中国市域自然保护区时空格局演变特征

City-scale spatiotemporal evolution characteristics of nature reserves in China

市域是自然保护地整合优化的具体实施单元,揭示市域自然保护区的时空格局演变特征和发展趋势对于全面建设中国特色自然保护地体系具有重要的现实意义。基于1975—2020年间隔5 a的10期中国自然保护区名录,通过标准差椭圆、探索性空间数据分析、空间Markov链等方法首次从市域尺度探讨了中国自然保护区的时空动态演变特征和发展趋势,并引入地学信息图谱构建其变化模式。结果表明:(1)中国市域自然保护区比例呈现先快速增长后逐步稳定的趋势,但整体仍以低值区为主。市域间自然保护区比例差异明显,逐步形成了“西高东低”的空间格局。重心整体表现为“东南-西北-东北”的迁移过程,重心移动距离和速度逐渐缩小。1990年以后,中国市域自然保护区比例始终呈现“东北-西南”向的空间分布格局。(2)市域自然保护区比例存在显著的空间相关性且相关性总体呈上升之势,但空间集聚水平的变化逐年缩小。局部空间异质性较强,高高和低低集聚区均呈扩张态势。(3)从变化模式图谱来看,中国市域自然保护区比例等级以“前期变化-低频-逐步提升”(ESC-LQ-T1)的方式进行,主要图谱类型为“空缺区转为低值区”。市域自然保护区比例等级类型转移具有稳定性和显著的时空异质性,后期出现了“俱乐部收敛”现象,且邻域背景在其动态变化过程中发挥着重要作用。未来要加强对空缺区和低值区市域单元的自然资源进行摸底评估,将其最有价值的区域纳入自然保护区,同时推广区域联合保护机制,促进自然保护地体系高质量建设。

Administrative city is the specific implementation unit for the integration and optimization of nature reserves.It is of great practical significance to reveal the spatio-temporal evolution characteristics and development trend of city-scale nature reserves for the comprehensive construction of the nature reserves system with Chinese characteristics.Based on 10 observations of China′s Nature Reserve Lists with a 5-year interval from 1975 to 2020,the standard deviation ellipse,exploratory spatial data analysis and spatial Markov Chain methods were first applied to characterize the spatio-temporal evolutions and developmental trends of Chinese nature reserves at the city-scale in this analysis,followed by the introduction of geo-informatic atlas analysis to construct the changing pattern of Chinese nature reserves.The results showed that:(1)The proportion of natural reserves increased obviously and tended to be stable at the city scale in China,but the low-value areas dominated overall.The proportion of nature reserves between cities was substantially different,and a spatial pattern characterized by"high in the west and low in the east"was gradually formed.The gravity center migration of the nature reserves showed a"southwest-northeast-northwest"spatial evolution pathway,with its moving distance and speed being gradually reduced.After 1990,the city-scale proportion of nature reserves had always shown a spatial distribution pattern of"northeast-southwest".(2)The city-scale proportion of natural reserves presented a significant spatial positive correlation and the overall correlation gradually increased,but the spatial aggregation level of nature reserves gradually decreased.The local spatial heterogeneity was strong,and the high-high and low-low aggregation areas were expanded.(3)The geo-informatic atlas analysis indicated that the city-scale proportion change of natural reserves followed the“early change-low frequency-step by step”mode,and the main change type was the vacant area changing into low value area.The transfer of the proportion of natural reserves types in the Chinese cities had stability and evident spatio-temporal heterogeneity,forming the"club convergence"phenomenon in the later stage(2005—2020),with the neighborhood background playing an important role in the transfer process.In the future,it is necessary to strengthen the assessment of natural resources in those vacant and low-value cities,to incorporate their most valuable areas into the nature reserve systems,and to popularize regional joint protection mechanisms to promote high-quality construction of the nature reserve systems.