摘要:谱系多样性（PD，Phylogenetic diversity）因包含植物之间的谱系关系和进化历史信息，被广泛用于植物多样性分布格局的研究中。现有研究表明PD变化受到古气候和现代气候等因素的影响，但结果并不统一且忽略了土壤养分对PD变化的影响。基于此，以新疆草地为研究对象，通过对全疆8个区域（阿尔泰山、准噶尔西部山地、准噶尔荒漠、天山北坡、伊犁河谷、天山南坡、塔里木盆地和昆仑山）中310个样地PD的调查，综合分析了古气候、现代气候、土壤养分、草地和土壤类型对PD的影响。结果显示：（1）样地是影响新疆草地PD变化的最主要因素，其次分别为草地和土壤类型，三者合计解释了新疆草地PD总变异的46.07%-78.80%。其中，PD最高值出现在塔里木盆地、低平地草甸和寒漠土，而最低值则出现在准噶尔荒漠、温性荒漠和风沙土；（2）PD也受到末次冰期以来降水变化（MAPano，Precipitation anomaly since the Last Glacial Maximum）、年均温度（MAT，Mean annual temperature）、季节性降水（PS，Precipitation seasonality）和土壤碳氮比（C ∶ N，Ratio of soil organic carbon to total nitrogen）单独和交互作用的影响。随MAPano增加，PD在新疆草地总体、准噶尔西部山地、伊犁河谷和昆仑山中呈先增加后降低的单峰型变化趋势。随MAT增加，PD在新疆草地总体中呈先降低后增加的"U "型变化趋势，在准噶尔荒漠则呈线性降低的趋势、而在伊犁河谷和昆仑山呈单峰型变化趋势。沿PS梯度，PD在新疆草地总体、阿尔泰山和伊犁河谷均呈现单峰型变化趋势，而在昆仑山则表现为负相关关系。C ∶ N仅对北疆部分地区PD有显著影响且呈" U"型变化趋势；（3）与之前新疆草地中物种丰富度变化特征相比，由于群落中物种亲缘关系的变化，PD与环境因子之间关系与物种丰富度呈相反或不同的变化趋势。表明以物种间亲缘关系为视角，不仅有助于我们深入理解植物多样性与环境因子之间的关系，也对未来多样性的保护有重要参考意义。



Abstract:Phylogenetic diversity (PD), a measure of community diversity in terms of phylogenetic relatedness and evolutionary history, is widely used to explore patterns of plant diversity. It is frequently reported that the PD was significantly affected by some factors, such as paleoclimate and present climate. However, the previous results were inconsistent and the influence of soil nutrients on PD was overlooked. Based on PD surveyed from 310 sites in 8 different areas (Mt.Altai, Mt.western Junggar, Junggar desert, Mt.North Tianshan, Ily Valley, Mt.South Tianshan, Tarim basin, and Mt.Kunlun) in Xinjiang grassland, we explored effects of paleoclimate, present climate, soil nutrients, soil and grassland types on PD. Our results showed that: (1) Sites was firstly important factor regulating PD variation, followed by grassland and soil types, these three factors together explained 46.07%-78.80% of total variation in PD. Tarim basin, lowland meadow and frigid desert soil had the highest PD in terms of regions, grassland and soil types, while Junggar desert, temperate desert, and aeolian sandy soil had the lowest PD. (2) The variation of PD was also affected by precipitation anomaly since the Last Glacial Maximum (MAPano), mean annual temperature (MAT), precipitation seasonality (PS), and ratio of soil organic carbon to total nitrogen (C ∶ N). The PD in Xinjiang grassland, Mt.western Junggar, Ily Valley, and Mt.Kunlun all exhibited a unimodal pattern (increased firstly and then decreased) with increasing MAPano. With increasing MAT, the PD in Xinjiang grassland decreased firstly and then increased, but linearly decreased in Junggar desert and exhibited a unimodal pattern in Ily Valley and Mt.Kunlun. Along PS gradient, the PD in Mt.Altai and Ily Valley exhibited a unimodal pattern but linearly decreased in Mt.Kunlun. Only PD in northern Xinjiang was significantly affected by soil C ∶ N and decreased firstly and then increased. (3) Compared with previous studies which focused on species richness, we found that PD responded contrastly or differently along environmental gradient due to variation of relatedness among species in community. Our study highlighted importance of PD in understanding relationship between diversity and environmental gradient and diversity conservation in future.





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