基于最大熵模型(MaxEnt)预测暗紫贝母的潜在分布

暗紫贝母(Fritillaria unibracteata)干燥的鳞茎是市场名贵药材"川贝"的主要来源,目前由于人们的过度挖采及环境的恶化,使得其野生资源已近枯竭,被列为国家三级濒危保护药材物种。该研究通过收集暗紫贝母的地理分布点经纬度,结合26项生态因子,运用最大熵模型(MaxEnt)并结合地理信息系统(ArcGIS),对其在中国的潜在分布区域进行了预测。结果表明:暗紫贝母的潜在适生区主要分布在四川西部和北部、青海南部、甘肃南部,其中四川阿坝藏族羌族自治州的理县、茂县、松潘县、红原县、黑水县等地区,青海省果洛藏族自治州的久治县、玛沁县、同德县、兴海县、河南县地区以及甘肃省甘南藏族自治州地区是暗紫贝母最佳适生区。此外,在西藏和云南也有零星的分布。对暗紫贝母的分布贡献率较大的主要生态因子有5个,分别是海拔(40.8%),年均降水量(28%),1月最高温度(7.1%),最干季平均温度(6.6%)和昼夜温差日均值(6.6%)。其中,海拔为2700~4 500m、年均降水量为400~1 400mm,是暗紫贝母最适宜生长的生态位参数。该研究结果为暗紫贝母的野生抚育和人工栽培提供了重要的科学依据。

Potential distribution of Fritillaria unibracteata predicted by the MaxEnt model

Fritillaria unibracteata is an important medicinal plant due to its dried bulbs. However, it was massively collected by the natives in recent years, so that its wild resources had been seriously damaged, and been listed as national the third-class protective medicinal plants. In this study, its potential distribution was predicted by collecting geographic coordinates, combining with 26 environmental variables based on the MaxEnt model and ArcGIS platform. The results showed that its potential distribution areas were mainly located in western and northern Sichuan, southern Qinghai, southern Gansu. Within these areas, Aba Tibetan and Qiang Autonomous Prefecture of Sichuan(Lixian, Maoxian, Songpan County, Hongyuan County and Heishui County), Kolo Tibetan Autonomous Prefecture of Qinghai(Jiuzhi County, Maqin County, Tongde County, Xinghai County and Henan County)and Gannan Tibetan Autonomous Prefecture of Gansu were determined as the best potential distribution areas. And the populations of F. unibracteata also fragmentally distributed in Tibet and Yunnan. In addition, there were another five major environmental factors which exerted obvious influence on its distributions, including altitude(40.8%), annual average precipitation(28%), maxmum temperature of January(7.1%), mean temperature of the driest quarter(6.6%)and the precipitation variation coefficient(6.6%). Its suitable ecological niche parameters were altitude around 2 700-4 500 m and annual average precipitation around 400-1 400 mm. This study can provide a scientific guidance for conservation and cultivation of Fritillaria unibracteata.