ABSTRACT

Investigating changes in belowground functional plant traits is an important step toward a better understanding of vegetation dynamics during primary succession. However, in alpine glacier forelands, we still lack an accurate assessment of plant rooting patterns. In this study, we established two proglacial chronosequences with contrasting bedrocks to investigate changes in rooting patterns and biomass allocation with terrain age. We extracted soil cores up to 1 m depth and measured root traits every 10 cm of each drilled core. Furthermore, we sampled aboveground biomass determining the contributions of functional groups to total aboveground biomass. We found that root traits associated with the root economics spectrum varied significantly along the chronosequences. Vertical root distribution coefficients revealed that early successional communities had more evenly distributed root systems compared to late successional communities. Biomass allocation showed diverging patterns. We found evidence for both the isometric allocation and optimal partitioning hypotheses. In addition, we observed a significant correlation between rooting parameters and plant community composition, suggesting that the dominance of distinct plant functional groups was one important factor explaining the observed rooting patterns. Our results shed light on the often neglected belowground compartments during plant succession and contribute to a better understanding of hillslope functioning.

摘要

调查地下功能性植物性状的变化是更好地了解一次演替期间植被动态的重要一步。但是，在高山冰川前陆，我们仍然缺乏对植物生根模式的准确评估。在这项研究中，我们建立了两个具有对比性基岩的冰川期时间序列，以研究生根模式和生物量分配随地形年龄的变化。我们提取了高达1 m深度的土壤岩心，并在每个钻孔岩心中每10 cm测量了根系性状。此外，我们对地上生物量进行了采样，以确定官能团对地上总生物量的贡献。我们发现与根经济学谱相关的根性状随时间序列有显着变化。垂直根系分布系数表明，与后期演替群落相比，早期演替群落的根系分布更均匀。生物量分配显示出不同的模式。我们发现了等距分配和最优分配假设的证据。此外，我们观察到生根参数与植物群落组成之间存在显着相关性，表明不同植物功能基团的优势是解释观察到的生根模式的重要因素。我们的研究结果揭示了植物演替过程中经常被忽视的地下区室，并有助于更好地了解坡地功能。我们发现了等距分配和最优分配假设的证据。此外，我们观察到生根参数与植物群落组成之间存在显着相关性，表明不同植物功能基团的优势是解释观察到的生根模式的重要因素。我们的研究结果揭示了植物演替过程中经常被忽视的地下区室，并有助于更好地了解坡地功能。我们发现了等距分配和最优分配假设的证据。此外，我们观察到生根参数与植物群落组成之间存在显着相关性，表明不同植物功能基团的优势是解释观察到的生根模式的重要因素。我们的研究结果揭示了植物演替过程中经常被忽视的地下区室，并有助于更好地了解坡地功能。