DOI: 10.5061/dryad.fttdz092k
title: Soil biota modulate the effects of microplastics on biomass and diversity of plant communities

description: The use of biodegradable plastics has been proposed as an alternative to
 mitigate the pollution problem caused by traditional non-biodegradable
 plastics. However, the relative impacts of both types of microplastics on
 plant community productivity and diversity are not known. Moreover, it is
 unclear whether soil biota can differentially mediate the impacts of
 biodegradable and non-biodegradable microplastics on plant communities. In
 this study, we investigated the effects of biodegradable and
 non-biodegradable microplastics on plant community biomass production and
 diversity, and whether soil biota mediate these effects. We employed a
 fully crossed factorial design, growing six plant communities in the
 presence or absence of 10 individual microplastics, and live soil versus
 sterilized soil. We hypothesized that: 1) Biodegradable microplastics have
 a less negative effect on plant community biomass production and diversity
 compared to non-biodegradable microplastics. 2) Soil biota differentially
 mediate the effects of biodegradable and non-biodegradable microplastics
 on plant community biomass production and diversity. Statistical analyses
 that included all 10 microplastics yielded two main findings. First, live
 soil ameliorated the negative effects of biodegradable microplastics on
 community shoot biomass. Second, the presence of microplastics, rather
 than their biodegradability, significantly reduced community diversity.
 Separate analyses of individual microplastics suggest that these patterns
 were driven by specific microplastics. The biodegradable microplastic
 Polybutylene succinate (PBS) was the main driver of the pattern observed
 in community shoot biomass. In contrast, the biodegradable microplastic
 Polycaprolactone (PCL) and non-biodegradable microplastics Ethylene-vinyl
 acetate (EVA) and Polyvinyl chloride (PVC) were the main drivers of the
 pattern observed in community diversity. Further analyses excluding PBS
 from the global models, but including the other nine microplastics,
 revealed no significant differences in community shoot biomass and
 diversity between biodegradable and non-biodegradable microplastics in
 live versus sterilized soil. Our findings suggest that
 biodegradable microplastics, often considered environmentally friendly,
 are not necessarily less harmful than non-biodegradable microplastics to
 the growth and diversity of plant communities. Some individual
 biodegradable microplastics, such as PBS, still pose significant
 ecological risks to plant community structure and productivity. However,
 the results also suggest that soil biota may mitigate the negative effects
 of some biodegradable microplastics.
description: We conducted a greenhouse experiment with six plant communities
 (each consisting of five plant species) and assigned them to the  2 soil
 treatments (live soil vs. sterilized soil) × 11 microplastic treatments
 (five biodegradable microplastics, five non-biodegradable microplastics,
 and one no-microplastic control) combinations. Four replicates per
 treatment. All plant data are collected from this experiment.
 Additionally, we collected soil from a parallel long-term experiment in a
 northeast China grassland (Hulunbuir; 119°38'E, 50°20'N) running
 since 2020, where we are examining the effects of microplastic pollution
 on plant community diversity and productivity in a grassland. We randomly
 collected 0.5 g of soil from each sample to extract. The 100 soil samples
 [10 microplastic (no-microplastic, 5 biodegradable microplastics, 4
 non-biodegradable microplastics) ×10 replicates] were immediately stored
 at -80 ℃ until DNA extraction.
description: # Soil biota modulate the effects of microplastics on biomass and
 diversity of plant communities
 [https://doi.org/10.5061/dryad.fttdz092k](https://doi.org/10.5061/dryad.fttdz092k) ## Description of the data and file structure ### Files and variables #### File: plant\_community\_biomass.xls **Description:** plant data ##### Variables * group: A through F represent 6 plant communities * soil: no = live soil, yes = sterilized soil * plastic: 10 commonly used microplastics * character: Microplastic properties * site: random numbers * Species 1-5: shoot biomass of each species (g) * total: shoot biomass of all species (g) * inverseSimpson: inverse Simpson's diversity index