中华韩愈鳄(鳄目：长吻鳄科)第四纪晚期在中国的潜在地理分布

文章运用 ENMeval 优化后的最大熵(maximum entropy, MaxEnt)模型,基于已知的中华韩愈鳄(Hanyusuchus sinensis)化石点位分布,并结合第四纪晚期不同时期的环境因子,模拟其在中国境内第四纪晚期的潜在分布;通过Jackknife方法筛选出优势环境因子,并对影响其地理分布的主要环境变量的响应作出分析。结果表明:在第四纪晚期的5个不同阶段,中华韩愈鳄在中国境内的适宜生境地主要分布在广西、广东、福建西南部、海南东部及台湾的极少部分区域;影响其分布的主要环境因子包括平均日较差( $ B_{2} $)、海拔(E)、气温季节性变动系数( $ B_{4} $)、最湿季度平均温度( $ B_{8} $)及最冷季度降水量( $ B_{19} $),平均日较差4.74~7.82℃、海拔低于126.44 m、气温季节性变动系数481.36~616.40、最湿季度平均温度24.76~32.88℃、最冷季度降水量109.99~168.68 mm是最适宜其生存的环境条件。因此,未来中华韩愈鳄化石的寻找应主要集中在上述分布地区。该文研究结果进一步验证了人类活动而非气候变化在中华韩愈鳄灭绝中占主导作用的假说。

Based on the known fossil occurrences and environmental factors throughout the late Quaternary, the ENMeval-optimized maximum entropy (MaxEnt) model was used to simulate the potential distribution of Hanyusuchus sinensis within China. The Jackknife method identifies environmental factors controlling the geographic distribution of Hanyusuchus sinensis and reveals small variations in the distribution range of this species during the late Quaternary. The results show that during five separate stages of the late Quaternary, the potential geographic distribution of Hanyusuchus sinensis within China is concentrated in Guangxi, Guangdong, southwestern Fujian, and eastern Hainan, with sporadic occurrences in Taiwan. Key environmental factors influencing the distribution of Hanyusuchus sinensis include mean diurnal range $ (B_{2}) $, altitude $ (E) $, temperature seasonality $ (B_{4}) $, mean temperature of the wettest quarter $ (B_{8}) $ and precipitation of the coldest quarter $ (B_{19}) $. Optimal survival conditions for Hanyusuchus sinensis are characterized by the mean diurnal range between 4.74 ℃ and 7.82 ℃, altitude below 126.44 m, temperature seasonality between 481.36 and 616.40 m, mean temperature of the wettest quarter between 24.76 ℃ and 32.88 ℃, and precipitation of the coldest quarter ranging between 109.99 mm and 168.68 mm. Therefore, it is suggested that future searches for Hanyusuchus sinensis fossils should focus on these regions. Furthermore, the results of this study support the hypothesis that human activities, rather than the climate change, caused the extinction of Hanyusuchus sinensis.