青藏高原建设用地的适宜性与适应性及后备潜力评价

Evaluation of suitability,adaptability,and reserve potential of construction land on the Qinghai-Tibet Plateau

青藏高原是重要的生态安全屏障区,厘清青藏高原建设用地的适宜空间对于协调生态保护与人类活动的关系,促进人口与产业的空间优化布局具有重要意义。基于建设用地适宜性评价模型,通过构建基于模型的建设用地适宜性评价“格局—过程”耦合分析框架,评价了青藏高原全域的建设用地适宜性,使用实际建设用地适应性指数和垂直梯度指数解析了1990—2020年实际建设用地对适宜性评价结果的适应性过程及其内部限制因素,测算了后备适宜建设用地潜力。结果表明:①青藏高原建设用地适宜、较适宜、一般适宜、欠适宜和不适宜等级面积占比分别为0.13%、4.04%、7.00%、9.34%和79.50%,青藏高原建设用地适宜性以不适宜等级为主;②1990—2020年青藏高原实际建设用地对适宜性评价结果的平均适应性在80%以上,实际建设用地总体适应建设用地适宜空间的分布特点,但具有显著的空间差异性;③1990—2020年青藏高原对适宜性评价结果低适应的实际建设用地以农村居民点、交通运输用地和特殊用地为主,城镇建设用地和其他建设用地的占比快速升高,青南高原、川西高山峡谷区和祁连山区的建设用地受到高程和坡度的双重限制,而藏北高原、冈底斯山区和喜马拉雅山区的主要限制因素是海拔;④青藏高原后备适宜建设用地潜力面积为12.41万km^(2),占土地总面积的4.81%,人均后备适宜建设用地面积为9928 m^(2)/人,柴达木盆地的后备适宜建设用地资源最为丰富。本文的研究结论可为青藏高原生态移民搬迁和生产力的空间布局优化提供决策参考。

Construction land is the main carrier of human activities such as production and living.Conducting the suitability evaluation of construction land on the Qinghai-Tibet Plateau(QTP)holds the significant implications for harmonizing the relationship between ecological preservation and human activities,as well as promoting the optimization of population and industrial spatial layout.However,there are no relevant studies which provide a complete assessment of the construction land suitability(CLS)on the QTP.In this paper,we developed a model-based CLS assessment framework coupling of patterns and processes to calculate the CLS across the entire QTP based on the CLS evaluation model.Then,using the land-use data of 1990,2000,2010,and 2020,we examined the adaptability of existing construction land to the assessment result of CLS through the adaptability index and vertical gradient index,and further analyzed the internal limiting factors of maladaptive construction land.Finally,we calculated the potential of reserve suitable construction land.This article includes four conclusions:(1)The area of CLS classes,including highly suitable,suitable,moderately suitable,marginally suitable,and unsuitable,are 0.33×104 km2,10.42×104 km2,18.06×104 km2,24.12×104 km2,and 205.29×104 km2,respectively,accounting for 0.13%,4.04%,7.00%,9.34%,and 79.50%of the total land area,respectively,with the unsuitable class being predominant.The highly suitable,suitable,and moderately suitable classes are mainly distributed in regions such as the Qaidam Basin,Yellow River-Huangshui River Valley,Gonghe Basin,Songpan Plateau,Shigatse Valley,Lhasa-Shannan Valley,and Nyingchi Valley.(2)The construction land adaptability index are 85.16%,85.93%,85.18%,and 78.01%in 1990,2000,2010,and 2020,respectively,with an average adaptability index exceeding 80%on the QTP.The distribution of existing construction land generally conforms to the characteristics of construction land suitable space,but with a significant spatial difference.(3)From 1990 to 2020,the mal-adaptive and low-adaptive construction land on the QTP is mainly composed of rural residential land,transportation land,and special land,the proportions of urban construction land and other construction land are rapidly increasing.The vertical gradient of elevation and slope of construction land have gradually strengthened,and the spatial extent has expanded.Construction land in the southern Qinghai Plateau,western Sichuan alpine canyon region,and Qilian Mountains is subjected to constraints of both elevation and slope,while the main limiting factor in the northern Tibetan Plateau,Gangdise Mountains,and Himalayan Mountains is elevation.(4)The potential area of reserve suitable construction land on the QTP is 12.41×104 km^(2),constituting 4.81%of the total land area,with suitable and moderately suitable classes dominant.The per capita potential area of reserve suitable construction land is 9928 m^(2)/person.The Qaidam Basin has the richest reserve of suitable construction land,while the Gonghe Basin and Lhasa-Shannan Valley can serve as preferred destinations for ecological migration.The research results can provide decision-making references for ecological migration and optimizing the spatial distribution of human activities on the QTP.