DOI: 10.5061/dryad.19s12tm
title: Data from: Two dimensions define the variation of fine root traits across plant communities under the joint influence of ecological succession and annual mowing

description: 1. Quantifying the variation in community-level fine root (&lt;2mm)
 traits along ecological gradients or in response to disturbances is
 essential to unravel the mechanisms of plant community assembly, but
 available surveys are scarce. Whether fine root traits covary along a
 one-dimensional economic spectrum, as previously shown for leaves, is
 highly debated. 2. We measured six fine root traits at the community-level
 along a 69-year succession, with or without annual mowing, offering a
 unique design of two nested disturbances. We examined whether (i) there is
 variation and covariation in community-level fine root traits along the
 succession and in response to mowing and (ii) morphological root traits
 mirrored analogous leaf traits (using previously acquired data). 3.
 Early-successional communities were herbaceous-dominated (48±6 % in
 &lt;10 year old plots) and possessed fine roots with high specific
 root length (SRL), low root dry matter content (RDMC) and low root carbon
 concentration (RCC), while later-successional communities were dominated
 by woody species (56±9 % in &gt;40 year old plots) and possessed
 opposite trait values. Root nitrogen concentration (RNC) did not vary
 across communities along the succession. The trait values at
 community-level were not affected by mowing, except for a reduction in
 root mass density. 4. We found covariation of fine root traits across
 communities along two dimensions: the first dimension (60% of total
 variation) represented changes in root foraging capacity (related to SRL)
 and resource conservation (related to RDMC, RCC, mean root diameter)
 whereas the second dimension (17 to 20% of the variation) represented
 variations in RNC, potentially related to root respiration and metabolism.
 5. SRL and SLA (specific leaf area) were correlated regardless of the
 mowing regime, but there was no analogous relationship between LDMC (leaf
 dry matter content) and RDMC in mown communities, showing a decoupling in
 the investment in tissue density above and belowground. 6. Synthesis. Our
 study demonstrates coordinated variations of community-level fine root
 traits along a succession gradient and provides evidence that fine root
 traits covaried along two-dimensions, regardless of mowing regime. The
 relationship between LDMC and RDMC observed in unmown communities was
 modified by mowing, reflecting an uncoupled response to mowing.
description: Soil and root trait data
 of roaside successional gradient in Montpellier, FranceData were collected in
 the field on roadsides near Montpellier, South of France. Abbreviated
 headlines are as follows: "Roadside" = Roadside;
 "Plot" = Plant communities on the roadsides;
 "GPS_coordinates" = GPS coordinate from the selected roadsides;
 "Age" = Age of the roadside in years; "Mowing" =
 Mowing regime (M=Mown, U=Unmown); "Road_Type" = Type of roadside
 (E=Embankment, C=Cutting); "Clay" = Clay content in soil in %;
 "Silt" = Silt content in soil in %; "Sand" = Sand
 content in soil in %; "SOC" = Soil organic content in g.kg-1;
 "SoilN" = Soil total nitrogen content in g.kg-1; "CEC"
 = Cationic exchange capacity in meq.kg-1; "Soil_pH" = Soil pH in
 water; "SoilP" = Soil available phosphorus in g.kg-1;
 "SRL" = Specific root length in m.g-1; "shannon" =
 Shannon index; "simpson" = Simpson index; "RNC" = Root
 nitrogen content in mg.g-1; "RCC" = Root carbon content in
 mg.g-1; "RDMC" = Root dry matter content in mg.g-1;
 "Dm" = Mean root diameter in mm; "RMD" = Root mass
 density in kg.m-3 of soil; "graminoid" = ground cover of
 graminoid species in %; "herbaceous" = ground cover of
 herbaceous species in %; "shrub" = ground cover of shrub species
 in %; "tree" = ground cover of tree species in
 %Erktan_JECol2018_.xlsx