Jiang Feng, Cadotte Marc W, Jin Guangze
Center for Ecological Research Northeast Forestry University Harbin China.
Department of Biological Sciences University of Toronto Scarborough Toronto ON Canada.
Ecol Evol. 2021 Mar 18;11(10):5344-5354. doi: 10.1002/ece3.7425. eCollection 2021 May.
Even with increasing interest in the ecological importance of intraspecific trait variation (ITV) for better understanding ecological processes, few studies have quantified ITV in seedlings and assessed constraints imposed by trade-offs and correlations among individual-level leaf traits. Estimating the amount and role of ITV in seedlings is important to understand tree recruitment and long-term forest dynamics. We measured ten different size, economics, and whole leaf traits (lamina and petiole) for more than 2,800 seedlings (height ≥ 10 cm and diameter at breast height < 1 cm) in 283 seedling plots and then quantified the amount of ITV and trait correlations across two biological (intraspecific and interspecific) and spatial (within and among plots) scales. Finally, we explored the effects of trait variance and sample size on the strength of trait correlations. We found about 40% (6%-63%) variation in leaf-level traits was explained by ITV across all traits. Lamina and petiole traits were correlated across biological and spatial scales, whereas leaf size traits (e.g., lamina area) were weakly correlated with economics traits (e.g., specific lamina area); lamina mass ratio was strongly related to the petiole length. Trait correlations varied among species, plots, and different scales but there was no evidence that the strength of trait relationships was stronger at broader than finer biological and spatial scales. While larger trait variance increased the strength of correlations, the sample size was the most important factor that was negatively related to the strength of trait correlations. Our results showed that a large amount of trait variation was explained by ITV, which highlighted the importance of considering ITV when using trait-based approaches in seedling ecology. In addition, sample size was an important factor that influenced the strength of trait correlations, which suggests that comparing trait correlations across studies should consider the differences in sample size.
尽管人们越来越关注种内性状变异（ITV）对更好地理解生态过程的生态重要性，但很少有研究对幼苗的ITV进行量化，并评估个体水平叶片性状之间的权衡和相关性所带来的限制。估计ITV在幼苗中的数量和作用对于理解树木更新和长期森林动态至关重要。我们在283个幼苗样地中，对超过2800株幼苗（高度≥10厘米且胸径<1厘米）测量了十种不同的大小、经济学和全叶性状（叶片和叶柄），然后在两个生物学（种内和种间）和空间（样地内和样地间）尺度上量化了ITV的数量和性状相关性。最后，我们探讨了性状变异和样本量对性状相关性强度的影响。我们发现，所有性状中约40%（6%-63%）的叶片水平性状变异可由ITV解释。叶片和叶柄性状在生物学和空间尺度上具有相关性，而叶片大小性状（如叶片面积）与经济学性状（如比叶面积）相关性较弱；叶片质量比与叶柄长度密切相关。性状相关性在物种、样地和不同尺度之间存在差异，但没有证据表明在更广泛的生物学和空间尺度上性状关系的强度比更精细的尺度上更强。虽然较大的性状变异增加了相关性强度，但样本量是与性状相关性强度呈负相关的最重要因素。我们的结果表明，大量的性状变异可由ITV解释，这突出了在幼苗生态学中使用基于性状的方法时考虑ITV的重要性。此外，样本量是影响性状相关性强度的一个重要因素，这表明在比较不同研究中的性状相关性时应考虑样本量的差异。
