伏牛山自然保护区物种多样性分布格局

The pattern of plant species diversity of Funiu Mountain Nature Reserve

在伏牛山自然保护区典型地段设立样方,通过群落调查和多样性分析对物种多样性的垂直分布格局进行研究。发现:α多样性,乔木层在中海拔的落叶阔叶混交林带最高,灌木层随海拔升高稍呈上升趋势,草本层在低海拔次生林带和山顶矮林带物种多样性较高;β多样性总体上呈"～"型变化,在中海拔建群种发生更替的落叶阔叶混交林区最高,物种更替速率最快,其次是山顶附近。γ多样性大致沿海拔升高递减,以700m以下和过渡带落叶阔叶混交林区总物种丰富度最高。沿海拔梯度升高,水热组合发生变化,地带性植被总体上表现为由栓皮栎(Quercus variabilis)林向锐齿栎(Quercus aliena var.acuteserrata)林更替,在建群种发生更替的中海拔过渡带形成混交林带,短柄枹(Quercus glandulifera var.brevipetiolata)、槲栎(Quercus aliena)等夹杂其间在一些小生境中形成优势种群。总体上体现了过渡带具有高的物种多样性和更替速率,总物种丰富度隐含着沿海拔升高而降低的负相关关系。

We established experimental plots in representative areas in the Funiu Mountain nature reserve. We investigated plant communities in these plots to discern the pattern of species diversity distribution along the altitudinal gradient. We calculated α-diversity,β-diversity,and γ-diversity using the data thus collected. Alpha diversity of the tree layer peaks in the deciduous broadleaved mixed forest zone at mid-elevation,alpha diversity of the shrub layer increases gradually along the altitudinal gradient,while alpha diversity of the herb layer peaks in low altitude secondary forests and the mountaintop elfin forest. Beta diversity peaks twice,first at mid-elevations where the composition of edificatory species changes,then in areas near the mountaintop. Gamma diversity decreases along the altitudinal gradient. The highest species richness levels occur in areas below 700m and the mid-elevation deciduous broadleaved mixed forest. As elevation rises,Quercus variabilis forest gradually gives way to Quercus aliena var. acuteserrata forest,forming a mixed forest at mid-elevations; dispersed among the edificatory trees are Quercus glandulifera var. brevipetiolata and Quercus aliena,secondary edificatory species that are dominant in some niches. The transition zone is characterized by relatively high levels of species diversity and species turn-over rate. Overall species richness is negatively correlated with altitude.