基于GIS和MaxEnt模型的合江方竹中国潜在分布区预测

探索合江方竹在我国的潜在适生分布区，了解影响其地理分布的主要环境因子，可为开展合江方竹种植区划及引种栽培提供参考。采用最大熵模型（MaxEnt）与地理信息系统（GIS）相结合，基于43个合江方竹地理分布记录和20项环境因子，通过相关分析、刀切法检验、创建分布预测图及因子响应曲线，预测合江方竹的潜在适生区及其适生等级，确定主导环境因子及其阈值，并采用受试者工作特征曲线（ROC）对预测结果进行验证。合江方竹在我国潜在适生区面积约1.88×10⁵ km²，主要分布在川、滇、黔、渝4个省（区），湛江、海口和漳州临海地区有零星低适生区分布，四川盆地与云贵高原过渡的大娄山地带是合江方竹的高适生区。最干月降水量（bio14）、温差月均值（bio2）、海拔（alt）和年均降水量（bio12）是影响合江方竹分布最主要的环境因子，累计贡献率超过85%，各因子的阈值分别为：18~25 mm、60~72℃、550~1 350 m、1 030~1 160 mm。ROC下的面积（AUC值）达0.996，模拟预测准确性高，结果可信。结果表明，合江方竹具有进一步拓展的空间和可能，其分布主要受降水和温度的影响，适宜生长在温暖湿润且有一定温差的中高山地区。

Prediction for Potential Distribution Area of Chimonobambusa hejiangensis in China Based on GIS and MaxEnt Model

The exploration of the potential suitable area for Chimonobambusa hejiangensis growth in China, and the better understanding of the major environmental factors which affect its geographical distribution will provide references for the planting area zoning and introduced cultivation of Ch. hejiangensis. The MaxEnt and GIS are employed to study the potential distribution prediction and suitability evaluation, main factors and threshold based on 43 geographic occurrence records and 20 environmental factors are determined using correlation analysis, jackknife test, making prediction map and response curves, and the prediction is verified by the ROC curve. The potential suitable area for Ch. hejiangensis growth is about 1.88×10⁵ km², mainly distributed in the four provinces of Sichuan, Yunnan, Guizhou and Chongqing, and also scattered sporadically in coastal zone of Zhanjiang, Haikou and Zhangzhou, among which the Dalou Mountain area in the transition zone between Sichuan basin and Yunnan-Guizhou plateau is the most suitable area. The precipitation of driest month (bio14), mean diurnal range (bio2), altitude (alt) and annual precipitation (bio12) are the most important environmental factors affecting the distribution of Ch. hejiangensis, with the cumulative contribution rate over 85%, and the thresholds of each factor are 18-25 mm, 60-72℃, 550-1 350 m and 1 030-1 160 mm, respectively. Area under the ROC (AUC value) is 0.996, which shows that the results are reliable and accurate. The results indicate that Ch. hejiangensis has further expansion of space and possibility, which distribution is mainly affected by precipitation and temperature, so the bamboo species is suitable to grow well in the warm and humid areas at middle and high mountains with a certain temperature difference.