长白山阔叶红松林系统发育和功能性状beta多样性

Beta多样性是生物多样性的重要组成部分,对于研究生物多样性的形成机制具有重要意义。基于物种进化历史和功能性状的系统发育和功能性状beta多样性的研究,能够从不同的角度反映群落格局形成的生态学过程。本文以长白山阔叶红松林40 hm2样地中45种木本植物(DBH≥1 cm)为研究对象,采集了最大树高、叶面积、比叶面积和叶氮含量4种功能性状,采用Srensen指数衡量功能性状与系统发育beta多样性在不同空间尺度(半径为10、20、25、50和75 m)的变化趋势,并通过比较系统发育和功能性状beta多样性格局与零模型的差异,进而推断潜在的生态过程。研究表明:1)长白山阔叶红松林系统发育和功能性状beta多样性均表现出距离衰减效应,并且随取样尺度的增大,系统发育和功能性状beta多样性逐渐降低。2)功能性状和系统发育beta多样性格局均具有非随机的变化趋势。随着取样尺度的增大,系统发育beta多样性呈现出先低于随机状态(10~20 m),随后趋于随机(25~50 m),最后又低于随机状态(75 m)的格局。而功能性状beta多样性格局则由随机状态(10~50 m)逐渐变为低于随机状态(75 m)。表明在中小尺度上(10~50 m),中性过程占主导作用,但不能排除生态位过程的影响;而随着尺度的增大,生境过滤在维持长白山阔叶红松林群落构建中起主导作用。3)功能性状与系统发育beta多样性格局变化趋势不一致,推测主要是由于功能性状系统发育信号较弱所导致。 

Phylogenetic and functional beta diversity in a broadleaved Korean pine mixed forest in Changbai Mountains,northeastern China

Beta diversity is an important component of biological diversity and plays a crucial role in the detecting of biodiversity. Based on the direct and indirect measure of ecological similarity, phylogenetic and functional beta diversity can provide new insights into assembly mechanisms of community ecology. To reveal the underlying ecological processes, we measured 4 functional traits of 45 woody species (maximum plant height, leaf area, specific leaf area, and leaf nitrogen contents) in a well-mapped 40 ha broadleaved Korean pine mixed forest plot in Changbai Mountains, Northeast China. Next, we calculated the functional and phylogenetic beta diversity through the Srensen index and compared observed pattern with null model approach to test for non-random functional and phylogenetic beta diversity at different spatial scales (radius 10, 20, 25, 50, and 75 m). Our results showed that: 1) the phylogenetic and functional similarity decreased with distances and increased with grain sizes. 2) All the phylogenetic and functional beta diversity showed non-random pattern. As the increase of grain size, the phylogenetic beta diversity showed random only in the 25-50 m scale, while lower than random in the scales of 10-20 m and 75 m. The functional beta diversity turned from random (10-50 m) to lower than random (75 m). The results suggest that in the middle and small scales (10-50 m), neutral process is more important, but we cannot rule out the role of niche process, and with the increase of scale, habitat filtering determines the community assembly in the broadleaved Korean pine forest. 3) The mismatch between functional and phylogenetic beta diversity patterns could be partly explained by the lack of phylogenetic signal for most traits.