How do functional traits influence tree demographic properties in a subtropical monsoon forest?

Abstract

1. Functional traits are good predictors of plant responses and adaptations to ever-changing environments. However, forecasting forest community dynamics is challenging because the relationships among different tree demographic properties (growth, mortality and recruitment) and how functional traits are associated with tree demography remain largely unknown.2. Here, in a 20-ha subtropical forest permanent plot, we quantified the rates of tree growth, mortality and recruitment across 53 dominant tree species (diameter at breast height; DBH ≥ 1 cm) from 2005 to 2020. Functional traits that are closely related to plant photosynthesis, nutrients, hydraulics and drought tolerance were measured.3. We found that tree growth rate (GR) varied independently from rates of tree mortality and recruitment. Hydraulic conductivity was positively correlated with GR (explaining 27% variation-the strongest relationship observed) whereas wood density was negatively correlated with GR. Leaf life span was negatively related to tree mortality. Species with high carbon assimilation rate, nutrient concentration and hydraulic conductivity had high recruitment rates. Leaf turgor loss point was unrelated to plant demography. Principal component analysis revealed that species with quick resource acquisition rates had high rates of growth and recruitment. 4. Our results illustrate that the correlations among tree demographic properties were weak in this subtropical forest with monsoonal climate. Most notably, against expectations, there was no observed trade-off between growth and mortality. Individual functional traits explained up to 27% of each demographic rate.

Differential tree demography mediated by water stress and functional traits in a moist tropical forest

“…High recruitment is likely to be more relevant to the characteristics of fast‐growing species, as they invest more resources in promoting the establishment and growth of seedlings and saplings. The significant positive correlations between Ks (linked to carbon gain and xylem efficiency) and both mortality and recruitment rates further proved the close connection between resource acquisition, hydraulic traits and interspecific differences in tree demography (He et al, 2022). Therefore, plant functional traits (such as WD) that are related to resource acquisition and hydraulic safety offer valuable insights into interspecific differences in tree demography, especially in terms of recruitment.…”

Linking plant functional traits to biodiversity under environmental change

“…Meanwhile, tree mortality was negatively correlated to leaf lifespan, indicating that traits would be helpful in predicting future community dynamics. 27 However, it has also been reported that trait-demographic rate correlations are phenotypic and environmental context dependent, which usually leads to a weak or inconsistent relationship between trait and demography. 28 Thus, it is necessary to further test the trait-demography correlations at different temporal and spatial scales, ideally with confound factors being controlled.…”

“…For example, in a subtropical forest, tree growth rate was positively correlated with hydraulic conductivity, and negatively correlated with wood density. Meanwhile, tree mortality was negatively correlated to leaf lifespan, indicating that traits would be helpful in predicting future community dynamics 27 . However, it has also been reported that trait‐demographic rate correlations are phenotypic and environmental context dependent, which usually leads to a weak or inconsistent relationship between trait and demography 28 .…”

Functional traits influence the growth and mortality of common woody plants in Dajinshan Island, Shanghai, China

“…功能性状是植物长期适应外部环境过程中, 在 器官或植株水平上形成的一系列相互关联的结构性 和功能性特征 (Westoby et al, 2002;刘晓娟和马克 平 , 2015) 。功能性状不仅影响植物个体的适应 (Cornelissen et al, 2003), 也很大程度上影响物种的 种群特征 (Poorter et al, 2008;Prado-Junior et al, 2016), 乃至群落结构与生态系统功能 (Garnier et al, 2004;McGill et al, 2006;Kraft et al, 2010;Prado-Junior et al, 2016)。植物功能性状反映了物种在资 源利用和分配策略等方面的差异, 植物功能性状变 异如何影响物种的生长和存活状况一直是生态学家 关 心 的 核 心 科 学 问 题 (Wright et al, 2004;Prado-Junior et al, 2016;Silva et al, 2017)。在全球 变化背景下, 研究植物功能性状如何影响物种的生 长-死亡权衡(the growth-mortality trade-off), 非常有 助于揭示物种定植、生长发育和死亡的生理生态机 制 (Prado-Junior et al, 2016), 尤其是有助于从植物 功能性状视角预测物种相对生长率和死亡率 (Yang et al, 2018;He et al, 2022)。 不同植物之间的功能性状差异一定程度上反映 了物种在适应各类资源限制过程中的内在差异, 包 括扩散限制、资源获取和环境胁迫耐受能力等方面, 这些差异最终可能导致物种间生长-死亡权衡的变 化 (Shen et al, 2019)。最大树高、叶面积、叶片养分 含量、叶厚度、组织密度代表了物种形态结构和生 理特征的生态策略, 反映了物种对资源的获取能力 和对害虫或机械损伤的抵抗能力, 因此与物种的生 长率和死亡率密切相关 (Cornelissen et al, 2003;Wright et al, 2004)。组织密度高的物种因每单位的 碳投资较高, 所以生长较慢, 但抵抗物理损伤、 真菌 和病原体侵害的能力较强 (Poorter et al, 2008;Kraft et al, 2010;Flores et al, 2014), 从而死亡率较低。 比 叶面积和叶片养分含量较高的物种, 因其具有较高 的资源获取、光合作用和碳净收益的能力, 所以生 长率较快, 但是, 由于其具有较高的呼吸速率和叶 片周转, 以及高的养分含量, 因此易遭受草食动物 和病原体的攻击, 从而死亡率较高 (Silva et al, 2017;Shen et al, 2019)。简言之, 植物功能性状是驱动不 同物种生长-死亡权衡的主要内在因素 (Reich et al, 2003)。但是, 前期的一些研究表明植物功能性状与 物种生长或死亡的关系较弱 (Poorter et al, 2008;Paine et al, 2015;Yang et al, 2018) (Yang et al, 2018), 忽视物种不同生活史阶段性状的差异 (He et al, 2022) (Cornelissen et al, 2003;Wright et al, 2004), 按照植物资源获取的快-慢将物种划分为资源获取型和保守型。资源获取型 物种位于植物经济谱快投资-快收益的一端, 具有 较高的叶片养分含量、叶面积和树高, 其光合能力 较强, 能够快速获取资源, 所以生长率较快, 但该 类物种防御组织投资较低(干材密度和叶干物质含 量较低)...…”