DOI: 10.5061/dryad.vhhmgqp3g
title: Traits associated with the conservation gradient are the strongest predictors of early-stage fine root decomposition rates

description: Fine root traits span two independent axes of variation, the conservation
 and collaboration axes, which define the root economic space (RES).
 However, whether early-stage fine root decomposition rates (quantified as
 proportion mass loss, i.e., pml) are more strongly related to
 collaboration or conservation traits remains unclear. We studied 63 tree
 species in New Zealand's temperate rain forest. We determined the
 phylogenetic signal in pml and fine root traits, conducted phylogenetic
 principal component analysis, and used phylogenetic generalized least
 squares to determine which traits are most strongly related to pml. Root
 decomposition exhibited a high phylogenetic signal and was more strongly
 related to the conservation than the collaboration axis. Root tissue
 density (RTD) was negatively correlated and root nitrogen (RN) was
 positively correlated with pml. Root diameter was positively yet weakly
 correlated with pml, but specific root length was uncorrelated with pml.
 The lignin-to-N ratio and root cellulose were the strongest predictors of
 pml. Synthesis. Early-stage fine root decomposition is most strongly
 driven by tissue quality traits, such as root nitrogen, tissue density,
 and lignin-to-N ratio, which all align with the conservation axis of the
 root economics space. However, root diameter plays a weak yet undeniable
 role in early-stage fine root decomposition. Some thick-rooted species
 decomposed faster, possibly due to the higher-quality cortical tissue.
 Thin rooted species decomposed slower, possibly because of their higher
 cellulose concentration that maintains the structural integrity of
 small-diameter roots. Relationships between decomposition and other traits
 that align with the collaboration gradient deserve further study across
 the phylogeny of vascular plants.
description: # Traits associated with the conservation gradient are the strongest
 predictors of early-stage fine root decomposition rates
 [https://doi.org/10.5061/dryad.vhhmgqp3g](https://doi.org/10.5061/dryad.vhhmgqp3g) ## Description of the data and file structure Traits associated with the conservation gradient are the strongest predictors of early-stage fine root decomposition rates. The dataset presented here was analyzed to support our paper with the title above. In this paper, we found that traits on the conservation axis of the root economics space are more closely related to fine root decomposition than traits on the collaboration axis. We also found that thick-rooted species exhibit faster decomposition due to their higher quality cortical tissues and thin-rooted species with high cellulose content that provide support for small-diameter roots decompose slowly. The nzRootDecomp.csv file contains the decomposition dataset. The root.trait.means.csv file has the functional root traits data and rootChem.csv has the root chemistry trait data. The species phylogeny data is in the species-tree for Daniel Laughlin.nwk file. The columns or variables used in the analyses are described under each data file below. ### Files and variables #### File: nzRootDecomp.csv **Description:**  **nzRootDecomp.csv** contains 172 rows with each observation describing the incubated fine root samples' initial and final dry weights. ##### Variables * Species: shows the species * Rep: indicates the number of replicates * Tag #: shows the tag used for each sample during the experiment * Dry weight initial: shows the initial weight of the incubated samples (g) * Final dry weight: denotes the final weight of the incubated samples (g) * proportion mass loss: denotes the calculated values of the proportional mass loss for each species. #### File: root.trait.means.csv **Description:** **root.trait.means.csv** contains 66 rows and each observation shows the plant functional trait values, species’ code, mycorrhizal, and phylogenetic information of each species. ##### Variables * species: shows the species * srl: specific root length (m/g) * rootdiam: root diameter (mm) * rdmc: root dry matter content (mg/g)  * branch: root branching index (tips/root length)  * rootn: root nitrogen (%) * rtd: root tissue density (mg/mm^3) * rootp: root phosphorus (%) * spcode: shows the species code * mycor: mycorrhizal type * phylo: phylogeny #### File: rootChem.csv **Description:** **rootChem.csv** files contain 49 rows; each observation indicates the root chemistry traits of the species. ##### Variables * species: shows the species * r.fibre: root fibre (%) * r.cellulose: root cellulose (%) * r.lignin: root lignin (%) * r.tannins: root tannins (%) * r.phenol: root phenol (%) The empty cells means we do not have the relevant data for those species #### File: **species-tree for Daniel Laughlin.nwk** **Description:** **species-tree for Daniel Laughlin.nwk** contains the phylogenetic relationships among the tree species. ## Code/software The R script ‘JECOL Code_Version 4.R’ contains the code for all data manipulation, analyses, and figures presented in the paper and supplementary figures. ## Access information Other publicly accessible locations of the data: * The dataset can be retrieved from [https://github.com/CONFIDENCESKT/Fine-Root-Decompositon_Postdoc/tree/main/data](https://github.com/CONFIDENCESKT/Fine-Root-Decompositon_Postdoc/tree/main/data)