呼和浩特市生境质量对城市用地扩展的时空响应

以呼和浩特市为研究区,采用梯度分析法,结合InVEST模型,在评价研究区近27 a城市用地扩展及生境质量演变的基础上,运用双变量空间自相关剖析生境质量对城市用地扩展的时空响应。结果表明:(1)研究时段内,城市扩展表现为核心区的低密度扩张及外围区的多点扩散,紧凑度不断下降,城市结构不稳定,扩展模式不尽合理。(2)生境平均值从0.49下降到0.44,质量等级跌至较差水平。低等级生境主要呈圈层向南部、东南部扩散,与建设用地扩展方向基本一致。(3)建设用地扩展强度与生境质量变化空间分布呈负相关关系,核心外围区的建设用地扩展始终为变化最强烈的地带,生境质量退化也最为剧烈。(4)斑块密度不断上升,特别是建设用地斑块的增加使得城市景观格局愈发破碎。

Spatiotemporal response of habitat quality to urban expansion in Hohhot City

This paper evaluated the evolution of urban expansion and habitat quality in the Hohhot City,Inner Mongolia,China from 1990 to 2017 using gradient analysis and an InVEST model. A bivariate spatial auto-correlation was employed to ascertain the impact of urban expansion on habitat quality. The results showed that urban expansion during the period was characterized by low-density expansion in core areas and multi-point diffusion in periphery areas. The urban areas became less compact and stable,exhibiting uneven development. Secondly,the average habitat value decreased from 0.49 to 0.44,and the quality dropped to a worse level. Low-grade habitats primarily diffused to the south and southeast in a circular layer,which is consistent with the direction of construction expansion. Thirdly,there was a negative spatial correlation between the change in urban expansion and habitat quality. This is because urban expansion in the core-periphery areas remains the most intense changing zones where habitat quality degradation happen. In addition,there is a rising trend in the density of patches and an increasing use of patches during construction,which have aggravated the fragmented urban landscape.