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

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.