Influences of temperature and time on habitat use patterns of a semi-aquatic turtle
Data files
Oct 27, 2025 version files 33.84 MB
-
daily_temps.csv
564.32 KB
-
README.md
3.31 KB
-
temp_smoothing.R
8.84 KB
-
unsmoothed_temps.csv
11.90 MB
-
wt_habitatuse_glmm.R
14.50 KB
-
wt_smoothed_temps.csv
21.35 MB
-
wt_temp_glmm.R
5.62 KB
Abstract
Many ectothermic vertebrates have predictable seasonal activity and habitat use patterns, but variable patterns at fine temporal scales (e.g., minutes to days) that are likely influenced by thermoregulatory demands on behavior. Wood turtles (Glyptemys insculpta) are freshwater turtles known to use terrestrial environments during their active period. However, little research has been conducted to quantify the influence of environmental factors on diel habitat use patterns. We used fine-resolution global positioning system (GPS) tracking and temperature data to quantify wood turtle aquatic-terrestrial habitat-use patterns from May through August 2015 and 2016, focusing on the influence of temporal variables and environmental temperature. We found that temporal variables and open canopy air temperature had strong explanatory power for wood turtle aquatic-terrestrial habitat use patterns, but temperature was a stronger predictor. Terrestrial activity was positively associated with air temperature, resulting in a consistent pattern of daytime terrestrial and nighttime aquatic activity during the pre-nesting period. Male and female activity patterns diverged during the post-nesting activity period, with most males returning to the river at night and most females remaining terrestrial, influenced by females moving farther from the river. The results of our study provide valuable information to inform population survey design, habitat management planning, and potential responses to climate change for this unique species of conservation concern.
Dataset DOI: 10.5061/dryad.cvdncjthb
Description of the data and file structure
We used fine-resolution GPS tracking and temperature data to quantify wood turtle aquatic-terrestrial habitat-use patterns from May through August 2015 and 2016, focusing on the influence of temporal variables and environmental temperature
Files and variables
File: temp_smoothing.R
Description: Code to identify and replace outliers in temperature data.
File: wt_habitatuse_glmm.R
Description: Code to create GLMMs to predict habitat use of wood turtles using temporal variables
File: wt_temp_glmm.R
Description: Code to create GLMMs to predict habitat use using temperature
File: daily_temps.csv
Description: Daily temperature values from a nearby weather station.
Variables
- Date: Day of the year
- Time: Time of day
- Temp: Recorded temperature in Fahrenheit
- Humidity: Relative humidity
- Speed: Wind speed
File: unsmoothed_temps.csv
Description: Raw temporal and temperature data for each wood turtle observation
Variables
- X: New record ID
- id: Original record ID
- yr: Year
- month: Month of year
- week: Week of year
- day: Day of year
- hr: Hour of day
- Min: Minute of hour
- TortID: Individual turtle ID
- turtle_temp: Temperature recorded from the iButton on the turtle in Celcius
- water_temp: Average temperature of stream in Celsius
- shade_temp: Average temperature of shade environments in Celsius
- sun_temp: Average temperature of sun environments in Celcius
File: wt_smoothed_temps.csv
Description: Temporal and smoothed temperature data for each wood turtle observation
Variables
- id.num: ID number
- yr: Year
- m: Month of year
- wk: Week of year
- day: Day of year
- hr: Hour of day
- min: Minute of hour
- dn: Binary variable indicating if its day time (1) or night time (0)
- date.time: Specially formatted date and time
- TortID: Individual turtle ID
- PathID: ID for each complete GPS path.
- GPS.fix: Indicates if there was a GPS fix
- turtle.temp: Smoothed emperature recorded from the iButton on the turtle in Celcius
- water.temp: Average temperature of stream in Celsius
- shade.temp: Smoothed average temperature of shade environments in Celsius
- sun.temp: Smoothed average temperature of sun environments in Celcius
- location: Classified habitat class location. Either water (W) or land (L)
- sex: Sex of wood turtle. Male (M) or female (F)
- doy: Day of year
- dist: Distance in meters to nearest water. NA values are land-classified values with no GPS-fix, so the data is unavailable.
- local.temp: Temperature values from a nearby weather station recorded on the same time and day.
Code/software
The analysis was completed with Program R version 4.3.0.
Loaded packages include the following: AICcmodavg (2.3-2), aplpack (1.3.5), car (3.1-2), dplyr (1.1.2), fmsb (0.7.5), influence.ME (0.9-9), lme4 (1.1-33), MuMIn (1.47.5), stats (4.3.0), and stringr (1.5.0).
The temperature smoothing script was run first to clean up the temperatures. The other two scripts use the smoothed temperature data, and can be run independently of each other.