气候变化背景下京津冀地区濒危水鸟潜在适宜区模拟及保护空缺分析

明确濒危水鸟栖息地分布并加以保护对于维持水鸟物种多样性和提高湿地环境质量具有重要意义.自1980年以来京津冀地区水鸟数量出现较大波动，为了分析濒危水鸟潜在分布区域及其变化特征，借助GIS平台和MaxEnt模型，基于2015年濒危水鸟"出现点"信息，定量识别了影响京津冀地区濒危水鸟分布的主要驱动因素和贡献率，并预测了2050年RCP2.6、RCP4.5、RCP8.5（依次代表低、中、高3种CO₂浓度排放模式）3种气候情景下濒危水鸟的潜在适宜区分布和保护空缺规律.结果表明:①京津冀地区濒危水鸟共有9种，东方白鹳、遗鸥和黑鹳3种濒危水鸟潜在适宜区面积较大.东方白鹳和遗鸥适宜区主要集中于环渤海湾沿岸和北京市中南部，黑鹳则主要集中于北京市南部房山区和东北部.②与2015年相比，2050年RCP2.6、RCP4.5和RCP8.5三种气候情景下濒危水鸟适宜区面积均较大，相应适宜区面积增幅依次为96.24%、103.94%和65.51%，适宜区空间分布上向西南和东北方向扩张.③国家自然保护区对濒危水鸟潜在适宜区和热点区的覆盖率较低，相较天津市，河北省和北京市对这两个区域的覆盖不足.④在京津冀地区尺度下，不同情景下保护区覆盖濒危水鸟适宜区比例依次为基准情景（1.26%）> RCP8.5情景（1.11%）> RCP2.6情景（0.70%）> RCP4.5情景（0.29%），保护区覆盖热点区比例依次为RCP4.5情景（0.83%）>基准情景（0.77%）> RCP8.5情景（0.08%）> RCP2.6情景（0）.研究显示，以单个水鸟为单位分析濒危水鸟潜在适宜区分布格局，能够精准有效地揭示国家自然保护区对濒危水鸟的覆盖情况. 

Simulation of Potential Suitable Distribution of Endangered Waterfowl and Its Gap Analysis of National Nature Reserves in Beijing-Tianjin-Hebei Region under Climate Change Scenarios

Determining the potential suitable distributions of endangered waterfowl species and protecting these areas have a great impact on maintaining the diversity of waterfowl species, protecting threatened waterfowl and improving wetland quality. As one of the most promising area of economic growth, the number of waterfowl in the Beijing-Tianjin-Hebei Region has greatly changed recently. Based on the GIS platform and MaxEnt model, we used occurrence sites of the endangered waterfowl in 2015 as input data, and analyzed potential suitable distribution of 9 endangered waterfowl species under different climate change in 2015 and 2050. Next, we quantitatively identified the main driving factors and their corresponding contribution rates for each water bird. Last, we used spatial analysis tool to do the gap analysis of nature reserves (NRs) for the whole region and each province. The results showed that:(1) Potential suitable area of Larus relictus, Ciconia boyciana and Ciconia nigra was larger than the other 6 species. Potential suitable distributions of Larus relictus and Ciconia boyciana were mainly focused on the coast of the Bohai Sea and south-central part of Beijing, while Ciconia nigra are mainly focused on Fangshan district and northeast of Beijing. (2) All of the potential suitable areas of 9 endangered waterfowl under 3 climate scenarios were larger than baseline situation in 2015. Increasing rates of RCP2.6, RCP4.5 and RCP8.5 (which represent the low, median and high values of emission concentration of CO₂) were 96.24%, 103.94% and 65.51%, respectively. Their spatial distributions expanded toward the southwest and northeast. (3) The coverage of national NRs for potential suitable area and hot spot of 9 endangered water birds was low. Compared with Tianjin, the coverage of potential suitable area and hot spot in Hebei and Beijing was exceptionally low. (4) At the whole regional scale, the coverage of potential suitable areas in descending order was:baseline scenario (1.26%) > RCP8.5 (1.11%) > RCP2.6 (0.70%) > RCP4.5 (0.29%), the coverage of hot spot in descending order was:RCP4.5 (0.83%) > baseline scenario (0.77%) > RCP8.5 (0.08%) > RCP2.6 (0). This study takes a single water bird unit, and synthesizes potential suitable distributions of 9 species of endangered waterfowl under 3 climate change scenarios, which can effectively reflect the coverage of NRs for endangered waterfowl. The spatial pattern of NRs in the Beijing-Tianjin-Hebei Region needs to be adjusted in the future.