• Large intraspecific functional trait variation strongly impacts many aspects of communities and ecosystems, and is the medium upon which evolution works. Yet intraspecific trait variation is inconsistent and hard to predict across traits, species and locations.
• We measured within‐species variation in leaf mass per area (LMA), leaf dry matter content (LDMC), branch wood density (WD), and allocation to stem area vs leaf area in branches (branch Huber value (HV)) across the aridity range of seven Australian eucalypts and a co‐occurring Acacia species to explore how traits and their variances change with aridity.
• Within species, we found consistent increases in LMA, LDMC and WD and HV with increasing aridity, resulting in consistent trait coordination across leaves and branches. However, this coordination only emerged across sites with large climate differences. Unlike trait means, patterns of trait variance with aridity were mixed across populations and species. Only LDMC showed constrained trait variation in more xeric species and drier populations that could indicate limits to plasticity or heritable trait variation.
• Our results highlight that climate can drive consistent within‐species trait patterns, but that patterns might often be obscured by the complex nature of morphological traits, sampling incomplete species ranges or sampling confounded stress gradients.

中文翻译：

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干旱驱动八种澳大利亚树木的地理范围内协调的性状转移，但并未减少性状方差。

• 种内功能性状的巨大变化强烈影响着社区和生态系统的许多方面，并且是进化起作用的媒介。然而，种内性状变异是不一致的，并且很难跨性状，物种和位置进行预测。
• 我们测量了种内物种在每面积叶片质量（LMA），叶片干物质含量（LDMC），分支木材密度（WD）以及物种在整个分支中的茎面积与叶片面积的分配的变化（分支胡贝尔值（HV））。七个澳大利亚桉树和一个同时出现的相思树种的干旱范围，以探讨性状及其变异如何随干旱变化。
• 在物种内部，我们发现随着干旱增加，LMA，LDMC和WD和HV持续增加，从而导致叶片和枝条之间的性状协调一致。但是，这种协调仅出现在气候差异较大的站点之间。与特质手段不同，特质变异与干旱的模式在种群和物种中混合在一起。只有LDMC在更多的干性物种和较干燥的种群中显示出受限的性状变异，这可能表明可塑性或可遗传性状变异受到限制。
• 我们的结果表明，气候可以驱动物种内部一致的性状模式，但是形态特征的复杂性，不完整的物种范围采样或混杂的应力梯度采样常常会掩盖这种模式。