DOI: 10.5061/dryad.ngf1vhj76
title: Predicting microbially mediated plant coexistence is sensitive to vital rate identity and soil conditioning history

description: Understanding the mechanisms that maintain the coexistence of plant
 species is critical to addressing the global biodiversity crisis.
 Increasing attention has been paid to interactions between plants and soil
 microbes (plant-soil feedback, PSF), which can promote plant coexistence
 by increasing stabilizing effects, but also hinder it by generating
 competitive fitness differences. However, the predictive power of the PSF
 has been questioned in recent studies because estimates of microbially
 mediated coexistence have correlated poorly with the outcomes of plant
 interactions observed in the field. This discrepancy may be due to the
 approaches typically used in PSF research, such as measuring PSF effects
 on a single vital rate or using soil conditioned for a short time period
 and without considering abiotic contexts. Here, I examined the effects of
 soil inoculum with different training histories and training environments
 (with and without added nutrients) on germination, seedling survival, and
 biomass of four grassland species. I then examined whether predictions of
 microbially mediated coexistence of four species pairs were sensitive to
 the vital rate identity, conditioning history, and soil training
 environment. I found that conspecific inoculum trained for longer had
 increasingly positive and negative effects on germination and biomass,
 respectively, although the effects of inoculum history varied across
 species and training environments. Estimates of microbially mediated
 outcomes were directly related to the vital rate used: when based on
 biomass and seedling survival, all four pairs were predicted to coexist,
 but only two pairs could do so when based on germination due to much
 reduced or even negative stabilization. Although coexistence predictions
 were not significantly related to conditioning history (including the
 effects of both variable conditioning durations and combinations of
 conditioning species) or nutrient treatments, both factors had a
 significant effect on stabilization. These results suggest that
 predictions of microbially mediated coexistence may be biased when based
 on a single vital rate, such as plant growth. To obtain more realistic and
 accurate outcome estimates, PSF effects should be integrated across
 different life stages, considering the temporal and abiotic contexts of
 these effects specific to a focal study system.
description: # Predicting microbially mediated plant coexistence is sensitive to vital
 rate identity and soil conditioning history --- Data from the test phase
 (greenhouse experiment from April 21, 2022, to June 9, 2022) --- ###
 Author Petr Dostál Inst. of Botany, The Czech Academy of Sciences,
 Průhonice, Czech Republic Correspondence: Petr Dostál
 ([petr.dostal@ibot.cas.cz](mailto:petr.dostal@ibot.cas.cz)) --- ### File
 list psf_vital.csv --- ### File descriptions 1. psf_vital.csv - Data from
 the test phase Variables: * pot_code * ID_focal_sp = identity of species
 used in the test phase * soil_history = conspecific training histories of
 soils used in the test phase: i) 'continuous' type, consisting
 of soil trained by conspecifics in two subsequent periods (June 2015-June
 2019 and July 2019-April 2022); ii) 'recent' type, when the soil
 was trained by conspecifics in the second period (July 2019-April 2022)
 but by heterospecifics in the first one; iii) 'past' type, if
 the soil was trained by conspecifics in the first period but by
 heterospecifics in the second; iv) 'no' type, if the soil was
 trained by heterospecifics in both periods. * sp_comb_train = species
 combinations used in the two phases (June 2015-June 2019 and July
 2019-April 2022) of soil training; ALO, Alopecurus pratensis; KOE,
 Koeleria macrantha; PLA, Plantago media; GAL, Galium mollugo; MIX – pooled
 inoculum of ca 40 species, but without focal species (phase 1, 2015-2019);
 OTHER, inoculum from Festuca pratensis, Geranium pratense, Bromus erectus
 or Prunella grandiflora (phase 2, 2019-2022). * FERTIL = whether nutrients
 were (1) or were not (0) added in the second training phase (2019-2022) *
 Nmax_germ = maximum number of seedlings in a pot recorded during six
 censuses (that emerged from 20 seeds added initially) * Nsurvivals = the
 number of seedlings in a pot at the last census * biomass = above-ground
 biomass of the largest seedling in a pot (in mg) 'n/a' = not
 applicable; 'n/a' is for 'Nsurvivals' when
 'Nmax_germ' = 0; 'n/a' is for 'biomass' when
 'Nmax_germ' = 0 or 'Nsurvivals'= 0