气候变化下青藏高原中亚紫菀木潜在适生区的时空动态变化

Spatial and temporal variations of the potential habitat of Asterothamnus centraliasiaticus on the Qinghai⁃Tibet Plateau under climate change

青藏高原在全球气候变化背景下展现出高度生态敏感性及脆弱性,而对其典型优势种的适生区时空动态进行预测既是实行生态恢复的前提,也能为制定保护对策提供依据。本研究以青藏高原温性荒漠草原的优势种中亚紫菀木(Asterothamnus centraliasiaticus)为对象,基于MaxEnt模型,结合82条中亚紫菀木在青藏高原的有效分布记录和筛选后的6个生物气候变量,模拟预测中亚紫菀木在历史(全新世中期)、当前及未来4种气候排放浓度情景下的潜在分布区,并结合气候因子的贡献率及刀切法检验来分析制约中亚紫菀木地理分布的重要气候因子。结果表明:温度变量是影响青藏高原中亚紫菀木地理分布的主要气候限制因素,而降水变量是影响中亚紫菀木潜在地理分布的辅助生物气候变量;适合中亚紫菀木生长的最暖月最高温度(Bio5)范围为16.5~38.5℃,最暖季降水(Bio18)变化范围为55.0~1885.5 mm;从全新世中期到当前阶段是青藏高原中亚紫菀木种群扩张阶段,其种群主要聚集在青藏高原东北缘干旱半干旱地区;从当前到未来阶段,中亚紫菀木总适生区变化呈“先增加后降低”趋势,但中、高适生区却呈直线下降趋势;此外,中亚紫菀木在未来有逐渐向东迁移趋势。综合分析表明,在全球气候变化背景下,中亚紫菀木在青藏高原范围内的生存繁殖仍存在较大挑战。可根据其迁移趋势建立相关合理保护利用措施,以保持中亚紫菀木栖息地的连续性。

The Qinghai-Tibet Plateau is highly ecologically sensitive and vulnerable to global climate change.Predicting the spatial and temporal variations of the habitats of dominant species is crucial for ecological restoration and the formulation of conservation measures.Using the Maxent model,we combined distribution records and bioclimatic variables to simulate and predict the potential distribution areas of Asterothamnus centraliasiaticus,a dominant species in the temperate desert steppe of the Qinghai-Tibet Plateau,under different climatic scenarios.Our results showed that temperature variables were the primary climatic constraints affecting the distribution of A.centraliasiaticus,while precipitation variables had a secondary impact.The suitable temperature range for growth was 16.5-38.5℃,with precipitation in the warmest season varying from 55.0-1885.5 mm.Population of A.centraliasiaticus has been expanding from the mid-Holocene to the present,mainly in the arid and semi-arid areas along the northeastern margin of the Qinghai-Tibet Plateau.The total habitat area of A.centraliasiaticus is predicted to decline in the future,particularly in the moderately and highly suitable habitats.Furthermore,the population is predicted to migrate gradually eastwards.Overall,our study highlights the challenges faced by A.centraliasiaticus in terms of survival and reproduction under global climate change.We recommend establishing relevant policies and regulations based on its migration trend to ensure the continuity of its habitat and develop effective conservation measures on the Qinghai-Tibet Plateau.