中国西南山区稻作梯田的时空演化——以苗岭西江镇和加榜乡为例

稻作梯田是中国南方山区重要的土地利用方式,分析其时空变化规律,对区域土地资源利用、生态环境保护以及农村农业可持续发展具有重要意义。本文基于多源数据获取苗岭山区西江镇（1977—2020年）和加榜乡（1962—2020年）的土地利用分类图,运用景观指数、空间分析和样带分析等方法,研究稻作梯田时空格局与功能的演化特征,以揭示稻田利用与人地关系演变过程及其特殊性变化。结果表明：① 研究区稻田规模长期稳定发展,但近年整体规模有所缩小,斑块破碎化趋势逐渐凸显。在2000年前稻田分布表现出同时向高、低海拔及微坡至急陡坡扩展,2000年后呈反向收缩趋势,种植强度呈相同的变化规律。② 研究区稻田核密度的空间分布,表现出小规模高密度集聚与大规模中低密度分布并存的格局。自2000年以来,两地稻田核密度以小幅变化为主,有明显的“东北-西南”向分布特性。③ 在生产用地导向阶段,大面积林地转为稻田;在生态-经济复合用地导向阶段,稻田规模保持稳定。④ 聚田比指数显示研究区“人多田少型”占比不断上升,这表明部分地区人地矛盾日渐凸显,以西江镇的变化最为强烈。⑤ 依据“林-田-村-河”四素同构的样带分析,稻田功能经历了“生产-生态、经济”的演变过程,与旅游业发展关系密切。研究结果较全面反映了研究区稻作梯田的时空演化特征,有助于促进山区传统稻田资源优化利用和保护传承,在一定程度上为乡村振兴发展提供借鉴。

Spatio-temporal evolution of rice terraces in mountainous areas of Southwest China: A case study of Xijiang and Jiabang townships,Miaoling

Rice terraces are an important land use way in mountainous areas of southern China, so analyzing its spatio-temporal change law is of great significance to regional land resource utilization, eco-environmental protection, and sustainable agricultural development. Based on multi-source data, we obtain the land use classification maps of Xijiang Township (1977-2020) and Jiabang Township (1962-2020) in the Miaoling Mountains. We use landscape index, spatial analysis and sample transect analysis methods to examine the spatio-temporal pattern and function evolution of rice terraces, and to reveal the evolution and particularity of rice field use and human-land relationship. The results show that: (1) The scale of the rice fields in the study area has been developing steadily for a long time, but the overall scale has decreased in recent years, and the trend of patch fragmentation has gradually become prominent. Before 2000, the distribution of rice fields expanded to high and low altitudes, from a slight slope to a sharp slope. After 2000, the distribution of rice fields showed a shrinking trend, and the planting intensity presented the same change pattern. (2) The spatial distribution of rice field kernel density showed a pattern of co-existence of small-scale high-density cluster area and large-scale medium-low density distribution. Since 2000, the kernel density of the rice fields has changed slightly, and the distribution of the rice fields is from northeast to southwest. (3) In the productive land-oriented stage, a large area of forest land is converted into rice fields; in the ecological-economic compound land-oriented stage, the rice field scale remains stable. (4) The ration index shows that the proportion of “more people and fewer fields” type is increasing, indicating that the human-land contradiction in some areas is increasingly prominent, especially in Xijiang Township. (5) According to the analysis of the four-element isomorphic transect of “forest-terraces-village-river”, the function of the rice fields has undergone a process of “production-ecology/economy,” which is closely related to the development of tourism. The research results comprehensively reflect the spatio-temporal evolution characteristics of rice terraces in the study area, which is helpful in promoting the optimal utilization, protection and inheritance of traditional rice field resources in mountainous areas as well as the revitalization and development of rural areas.