Department of Zoology, University of British Columbia, 4200-6270 University Blvd, Vancouver, BC, V6T1Z4, Canada,
Oecologia. 2013 Dec;173(4):1531-8. doi: 10.1007/s00442-013-2727-3. Epub 2013 Jul 13.
Understanding the links between intraspecific genetic variation and patterns of diversity in associated communities has been the primary focus of community genetics or 'genes-to-ecosystem' research in ecology. While other ecological factors, such as the abiotic environment, have well-documented influences on communities, the relative contributions of genetic variation versus the environment to species interactions remains poorly explored. In this study, we use a common garden experiment to study a coastal dune plant community dominated by the shrub, Baccharis pilularis, which displays a morphological dimorphism in plant architecture. We found the differences in the understory plant community between erect and prostrate morphs of Baccharis to be statistically significant, but small relative to the impacts of nutrient additions (NPK and C additions), for the richness, cover, and biomass of the understory plant community. There were no significant interactions between Baccharis morphology and nutrient-addition treatments, suggesting the influence of nutrient addition was consistent between erect and prostrate morphs. Moreover, we found no difference in overall plant community composition between Baccharis morphs, while NPK additions led to shifts in understory community composition compared to unfertilized shrubs. In sum, our results indicate that nutrients are the more important factor governing understory plant community structure in a coastal dunes ecosystem followed by intraspecific variation in dominant shrub architecture. Our results address a growing call to understand the extended consequences of intraspecific variation across heterogeneous environments in terrestrial ecosystems.
理解种内遗传变异与相关群落多样性模式之间的联系一直是群落遗传学或“从基因到生态系统”生态学研究的主要焦点。虽然其他生态因素，如非生物环境，对群落有很好的影响，但遗传变异与环境对物种相互作用的相对贡献仍未得到充分探索。在这项研究中，我们使用一个常见的花园实验来研究一个由灌木 Baccharis pilularis 主导的沿海沙丘植物群落，该灌木在植物结构上表现出形态二态性。我们发现 Baccharis 的直立和匍匐形态之间的林下植物群落差异在统计学上是显著的，但相对于养分添加（NPK 和 C 添加）对林下植物群落的丰富度、盖度和生物量的影响较小。Baccharis 形态和养分添加处理之间没有显著的相互作用，这表明养分添加的影响在直立和匍匐形态之间是一致的。此外，我们没有发现 Baccharis 形态之间的整体植物群落组成有差异，而与未施肥的灌木相比，NPK 添加导致林下群落组成发生变化。总之，我们的结果表明，在沿海沙丘生态系统中，养分是控制林下植物群落结构的更重要因素，其次是优势灌木结构的种内变异。我们的结果满足了越来越多的要求，即在陆地生态系统中，要了解种内变异在异质环境中的扩展后果。
