基于生境质量的绿洲城镇空间扩展模拟研究——以黑河中游地区为例

绿洲是生态环境极为脆弱的区域。实现绿洲城镇化与生态安全的双赢,是干旱区面临的重大问题。传统城镇空间扩展模拟研究,只是单向考虑了城镇发展趋势,而较少兼顾区域生境质量的约束。利用1992、2000、2008、2015年四期Landsat TM、ETM+、OLI遥感影像数据,以黑河中游地区为例。从城镇空间扩展与生态环境协调发展的角度出发,通过InVEST模型与SLEUTH模型的结合,将生境质量的评估结果融入到城镇扩展模型中,对研究区2015—2030年城镇扩展的土地利用变化格局进行模拟。研究表明:①生境质量整体较低,质量阶序和退化程度分异明显。高、中等级生境质量区域主要分布在黑河干流沿线和绿洲核心区,分别占5.69%、32.77%,生境退化程度高;低等级生境质量区域主要分布在戈壁荒漠区和城镇建设区,占61.54%,生境退化程度低。②生境质量对城镇空间扩展的约束作用显著。相比较无生境质量约束,2030年城镇建设用地面积和占用生态用地面积分别减少了27.08%、63.61%,并且,城镇斑块间连接性较好、集聚程度高,以"填充式"扩展为主。③城镇空间扩展总体体现了生境质量的要求。2030年新增城镇建设用地主要占用中、低等级生境质量区域,分别为34.88%、63.36%。绿洲平原区和山前洪积扇区生境质量约束较强,较2015年仅增长了51.53%、48.31%;绿洲边缘区生境质量约束性低,较2015年增长了110.18%,是未来城镇发展的潜力区。研究结果为绿洲城镇与生态环境协调发展提供科学依据。

Simulation of urban spatial expansion in oasis towns based on habitat quality: a case study of the middle reaches of Heihe River

The oasis is a region with extremely fragile ecological environment. It is a major problem for arid areas to realize the win-win situation of urbanization and ecological security in oasis. The traditional simulation of urban spatial expansion only considers the urban development trend unilaterally, but less think about the constraints of regional habitat quality. Based on the Landsat TM, ETM+, OLI remote sensing image data of 1992, 2000, 2008 and 2015, we took the middle reaches of Heihe River as an example. From the perspective of coordinated development of urban spatial expansion and ecological environment and through the combination of InVEST model and SLEUTH model, the assessment results of habitat quality were integrated into the urban expansion model to simulate the land use change pattern of urban expansion in the study area from 2015 to 2030. The results showed that: 1) the overall quality of habitat in the study area was low, and the order of quality and the degree of degradation were obviously different. The high and middle grade habitat quality areas were mainly distributed along the main stream of Heihe River and the core area of oasis, accounting for 5.69% and 32.77%, respectively, but with a high degree of habitat degradation. The low-grade habitat quality areas were mainly distributed in Gobi desert area and urban construction area, accounting for 61.54%, with a low degree of habitat degradation. 2) The restriction effect of habitat quality on urban spatial expansion was significant. Compared with the non-habitat quality constraints, the area of urban construction land and the area of ecological land occupied decreased by 27.08% and 63.61% in 2030, respectively. Moreover, the connectivity between urban patches was better and the degree of agglomeration was higher, and the "filling" expansion was the main type. 3) Urban spatial expansion generally reflects the requirements of habitat quality. In 2030, the newly added urban construction land mainly would occupy the middle and low grade habitat quality areas, accounting for 34.88% and 63.36%, respectively. The habitat quality of oasis plain and piedmont alluvial sector would be strongly constrained, which only increased by 51.53% and 48.31% compared with 2015. The constraint of habitat quality in oasis marginal area would be low, which increased by 110.18% compared with 2015. It would be the potential area of urban development in the future. The results of study provides scientific basis for the coordinated development of oasis towns and ecological environment.