基于线性拟合的城市化过程对陆地生态系统生产能力的影响——以江苏省为例

Impact of urbanization on terrestrial ecosystem production using Linear Modeling for Jiangsu

陆地生态系统生产能力是区域生态系统服务的基础。城市化过程已经成为区域陆地生态系统生产能力损失的重要影响因素。借助遥感与地理信息技术估算区域的净初级生产力(NPP)、分析城市化过程对于定量评估城市化过程造成的区域陆地生态系统生产能力损失具有重要意义。本研究以城市化进程较快的江苏省为例,通过1985—2015年间5期江苏土地利用与覆被(LUCC)数据,分析近30年来江苏省城市化过程。同时,利用改进的CASA模型估算对应年份的NPP,引入分段线性回归拟合的方法精确评估城市化过程对NPP演变的影响。结果表明:借助线性拟合方法可以有效提高NPP损失评估的精度;江苏省1985—2015年间城市建设用地扩张呈缓慢的上升趋势,累计扩张10 452.74 km^2,2005—2010年间扩张最快,苏南快于苏北;江苏省陆地生态系统生产能力(NPP)为(33.3~40.23)Tg C/a,呈缓慢上升的趋势,中南部的盐城与南通最高;近30年来江苏省城市建设用地扩张累计造成的陆地生态系统生产力损失约为4.43 TgC^5.99 TgC,其中,耕地被占用损失最大,湿地次之。研究预示,苏北未来陆地生态系统生产能力损失将大于苏南。提高未来城市化的质量,特别是绿地率,可以缓解城市化带来的未来陆地生态系统生产能力的损失。

Terrestrial ecosystem production capacity is fundamental to regional ecosystem service functioning. Urbanization processes have been the main influencing factor to reduce terrestrial ecosystem production. Here we use net primary productivity（NPP） and urbanization determined using remote sensing and GIS to study the impact of urbanization on terrestrial ecosystem production losses. Remote sensing images from Jiangsu in 1985, 1995, 2005, 2010 and 2015 were collected to record land use and cover change（LUCC） processes from 1985 to 2015. NPP of corresponding times were determined using the Carnegie-Ames-Stanford Approach. We found that urban construction lands of Jiangsu rose slowly from 1985 to 2015, and reached 10452.74 km2.During this period, the expansion rate peaked from 2005 to 2010. The urban construction land expansion rate in southern Jiangsu is significantly higher than that of northern Jiangsu. Jiangsu＇s NPP varied from 33.3 to 40.23 Tg C/yr and had a rising tendency from 1985 to 2015 and the southcentral part of which is highest including Yancheng City and Nantong City. The precision of NPP loss estimation rises significantly under linear modeling comprised using the traditional equalization method. Urban construction land expansion of Jiangsu triggered a significantly decrease in terrestrial ecosystem production losses of 4.43-5.99 Tg C over the past 30 years, of which the decreasing NPP in croplands caused by urbanization was the major reason, followed by wetlands. This study reveals that the rate of terrestrial ecosystem production loss in northern Jiangsu will be faster than that of southern Jiangsu in the future. Promoting urbanization quality,especially increasing the greening rate, will effectively mitigate the risk of terrestrial ecosystem production loss.