Breakpoint phenological responses in high-Arctic arthropods
Data files
Jun 12, 2025 version files 1.89 MB
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Air_temp_30_days_rolling.csv
989.37 KB
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df_phenology_metrics.csv
666.43 KB
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df_summary_end_snow_final_new.csv
19.03 KB
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df_summary_end_snow_temp_final_new.csv
18.53 KB
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df_summary_end_temp_final_new.csv
19.48 KB
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df_summary_end_temp_snow_final_new.csv
19.04 KB
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df_summary_onset_snow_final_new.csv
18.79 KB
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df_summary_onset_snow_temp_final_new.csv
18.47 KB
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df_summary_onset_temp_final_new.csv
18.94 KB
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df_summary_onset_temp_snow_final_new.csv
18.96 KB
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df_summary_peak_snow_final_new.csv
18.99 KB
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df_summary_peak_snow_temp_final_new.csv
18.48 KB
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df_summary_peak_temp_final_new.csv
19.47 KB
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df_summary_peak_temp_snow_final_new.csv
18.93 KB
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README.md
7.87 KB
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Snowmelt_Climatestation_updated.csv
294 B
Abstract
Many arthropod species show earlier seasonal activity trends with warming, but these responses cannot continue indefinitely. Beyond a threshold, phenological responses may no longer keep pace with climate change. While many studies estimate linear phenological responses to climate, few test for breakpoint responses. Here, across a 28-year time series, we examined linear and breakpoint responses to temperature and snowmelt across 15 arthropod taxa in seven plots from high-Arctic Greenland, a region experiencing pronounced warming. Our meta-analysis revealed support for a breakpoint response in two of six phenological driver and event combinations. This breakpoint response was found in the onset and peak of activity to the timing of snowmelt, where activity advanced with snowmelt until a threshold, after which the relationship levelled off. While we also found a breakpoint response in peak phenology to temperature, this disappeared when controlling for snowmelt in the model, underscoring the importance of considering multiple environmental cues to prevent incorrect inferences about plasticity limits. Most responses did not show evidence of a breakpoint in phenological response, and instead showed consistent phenological sensitivity to environmental cues across our study period. Our findings point to a need for a wider assessment of the prevalence of breakpoint phenological responses to climate change.
Description of the data and file structure
This repository contains the code and data necessary to replicate data analyses, figures, and tables in:
Keeping up with climate change - have Arctic arthropods reached their phenological limits?
Data usage guidelines
Note on data provenance and licensing:
This dataset includes original data and materials created by the authors, which are released under the Creative Commons Zero (CC0 1.0) Public Domain Dedication. These original contributions are free to use without restriction.
File: df_phenology_metrics
- Year: Year of sampling.
- Plot: Vegetation type in which arthropods were sampled.
- SpeciesID: Arthropod taxon sampled (taxonomic resolution: family, super-family, or order).
- TotalAbundance: Total number of individuals of the arthropod taxon caught in a given plot and year.
- Onset: Estimated start day of the year of activity.
- Peak: Estimated peak day of the year of activity.
- End: Estimated end day of the year of activity.
- Duration: Estimated duration of activity, calculated as the number of days between onset and end.
Files with climate data:
File: Snowmelt_Climatestation*_*updated.csv
Description: Annual estimates of snowmelt timing.
- Year: Year of sampling.
- SnowmeltDOY: Day of year of annual snowmelt.
File: Air_temp*30_days*rolling.csv
Description: Temperature data calculated as the 30-day average temperature preceding a mean phenological event.
- Year: Year of sampling.
- Plot: Vegetation type in which arthropods were sampled.
- SpeciesID: Arthropod taxon sampled (taxonomic resolution: family, super-family, or order).
- TotalAbundance: Total number of individuals of the arthropod taxon caught in a given plot and year.
- Onset: Estimated start day of the year of activity.
- Peak: Estimated peak day of the year of activity.
- End: Estimated end day of the year of activity.
- Duration: Estimated duration of activity, calculated as the number of days between onset and end.
- Onset_DOY: Mean onset of activity across years.
- Peak_DOY: Mean peak of activity across years.
- End_DOY: Mean end of activity across years.
- Onset_temp: Average air temperature (°C) over the 30 days preceding the mean phenological event (Onset_DOY) for each taxon-plot-year combination.
- Peak_temp: Average air temperature (°C) over the 30 days preceding the mean phenological event (Peak_DOY) for each taxon-plot-year combination.
