冰期非对称气候变化模式与生物多样性的形成机制

Asymmetric pattern of climate oscillations and the origin of biodiversity

生物多样性的形成与维持机制是生态学中最具挑战的核心问题之一.本文研究了大量冰期相关文献,发现冰期除周期性的气温变化之外,每个气温变化周期都经历了漫长的降温过程和相对快速的升温过程,由此提出了冰期"慢降—快升"非对称气温变化模式.在非对称气候变化模式下,地球上的生物地理分布随之发生"慢退—快进"的收缩和扩张,群落中的物种经历了长时间的隔离和相对快速的重组,呈现"聚少离多"的特征.同时,通过许多亲缘地理学的研究案例,发现物种的遗传变异多发生于缓慢降温阶段,在升温阶段时,这些已经存在的突变常沿不同路线扩张,并再次相遇,是遗传变异重组的过程.本文提出通过建立大尺度的天然群落格局平台,涵盖群落"慢退—快进"历史演变过程,结合亲缘地理学方法,从多尺度、多维度真实地还原群落形成和维持过程,预测气候变化和人类影响下生物群落的未来.

Understanding the origin and maintenance of biodiversity is a central challenge in ecology. Literature search found that global temperature changed cyclically but asymmetrically during Quaternary Glaciations.Slow global temperature decrease but rapid increase in every climate oscillation cycle is presented as an asymmetric temperature pattern:‘slow cooling but rapid warming’.Asymmetric temperature changes have drived geographic distribution of communities to a pattern of ‘slow retreat and rapid expansion’.Species in a community were isolated in the long term and were reassembled provisionally.As in many phylogeographic cases,genetic variations in general occurred in ‘slow retreat’stages.In rapid expansion stages,variations expanded in different routes and were recomposed in species populations.Our study suggests that a large-scale research platform for natural community reflecting ‘slow retreat and rapid expansion’should be established. Combined with phylogeographic methods,origin and maintenance of community should be reconstructed in multi-scale and multi-dimension to predict the future of natural communities in climate change and human influence.