清末民国时期新疆玛纳斯河流域耕地格局重建

Reconstruction of cropland spatial patterns of the Manas River Basin of Xinjiang in the late Qing and Republican period

典型地区历史时期高分辨率土地利用变化重建对研究过去全球环境变化具有十分重要的意义。本文选取干旱区典型的玛纳斯河流域,在整理历史耕地记载的基础上,订正了1909年和1944年两个时间断面上的流域耕地面积,并通过选取河流渠道等影响因子建立了土地宜垦性模型、网格化分配模型,重建了1909年和1944年玛纳斯河流域1 km×1 km耕地网格化空间分布格局。结果显示:①1909年和1944年玛纳斯河流域耕地面积分别约为140.5 km^2和241.7 km^2,年均增长2.9 km^2,清末民国时期耕地面积增长迅速;②北部沙漠区和南部山区均受到开发限制,无法开垦,耕地主要分布在中下游平原的河渠两岸,玛纳斯河中游地势平坦、渠道众多,耕地分布比较集中;③从垦殖强度分析,玛纳斯河流域1909年平均垦殖率仅有0.2%,最高垦殖率为6.4%,1944年平均垦殖率为0.4%,最高垦殖率为11.0%,因此,清末民国时期流域内开发程度较低;④通过对HYDE3.2中1910年和1940年耕地数据的比较,HYDE3.2在玛纳斯河流域的数据明显偏高。本文重建的两个时间断面上的玛纳斯河流域耕地网格化数据集,进一步修正了全球变化数据集的区域精度,可为深入研究干旱区乃至全球环境变化提供数据支持。

Many studies have shown that land use and land cover change(LUCC)has played a key role in regional and global environmental change.It is important to have a historical LUCC database,especially high-resolution land cover database,to simulate the influence of LUCC on the climate and ecosystem.There exist several important historical databases of the global environment,but the accuracy of regional data should be reexamined.In this study,we extracted the archival data that are related to the cropland area in 1909 and 1944 for the Manas River Basin in Xinjiang.These data were subsequently revised and calibrated to estimate historical cropland areas.We reconstructed cropland change of the basin in the late Qing and Republican period.We divided the study area into 1 km×1 km grids and allocated cropland area to these grids and built a high resolution dataset(at a 1 km×1 km resolution).We analyzed the spatiotemporal variation characteristics of cropland,and reached the following conclusions:The cropland area of the Manas River Basin in 1909 was about 140.5 km^2,and in 1944 it was about 241.7 km^2.The cropland area average annual increase rate was about 2.9 km^2 from 1909 to 1944.Limited by the natural environment and water resources,the cropland was mainly distributed on the plains in the middle and lower reaches of the river.The cropland covered about 19.9%of the Manas River Basin.The mean cropland fraction of the Manas River Basin in 1909 was about 0.2%and in 1944 it was about 0.4%.The maximum cropland fraction in 1909 was about 6.4%and in 1944 it was about 11.0%.Compared with HYDE3.2(cropland 1910 AD and cropland 1940 AD),the cropland area from HYDE is higher than the reconstruction results.