Prediction of Historical, Current, and Future Configuration of Tibetan Medicinal Herb Gymnadenia orchidis Based on the Optimized MaxEnt in the Qinghai–Tibet Plateau

Abstract

Climate change plays a pivotal role in shaping the shifting patterns of plant distribution, and gaining insights into how medicinal plants in the plateau region adapt to climate change will be instrumental in safeguarding the rich biodiversity of the highlands. <i>Gymnosia orchidis</i> Lindl. (<i>G. orchidis</i>) is a valuable Tibetan medicinal resource with significant medicinal, ecological, and economic value. However, the growth of <i>G. orchidis</i> is severely constrained by stringent natural conditions, leading to a drastic decline in its resources. Therefore, it is crucial to study the suitable habitat areas of <i>G. orchidis</i> to facilitate future artificial cultivation and maintain ecological balance. In this study, we investigated the suitable zones of <i>G. orchidis</i> based on 79 occurrence points in the Qinghai-Tibet Plateau (QTP) and 23 major environmental variables, including climate, topography, and soil type. We employed the Maximum Entropy model (MaxEnt) to simulate and predict the spatial distribution and configuration changes in <i>G. orchidis</i> during different time periods, including the last interglacial (LIG), the Last Glacial Maximum (LGM), the Mid-Holocene (MH), the present, and future scenarios (2041-2060 and 2061-2080) under three different climate scenarios (SSP126, SSP370, and SSP585). Our results indicated that annual precipitation (Bio12, 613-2466 mm) and mean temperature of the coldest quarter (Bio11, -5.8-8.5 °C) were the primary factors influencing the suitable habitat of <i>G. orchidis</i>, with a cumulative contribution of 78.5%. The precipitation and temperature during the driest season had the most significant overall impact. Under current climate conditions, the suitable areas of <i>G. orchidis</i> covered approximately 63.72 × 10⁴/km², encompassing Yunnan, Gansu, Sichuan, and parts of Xizang provinces, with the highest suitability observed in the Hengduan, Yunlin, and Himalayan mountain regions. In the past, the suitable area of <i>G. orchidis</i> experienced significant changes during the Mid-Holocene, including variations in the total area and centroid migration direction. In future scenarios, the suitable habitat of <i>G. orchidis</i> is projected to expand significantly under SSP370 (30.33-46.19%), followed by SSP585 (1.41-22.3%), while contraction is expected under SSP126. Moreover, the centroids of suitable areas exhibited multidirectional movement, with the most extensive displacement observed under SSP585 (100.38 km²). This study provides a theoretical foundation for the conservation of biodiversity and endangered medicinal plants in the QTP.