小陇山锐齿栎林木本植物物种丰富度与生产力关系研究

  目的  物种丰富度?生产力关系研究是天然林生物多样性保护和生态系统功能维持的理论依据。由于物种丰富度间接包含了功能多样性、系统发育多样性和基因组多样性，因此从物种丰富度的角度探讨多样性?生产力关系，可以分析发现影响植被生产力的其他多样性因素。以往关于森林物种丰富度与生产力关系的研究大多集中在群落水平，而对于单个物种生产力对邻域物种丰富度的响应是如何影响群落水平的物种丰富度与生产力关系的研究却鲜见报道。  方法  本研究以小陇山地区的锐齿栎天然林为研究对象，通过回归分析、关联指数模型和异质性泊松模型，分析群落和物种水平的木本植物物种丰富度与生产力关系。  结果  丰富度?生产力关系在群落水平上表现出明显的尺度依赖性:在10 m × 10 m的研究尺度上，物种丰富度与群落生产力呈单峰曲线关系；而在20 m × 20 m的研究尺度上，物种丰富度对群落生产力无显著影响。物种水平上，0 ~ 20 m范围内物种丰富度?生产力关系中性种占比最大，占所有目标种总和的68.8% ~ 81.3%；其次为促进种；抑制种所占比例最小。研究区部分的树种表现出明显的偏离中性关系的情况，种间促进或抑制作用对丰富度?生产力关系有重要影响。  结论  物种丰富度和物种属性均会影响小陇山锐齿栎林生产力。 

Relationship between tree species richness and productivity of Quercus aliena var. acutiserrata forest in Xiaolongshan Mountain,Gansu Province of northwestern China

  Objective  The relationship between species richness and productivity (PDR) is the theoretical basis of biodiversity conservation for natural forests and maintenance of ecosystem functions. Species richness indirectly covers functional diversity, system development diversity and genetic diversity; therefore, the study of the diversity-productivity relationship could analyze the effect of other diversity factors on the productivity of vegetation. Previous studies about PDR mostly focused on the community level. Responses of single species productivity to neighboring biodiversity could affect the relationship between species richness and productivity at the community level. The studies focusing on this topic are rarely conducted.   Method  This study conducted regression analysis, the index of association (AI) model and heterogeneous Poisson model on inventory data from the Quercus aliena var. acutiserrata natural forest in Xiaolongshan Mountain, Gansu Province of northwestern China to discuss the relationship between species richness and productivity at community and species levels.   Result  The diversity-productivity relationship had significant scale dependence at the community level. At the 10 m × 10 m sampling scale, a quartic correlation (the hump curve first increased and then decreased) was found between species richness and productivity. At the 20 m × 20 m scale, species richness had no significant effect on productivity. At the species level, the species that behave neutrally in the diversity-productivity relationship had the highest proportion, and accounted for 68.8%?81.3% of total target species; followed by accumulators (i.e., the species increase diversity); and repellers (i.e., the species decrease diversity) had the smallest proportion. A fraction of the species in the study area showed a clear deviation from the neutral relationship. This indicated that the interaction between interspecific promotion or inhibition had an important impact on the diversity-productivity relationship.   Conclusion  Species richness and species attributes can both affect the productivity of Q. aliena var. acutiserrata forests in Xiaolongshan Mountain of northwestern China.