DOI: 10.5061/dryad.0gb5mkmc5
title: Data from: Long-term effects of host-specific soil microbiota on plant interactions

description: It is increasingly recognised that resource competition and plant-soil
 feedback (PSF) effects can jointly determine outcomes of plant
 interactions. However, it is less clear whether PSF modulates
 intraspecific or interspecific competition, or intrinsic growth rate.
 Thus, it remains to be answered whether PSF alters coexistence predictions
 by changing competitive ability of interacting species (fitness
 differences) or rather by altering self-limitation (niche differences).
 Here, I examined the effects of host-specific soil inoculum, including
 target and competitor species inoculum, and non-specific inoculum on
 pairwise interactions of four pairs of grassland perennials. To explore
 whether the effects of PSF were persistent and dependent on resource
 availability, interactions were studied over a two-year period under
 control and fertilized conditions. These data were then used to estimate
 fitness differences and niche differences and to predict species
 coexistence. I found that a host-specific inoculum can promote the
 coexistence of competing plants in two ways. First, it increased niche
 differences due to less intense interspecific competition in the inoculum
 of a competitor. Second, a competitively inferior species was more likely
 to be found in the conspecific inoculum due to its negative effect on the
 intrinsic growth rate. These effects persisted throughout the experimental
 period but were absent after nutrient addition. In conclusion, PSF can
 promote plant coexistence by increasing niche differences and reversing
 competitive dominance. Although PSF effects can have long-term effects on
 competitive plant interactions, they depend on abiotic (nutrient)
 contexts. Therefore, they are less likely to mitigate competitive
 inequality and prevent competitive exclusion after anthropogenic
 fertilization.
description: # Long-term effects of host-specific soil microbiota on plant interactions
 **Authors** 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
 (files found within DataS1.zip) The study examined the impact of
 host-specific soil inoculum on grassland perennials over two years under
 control and fertilized conditions. PSF promoted coexistence by increasing
 niche differences (reducing interspecific competition) and altering growth
 rates (favoring inferior competitors). These effects were persistent but
 disappeared with nutrient addition, suggesting that PSF can promote
 coexistence but may not prevent competitive exclusion in fertilized
 environments. **psf_compet.csv** **File descriptions** 1. psf_compet.csv -
 Data from the garden competition experiment **Variables:** * pot_code *
 ID_targ = target species * N_comp = number of planted competitor
 individuals * FERTIL = whether nutrients were (1) or were not (0) added. *
 ID_comp = competitor species * TARGbiom_oct19 (mg) = biomass of target
 species harvested in October 2019 * TARGbiom_jun20 (mg) = biomass of
 target species harvested in June 2020 * TARGbiom_oct20 (mg) = biomass of
 target species harvested in October 2020 * TARGbiom_jun21 (mg) = biomass
 of target species harvested in June 2021 * TARGbiom_oct21 (mg) = biomass
 of target species harvested in October 2021 * ID_inoculum = identity of
 the species used as the source of inoculum