西安市城市景观的正负生态系统服务测算及空间格局

Positive and negative ecosystem services evaluation and its spatial pattern analysis on urban landscape:A case study of Xi'an City

综合测评城市景观的复合（正负）生态系统服务功能和评价不同城市景观类型的生态系统服务贡献，对优化、调控在城市化影响下的景观转换和城市生态环境建设等具有重要的科学意义。运用景观生态学理论与生态系统服务理论，基于研究区的TM遥感影像和Erdas、Arc GIS10．1软件对西安市建成区2013年城市景观的复合生态系统服务进行测算和空间分析。结果表明：①西安城市景观产生的负向生态系统服务价值远高于正向生态系统服务价值，净生态系统服务达-12．71×10^8元；在城市化过程中，随着自然景观向半人工景观、人工景观的转变，导致景观生态系统服务的价值急剧下降，负向生态系统服务占主导，87．81％的土地复合生态系统服务为负值，仅有12．19％的土地复合生态系统服务为正值，以建筑用地为主体的城市景观体系必然会导致生态系统服务的下降。②西安市城市景观的总正向生态系统服务空间分布差异明显，整体呈现为研究区中心值低于四周，沿行道绿地、公园绿地等景观形成格网状、斑块状分布的高值区；总负向生态系统服务整体上呈现中心值高于四周，高值区较集聚，自然景观和半人工景观是维系城市正向生态系统服务的主要景观类型。③城市景观的空间分布基本上决定了复合生态系统服务的空间大格局，西安市各城市景观类型的空间组合与镶嵌状况，使得生态系统服务正负值呈斑块状、棋盘状交错分布的格局。愈向城市外围，复合生态系统服务价值越高；城中林地、绿地和水域分布的地方是复合生态系统服务价值网状高值区。

Comprehensive assessment of the positive ecosystem services and disservices provided by urban landscape and evaluation of its contribution of different urban landscapes to total value of ecosystem services, are crucial to optimizing and regulating the urban landscape configuration and the eco-environment construction in rapid urbanization. Based on the knowledge of landscape ecology and ecosystem service and the Landsat images （OLI-TIRS） data, we valued the ecosystem services of urban landscape including its disservices and analyzed their spatial pattern of Xi＇an urbanized area by building the models and employing software of ERDAS, ArcGIS 10.1 in 2013. The results showed that： （1） The disservice value of urban landscape is remarkably higher than the positive ecological service value, and the net value is approximately -12.71×10^8 yuan in Xi＇an city. In the process of rapid urbanization, the positive service value of urban landscape dramatically decreased and the negative service took up a large proportion of total values resulting from the transformation from natural landscape to semi-artificial landscape and artificial landscape, 87.81% of the urbanized area provided for negative net value of ecosystem services, and only 12.19% of the area provided positive net services. The expansion of urban landscape dominated by large built-up area will inevitably lead to the decline in ecosystem service value. （2） The value of positive ecosystem services provided by urban landscape in Xi＇an city varied from urban core area to urban fringe obviously, which is lower in central area than in fringe area; And the high value area close to the road and in the parks shows the mixed patterns with plaque and grid. The total value of negative ecosystem services in the inner area is higher than that in the urban fringe, and high value area is more concentrated in space. Natural landscape and semi-artificial landscape are the main providers of the positive ecosystem services in city. （3） The spatial distribution of the urban landscape fundamentally determines the spatial pattern of the comprehensive ecosystem services, and the mosaic of different urban landscape types reflects the spatial pattern of the positive and negative ecosystem services shaped by the patches and the chessboard structure. The nearer to the area of urban fringe, the higher the comprehensive ecosystem services value is. There are the high value areas where the forest, grassland and water were distributed or scattered in the park or along road side in the city.