气候变化下野生扬子鳄(鳄目:短吻鳄科)在中国的分布模拟

Simulation of the distribution of wild Alligator sinensis(Crocodylia:Alligatoridae)in China under climate change

气候变化及人类活动对极危物种的分布及生存产生重要影响。运用ENMeval优化后的MaxEnt模型对中国特有极危物种扬子鳄(Alligator sinensis)在CMIP6(Coupled Model Intercomparison Project 6,第六次国际耦合模式比较计划)未来气候情景下的潜在适生区做出模拟预测,通过Jackknife检验找出对影响其分布的主要环境因子,并对扬子鳄对主要环境变量的响应做出分析。结果表明,最冷季度降水量(Bio19)、最干季度平均温度(Bio9)、最湿月份降水量(Bio13)、海拔(Elevation)以及气温季节性变动系数(Bio4)是影响扬子鳄分布的最主要环境因素。最冷季度降水量132.12—156.84 mm、最干季度平均温度5.94—7.81℃、最湿月份降水量180.44—221.65 mm、海拔4.60—121.69 m、气温季节性变动系数872.08—903.30是最适宜扬子鳄生存的环境条件。人类活动会造成野生扬子鳄栖息范围的减小。在未来不同气候变化场景下,扬子鳄的适生面积在SSP126气候情景下高于SSP585气候情景,低脆弱性、低辐射强迫的可持续发展路径可以减缓扬子鳄适生范围的丧失。根据预测结果,可在江苏宜兴及湖南洞庭湖平原地区设置野外放归地或建立新的自然保护区。本研究对于扬子鳄的野外放归及遗传多样性保护具有科学指导意义。

Climate change and human activities have an essential impact on the distribution and survival of critically endangered species.Here we used the ENMeval-optimized MaxEnt model to simulate the potential habitat of the endemic and critically endangered species Alligator sinensis in China under the future climate scenario of CMIP6.We identified the main environmental factors affecting the geographic distribution of Alligator sinensis by Jackknife test and analyzed the response of the species′geographic distribution to these environmental factors.The results show that the coldest quarterly precipitation(Bio19),the driest quarterly mean temperature(Bio9),the wettest monthly precipitation(Bio13),elevation,and the seasonal coefficient of temperature change(Bio4)are the most important environmental factors influencing the distribution of Alligator sinensis.The coldest quarterly precipitation of 132.12—156.84 mm,the driest quarterly average temperature of 5.94—7.81℃,the wettest monthly precipitation of 180.44—221.65 mm,the elevation of 4.60—121.69 m,and the seasonal variation coefficient of the temperature of 872.08—903.30 are the most suitable environmental conditions for the survival of Alligator sinensis.Human activities would cause the reduction of the habitat range of wild Alligator sinensis.Under different climate change scenarios in the future,the suitable habitat of Alligator sinensis will be larger under the SSP126 climate scenario than the SSP585 climate scenario,and the sustainable development path of low vulnerability and low radiative forcing can slow down the loss of suitable habitat of Alligator sinensis.Based on the modelled results,wild release sites or new natural reserves can be established in Yixing,Jiangsu Province,and Dongting Lake Plain,Hunan Province.Our study provides a scientific guide to the wild release and genetic diversity conservation of Alligator sinensis.