Data from: Effect of a severe cold spell on overwintering survival of an invasive forest insect pest
Data files
Dec 13, 2023 version files 63.42 KB
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coldspell.csv
55.96 KB
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NovaScotiaHistoricalMortality.csv
2.65 KB
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README.md
4.81 KB
Abstract
Data from a study of a servere cold event in February 2023 on the survival of hemlock woolly adelgid (Adelges tsugae Annand) from four populations in Canada. Cold temperatures can play a significant role in the range and impact of pest insects. Severe cold events can reduce the size of insect outbreaks or in some cases even cause outbreaks to end. Measuring the precise impact of cold events, however, can be difficult because estimates of insect mortality are often made at the end of the winter season. In late January, 2023 long-term climate models predicted a significant cold event to occur over eastern North America. We used this event to evaluate the immediate impact on hemlock woolly adelgid overwintering mortality at four sites on the northern edge of the insects invaded range in eastern North America. We observed complete mortality, partial mortality and no effect of the cold event that correlated with the location and strength of the cold event. Our data also showed lack of support for preconditioning of overwintering adelgids as impacting their overwintering survival following this severe cold event. Finally, we compared the climatic conditions at our sites to historical weather data. The cold event observed in February 2023 resulted in the coldest temperatures observed at these sites, including the period within which hemlock woolly adelgid invaded these sites, suggesting cold conditions, especially under anthropogenic climate forcing, may not be a limiting factor in determining the ultimate northern range of hemlock woolly adelgid in eastern North America.
README: Data from: Effect of a severe cold spell on overwintering survival of an invasive forest insect pest
https://doi.org/10.5061/dryad.5qfttdzcc
Description of the data and file structure
There are 6 files in total: 1 ReadMe file, 2 data files and 6 associated code files (See Code/Software section).
ReadMe.txt: This file.
coldspell.csv: Records of number of hemlock woolly adelgid living and dead on shoots of hemlock trees collected from 4 sites in Canada, before and after a severe cold spell.
Description of fields:
-[];numeric; The row number for each record.
-[province];text; either "Ontario" or "Nova Scotia"; the Canadian province where the site was located.
-[site]; text; either "Annapolis Royal NS", "Mersey River NS", "Grafton ON" or "Wainfleet ON"'; the sites where samples were collected.
-[col_date]; text; the date, in d/m/y format, that samples were collected.
-[as_date]; text; the date, in d/m/y format, that samples were assessed.
-[twig_age]; text; either 'c' or 'o''; the age of the twig (shoot) sampled (current year or old); not used in analysis.
-[no_hwa]; numeric; the number of hemlock woolly adelgid found on the shoot
-[live_hwa]; numeric; the number of live hemlock woolly adelgid found on the shoot.
-[sht_len]; numeric; the length of the shoot, in cm; not used in analysis.
-[comment]; text; notes made by the data collector; not used in analysis.
-[Branch]; numeric; the branch number of that the sample was collected from; not sued in analysis.
NovaScotiaHistoricalMortality.csv; Records of post-winter mortality of hemlock woolly adelgid recorded at sites in the Canadian province of Nova Scotia. Transcribed and cleaned from the original data files recorded in .xls spreadsheets.
Description of fields:
-[];numeric; The row number for each record.
-[site]; text; various; the sites where samples were collected.
-[year]; numeric; various; the year recorded in the raw data.
-[mortality]; numeric; the mortality, in percentage, of hemlock woolly adelgid in samples taken at that site as recorded in the raw data
-[mortality_true]; numeric; the true mortality, in percentage, of hemlock woolly adelgid in samples taken at that site. False '0's have been replaced with 'NA'.
-[winter_true]; text; various; the two years spanned by the winter within which mortality occurred; e.g., '2018-2019' is the winter that began in 2018 and ended in 2019 and insect mortality was measured in the spring of 2019. Determined from notes recorded in the raw data.
Sharing/Access information
There are no other available versions of the data.
Code/Software
The data were analyzed using the R statistical computing environment and associated library packages authored for R. All analyses were done within the RStudio IDE. Associated files (not in repository) were used to generate figures in the associated manuscript.
analysis_coldEventHWA.R; R statistical computing language script; Plots survival of hemlock woolly adelgid survival and observed temperatures, and conducts analysis of survival pre- and post-event. See comments in file for more detail. Requires coldspell.csv, hwaWeatherOctober22-March23.Rdata (prepared by GetReadAndCleanWeatherData.R, see below) and the R packages 'tidyverse' & 'patchwork'.
analysis_historicalNovaScotiaMortality.R; R statistical computing language script; Analyses and plots hemlock woolly adelgid mortality from multiple sites in Nova Scotia, Canada. See comments in file for more detail. Requires NovaScotiaHistoricalMortality.csv and the R package 'tidyverse'.
analysis_historicalWeather.R; R statistical computing language script; Plots winter temperatures for previous 10 years at 4 sites where hemlock woolly adelgid were collected. See comments in file for more detail. Requires hwaHistoricalWeatherDecember12-March23.Rdata (prepared in GetHistoricalWeatherData.R, see below) and the R packages 'tidyverse' & 'patchwork'.
computeEstimatedMortalityMcCavoy.R; R statistical computing language script; Computes an estimated survival of hemlock woolly adelgid using equation 2 from McAvoy et al. (doi: 10.3390/f8120497). See comments in file for more detail. Requires coldspell.csv, hwaWeatherOctober22-March23.Rdata (prepared by GetReadAndCleanWeatherData.R, see below) and the R package 'tidyverse'.
GetHistoricalWeatherData.R; R statistical computing language script; Fetches observed weather data from four sites in Canada from Environment and Climate Change Canada server. See comments in file for more detail. Require the R packages 'weathercan' and 'tidyr'.
GetReadAndCleanWeatherData.R R statistical computing language script; Fetches observed weather data from four sites in Canada from Environment and Climate Change Canada server. See comments in file for more detail. Require the R packages 'weathercan' and 'tidyr'.
Methods
Insects were collected from infested trees at 4 sites in 2 Canadian provinces immediately before and immeditely after a severe cold spell. The health and status of the insects (live/dead) was determined in a laboratory. The survival was then compared to observed temperature data extracted from Environment and Climate Change Canada weather stations.