沂河流域土地利用时空变化图谱特征分析

基于沂河流域1995年、2005年和2015年土地利用空间数据,运用地学信息图谱方法构建1995-2005年和2005-2015年两个时序单元的土地利用转移图谱和涨落势图谱,分析了沂河流域近20年来的土地利用时空变化规律及发展过程。结果表明:(1)1995-2015年,沂河流域土地利用结构以耕地和林地为主,其中耕地和草地减少,林地和建设用地增加是主要变化趋势。(2)土地利用转移图谱以耕地与林地、草地之间的相互转换以及建设用地占用耕地为主,林地、草地转变为耕地主要发生在费县和平邑县中部地势平缓的山前平原,耕地转变为林地、草地则主要分布于研究区北部和西南部土壤侵蚀较为严重的山区,耕地转变为建设用地主要集中在各县市城区周边经济相对发达的区域。两个时序单元中,发生变化的主要图谱单元类型及面积存在显著差异,2005-2015年土地利用发生转换的空间进一步扩张。(3)土地利用涨势图谱中新增耕地面积最大,占新增面积的比例为33.87%;落势图谱中耕地萎缩面积最大,占萎缩面积的比例为51.38%。两个时序单元中,各县市涨落势图谱变化存在明显差异。该研究可为沂河流域土地资源的可持续利用及生态建设提供科学依据。

TUPU characteristics of spatiotemporal variation for land use in the Yihe River Basin

Research on the land use change in the Yihe River Basin is of great significance to the comprehensive management of regional ecological environment, rational exploitation of land resources and conservation of soil and water. Based on spatial data of land use covering three periods (1995, 2005, 2015) in the Yihe River Basin, this paper used geo-information TUPU methods to build transition TUPU and fluctuation TUPU of land use at two stages (1995-2005, 2005-2015) supported by 3S technology. Then the spatial-temporal change characteristics, laws and development process of land use in recent 20 years in the study area are discussed. The results showed that: (1) From 1995 to 2015, the land use structure in the Yihe River Basin was dominated by cultivated land and forest land, among which the decrease in cultivated land and grassland and the increase in forest land and construction land were the main change trends. (2) The transition TUPU of land use was dominated by the conversion of cultivated land, forest land and grassland, and the occupation of cultivated land by construction land. The conversion of forest land and grassland to cultivated land mainly occurred in the plains of the central part of Feixian county and Pingyi county. The conversion of cultivated land to forest land and grassland was mainly found in the mountainous areas where soil erosion was more serious in the north and southwest of the study area. The conversion of cultivated land to construction land was mainly concentrated in the regions with relatively developed economy around the urban areas of counties and cities. Between the two stages, there were significant differences in the types and areas of the main TUPU units that have changed. The space of land use conversion between 2005 and 2015 was further expanded. (3) In the rising TUPU of land use, the area of newly added cultivated land was the largest, accounting for 33.87% of the newly added area. Moreover, in the falling TUPU of land use, the area of decreased cultivated land was the largest, accounting for 51.38% of shrinking area. In the two sequential elements, there were significant differences in the changes in the rising TUPU and falling TUPU of each county. This study can provide a scientific basis for the sustainable utilization of land resources and ecological construction in the Yihe River Basin.