石山苣苔属的潜在适生区特征及其环境驱动变量

Characteristics of potential suitable areas of Petrocodon Hance and its environmental driving variables

关键词:  潜在适生区, 气候变化, 环境变量, MaxEnt 模型, 分布质心

Key words:  potential suitable area, climate change, environmental variable, MaxEnt model, distribution centroid

摘要:

石山苣苔属(Petrocodon Hance)是著名的观赏花卉之一,但气候动荡和人类活动的强烈干扰,使其绝大部分被评估为极危(CR),至少也是易危(VU)以上。为重建末次间冰期以来石山苣苔属潜在适生区的时空变化,探讨适生区对环境变化的响应关系,为石山苣苔属的起源、地理分化研究和中国特有种质资源保护、园林开发利用提供理论指导,该研究结合120个分布记录和17个环境变量,应用优化的MaxEnt模型和地理信息技术(ArcGIS)对石山苣苔属在中国及中南半岛的适生区及其分布格局进行模拟,并基于逐步多元线性回归分析、冗余分析和蒙特卡洛检验评估影响石山苣苔属当前地理分布的主导变量。结果表明:(1)优化的MaxEnt模型的预测精度高,AUC值大于0.96; 石山苣苔属当前适生区从中国西南部连续分布至越南北部,零散分布于中国中部和南部、块状分布于缅甸北部,其中以中国云贵高原南部为最佳适生区。(2)制约石山苣苔属当前地理分布的主导环境变量为最干月降雨量(bio14)、最热季度平均降雨量(bio18)、最湿季降雨量(bio16)、温度变化方差(bio4)、最冷月最低温度(bio6)、海拔(alt)。(3)在气候变化情景下,石山苣苔属适宜生境的扩张和收缩区位于当前潜在分布区的北部和东北部,是易受气候变化影响的敏感区。末次间冰期,石山苣苔属适生区大规模扩张,但末次盛冰期干冷的环境中几乎没有石山苣苔属适生区。之后,石山苣苔属的适宜生境向高纬度急速增加,而低纬度的适宜生境减少。(4)石山苣苔属适生区的质心从广西永福县(110.10° E、24.69° N)向北迁移至湖南城步县(110.29° E、26.05° N)。综上认为,全球气候变暖对石山苣苔属潜在分布区具有一定积极影响,但是极度的增温会造成石山苣苔属的适宜生境缩减、生态位变窄,而具有成熟喀斯特地貌优势的中国西南部至越南北部可能是其避难的主要场所。

Abstract:

Petrocodon Hance is one of the famous ornamental flowers, but most of them are assessed as extremely dangerous(CR), or at least above vulnerable(VU)due to climate turbulence and strong interference of human activities. To reconstruct the temporal and spatial changes of the potential suitable areas of Petrocodon since the last interglacial period, and explore the response of the suitable areas to environmental changes, which provided theoretical guidance for the origin of Petrocodon, the study of geographical differentiation, the conservation of unique germplasm resources in China, and the development and utilization of gardens. In this paper, combined with 120 distribution records and 17 environmental variables, the optimal MaxEnt model and geographic information technology(ArcGIS)were used to simulate the suitable areas and distribution pattern of Petrocodon in China and Indo-China Peninsula. Based on stepwise multiple linear regression analysis, redundancy analysis and Monte-Carlo test, the dominant variables affecting the current geographical distribution of Petrocodon were evaluated. The results were as follows:(1)The prediction accuracy of the optimized MaxEnt model was high, and the AUC value was greater than 0.96. The potential suitable areas of Petrocodon for the present distribution are continuous from Southwest China to North Vietnam, scattered in central and southern China and blocky in North Myanmar, of which the South Yunnan-Guizhou Plateau in China was the most suitable.(2)The environmental variables which restrict the geographical distribution of Petrocodon included precipitation of the driest month(bio14), precipitation of the warmest quarter(bio18), precipitation of the wettest quarter(bio16), SD of the temperature seasonality(bio4), min temperature of the coldest month(bio6)and altitude(alt).(3)Under the climate change scenario, the expansion and contraction areas of the suitable habitat of Petrocodon were located in the north and northeast of the current potential distribution area, which were sensitive areas susceptible to climate change. During the last interglacial period, the suitable area of Petrocodon expanded on a large scale, but there was almost no suitable distribution area of Petrocodon in the dry and cold environment during the last glacial maximum. After that, with the aggravation of climate warming, the suitable habitats of Petrocodon increased rapidly to high latitudes, while the suitable habitat in low latitudes decreased.(4)The centroid position of the suitable area for Petrocodon migrated northwards from Yongfu County, Guangxi(110.10° E, 24.69° N)to Chengbu County, Hunan(110.29° E, 26.05° N). To sum up, global warming has a positive impact on the potential distribution area of Petrocodon, but extreme warming will cause the suitable habitat of Petrocodon to shrink, and the niche of Petrocodon will narrow. Southwest China to North Vietnam, which has the advantage of mature karst landform, may be its main refuge.