Intraspecific variation in epiphyte functional traits reveals limited effects of microclimate on community assembly in temperate deciduous oak canopies

本文作者是一个人，所以全文主动语态用的都是I。

解题：

Intraspecific variation in epiphyte functional traits reveals limited effects of microclimate on community assembly in temperate deciduous oak canopies

题目比较长不好翻译，就意译吧。

和上一篇文章一样，种内size变异（表型可塑性）和群落结构改变是群落适应环境（气温）变化的两种机制，本文中，功能形状的种内变异（Intraspecific variation in epiphyte functional traits ）和群落组成（community assembly）均受微气候（microclimate）的影响，而且种内的性状变异限制了微气候对群落组成的影响的。本文的研究对象是地衣，epiphyte是附生植物或者真菌的意思，这里应该取前者；而微气候差异的产生是由树冠产生的（ in temperate deciduous oak canopies，温带落叶栎树冠层）。

 

摘要如下：

 

Forest canopies are heterogeneous environments where changes in microclimate over short distances create an opportunity for niche-based filtering of canopy-dwelling species assemblages.

 森林冠层提供了研究微气候下物种生态位过滤的机会。

 

This environmental filtering may not occur if species‘ physiological capacities are flexible or if rapid dispersal alleviates compositional differences. I assess the role of humidity, light and temperature gradients in structuring epiphyte communities in temperate deciduous oak (Quercus) canopies and determine whether gradients filter species with fixed traits or whether environmental constraints act primarily to alter individual phenotypes.

 

提出假说，两种机制，环境（指标标红）是筛选物种还是改变个体性状。实际上，仍旧是物种水平的selection和种内性状水平的plasticity的策略选择，群落水平的物种还是个体水平的性状。

 

I measured environmental conditions and seven functional traits related to water and light acquisition on individual macrolichens at 60 sample locations in northern red oaks Quercus rubra in two Piedmont forests in North Carolina, USA.

The effects of environmental variables on individual-level traits and community composition were evaluated using linear mixed models and constrained ordination (RDA).

以上是取样和数据处理方法。

 

以下是结果，结果实际上是阴性的，

 

1、In general, traits and community composition responded weakly to environmental variables and trait variation within taxa was high.

2、Cortex thickness exhibited the strongest response, such that individuals with thicker cortices were found in samples experiencing lower humidity and higher light levels.

 

以下是讨论，湿度、光和温度都没有成为有利的过滤环境因子，湿度一定程度上和一些性状相关但不，原因归结于种内的可塑性变异。

This was probably due to phenotypic variability within taxa that enabled species to persist across the full range of environmental conditions measured.

Thus, humidity affected the phenotype of individuals, but did not limit species distributions or alter community composition at the scale of branches within trees.

最后谈及site-level（指的是两个地区）层次的差异，认为更大的景观尺度的气候梯度比现在研究的冠层内的环境梯度更能驱动群落构建。

 

Community and trait responses were primarily associated with site-level differences in humidity, suggesting that in these forests landscape-scale climatic gradients may be stronger drivers of epiphyte community assembly than intra-canopy environmental gradients.

 

 

感兴趣，可以再去查看全文考究实验背景、实验指标测度、实验数据处理、具体结果、以及讨论。