Mean Traits Data Compiled for Tree Taxa from BIEN Database for HJA, HFR, BCI, CWT, LUQ, and NWT

Patterns of biodiversity, such as the increase toward the tropics and the peaked curve during ecological succession, are fundamental phenomena for ecology. Such patterns have multiple, interacting causes, but temperature emerges as a dominant factor across organisms from microbes to trees and mammals, and across terrestrial, marine, and freshwater environments. However, there is little consensus on the underlying mechanisms, even as global temperatures increase and the need to predict their effects becomes more pressing. The purpose of this project is to generate and test theory for how temperature impacts biodiversity through its effect on biochemical processes and metabolic rate. A combination of standardized surveys in the field and controlled experiments in the field and laboratory measure diversity of three taxa -- trees, invertebrates, and microbes -- and key biogeochemical processes of decomposition in seven forests distributed along a geographic gradient of increasing temperature from cold temperate to warm tropical. This dataset contains list of all tree taxa from all experimental sites at HJA, HFR, BCI, CWT, LUQ, and NWT was compiled and traits for each were downloaded from BIEN database. Averages for each BIEN trait were calculated using R code below at the family, genus, and species taxonomic level. The "best" average (to the finest taxonomic resolution) was then used. Traits included isotope ratios of carbon and nitrogen, plant height, leaf area, leaf carbon, nitrogen, and phosphorus concentrations, seed mass, specific leaf area, and wood density. This was done by the Enquist Lab (PI, Brian Enquist) from the University of Arizona to measure annual tree growth as part of a macrosystems biodiversity and latitude project supported by the National Science Foundation under Cooperative Agreement DEB#1065836.

生物多样性（biodiversity）格局——诸如向热带递增的分布规律与生态演替（ecological succession）过程中的单峰动态，是生态学的核心基础现象。这类格局存在多种相互作用的成因，但温度始终是支配从微生物、树木到哺乳动物各类生物，以及陆地、海洋与淡水各类生境的核心驱动因子。然而，尽管全球气温持续攀升，预测其生态影响的需求日益迫切，学界对其背后的作用机制仍未达成广泛共识。本项目旨在构建并验证相关理论，阐释温度如何通过影响生化过程与代谢速率（metabolic rate）来调控生物多样性。本研究结合野外标准化调查与野外、室内受控实验，对沿温度递增地理梯度（从寒温带至暖热带）分布的7处森林中的3类生物类群（树木、无脊椎动物与微生物）的多样性，以及核心生物地球化学分解过程进行了测定。本数据集整合了HJA、HFR、BCI、CWT、LUQ及NWT所有实验样地的全部树木类群名录，并从BIEN数据库（BIEN database）下载了各分类群的功能性状数据。研究人员基于如下R代码，在科、属、种三个分类学层级上对每一项BIEN数据库性状计算平均值，并选取分类分辨率最高的“最优”平均值用于后续分析。所涵盖的功能性状包括碳、氮同位素比值，植株高度，叶面积，叶片碳、氮、磷浓度，种子质量，比叶面积以及木材密度。本数据集由美国亚利桑那大学恩奎斯特实验室（Enquist Lab）完成，该实验室首席研究员（PI）布莱恩·恩奎斯特（Brian Enquist）负责相关工作，作为“宏系统生物多样性（macrosystems biodiversity）与纬度梯度”项目的一部分，旨在测定树木年生长量，该项目由美国国家科学基金会（National Science Foundation）通过合作协议DEB#1065836资助。