格网尺度下青海玛多县土地利用及生态系统服务价值空间自相关分析

Spatial autocorrelation analysis of land use and ecosystem service value in Maduo County, Qinghai Province, China at the grid scale

开展黄河源区土地利用和生态系统服务价值空间量化评估,对于保障黄河流域生态安全具有重要意义。以黄河源区玛多县为例,基于3 km×3 km网格单元,应用空间自相关方法构建生态系统服务价值评价模型,定量评价了2015年玛多县土地利用/覆被空间自相关格局特征,可视化表达了玛多县生态系统服务价值空间信息。结果表明:在3 km×3 km格网尺度下,不同覆盖度草地覆盖范围广阔;水域网格占总网格数的42.9%,在玛多县西北部分布密集;建设用地呈东北-西南走向的"线条式"分布;未利用土地体现为西南多、东北少的分布格局。在空间上,玛多县土地利用类型网格之间相互影响,表现为正相关性和聚集分布。水域的全局Moran I和局部Moran I值均最大,空间聚集性最强,局部连片度较高。建设用地的全局Moran I和局部Moran I值分别为0.293和0.127,空间自相关性最弱,在小范围内呈聚集特点。2015年,玛多县生态系统服务价值(ESV)为938.87亿元,网格的ESV平均值为3.20×10~7元,最大值为19.96×10~7元,水域分布网格是ESV的高值区。玛多县ESV分布格局整体上呈显著的空间正向自相关,ESV在网格之间为聚集分布。不同土地利用类型ESV网格总体呈高高、低低聚集,在局部零星为高低、低高聚集。可采取的国土空间规划与用途管制策略包括:水域、未利用土地采用强调生态溢出价值的"集中连片式"保护模式,高、中、低覆盖度草地采取主次分明、划区管理的"组团式"生态治理模式,建设用地在"廊道式"分布格局中采取小范围集约化开发利用模式。

Research on the spatial quantitative evaluation of land use and ecosystem service value in the source region of the Yellow River is of great significance for ensuring the ecological security of the river basin. Taking Maduo County in the source region of the Yellow River as an example, based on a 3 km × 3 km grid unit, the spatial autocorrelation method was applied to construct an evaluation model of ecosystem service value. The spatial autocorrelation pattern characteristics of Maduo County in 2015 was quantitatively evaluated, and the spatial information of ecosystem service value was visually expressed. The results showed that, at the examined grid scale, the area of grasslands with different coverages was large, and water grid area accounted for 42.9% of the total grids and was mainly distributed in the northwest of Maduo County. The construction land showed a "line-like" distribution from northeast to southwest, while the unutilized land was more distributed in southwest and less in northeast. In space, different land use type grids interacted with each other, with positive correlation and cluster distribution. The values of global Moran I and local Moran I of water area was the largest, with strongest spatial aggregation and high local connectivity. The global Moran I and local Moran I values of the construction land were 0.293 and 0.127, respectively, with the weakest spatial autocorrelation and clustering characteristics in a small range. In 2015, ecosystem service value(ESV) of Maduo County was 93.887 billion yuan, the mean ESV across all the grids was 3.20×10~7 yuan, with a maximum of 19.96×10~7 yuan. The water distribution grid had high ESV. On the whole, the ESV distribution pattern in Maduo County had a significant spatial positive correlation, with clustered ESV grids. The ESV grids of different land use types generally showed high-high cluster and low-low cluster, with the spatial pattern of high-low cluster and low-high cluster being sporadic. We proposed several possible strategies of land space planning and use control. First, the water and unused land should adopt a "centralized continuum" protection mode that emphasize the value of ecological spillovers. Second, grasslands with different coverage levels should adopt a "group-type" eco-governance model of primary and secondary division and zoning management. Third, construction land should adopt a small-scale intensive development and utilization model in a "corridor " distribution pattern.