DOI: 10.5061/dryad.7d7wm385s
title: Data from: Higher plant diversity does not moderate the influence of changing rainfall regimes on plant-soil feedback of a semi-arid grassland

description: Climate change is expected to increase the frequency of severe droughts,
 but it remains unclear whether soil biotic conditioning by plant
 communities with varying species richness or functional group diversity
 moderate plant–soil feedback (PSF)—an important ecosystem process driving
 plant community dynamics—under altered rainfall regimes. We conducted a
 two‐phase PSF experiment to test how plant diversity affects biotic PSF
 under different rainfall regimes. In Phase 1, we set up mesocosms with 15
 plant assemblages composed of two grasses, two forbs and two
 nitrogen‐fixing legumes [one, two, three, or six species from one, two, or
 three functional group(s)] common to the semi‐arid eastern Eurasian
 Steppe. Mesocosms were subjected to two rainfall amounts (ambient, 50%
 reduction) crossed with two frequencies (ambient, 50% reduction) for a
 growing season (~3 months). Conditioned soil from each mesocosm was then
 used in Phase 2 to inoculate (7% v/v) sterilised mesocosms planted with
 the same species as in Phase 1 and grown for 8 weeks. Simultaneously, the
 same plant assemblages were grown in sterilised soil to calculate PSF
 based on plant biomass measured at the end of Phase 2. Feedback effects
 differed amongst plant assemblages, but were not significantly altered by
 reduced rainfall treatments within any plant assemblage. This suggests
 that the examined interactions between plant and soil microbial
 communities were resistant to simulated rainfall reductions and that
 increasing plant diversity did not moderate PSF under altered rainfall
 regimes. Moreover, increasing plant species richness or functional group
 diversity did not lessen the magnitude of PSF differences between ambient
 and reduced rainfall treatments. Collectively, these findings advance our
 understanding of plant diversity's potential to mitigate climate
 change effects on PSF, showing that in semi‐arid grasslands, higher plant
 diversity may not moderate PSF responses to altered rainfall regimes and
 highlighting the importance of considering species‐specific traits and
 interaction stability.
description: # Higher plant diversity does not moderate the influence of changing
 rainfall regimes on plant-soil feedback of a semi-arid grassland
 [https://doi.org/10.5061/dryad.7d7wm385s](https://doi.org/10.5061/dryad.7d7wm385s) ## Description of the data and file structure ### Files and variables #### File: DIVRAINPSF\_mesolvl\_data.csv **Description:** Phase 2 mesocosm-level plant biomass and plant-soil feedback data. We conducted a two-phase PSF experiment to test how plant diversity affects biotic PSF under different rainfall regimes. In Phase 1, we set up mesocosms with 15 plant assemblages composed of two grasses, two forbs, and two nitrogen-fixing legumes [one, two, three, or six species from one, two, or three functional group(s)] common to the semi-arid eastern Eurasian Steppe. Mesocosms were subjected to two rainfall amounts (ambient, 50% reduction) crossed with two frequencies (ambient, 50% reduction) for a growing season (~3 months). Conditioned soil from each mesocosm was then used in Phase 2 to inoculate (7% v/v) sterilised mesocosms planted with the same species as in Phase 1 and grown for 8 weeks. Simultaneously, the same plant assemblages were grown in sterilised soil to calculate PSF based on plant biomass measured at the end of Phase 2. This file was created using Microsoft Excel 2016. See 'README' file for descriptions of (abbreviated) column headings. ##### Variables * meso_assemb: [plant assemblage in mesocosm] G1; G2; F1; F2; N1; N2; G1+G2; F1+F2; N1+N2; G1+F1; G2+N1; F2+N2; G1+F1+N1; G2+F2+N2; ALL (i.e., G1+G2+F1+F2+N1+N2) * \ G1, *Leymus chinensis* (grass); G2, *Stipa grandis* (grass); F1, *Allium ramosum* (forb); F2, *Artemisia sieversiana*  forb); N1, *Lespedeza daurica* (nitrogen-fixing legume); N2, *Medicago ruthenica* (nitrogen-fixing legume) * sterile: [soil sterilisation] ster (Phase 2 mesocosm with fully sterilised soil); non (Phase 2 mesocosm inoculated with unsterilised Phase 1 treatment soil) * rain_amt_mm_per_10d: [rainfall amount (mm) over every 10-day-period] con (no rainfall treatment in Phase 1); 40mm (ambient rainfall amount in Phase 1); 20mm ( -50% rainfall amount of ambient in Phase 1) * rain_freq_d:  [rainfall frequency (days between rainfall events)]  0d (no rainfall treatment in Phase 1); 5d (ambient rainfall frequency in Phase 1); 10d (-50% rainfall frequency of ambient in Phase 1) * replicate: [mesocosm replicate number] * no_spp: [number of plant species in mesocosm] * no_func_group: [number of plant functional group(s) in mesocosm] * comm_ag_bm_g: [Phase 2 mesocosm plant aboveground dry biomass (g)] * comm_bg_bm_g: [Phase 2 mesocosm plant belowground dry biomass (g)] * comm_total_bm_g: [Phase 2 mesocosm plant above+belowground dry biomass (g)] * comm_total_bm_fb:  Feedback effect = log<sub>10</sub>(Total plant biomass in mesocosm with non-sterilised soil inoculum treatment ÷ Average total plant biomass of mesocosms with same assemblage in sterilised soil) * abs_change_comm_total_bm_fb: | Δ feedback effect | = | (Feedback effect of mesocosm under specific reduced rainfall frequency and/or amount) – (Average feedback effect of mesocosms with same plant assemblage under ambient rainfall) | NB   'n/a' in cell: Value of specific variable (column) of an experimental unit not relevant or not applicable to analysing that same variable #### File: DIVRAINPSF\_constituent\_spp\_data.csv **Description:** Detailed biomass data of constituent plant species in Phase 2 mesocosms. We conducted a two-phase PSF experiment to test how plant diversity affects biotic PSF under different rainfall regimes. In Phase 1, we set up mesocosms with 15 plant assemblages composed of two grasses, two forbs, and two nitrogen-fixing legumes [one, two, three, or six species from one, two, or three functional group(s)] common to the semi-arid eastern Eurasian Steppe. Mesocosms were subjected to two rainfall amounts (ambient, 50% reduction) crossed with two frequencies (ambient, 50% reduction) for a growing season (~3 months). Conditioned soil from each mesocosm was then used in Phase 2 to inoculate (7% v/v) sterilised mesocosms planted with the same species as in Phase 1 and grown for 8 weeks. Simultaneously, the same plant assemblages were grown in sterilised soil to calculate PSF based on plant biomass measured at the end of Phase 2. This file was created using Microsoft Excel 2016. See 'README' file for descriptions of (abbreviated) column headings. ##### Variables * meso_assemb: [plant assemblage in mesocosm] G1; G2; F1; F2; N1; N2; G1+G2; F1+F2; N1+N2; G1+F1; G2+N1; F2+N2; G1+F1+N1; G2+F2+N2; ALL (i.e., G1+G2+F1+F2+N1+N2) * sterile: [soil sterilisation] ster (Phase 2 mesocosm with fully sterilised soil); non (Phase 2 mesocosm inoculated with unsterilised Phase 1 treatment soil) * rain_amt_mm_per_10d:  [rainfall amount (mm) over every 10-day-period] con (no rainfall treatment in Phase 1); 40mm (ambient rainfall amount in Phase 1); 20mm ( -50% rainfall amount of ambient in Phase 1) * rain_freq_d: [rainfall frequency (days between rainfall events)]  0d (no rainfall treatment in Phase 1); 5d (ambient rainfall frequency in Phase 1); 10d (-50% rainfall frequency of ambient in Phase 1) * replicate: [mesocosm replicate number] * sp_in_meso: [plant species ID] G1, *Leymus chinensis* (grass); G2, *Stipa grandis* (grass); F1, *Allium ramosum* (forb); F2, *Artemisia sieversiana*  forb); N1, *Lespedeza daurica* (nitrogen-fixing legume); N2, *Medicago ruthenica* (nitrogen-fixing legume) * no_spp: [number of plant species in mesocosm] * no_func_group: [number of plant functional group(s) in mesocosm] * ag_bm_g: [aboveground dry biomass (g) of a constituent plant species in Phase 2 mesocosm] * bg_bm_g: [belowground dry biomass (g) of a constituent plant species in Phase 2 mesocosm] * total_bm_g: [above+belowground dry biomass (g) of a constituent plant species in Phase 2 mesocosm] * change_total_bm_g: Biotic effect on constituent species biomass = Total dry biomass (g) of a given species in multi-species mesocosm with specific inoculated soil treatment – Average total biomass of conspecifics grown in same-assemblage mesocosms with sterilised soil NB   'n/a' in cell: Value of specific variable (column) of an experimental unit not relevant or not applicable to analysing that same variable