基于模糊物元模型的桃儿七潜在地理分布研究

Potential distributions of Sinopodophyllum hexandrum based on fuzzy matter element model

桃儿七(Sinopodophyllum hexandrum(Royle)Ying)为小檗科多年生草本植物,是我国传统濒危藏药。依据模糊物元模型建立桃儿七分布点位以及其产量数据与12个气候环境因子之间的模糊隶属函数,采用最大信息熵模型确定评价指标权重,利用GIS空间分析功能确定我国西部7省桃儿七生境适宜性空间分布。研究表明研究区桃儿七不适宜生境面积占研究区总面积的61.76%;低适宜生境占20.11%;中适宜生境占7.70%;高适宜生境占10.43%,主要集中在青藏高原东缘的四川、甘肃、青海境内次生植被丰富、地形复杂的高海拔地区。结果显示基于GIS与模糊物元构建的生境适宜性评价模型可以准确的对我国西部7省桃儿七生境适宜性做出科学综合评价,量化适宜生境面积和空间分布,为其资源保护和管理提供科学依据。

Specific geographic spatial information about species is an important part of species conservation. This information is essential for addressing many challenges to species conservation such as those induced by climate change, as well as other ecological or biological factors. It is also important for both the domestication of a wild species. Sinopodophyllum hexandrum, a perennial herb in the berberidaceae family, is an endangered traditional Tibetan medical plant. The wild populations of this species are scarce, and its natural reproductive ability is weak. With an increase in popularity of this herb in both the domestic and international drug market, Sinopodophyllum hexandrum wild resources are being depleted, and traditional areas where the plant could be found no longer host this species. Without good knowledge about the habitat requirements of this species, species protection via habitat protection measures is not possible. Thus, the only viable strategy for protecting this species in the wild is to restrict sales of the plant when sourced from certain countries where the plant populations are known to be endangered. In addition to being essential for effective habitat protection, specific information about habitat requirements for Sinopodophyllum hexandrum also facilitate cultivating the plant more effectively-thus providing a sustainable supply for medical use. In our research, many samples of Sinopodophyllum hexandrum were collected from 25 sampling sites. Based on Matter Element Mode theory, the relationships between plant yield and 12 climatic and environmental factors were established. Using these data as a base, we calculated the optimum habitat conditions for Sinopodophyllum hexandrum. The next step was to use the maximum entropy model to determine the relative importance of each environmental factor, and thus determine the most limiting habitat criteria. Finally, the probable spatial distribution of Sinopodophyllum hexandrum across seven provinces in western China was determined based on the weighted average method and GIS spatial analysis of habitat conditions. The root-mean-square error （RMSE） was used to evaluate the accuracy of the model＇s prediction.The RMSE value reached 8.6%： a value which indicates predictive accuracy of the model to have reached the level of ＂Excellent＂. The results show five dominant climatic factors controlling Sinopodophyllum hexandrum distribution. These five dominant features are 1） minimum temperature of coldest month （TMIN）, 2） annual mean temperature （AMT）, 3） maximum temperature of warmest month （TMAX）, 4） Annual sunshine hours （ASH） and 5） elevation above sea level （ASL）. The percentage of unsuitable habitat for Sinopodophyllum hexandrum in this area was 61.76%, with 20.11% classified as marginally suitable habitat, 7.70% classified as moderately suitable habitat, and 10.43% highly suitable habitat. Thus the growing area for Sinopodophyllum hexandrum, whether natural or cultivated, is limited. Our results showed that moderately suitable habitats and highly suitable habitats are mainly located in Sichuan, Gansu, and Qinghai on the Eastern edge of the Qinghai-Tibet Plateau. This area has rich secondary vegetation and is at high altitude. In conclusion, the habitat suitability assessment model based on GIS and Matter Element Mode theory could accurately evaluate the habitat suitability of Sinopodophyllum hexandrum, quantify the area of suitable habitat, and analyze the spatial distribution. This information is of value to address the choice of good agricultural practice （GAP） and provide insight for choosing the most suitable cultivation sites, as well as habitat protection zones.