Species traits mediate environmental responses but not conspecific density dependence in tropical tree saplings

Understanding how functional traits mediate species-specific responses to environmental variation and neighborhood interaction is fundamental for linking individual performance to community assembly. We used a hierarchical framework to examine how functional traits along the acquisitive-conservative spectrum mediate growth responses to environmental effects and density dependence. We monitored the growth of 16,717 saplings from 115 tree species over five years in a tropical rainforest and measured 10 functional traits reflecting the acquisitive-conservative spectrum. We employed Bayesian hierarchical models to quantify the relative importance of environmental and density factors on sapling growth and investigate how functional traits mediate species-specific responses to these factors. Sapling growth rates were primarily influenced by soil conditions, light availability (canopy closure), and conspecific adult neighbor density. Acquisitive species exhibited enhanced growth under high lig..., Tree census
The tree censuses data were collected from the 20-ha (400 m × 500 m) Tropical Seasonal Rainforest Dynamics Plots in 2017 and 2021. The plot located in Naban River Watershed National Nature Reserve, Yunnan Province, Southwestern China (100°36′E, 22°14′N).  All woody stems ≥ 1 cm DBH (diameter at breast height, 1.3 m above ground) in the plot were measured, tagged, mapped and identified to species. 
Functional traits measurement
We measured functional traits following the standardized protocol (Cornelissen et al. 2003, Pérez-Harguindeguy et al. 2016). These included key whole-plant traits (wood density, WD, g/cm3; seed mass, SM, g) and leaf traits (specific leaf area, SLA, mm2/mg; leaf area, LA, mm2; leaf thickness, LT, mm; leaf dry mass content, LDMC, mg/g; leaf carbon content, LCC, mg/g; leaf phosphorus content, LPC, mg/g; leaf nitrogen content, LNC, mg/g; leaf potassium content, LKC, mg/g). These traits were measured in in the 20-ha (400 m × 500 m) Xishuangbanna F..., , Data and R code from: Species traits mediate environmental responses but not conspecific density dependence in tropical tree saplings

Author: Xiaohua Ma[1, 2#], Rong Gu[1, 2#], Guoshan Shi[2], Feng Liu[3, 4], Guanghong Cao[3], Yun Deng[2], Shangwen Xia[2], Xiaodong Yang[2], Zhiming Zhang[1*], Luxiang Lin [2, 5*]
\[1] School of Ecology and Environment Science, Yunnan University, Kunming 650504, China
\[2] Yunnan Key Laboratory of Forest Ecosystem Stability and Global Change, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 666303, China
\[3] Administration Bureau of Naban River Watershed National Nature Reserve, Jinghong, Yunnan 666100, China
\[4] Yunnan Academy of Forestry and Grassland, Kunming, Yunnan 650204, China
\[5] National Forest Ecosystem Research Station at Xishuangbanna, Mengla, Yunnan, 666303, China
\[#] These authors have equal contributions.
\[*] Corresponding authors: Zhiming Zhang: E-mail: [[e-mail]](mailto:zzming76@ynu.e...,

阐明功能性状（functional traits）如何介导物种对环境变化与邻体互作的特异性响应，是将个体表现与群落构建联系起来的核心基础。本研究采用层级框架，探究沿获取-保守策略轴（acquisitive-conservative spectrum）分布的功能性状如何调控植物生长对环境效应与密度依赖（density dependence）的响应。我们在一处热带雨林中开展了为期5年的监测，共记录115个树种共计16717株幼树（saplings）的生长情况，并测定了10个反映获取-保守策略轴的功能性状。本研究采用贝叶斯层级模型（Bayesian hierarchical models），量化环境与密度因子对幼树生长的相对重要性，并探究功能性状如何介导物种对这些因子的特异性响应。幼树生长速率主要受土壤条件、光照可获得性（林冠闭合度，canopy closure）以及同种成年邻体密度（conspecific adult neighbor density）的影响。获取型物种在高光照条件下生长速率提升……（原文截断）

树木普查

树木普查数据采集自2017年与2021年的20公顷（400米×500米）热带季节性雨林动态监测样地。该样地位于中国西南云南省纳板河流域国家级自然保护区内（东经100°36′，北纬22°14′）。样地内所有胸径（DBH, diameter at breast height，即离地1.3米处的直径）≥1厘米的木本茎干均被测量、标记、定位并鉴定至物种水平。

功能性状测定

本研究遵循标准化实验规程（Cornelissen等，2003；Pérez-Harguindeguy等，2016）开展功能性状测定。测定的性状涵盖关键的整株性状：木材密度（WD, wood density），单位：g/cm³；种子质量（SM, seed mass），单位：g；以及叶片性状：比叶面积（SLA, specific leaf area），单位：mm²/mg；叶面积（LA, leaf area），单位：mm²；叶厚度（LT, leaf thickness），单位：mm；叶干物质含量（LDMC, leaf dry mass content），单位：mg/g；叶碳含量（LCC, leaf carbon content），单位：mg/g；叶磷含量（LPC, leaf phosphorus content），单位：mg/g；叶氮含量（LNC, leaf nitrogen content），单位：mg/g；叶钾含量（LKC, leaf potassium content），单位：mg/g。本研究在20公顷（400米×500米）西双版纳……（原文截断）

数据与R代码来源：《热带树幼树的功能性状介导环境响应而非同种密度依赖》

作者：马晓华[1,2#]、顾荣[1,2#]、石国山[2]、刘峰[3,4]、曹广宏[3]、邓云[2]、夏尚文[2]、杨晓东[2]、张治明[1*]、林鹿翔[2,5*]

[1] 云南大学生态与环境学院，昆明 650504，中国

[2] 中国科学院西双版纳热带植物园 云南省森林生态系统稳定与全球变化重点实验室，昆明 666303，中国

[3] 纳板河流域国家级自然保护区管理局，景洪 666100，中国

[4] 云南省林业和草原科学院，昆明 650204，中国

[5] 西双版纳国家森林生态系统定位研究站，勐腊 666303，中国

[#] 本文作者贡献相等

[*] 通讯作者：张治明，电子邮箱：[e-mail]（原文截断）