Data for: Interactions between temperature and predation impact insect emergence in alpine lakes
Data files
Jun 08, 2023 version files 2.80 MB
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combined_orderlevel_etraps.csv
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combined_unsummed_etraps.csv
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emerg_models_2022.csv
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README.md
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temps_all.csv
Dec 20, 2023 version files 2.80 MB
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combined_orderlevel_etraps.csv
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combined_unsummed_etraps.csv
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emerg_models_2022.csv
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README.md
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temps_all.csv
Abstract
While insect populations are simultaneously threatened by many local and global scale stressors, the interacting effects of these factors remain poorly understood. These interactions between stressors, whether additive or antagonistic, may have profound effects on our assumptions about and predictions for any given system. Here we address this gap by exploring the interactive effects of introduced predators and elevated temperatures on emerging aquatic insects across alpine lakes. Using a crossed factorial field survey, we examine whether warmer temperatures either directly affect the magnitude or diversity of insect emergence, or mediate the impacts of predation via interactions with predator presence. Based on data from >11,000 insects collected across a two-year period, we find a 71% reduction in insect emergence associated with an additional 3.6° C of water temperature in oligotrophic alpine lakes. While our work confirms prior findings that predator presence drives strong reductions in insect emergence, we find that the effects of predation are significantly weaker in warmer lakes (2% reduction in warmest lakes studied vs 75% reduction in coldest). Combining our results with regional studies of predator communities to identify mechanisms suggests that the interaction effects between temperature and predator presence are likely due to changes in predator behavior across temperatures. Critically, to fully understand the multiple stressors that impact insect populations and predict their future effects we must consider the interactions between stressors across spatial scales.
README: Data from: Interactions between temperature and predation impact insect emergence in alpine lakes
This repository contains all data and code used to prepare the manuscript "Interactions between temperature and predation impact insect emergence in alpine lakes" (Owens et al 2023).
Description of the Data and file structure
Data files
Data files combined_unsummed_etraps
and combined_orderlevel_etraps
contain the raw counts of insects that were collected from our emergence traps in alpine lakes in California's Sierra Nevada during summers 2019 and 2021.
The column 'fish' indicates the absence (0) or presence (1) of introduced trout. The column 'block' indicates the relative elevation of each lake (1 = highest; 2 = mid; 3 = lowest pair). The column 'lake' has a 3 letter code that uniquely identifies each lake in the study (see Owens et al. 2023 supplementary material for list of exact lake locations). The column 'sample_date' is the day on which each trap was collected. The column 'trap' indicates the approximate cardinal direction around the lake where each trap was placed. The column 'data_flag' was initially used for QA/QC and can now be ignored. Remaining columns indicate the number of individuals collected from each trap after a 24-hour deployment (number per trap per day).
The following abbreviations are used in column headers:
abbreviation | taxonomic name |
---|---|
dip | Diptera |
chir | Chironomidae |
sim | Simuliidae |
culic | Culicidae |
tot | total |
cole | Coleoptera |
hemip | Hemiptera |
trichop | Trichoptera |
hemip | Hemiptera |
The file emerg_models_2022
contains insect data for each trap, paired with information on lake daily temperature ('dailytemp'), peak seasonal temperature ('peaktemp'), and number of days since lake iceoff ('DSI'). Temperature values in this file are nighttime averages that were derived from the file temps_all
by restricting times to between 2hrs post sunset and sunrise each day. All temperatures are measured in degrees Celsius.
In this file, the column 'total' indicates the total number of insects in each trap. 'total_dip' indicates the number of those which were Diptera, and 'total_nd' the number which were Ephemeroptera (mayflies) or Trichoptera (caddis flies). 'presence' is a logical variable indicating whether any non-Dipteran taxa were present in the trap.
The columns 'tot_m2' and 'dip_m2' scale the number of total insects, or number of Diptera, by the area of the trap (0.27m$^2$) to get an areal estimate of insect emergence per trap night per meter squared.
The columns 'tot_mass', 'tot_dip_mass', and '*_mass_m2' are scaled estimates of emerging biomass obtained by multiplying total and areal counts by taxon-specific biomass estimates obtained by measuring our specimens and applying the formulae from Sabo and Power (2002). Units for each of these columns are mg per trap night per trap, or mg per trap night per meter squared.
The columns 'tot_per', 'dip_per', and 'nd_per' are the estimates of body size obtained by dividing emerging biomass in each category by insect abundance in that category. Units for each of these columns are mg per individual.
In the file temps_all
, temperature is measured in degrees Celsius and DSI represents the number of days since lake iceoff.
Code files
The R markdown file model_confirmation
contains the code that was used to calculate temperature averages using full daily records, combine those averages with the nighttime restricted temperatures, and then fit and evaluate statistical models for each response variable studied in the paper.
The file slip_data_viewing
contains the code that was used to explore and visualize data from the Sierra Lakes Inventory Project (Knapp et al. 2020) for comparison to our samples.
The file emerg_NMDS_v3
contains the code that was used to create fig. 3 and conduct dimension reduction analyses.
The file emerg_clean_models
contains code that was used for initial model fitting and exploration, as well as to create figure 2.
The file visualizations
contains code that was used to create figure 1.
Sharing/access Information
Links to other publicly accessible locations of the data:
- SLIP data is available from the Environmental Data Initiative repository. Please cite any use of that data separately and appropriately.
- Lake ice-off dates were determined using PlanetLabs Planet Explorer interface to view meter-scale satellite imagery. See the PlanetLabs site for more information.
Please contact Caroline Owens (carolinehowens@gmail.com) with any questions or concerns.
Usage notes
Raw data files are in .csv format and can be opened with any text editor.
We used open source R software to write code, conduct analyses, and produce visualizations.