Dataset DOI: 10.5061/dryad.qnk98sg0j

Description of the data and file structure

In this study, we examined root biomass, root traits, and mycorrhizal colonization along a disturbance gradient in a tropical peat swamp forest in to measure how belowground C allocation shifts with disturbance from an intact peat swamp forest to drained, vegetative peatland. We sampled peat at four randomly selected points using a Russian D-Sampler (Royal Eijkelkamp) with a 5.2 cm diameter and at 4 depths to 1.5 m (0-10 cm, 10-50 cm, 50-100 cm, and 100-150 cm) and homogenized them into one sample per plot for each depth. To examine changes in root traits with peat swamp forest disturbance and depth, several indices of root biomass C estimates were measured: fine and coarse root biomass (g/m^-3), and fine root necromass (g/m^-3), as well as indices of root traits, including specific root length (m/g), branching intensity (tips/cm), root tissue density (fine root biomass over root volume, g/cm³), average root diameter (mm), and number of root tips (tips/g).To measure the impact of peat swamp forest disturbance on symbiosis between ectomycorrhizal fungi and R. albida roots, we measured the percent of ectomycorrhizal colonization of tree roots at each depth (n=4) for the three forested plots along each transect (plots 3-5 at 250-1900 m from the canal).

Files and variables

File: allrootdata.csv

Description: 

Variables

• transect: The number corresponds to the transect number, 1-5.
• plot: The plot along each transect, 1-5.
• depth: The depth sampled, 1-4, corresponds to 1: 0-10 cm, 2: 10-50 cm, 3: 50-100 cm, and 4: 100-150 cm
• type: Wether open vegetative plots or forested plots
• distancenum: the point of the plot at the distance from the disturbance: 30 m, 75 m, 250 m, 900 m, and 1900 m away. 
• fine: fine root biomass (g/m^2)
• coarse: coarse root biomass (g/m^2)
• necro: root necromass (g/m^2) 
• length: specific root length (m/g)
• diam: fine root diameter (mm)
• tips: fine root tips (tips/g)
• rtd: root tissue density (g/cm^3)
• bi: root branching intensity (tips/cm)
• frdensity: fine root density (g/m^3)
• cdensity: coarse root density (g/m^3)
• ndensity: fine root necromass density (g/m^3)
• sumrtd: adjusted root tissue density corrected for the WinRhizo equation by sum of averages from all diameter classes with 0.2 mm bins (g cm^3)
• sumlength: adjusted specific root length corrected for the WinRhizo equation by sum of averages from all diameter classes with 0.2 mm bins (m per g)

File: MycoColonization.csv

Description: 

Variables

• Sample: sample number used in analysis
• Transect: the transect number, 1-5
• distance: the point of the plot at the distance from the disturbance: 250 m, 900 m, and 1900 m away. 
• plot: plots 3, 4, or 5 along the transect.
• depth: The depth sampled (1-4) corresponds to d1: 0-10 cm, d2: 10-50 cm, d3: 50-100 cm, and d4: 100-150 cm
• myco: Mycorrhizal present in the sample
• nonmyco: The non-mycorrhizal root crossings present in the sample
• total: The total counts; NA indicates missing values
• ECM: the percent of ectomycorrhizal colonization for each sample (%)

Code/software

To determine the interactive effects of distance from canal and peat depth on root biomass (fine, coarse, and necromass) and root morphology (H1 and H2), we conducted a linear mixed-effects model for root biomass and root traits using the ‘lme4’ package in R 4.4.2 (R Core Team).  We ran full models with the individual root traits as the response variables, distance from canal, depth, and their interaction as the fixed factors, and plot nested in transect as random effects. To determine if the effect of distance from the canal and depth impacted the percent mycorrhizal colonization (H3), we constructed a generalized linear mixed-effects model with a ‘Poisson’ family to account for the data structure (0-100) (Appendix S1). All models were visually assessed using the ‘performance’ package (Lüdecke et al., 2021).