Abstract

Lianas have a huge influence on forest structure and function. However, it is unclear how the surrounding environment affects the establishment of liana seedlings in temperate forests. We addressed the following questions: (1) Can current-year seedlings persist under a closed canopy? (2) Do current-year seedlings form aggregated distribution and how has their spatial distribution varied over the years? (3) How does the light condition, soil moisture content, forest floor litter, understory vegetation, and the distance from the conspecific adults affect the establishment and survival of seedlings? We examined the distribution pattern and survivorship of current-year seedlings of the temperate liana species, Wisteria floribunda, across a heterogeneous environment for 6 years using 1 m² sub-quadrats (n = 651) in a 6 ha plot within the Ogawa Forest Reserve, an old-growth, temperate, deciduous forest in central Japan. In total, 908 current-year seedlings were observed during the study period, 87% of which emerged in 2014. Over half (56%) of these seedlings survived until 1 year after germination, which was relatively high compared with other tree species in this forest. The seedlings formed significantly aggregated distribution, but the degree of aggregation decreased over time. The number of emerged seedlings was negatively associated with the presence of dwarf bamboo (Sasa borealis) and the distance from the nearest conspecific adult. However, the survival rate of the seedlings was negatively associated with the presence of dwarf bamboo and soil moisture content and was positively associated with the openness of the canopy and the distance from the nearest conspecific adult. An enhanced survival rate under more intense light conditions and the ability to persist within the shaded understory may be important for the survival of this species in the earlier stage of the life history.

中文翻译：

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温带藤本植物紫藤多年生苗在不同环境中的成活率和对环境的响应。

摘要

藤本植物对森林的结构和功能具有巨大的影响。但是，尚不清楚周围环境如何影响温带森林中藤本植物幼苗的生长。我们解决了以下问题：（1）当年的幼苗在密闭的树冠下还能持续吗？（2）当年的幼苗是否形成聚集分布，并且它们的空间分布多年来如何变化？（3）光照条件，土壤含水量，林地凋落物，林下植被以及距同种成虫的距离如何影响幼苗的形成和存活？我们使用1 m ²在6年的非均质环境中研究了温带藤本植物紫藤（Wisteria floribunda）的当年幼苗的分布格局和存活情况。 在小川森林保护区（日本中部的一种古老，温带，落叶森林）内占地6公顷的土地中，形成了四分之一次方（n = 651）。在研究期间，总共观察到908棵当年幼苗，其中87％出现在2014年。其中一半以上（56％）的幼苗存活到发芽后1年，相对于该树种而言，相对较高森林。幼苗形成明显的聚集分布，但聚集程度随时间降低。出现苗矮化竹的存在负相关的（数箬竹）以及距最近的同种成年人的距离。然而，幼苗的成活率与矮竹的存在和土壤水分含量成负相关，与冠层的开放度和与最近的同种成年植物的距离成正相关。在更强烈的光照条件下提高的存活率以及在阴影下的林间持久的能力对于该物种在生命史早期阶段的生存可能很重要。