Data and code from: Competition and soil conditions limit the growth of High Arctic non-native plants
Data files
Sep 23, 2026 version files 330.76 KB
-
dataset.csv
238.53 KB
-
R_Code_revised.R
87.77 KB
-
README.md
4.46 KB
Abstract
Non-native vascular plant species in the High Arctic are currently restricted mainly to settlements and other anthropogenically disturbed areas. The reasons for this remain unclear, but climate or dispersal do not appear to be the main limiting factors. Instead, biotic interactions combined with soil conditions may play important roles. As the High Arctic becomes warmer and human activity increases, identifying the factors that currently limit non-native plant establishment in tundra ecosystems will be important for managing invasions. To address this, we conducted a growth experiment with three non-native vascular plant species from the archipelago of Svalbard, manipulating temperature, nitrogen availability, competition with four native vascular plant species, and simulated different stages of soil development. We found that favourable combinations of environmental factors, including well-developed soils, increased soil nitrogen availability, and higher temperature, enhanced non-native plant performance. However, competition from native plants strongly reduced the growth of non-native plants, especially with elevated nitrogen availability. Together, our results suggest that nutrient limitation and competition from native plants pose a significant barrier to the spread of non-native plants into undisturbed tundra ecosystems, under both current and possible future environmental conditions. In this dataset, you can find all data and codes to conduct the analyses used in the related manuscript.
Dataset DOI: 10.5061/dryad.05qfttfj5
Description of the data and file structure
The data originate from a fully factorial climate chamber experiment that started on 02 August 2023 at ETH Zurich. The experiment consisted of two simulated summer seasons (three months each), separated by a combined autumn–winter period of three months. We manipulated temperature (12 °C, ambient vs. 18 °C, warming), soil development stage (poorly vs. well-developed soil), nitrogen availability (no addition vs. nitrogen addition), and competition. For the competition treatment, we included three focal non-native plant species from Svalbard (Achillea millefolium, Barbarea vulgaris, Deschampsia cespitosa) and four native competitor species (Alopecurus ovatus, Cerastium arcticum, Poa arctica/alpigena viv., Silene acaulis), which were germinated or propagated in the lab in Zurich. Each focal non-native species was grown either alone or in a pairwise design with each native competitor species.
We replicated each treatment combination eight times, resulting in a total of 1344 experimental pots (3 focal non-native species x 8 competitor species (4 native, 3 non-native, or none) x 2 temperature treatments x 2 soil treatments x 2 nitrogen treatments x 8 replicates). Initial height was measured for every individual at the start of the experiment, and biomass as well as reproductive data were collected at the end of the experiment.
Files and variables
File: dataset.csv
Description: Plant biomass and reproductive data from fully factorial climate chamber experiment.
Variables
- Pot_ID: Unique pot identifier
- Tray: Unique number of tray the respective pot was placed into.
- Chamber: Name of climate chamber the respective tray was placed into during summer seasons. If NA: Chamber number is not existent
- Species: Focal non-native species (Ach_mil = Achillea millefolium; Bar_vul = Barbarea vulgaris; Des_ces = Deschampsia cespitosa)
- Ind: Respective individual number per pot (1; 2)
- Nutrient: Nitrogen treatment (C = no nitrogen addition; F = nitrogen addition)
- Temperature: Temperature treatment (A = Ambient 12°C; W = Warming 18 °C)
- Soil: Soil environment treatment (T = poorly developed soil; D = well-developed soil)
- comp_present: Indicates whether competition is present in the respective pot or if focal species grows alone (comp = competition present; alone = growing alone)
- comp_species: Competing species ( Ach = Achillea millefolium, Alo = Alopecurus ovatus, Bar = Barbarea vulgaris, Cer = Cerastium arcticum, Des = Deschampsia cespitosa, Poa = Poa arctica/alpigena viv., Sil = Silene acaulis, alone = growing alone)
- competition: Abbreviations of pair of competing species according to comp_species
- total_bm: Total aboveground dried biomass [g] measured at the end of the experiment; If NA: the respective individual was dead and no biomass available
- Bar_siliques: Number of siliques (reproductive units) of Barbarea vulgaris at the end of the experiment; If NA: the respective species was not Barbarea vulgaris; if 0: Barbarea vulgaris had no siliques
- Des_Spikelets: Number of spikelets (reproductive units) of Deschampsia cespitosa at the end of the experiment; If NA: the respective species was not Deschampsia cespitosa; if 0: Deschampsia cespitosa had no spikelets
- Ach_flower: Number of flowerheads (reproductive units) of Achillea millefolium at the end of the experiment; If NA: the respective species was not Achillea millefolium; if 0: Achillea millefolium had no flowers
- Date: Date of biomass collection
- Comment: Any additional information about the respective individual in the pot; If NA: No comment existent
- initial_height: Stretched plant height [mm] measured at the start of the experiment; If NA: no initial stretched plant height existent
- initial_height_scaled: Scaled initial height (mean-centered and standardised); If NA: no initial stretched plant height existent
- comp_native: Classification of competitor species (native; non-native; alone = no competitor species)
Code/software
All analyses were conducted using RStudio (Version 2025.5.1.513).
The R-Code that was used for the analyses and graphics is attached within the datafiles (R_Code_revised.R).
