城市滨江地区生态用地演变及驱动因素分析——以长江南京段为例

Changes of Ecological Land and Driving Factors in Urban Riverside Area: the Case of Nanjing Section of the Yangtze River

从中小尺度对城市滨江生态用地演变进行研究,可为制定生态用地开发与保护政策提供重要参考。基于2005、2009、2014和2018年土地利用数据,利用转移矩阵等方法分析了南京滨江1 km范围内生态用地演变特征,并从城乡用地冲突和政策有效性角度对这些变化进行探讨。结果表明:(1)耕地大面积减少导致滨江地区生态用地比重下降,由2005年的71.86%下降到2018年的65.54%,但是林草地等半自然生态用地的比重略有上升;(2)林地、内陆滩涂保留率较高,耕地、园地、水域等地类变化以数量净变化为主,而林草地以空间交换变化为主;(3)生态用地流失热点区主要位于中心城区与近郊区间的城乡过渡带,并临近产业园区,建成区扩张是其主要成因;(4)政策规划对滨江生态用地演变作用明显,沿江开发政策加剧了生态用地流失程度,而生态红线等规划对某些重要生态用地保护效果显著,土地利用规划在用地管理方面效果显著,但仍存在耕地、裸地、内陆滩涂被违规侵占现象,长江防洪堤对生态用地保护作用不显著。要使生态空间得以长期存在,不仅需要明晰的政策边界,还需要加快形成公众对生态景观的整体认知和基于生态用地功能目标的保护政策。

The study on the evolution of ecological land in urban waterfront from the middle and small scale can provide important reference for the development and protection policy of ecological land.Based on the land use data in 2005,2009,2014 and 2018,the spatial and temporal dynamic characteristics of the evolution of ecological land use within one kilometer of Nanjing waterfront are analyzed using the transfer matrix and other methods,and the changes are discussed from the perspective of urban and rural land use conflict and policy effectiveness.The results show that:(1)The great loss of cultivated land leads to a sharp decline in the proportion of ecological land in Nanjing waterfront,from 71.86%in 2005 to 65.54%in 2018,while the proportion of semi-natural ecological land such as forest and grass land rises slightly.(2)The forest land and inland beach are highly retained,and the changes of farmland,garden land,water area and inland beach are mainly net change,while the changes of the forest land and grassland are mainly exchange change.(3)The ecological land loss hot spots are mainly located in the urban-rural transitional zone and close to industrial parks.The expansion of built-up area is the main cause.(4)The policy and planning have obvious effects on the evolution of ecological land along the river.The development policies along the river aggravate the degree of ecological land loss,but plannings such as ecological red line have a significant effect on the protection of some important ecological land.Land use planning has a significant effect on land use management,but there are still illegal encroachments of cultivated land,bare land and inland beach.The Yangtze river levees have no obvious effect on the protection of ecological land.To ensure the long-term existence of ecological space,not only clear policy boundaries are needed,but also cultural and image cognitive construction needs to be strengthened to form the public’s overall cognition and the protection policy based on the function goal of ecological land.