三峡库区城市消落带生态规划与保护探讨

三峡库区消落带因反季节涨落、落差大、面积广等特点，其生态环境的保护和恢复一直是困扰世界的难题。而位于城市区域的消落带，因受人类活动的干扰强度大，生态环境更易遭受破坏。根据消落带功能的不同，将城市消落带划分为生态景观区、生态屏障区和航运枢纽区3个功能区。根据消落带生态类型的不同，以坡度和高程作为消落带类型划分主要指标，将城市消落带划分为平坝阶地型 (0~15°)、缓坡型 (15~25°)、陡坡型 (>25°)3个坡类和145~155、155~170、170~175 m 3个区段。基于城市消落带的功能分区，根据其生态类型的划分，应用生态恢复和植物配置等原理和技术，因地制宜地提出了城市消落带的生态规划与保护方案，以充分发挥城市消落带拦截降解污染物、吸附削减营养盐、提供亲水空间及改善城市景观等综合功能，为城市消落带的生态规划与管理提供决策依据和科学支撑。

ECOLOGICAL PLANNING AND PROTECTION OF URBAN WATER-LEVEL-FLUCTUATION ZONE IN THE THREE GORGES RESERVOIR

The 30 m-water-leve-fluctuation-zone(WLFZ) in the Three Gorges Reservoir has the characteristics of seasonal reversal with large variations of altitude fluctuation and horizontal area.To protect and reconstruct the ecosystem of WLFZ is the world hot issue.It is widely accepted that WLFZ in urban area suffers intensive anthropogenic perturbations that impact ecological reconstruction of WLFZ.According to the different functions of WLFZ in urban areas,it is classified into three function areas:ecological landscape area,ecological barrier area and navigation junction area.Taking slope and elevation as the two major evaluating parameters,each type in the urban WLFZ is divided into:flat slope type(0~15°),gentle slope type(15~25°),steep slope type(>25°) and the elevation of 145~155 m,155~170 m,170~175 m.According to the functional partition and type classification of urban WLFZ,based on the principles and technologies of ecology restoration and plant configuration,ecological planning and protection of urban WLFZ are proposed.It is suggested that the urban WLFZ can act as multiple functions,e.g.the buffer zone that intercepting the transport of nutrients from terrestrial ecosystem to aquatic ecosystem,hydrophilic space,improving the urban landscape,etc.The results from this study will provide decision-making basis and scientific support for ecological planning of urban WLFZ in future.