珍稀濒危植物野生莲的适生分布区预测

基于野生莲（Nelumbo nucifera Gaertn.）136个分布点的数据和14个环境因子参数，运用规则集遗传算法（GARP）和最大熵（MaxEnt）两个生态位模型对他们在我国的适生分布区进行预测。结果显示：根据GARP和MaxEnt模型计算得到的ROC曲线下面积的AUC均值分别为0.861和0.964，其中MaxEnt模型的AUC值更大，预测结果更精准。MaxEnt模型预测结果表明，莲的最适分布区主要集中在四川、湖北、湖南等地的大部分地区，江西北部，以及黑龙江、辽宁、浙江、广东等地的小部分地区。刀切法（Jackknife）检测结果表明，影响莲适生分布区的主要环境因子包括：水汽压、海拔、年平均气温、多年平均降水量、最热季节平均温度、最冷季节平均温度、最干月降水量、最冷月最低温和最热月最高温等。适生区环境因子的统计分析结果显示，野生莲最适宜生长在海拔1~2216 m、年降水量丰富（1202.50 mm）、年均温约为16.19℃、最热月温度范围在24.60℃~35.10℃、最冷月均温不低于-0.53℃的地区。研究结果可为有效保护中国野生莲资源提供有利依据。

Prediction of suitable distribution areas of the endangered plant wild Nelumbo nucifera Gaertn. in China

Based on data of 136 distribution points and 14 environmental factor parameters, we applied both the GARP and MaxEnt niche models to predict the suitable distribution areas of wild Nelumbo nucifera Gaertn. in China. The average AUC values under the ROC curves from the GARP and MaxEnt models were 0.861 and 0.964, respectively, indicating that the MaxEnt model had more accurate prediction results. Furthermore, the MaxEnt model results showed that the optimal distribution areas of N. nucifera were mainly located in Sichuan, Hubei, and Hunan provinces, northern Jiangxi province, and a small part of Heilongjiang, Liaoning, Zhejiang, and Guangdong provinces. The Jackknife test indicated that the main environmental factors determining the potential distribution areas of N. nucifera were vapor pressure, elevation, mean annual temperature, annual average precipitation, average temperature in the hottest season, average temperature in the coldest season, the driest monthly precipitation, the lowest temperature in the coldest month, and the highest temperature in the hottest month. Statistical analysis of the environmental factors related to the potential distribution demonstrated that the most appropriate habitat conditions for N. nucifera were an elevation of 1-2216 m, high annual average precipitation (1202.50 mm), mean annual temperature of 16.19℃, average temperature in the hottest month from 24.60℃ to 35.10℃, and mean tolerated temperature in the coldest month of -0.53℃. These results will provide a favorable basis for the effective conservation of wild resources of N. nucifera in China.