DOI: 10.25349/d9qw5x
title: Data for: Interactions between temperature and predation impact insect emergence in alpine lakes

description: 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 &gt;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.
description: 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.
description: # 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](https://portal.edirepository.org/nis/mapbrowse?scope=edi&identifier=577). 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](https://www.planetlabs.com/explorer) for more information. Please contact Caroline Owens () with any questions or concerns.