孑遗植物裸果木历史分布格局模拟及避难区研究

Study on the History Distribution Pattern of Gymnocarpos przewalskii and Refuge Area

裸果木(Gymnocarpos przewalskii)是国家一级保护植物,亦是古地中海第三纪孑遗成分。该文基于Maxent模型结合ArcGIS预测裸果木种群自冰期以来的分布变化、影响种群分布的主导气候因子及气候避难所位置。结果表明:随历史气候的变迁裸果木由末次间冰期经末次盛冰期进入全新中期,分布区面积呈现显著下降的趋势,而适应区面积呈先降低后增加趋势。目前主要分布于新疆中西部、甘肃河西走廊中部、玉门关以西北缘、内蒙古西部及宁夏北部等地。因祁连山山脉、阿尔金山山脉、昆仑山山脉及贺兰山山脉的阻挡,冰期在甘肃的河西走廊(疏勒河、党河流域)、玉门关西北缘(哈密)、内蒙古西部(雅布赖)及新疆(塔里木)等盆地形成了部分避难区。采用刀切法筛选出影响种群分布变化的4个主导因子及变化区间,即年降雨量变化范围为64.49~116.36mm、最湿季度降雨量变化范围为35.99~72.82mm、最冷季节温度变化范围为-13.31^-8.18℃及年均温变化范围为6.20~7.31℃。相对于温度的影响,水分对种群分布的影响更大。

Gymnocarpos przewalskii is national level protecting plants and composition of the ancient Mediterranean tertiary relic.This article is based on combined ArcGIS and Maxent model to predict the species distribution of G.przewalskii in the ice age,the main climate factors of population distribution and climate refuge.Results show that the distribution area of G.przewalskii showed a significant downward trend with the climate change of history from the last interglacial period to the middle of the ice age to enter the new medium period while the area of adaptation area decreased first then increased.At present,mainly distributed in the midwest Xinjiang,centre of Gansu Hexi corridor,northwestern margin of Yumenguan,western Inner Mongolia and northern Ningxia.Because the block of Qilian Mountain,the Altun,Kunlun Mountains and the Helan Mountains,the Hexi Corridor in Gansu Province(Danghe and Shule river basin),Yumenguan northwestern margin(Hami),western Inner Mongolia(Lai),cloth and Xinjiang(Tarim)basin of ice age formed part of the refuge area.Knife cutting method was used to filter out four dominant factors that result in the change of the distribution and change interval,the annual precipitation change range is64.49-116.36mm,the wet season rainfall was35.99-72.82mm,the coldest season temperature was13.31-8.18℃and annual average temperature was6.20-7.31℃,precipitation also affected the distribution of G.przewalskii population much as compared to temperature.