中文摘要：

适度的人口规模是城市可持续发展的关键，城市生态适度人口的确定取决于区域生态承载力与区域人口对生态资源的需求，生态敏感性分区和区域可利用土地资源评价是生态适度人口测算的前提。本文以兰州新区为例，针对新区存在的主要生态环境问题，在GIS支持下对其生态环境敏感性进行综合评价。明确了生态环境敏感性分布规律。利用数字高程模烈、遥感影像解译土地利用图和国土部门土地利用数据，测算和评价了兰州新区可利用土地资源的数量和空间分布特征。基于多情景模型方法，从用地空间、可供水量、绿地指标、生态足迹和生态敏感性分区5个方面测算了兰州新区的生态适度人口与最大人口规模。结果表明：兰州新区生态适度人口规模为82．28万人一119．93万人。生态环境和用地空间对兰州新区人口容量规模的限制作用较其它因素强烈。2030年新区人口将达到或接近适度人口规模。新区发展应统筹城乡各类资源的利用，提高土地节约集约利用水平，提升±地生态承载力。

英文摘要：

Optimum population scale plays a key role in ensuring urban sustainability in the long run. The ecological optimum population of a city is decided by ecological capacity in the region and regional population＇ demand about the ecological resources. Ecosensitivity regionalization and available land （reserved construction land potential） assessment is a key foundation of eco-optimum population estimation. In this paper, taking Lanzhou New Area as a case, integrated assessments of sensitivity to water erosion, river buffer, geological hazard and its spatial distribution in Lanzhou New Area was done by GIS spatial analysis method, and the spatial distribution of ecosensitivity were characterized. Using Digital Elevation Map （ DEM）, TM remote sensing land use map and land use investigation data, the paper calculated and assessed quantitative and spatial differentiation of available land of Lanzhou New Area. On these basis, the authors adopt scenarios analysis to explore the city＇s appropriate scale and maximal ecological population scale from the aspects of land space, water supply, grass-land norms, GDP, ecological footprint and ental sensitivity. The results showed that, considering the available land, water resources and environmental determinants, the local ecological optimum population scale was expected to amount to around 0.82 - 1.19 million. The calculation outcome reflected that the restriction effect of ecological environment and proper land space to population scale were sharper than effect of other factors. The authors drew the conclusion that the urban population would reach close to the scale of ecological optimum population in 2030. Finally, the authors presented countermeasures for development of Lanzhou New Area from the perspective of integrating the utilization of urban and rural resources improving, intensive using and saving of land and raising land ecological bearing capacity.