Volcanic soils alleviate the allelopathic capacity of Empetrum nigrum in degraded tundra ecosystems

Land degradation due to unsustainable land use is of major concern worldwide, and recovery is often slow. A potential mechanism behind slow recovery of degraded ecosystems is the retarding impacts of allelopathic plant species on the establishment of species that might facilitate the recovery process. However, the strength of the retarding impact may depend on soil type. In this study, we investigated the potential role of an abundant, evergreen, and allelopathic dwarf shrub, Empetrum nigrum, in trapping tundra ecosystems in a degraded state in Iceland after centuries of unsustainable land use. We first run a series of bioassays to assess the potential allelopathic legacy effects of the Empetrum-associated volcanic soils (Andosol and Vitrisol) on seed germination and root elongation of the common grass species Festuca richardsonii in comparison with Empetrum-associated non-volcanic Histosol and Podzol soil types. Then we assessed the Empetrum leaf-soil interactions for all soil types us..., , # Data from: Volcanic soils alleviate the allelopathic capacity of *Empetrum nigrum* in degraded tundra ecosystems

Dataset DOI: [10.5061/dryad.tx95x6b8b](10.5061/dryad.tx95x6b8b)

## Description of the data and file structure

The data files contain recordings of germination and root elongation of the grass species *Festuca richardsonii* seeds and seedlings, incubated with and without the addition of leaves from the allelopathic dwarf shrub *Empetrum nigrum,* and different types and particle sizes of *Empetrum*-associated soil.

### Files and variables

Inside the folder Ryde_et_al_2025.zip, there are six data files (.csv) accompanied by six code files (.R) used for statistical analyses. The file names, indicate which research question the data is related to (i.e. Q1 or Q2), which response variable was recorded (i.e. seed germination or seedling root elongation), and which soil particle size the seed or seedlings were incubated with (small or large soil particles). Code files are name...,