Intraspecific variation in traits and tree growth along an elevational gradient in a subtropical forest
Intraspecific variation in traits and tree growth along an elevational gradient in a subtropical forest
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DOI：
10.1007/s00442-019-04453-6
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发表时间：
2019-07
期刊：
影响因子：
2.7
通讯作者：
M. Umaña;N. Swenson
中科院分区：
文献类型：
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作者：
M. Umaña;N. Swenson
自然群落的一个显著特征是物种内的个体在表型上表现出广泛的差异。虽然物种间的表型差异是突出的，并且在早期的研究中受到了相当大的关注，但最近的研究结果表明，大约40%的性状变异是在物种内发现的。这种种内变异如何与潜在的环境梯度相关，并最终与表现相关，是生态学和进化中的一个悬而未决的问题。在这里，我们研究了亚热带森林中跨越海拔梯度的六种广泛分布的物种。我们重点研究了反映植物茎运输、叶结构和叶片资源获取功能分化的5个功能性状。结果表明，叶片厚度、叶片韧性和比叶面积随海拔高度的变化而变化，而木材密度和比叶面积的变化受限制。多变量性状轴的结果也显示出混合证据，PC1值（与叶片韧性正相关，与比叶面积负相关）随海拔而变化，而PC2值（与木材密度负相关）不随海拔而变化。我们还发现，尽管一些性状在梯度上有重要的变化，但生长性能并没有遵循相同的趋势。这表明，沿着梯度的特征的强烈方向性变化可能导致相似水平的人口统计学表现。因此，研究结果挑战了一个简单的预期，即一个特征将与人口统计率相关。必须考虑更细致入微的方法和额外的机制，以促进对绩效-特质关系的理解。
A conspicuous feature of natural communities is that individuals within species exhibit broad variation in their phenotype. While the phenotypic differences among species are prominent and have received considerable attention in earlier studies, recent findings suggest that about 40% of the trait variation is found within species. How this intraspecific variation is related to underlying environmental gradients and ultimately linked to performance is an outstanding question in ecology and evolution. Here, we study six broadly distributed species across an elevational gradient in a subtropical forest. We focused on five functional traits reflecting plant functional differentiation in stem transport, leaf architecture, and leaf resource acquisition. We found that leaf thickness, leaf toughness, and specific leaf area generally varied with elevation, while wood density and leaf area exhibited constrained variation. Results on multivariate trait axes also showed mixed evidence with the PC1 values (positively related to leaf toughness and negatively related to specific leaf area) shifting with elevation, while PC2 values (negatively related to wood density) did not change with elevation. We also found that, despite the important variation in some traits along the gradient, growth performance did not follow this same trend. This suggests that strong directional changes in traits along the gradient may result in similar levels of demographic performance. The results, therefore, challenge the simple expectation that a trait will correlate with a demographic rate. More nuanced approaches and additional mechanisms must be considered to advance understanding of the performance–trait relationships.