School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia.
CSIRO Land and Water, EcoSciences Precinct, Dutton Park, Queensland, Australia.
Ecol Appl. 2022 Sep;32(6):e2636. doi: 10.1002/eap.2636. Epub 2022 Jun 2.
Functional traits are proxies for a species' ecology and physiology and are often correlated with plant vital rates. As such they have the potential to guide species selection for restoration projects. However, predictive trait-based models often only explain a small proportion of plant performance, suggesting that commonly measured traits do not capture all important ecological differences between species. Some residual variation in vital rates may be evolutionarily conserved and captured using taxonomic groupings alongside common functional traits. We tested this hypothesis using growth rate data for 17,299 trees and shrubs from 80 species of Eucalyptus and 43 species of Acacia, two hyper-diverse and co-occurring genera, collected from 497 neighborhood plots in 137 Australian mixed-species revegetation plantings. We modeled relative growth rates of individual plants as a function of environmental conditions, species-mean functional traits, and neighbor density and diversity, across a moisture availability gradient. We then assessed whether the strength and direction of these relationships differed between the two genera. We found that the inclusion of genus-specific relationships offered a significant but modest improvement to model fit (1.6%-1.7% greater R than simpler models). More importantly, almost all correlates of growth rate differed between Eucalyptus and Acacia in strength, direction, or how they changed along the moisture gradient. These differences mapped onto physiological differences between the genera that were not captured solely by measured functional traits. Our findings suggest taxonomic groupings can capture or mediate variation in plant performance missed by common functional traits. The inclusion of taxonomy can provide a more nuanced understanding of how functional traits interact with abiotic and biotic conditions to drive plant performance, which may be important for constructing trait-based frameworks to improve restoration outcomes.
功能性状是物种生态和生理学的替代指标，通常与植物生活力相关。因此，它们有可能指导用于恢复项目的物种选择。然而，预测性基于性状的模型通常只能解释植物表现的一小部分，这表明常用的性状并不能捕捉到物种之间所有重要的生态差异。一些生活力的剩余变异可能在进化上是保守的，可以与常见的功能性状一起使用分类群来捕获。我们使用来自桉树 80 个物种和金合欢 43 个物种的 17299 株树木和灌木的生长率数据来测试这个假设，这些数据是从澳大利亚 137 个混合物种再造林种植点的 497 个邻域样方中收集的。我们将个体植物的相对生长率建模为环境条件、物种平均功能性状以及邻居密度和多样性的函数，跨越水分可利用性梯度。然后，我们评估了这些关系的强度和方向在两个属之间是否不同。我们发现，包含属特异性关系的模型拟合度有显著但适度的提高（比简单模型高 1.6%-1.7%）。更重要的是，在强度、方向或它们在水分梯度上的变化方式方面，生长率的几乎所有相关因素在桉树和金合欢之间都存在差异。这些差异映射到两个属之间的生理差异上，而这些差异仅通过测量的功能性状无法捕捉到。我们的研究结果表明，分类群可以捕捉或介导常用功能性状错过的植物表现的变化。分类学的纳入可以提供对功能性状如何与非生物和生物条件相互作用以驱动植物表现的更细致的理解，这对于构建基于性状的框架以改善恢复结果可能很重要。
