喀斯特多山城市生境质量对土地利用变化的时空响应——以贵阳市为例

在喀斯特地区，随着城市的快速扩展，城市建设用地在山间平缓地带延展，大量的自然山体被包围，最终被镶嵌于城市建成区内，形成了城市遗存山体。喀斯特多山城市内部的城市遗存山体是城市生境的主要组成部分，具有多种不可替代的生态系统服务功能。以典型喀斯特多山城市贵阳市建成区为例，基于2008—2018年土地利用数据和InVEST模型定量分析研究区土地利用、景观格局和生境质量时空演变特征。最后利用地理加权回归模型揭示生境质量与土地利用变化之间的响应关系。研究结果表明：(1)2008—2018年耕地、城市遗存山体、林地在研究期间分别减少94.56 km²、8.74 km²、6.8 km²,土地利用变化主要以耕地、城市遗存山体和林地转化为建设用地为主，景观斑块破碎化和空间异质性逐渐加强。(2)2008—2018年生境质量空间聚集效应明显，平均水平较低且呈现下降的趋势，低水平生境质量面积占比从2008的38.29%增加到2018年的60.32%。适中和高水平生境质量面积占比分别下降1.95%和4.15%,生境质量退化面积达82.78 km

Spatio-temporal responses of urban environment quality to land use change in mountainous cities of Karst areas

In the karst area along with the rapid expansion of the city, the urban construction land extends in the gentle area between the mountains, and a large number of natural mountains were surrounded by construction land, and finally were inlaid in the urban built area, forming the urban remnant mountains (URMs). The URMs in karst mountainous cities were the main part of urban habitat and have many irreplaceable ecosystem service functions. Taking the built-up area of Guiyang city, a typical karst mountainous city, as an research area, the temporal and spatial evolution characteristics of land use, landscape pattern and habitat quality (HQ) were studied based on the land use data from 2008 to 2018 by InVEST model. Finally, the geographical weighted regression model was used to reveal the response relationship between HQ and land use change. The results showed that:(1) from 2008 to 2018, the areas of cultivated land, URMs and woodland decreased by 94.56 km², 8.74 km² and 6.8 km² respectively. The land use change was mainly dominated by the transformation of cultivated land, URMs and woodland into construction land, and the fragmentation of landscape patches and spatial heterogeneity were gradually strengthened. (2) The spatial aggregation effect of HQ was obvious from 2008 to 2018, with a low average, and the proportion of low level HQ area increased from 38.29% in 2008 to 60.32% in 2018. The proportion of moderate and high level HQ area decreased by 1.95% and 4.15% respectively, the degraded HQ area reached 82.78 km², and the proportion of comparatively high level HQ area increased by 3.98%. The patches of HQ tended to be fragmented, diversified and uniform, and the high HQ areas mainly distributed in the urban parks and the URMs. (3) The HQ was positively correlated with the land use change of urban green space, URMs, woodland and water, but negatively correlated with the changes of land use of construction land, transportation land, cultivated land and unused land. The HQ changes were dominated by human activities. (4) URMs were the main contribution sources of high level HQ in mountainous cities. However, from 2008 to 2018, with the increase of the complexity of urban land use, the HQ of URMs was obviously degraded. This study contributes to further understanding of the relationship between land use change and HQ in karst mountainous cities and could provide scientific support for ecological conservation and landscape planning in China and other similar regions around the world.