洞庭湖区土地生态系统的服务价值时空变化

采用5期遥感影像数据,在ArcGIS等软件支撑下,运用当量因子法、空间自相关分析法,估算洞庭湖区土地生态系统服务价值,探究其时空变化。结果表明：① 1995—2015年洞庭湖区林地面积持续减少,未利用地面积稳步增加,林地与未利用地面积的增减主导着区域土地利用变化。② 1995—2015年洞庭湖区土地生态系统服务总价值经历1995—2000年的陡增后不断下降,近20年来累计减少21.64亿元,减少幅度为1.06%,林地面积减少是洞庭湖区土地生态系统服务总价值减少的根本原因。③ 从土地生态系统服务价值结构变化来看,1995—2015年洞庭湖区除废物处理价值有小幅增加外,其他各项生态服务价值均有不同程度的下降,但生态环境保育始终是洞庭湖区土地生态系统的主要功能。④ 1995—2015年洞庭湖区土地生态系统服务价值分布的空间自相关性较为显著,格局变化较明显,高值区、低值区趋于集中,高-高类型区在西部的沅江流域常德段有所减少,向东部的汨罗江流域快速扩展,低-低类型区集中在北部、南部、西部的城镇相对密集区并沿城镇发展轴逐步扩张凝结成带片状。

Spatial and temporal changes of land ecosystem service value in Dongting Lake area in 1995-2015

Based on the 5 phases remote sensing image data of Dongting Lake area in 1995, 2000, 2005, 2010 and 2015, under the support of ArcGIS and Geoda software, this paper used the equivalent factor method, spatial autocorrelation analysis method to estimate the service value of land ecosystem in Dongting Lake area and explore the temporal and spatial changes of land ecosystem service value in the Dongting Lake. The results are shown as follows: (1) The forest area continued to decrease and unused land area increased steadily from 1995 to 2015, cultivated land area kept rising after a large scale reduction in 1995-2000, wetlands area and waters area decreased gradually after a mass increment in 1995-2000, grassland area fluctuated from 1995 to 2015; a great reduction of forest area and significant increment of unused land area dominated the land use changes in this area in recent 20 years. (2) The total service value of land ecosystem in the study area from 2000 to 2015 was declining after the steep increment in 1995-2000, and it decreased by 21.64×10⁸ yuan, or 1.06%, in the past 20 years. The reduction of forest area was the fundamental reason for the decrease of total value of land ecosystem service in Dongting Lake area. The overall increment of wetlands area cut down the reduction margin of land ecosystem service total value. (3) In terms of the change of land ecological service value structure, the other individual ecological service value had been reduced in varying degrees apart from the slight increment of the waste treatment value, and the eco-environment conservation was always the main function of the Dongting Lake area. (4) The spatial autocorrelation of land ecosystem service value distribution was more significant in Dongting Lake area from 1995 to 2015, its high-value and low-value zones tended to be concentrated, and the agglomeration of spatial distribution of land ecosystem service value was enhancing. The spatial distribution pattern of land ecosystem service value changed obviously, the area of high-high value type zones had been reduced in the Yuanjiang River watershed of Changde, but was rapidly extending to Miluojiang River watershed, while low-low value type zones were mainly concentrated in highly concentrated town area in the north, south, west of the Dongting Lake area, and was expanding gradually to form a sheet along the town development axes and important traffic corridors.