- End_temp: Average air temperature (°C) over the 30 days preceding the mean phenological event (End_DOY) for each taxon-plot-year combination.
Files with output from the breakpoint analysis used for meta-analysis:
File: df_summary_onset_snow_final_new.csv
File: df_summary_peak_snow_final_new.csv
File: df_summary_end_snow_final_new.csv
File: df_summary_onset_temp_final_new.csv
File: df_summary_peak_temp_final_new.csv
File: df_summary_end_temp_final_new.csv
File: df_summary_onset_snow_temp_final_new.csv
File: df_summary_peak_snow_temp_final_new.csv
File: df_summary_end_snow_temp_final_new.csv
File: df_summary_onset_temp_snow_final_new.csv
File: df_summary_peak_temp_snow_final_new.csv
File: df_summary_end_temp_snow_final_new.csv
Description: Statistical output from the breakpoint analysis is calculated separately for each phenological event. There are three summaries for snowmelt as a single predictor, three summaries for temperature as a single predictor, three summaries for snowmelt controlling for temperature, and three summaries for temperature controlling for snowmelt.
- Plot: Vegetation type in which arthropods were sampled.
- SpeciesID: Arthropod taxon sampled (taxonomic resolution: family, super-family, or order).
- Intercept: Intercept of the first segment before the breakpoint.
- Slope1: Slope of the regression line before the breakpoint.
- Slopediff: Difference in slope before and after the breakpoint (Slope2 - Slope1).
- Pvalue: P-value associated with the test for a change in slope at the breakpoint.
- Break: Estimated year or position of the breakpoint (i.e., where the slope changes).
- Meanslope: Mean slope across the full time series (no breakpoint model).
- Meanslopediff: Difference between the mean slope and Slope1.
- SEslope: Standard error of the slope before the breakpoint.
- SEslopediff: Standard error of the slope difference.
- CI_lwr: Lower bound of the confidence interval for the slope difference.
- CI_upr: Upper bound of the confidence interval for the slope difference.
- n: Number of years (observations) used in the model.
- AIC_0: Akaike Information Criterion (AIC) for the no-breakpoint model (single slope).
- AIC_1: AIC for the segmented (breakpoint) model.
- OriginalSlope: Slope from the original unsegmented model (prior to breakpoint analysis).
- OriginalSE: Standard error of the original slope.
- Order: Ecological role or trophic guild of the arthropod taxon (e.g., "Decomposer").
- Habitat: Dominant habitat or vegetation type where the taxon was found.
Code/software
Software used: R Statistical Software (v4.4.1; R Core Team 2024)
Packages: “tidyverse” v. 2.0.0, “mgcv” v. 1.9-1, "metafor" v. 4.8-0
Access information
Other publicly accessible locations of the data:
This dataset was originally informed by environmental and phenological observations published by the Greenland Ecosystem Monitoring Programme under the Creative Commons Attribution-ShareAlike 4.0 International (CC-BY-SA-4.0) license. However, no raw data or materials under that license are included in this Dryad submission. Only derived summaries or references to those external sources remain, and all third-party content has been clearly cited below for attribution and reproducibility.
Appropriate ways to cite third-party sources:
Phenological observations:
Observations at Zackenberg were provided by the Greenland Ecosystem Monitoring Programme. Family data for arthropods are available at: https://data.g-e-m.dk/.
Cite as:
Greenland Ecosystem Monitoring (2025). BioBasis Zackenberg - Arthropods - Arthropod emergence (Version 1.0). [Data set] [CC-BY-SA-4.0]. Greenland Ecosystem Monitoring. https://doi.org/10.17897/V285-Z265
Environmental predictors:
Temperature and snowmelt observations for Zackenberg were also provided by the Greenland Ecosystem Monitoring Programme. Data are available at: https://data.g-e-m.dk/. A formatted version, including all estimated temperature and snowmelt timing values, is included in this repository. If using the original data downloaded directly from the database, please cite as:
- Greenland Ecosystem Monitoring (2025). ClimateBasis Zackenberg – Air temperature – Air temperature, 200 cm @ 60 min sample (°C) (Version 1.0). [Data set] [CC-BY-SA-4.0]. Greenland Ecosystem Monitoring. https://doi.org/10.17897/XV96-HC57
- Greenland Ecosystem Monitoring (2025). ClimateBasis Zackenberg – Precipitation – Snow depth – 180 min sample (m) (Version 1.0). [Data set] [CC-BY-SA-4.0]. Greenland Ecosystem Monitoring. https://doi.org/10.17897/7RVV-Z412