspace must be conducted periodically, with long-term monitoring systems established. Assessment and monitoring should be integrated into the management and planning of urban landscapes following an adaptive approach.