Tree seedling trait optimization and growth in response to local‐scale soil and light variability
Tree seedling trait optimization and growth in response to local‐scale soil and light variability
复制标题
针对局部土壤和光照变化的树苗性状优化和生长
DOI：
10.1002/ecy.3252
复制
发表时间：
2021
期刊：
影响因子：
4.8
通讯作者：
Zambrano, Jenny
中科院分区：
文献类型：
--
作者：
Umaña, María Natalia;Arellano, Gabriel;Swenson, Nathan G.;Zambrano, Jenny
在局部尺度上，有人认为高水平的资源通过性状优化（高峰值性状分布）导致树木生长增加。然而，这与（1）理论表明，性状优化和高增长发生在最常见的资源水平和（2）经验证据表明，高性状优化也可以在低资源水平。这就提出了一个问题，即如何在高度多样化的植物群落中优化性状和生长。在这里，我们提出了一系列的假设如何性状和增长预计将在不同的资源水平（低，最常见的，高）在树苗社区从亚热带森林在波多黎各，美国最大化。我们研究了生物量分配的变化和叶片性状和幼苗生长速率沿着四个资源梯度：光可用性（冠层开放度）和土壤K，Mg和N含量。我们的分析包括比较性状峰度（性状优化的测量），社区性状的手段，并在三个资源水平（低，普通，高）的相对增长率。性状优化在三个资源水平上不同，这取决于资源和性状的类型，在高氮和最常见的K和Mg条件下优化叶性状，但在任何光照水平下都不优化。此外，幼苗生长在高光条件下和高N和K增加，但与性状峰度无关。我们的研究结果表明，土壤肥力和林下光照条件的局部尺度变异导致物种生态策略的转变，尽管性状优化较弱，但仍能增加生长，这表明存在实现类似高性能的替代表型。揭示非生物因子，功能性状多样性和性能之间的联系是必要的，以更好地预测树木对未来非生物条件变化的反应。
At local scales, it has been suggested that high levels of resources lead to increased tree growth via trait optimization (highly peaked trait distribution). However, this contrasts with (1) theories that suggest that trait optimization and high growth occur in the most common resource level and (2) empirical evidence showing that high trait optimization can be also found at low resource levels. This raises the question of how are traits and growth optimized in highly diverse plant communities. Here, we propose a series of hypotheses about how traits and growth are expected to be maximized under different resource levels (low, the most common, and high) in tree seedling communities from a subtropical forest in Puerto Rico, USA. We studied the variation in the distribution of biomass allocation and leaf traits and seedlings growth rate along four resource gradients: light availability (canopy openness) and soil K, Mg, and N content. Our analyses consisted of comparing trait kurtosis (a measurement of trait optimization), community trait means, and relative growth rates at three resource levels (low, common, and high). Trait optimization varied across the three resource levels depending on the type of resource and trait, with leaf traits being optimized under high N and in the most common K and Mg conditions, but not at any of the light levels. Also, seedling growth increased at high‐light conditions and high N and K but was not related to trait kurtosis. Our results indicate that local‐scale variability of soil fertility and understory light conditions result in shifts in species ecological strategies that increase growth despite a weak trait optimization, suggesting the existence of alternative phenotypes that achieve similar high performance. Uncovering the links between abiotic factors, functional trait diversity and performance is necessary to better predict tree responses to future changes in abiotic conditions.