Considering limited manpower,funding,and land available for conservation projects,selecting a set of key areas to maintain biodiversity is important.The Yangtze River Basin (YRB) is a globally significant center for biodiversity but faces many threats and pressures.Previous research attempted to identify conservation gaps in the YRB based solely on species distribution in terrestrial ecosystems.This study focused on wetland ecosystem conservation patterns on an entire river basin scale.Systematic conservation planning (SCP) is a framework that has been developed to prioritize and manage habitats deemed important for the protection of natural values.We used SCP methods to define watersheds as planning units and developed a comprehensive map of wetland types,considering climatic factors and geomorphological factors as coarsefilter surrogates of biodiversity elements,which included 28 wetland classes.We integrated the distribution of 113 focal birds as fine-filter surrogates of biodiversity elements.Marxan is a software used to determine the optimal set of planning units to form a pattern that meets the protection target with the minimum of social economy cost and land resources.We used Marxan to identify a conservation priority pattern by calculating the irreplaceability of each unit.Then,we compared the priority pattern with the existing reserve system to analyze conservation gap in the YRB.The results showed that the wetlands at the source of the YRB are large and well-protected;the proportion of protected wetlands in the Jinshajiang sub-basin arrived at 38.74％ in the priority pattern,improved by 19.74％ compared to the existing protection system.The protected proportion in the Ming-Tuo sub-basin is 7.05％ at present,and improved to 22.08％ after the optimization;the priority protection areas are mainly distributed in Sichuan.The additional proportions in the Jialinjiang sub-basin and the upper mainstream sub-basin are large with conservation gaps mainly distributed in Sichuan province;Dongting Lake Basin and Hanjiang sub-basin are relatively well-protected.The protected proportion of wetlands in the Poyang Lake basin can rise from 7.10％ to 28.49％ with the additional proportion rising up to 40.89％ in the Taihu sub-basin;most conservation gaps in the middle and lower reaches of the Yangtze River were distributed among riparian wetlands.In summary,the main conservation gaps are distributed in Chongqing,Guizhou,Hunan,and Hubei provinces.The results provide a reference for conservation planning in the YRB.Moreover,the identification of priority conservation areas on a large scale can be used to influence the building of a well-connected protection network in each individual area.For conservation gaps in the middle and lower reaches of the Yangtze River,we can build wetland parks and restore the river bank.For small conservation gaps distributed around existing reserves,we can extend the boundary of the reserves or adjust their scope.The results provide decision makers with scientific evidence for conservation planning for Yangtze River wetlands,and enrich the examples of SCP for freshwater wetlands.%基于系统保护规划的理论和方法,以长江流域湿地为研究区,构建了基于气候、地貌分异的湿地生态地理综合分类单元,并将其作为宏观尺度湿地生态系统保护目标,同时考虑以湿地鸟类为代表的物种保目标,依托Marxan系统保护规划工具,确定了长江流域湿地保护具有不可替代性的优先保护格局.该格局能以最小的社会经济和土地资源代价最大程度的保护湿地生物多样性,对比现有湿地保护格局,最终确定了游离于现有保护体系外的湿地保护空缺.研究结果表明:长江流域源区和长江三角洲地区的湿地保护体系完善,无需新建保护区;金沙江流域湿地保护空缺主要分布在现有保护区周围,可以适当扩充保护区外围或调整边界;嘉陵江流域和长江上游干流流域的保护空缺严重,大面积集中在重庆西北部,乌江流域的贵州省习水县北部湖泊湿地存在保护空缺,这些区域建议适当新建保护区或者保护小区;长江中下游湿地保护空缺主要分布在湖北、湖南、江西与安徽境内的沿江湖泊湿地,建议建立湿地公园及合理进行河流岸坡修复.研究结果可为长江流域湿地保护体系调整、保护规划制定提供参考依据,从宏观层面上为长江流域湿地统筹保护及合理开发利用提供科学依据.
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