典型经济快速发展区耕地变化区域分异研究

耕地变化的区域分异研究可为确保国家粮食安全和生态安全提供重要依据。基于RS和GIS技术,分析太湖流域1985~2015年耕地数量、质量和动态结构的时空演化格局。结果表明:近30a流域耕地呈现以城镇为中心面的边缘扩散和以乡镇为中心点的散布流失特征,导致耕地净减少了38.87%,其中环湖、沿江城市密集区及县域空间拓展区是耕地流失的热点区域。耕地集中连片分布区与经济发展快速区的空间复合导致耕地缩减与建设用地扩张呈现空间对应关系,建设占用始终是驱动耕地减少的主要因素。不同阶段受经济发展水平和农业政策影响,不同地类对耕地转移的贡献率和空间分布差异明显,且转移比例在数量和质量上均不对等。总体上,耕地变化呈现由缓慢零散占用到快速集聚流失的过程,耕地数量和质量变化高值和低值区亦表现由分散到集中的格局,最终驱动了耕地优势区由环湖平原区向西南丘陵区的空间转移。

RESEARCH ON SPATIAL HETEROGENEITY OF CROPLAND CHANGE IN RAPID ECONOMIC DEVELOPMENT AREA

Research on spatial heterogeneity of cropland is an important basis for ensuring food security and ecological security.This study analyzed spatio-temporal variations of cropland quantity and cropland quality during 1985 to 2015 based on Remote Sensing(RS) and Geographic Information System(GIS).The results showed that the cropland decreased by 38.87％ in the past 30 years.It was characterized with high level of urbanization in the suburbs,where had a special pattern as ‘ marginal spreading'to the loss of cropland,whereas the area of underdeveloped villages featured a pattern of ‘ scattered points' to the loss of cropland.The intensive urban areas and spatial extension areas along the Yangtze River and the Taihu Lake were identified as the hot spot with a huge cropland loss.The reduction of cropland and the expansion of construction land showed a significant consistency in space.It was highly related to the spatial overlay of the rapid-economic-development areas and the concentrated cropland areas.Urban land expansion was the major driver force to cropland loss.Due to the impact of economic development level and agricultural development policy,the adjustment between cropland and other land use types varied in different stages.The roll-in and roll-out of cropland did not match both in surface area and quality.Generally,the change pattern of cropland shifted from a slow-scattered loss to a rapid-agglomeration loss.The distribution pattern of cropland with steep variation (in both quantity and quality) had shifted from dispersion to centralization,which was also showed in the cropland with slowly variation.It drives the dominant area of cropland shift from the plains surrounding Taihu Lake to the hilly area in the southwest.