基于MaxEnt濒危植物独叶草的中国潜在适生分布区预测

Prediction of potential suitable distribution of endangered plant Kingdonia uniflora in China with MaxEnt

独叶草（Kingdonia uniflora Balf．f．et W．W．Smith）属毛茛科独叶草属多年生草本植物，属国家二级濒危保护植物。近年来，随着森林采伐和人类活动加剧生境的破碎化，独叶草自然分布区迅速缩减，存在濒临灭绝的风险。预测独叶草潜在的适宜分布区，对于合理保护和利用独叶草具有重要意义。本文结合64份独叶草的标本地理信息和14个环境因子参数，应用最大熵模型（MaxEnt）和地理信息技术（GIS），对独叶草在中国的潜在适生分布区和影响分布的关键环境因子进行了预测。受试者工作特性曲线（ROC）分析法的AUC值为0．990，表明MaxEnt模型预测可靠性极高。预测结果显示，独叶草最适潜在分布区主要在陕西秦岭北坡（眉县，太白县）、四川省的邛崃山（理县，马尔康县）和大凉山（马边彝族自治县），云南东北部和贵州西北部交界的大娄山（金沙县）和乌蒙山（赫章县）部分地区（适生指数〉0．5）。刀切法检测（Jackknifetest）分析表明，影响独叶草适生分布的关键环境因子包括年均降水量（贡献率33．1％）、海拔（22．3％）、温度季节性变化的标准差（11．4％）、降水量变异系数（7．2％）、土壤pH（5．4％）、1月最低温（5．1％）和土壤碎石百分比（4．9％）。适生区环境参数综合统计分析表明，独叶草最适宜生长在高海拔（1646～2810m）、年均降水量大（856mm）、1月最低温适中（-7．2℃二）和土壤偏酸性（pH6．89）的地区。上述研究结果将为在最适生区通过合理规划自然保护区来保护独叶草野生资源提供理论依据。

Kingdonia uniflora Ball. f. et W. W. Smith, a perennial herb, is listed as an endan- gered plant of the national second-grade protection of China. In recent years, human activities （e.g. excessive deforestation and aggravating habitat fragmentation） have caused rapid shrinking of the distribution range of K. uniflora, thereby making this species being under serious risk of extinction. Prediction of potential suitable distribution of K. uniflora has important values for rea- sonable conservation and utilization of natural resource. In this study, 64 specimen records and 14 environmental factors were used to predict the potential suitable distribution and the key fac- tors determining such distribution areas in China based on MaxEnt modeling and geographic infor- mation system （GIS）. The receiver operating characteristic curve （ROC） was applied to produce modeling reliability of MaxEnt. As a result, the modeling process gave an AUC of 0.990 with high precision. Our results also showed that the highly potential distribution was mainly located in the north slope of Qinling Mountain in Shaanxi Province （Mei County, Taibai County）, Qionglai Mountain （Li County, Maerkang County） and Daliang Mountain （Mabian County） in Sichuan Province, and the border zone including Dalou Mountain （Jinsha County） and Wumeng Moun- tain （ Hezhang County） in the northeast of Yunnan and the northwest of Guizhou （ suitability in- dex 〉0.5）. The Jackknife test analysis indicated that the main environmental factors determining the potential suitable distribution were annual average precipitation （contribution rate, 33.1%）, altitude （ 22.3% ）, temperature seasonality （ 11.4% ）, precipitation seasonality （ 7.2% ）, topsoil pH （5.4%）, average monthly precipitation of January （5.1%） and topsoil gravel content （4.9%）. The statistical analysis of environmental variables in highly potential areas demonstrated that K. uniflora prefers to grow in areas with high altitude （ 1646-2810 m）, high annual average precipitation （856 mm）, moderate average monthly temperature of January （-7.2 ℃ ） and top- soil pH 6.89. These results will provide valuable reference for conservation of the wild resource of K. uniflora as well as the establishment of nature reserves.