| Type: | Package |
| Title: | Constant Temperature Equivalent |
| Version: | 0.1.3 |
| Date: | 2026-01-18 |
| Maintainer: | Donald T. McKnight <donald.mcknight@my.jcu.edu.au> |
| Description: | Under natural conditions, nest temperatures fluctuate daily around a mean value, whereas in captivity they are often held constant. The Constant Temperature Equivalent is designed to bridge the gap between the two by calculating a single temperature value for wild nests that corresponds with the amount of development that would occur in an incubator set to the same temperature. The theory and formulas behind this method were developed by Professor Author Georges and are implemented here as a single function. |
| License: | GPL (≥ 3) |
| Encoding: | UTF-8 |
| LazyData: | true |
| RoxygenNote: | 7.3.3 |
| Suggests: | dplyr,knitr,rmarkdown |
| Depends: | R (≥ 3.5) |
| VignetteBuilder: | knitr |
| NeedsCompilation: | no |
| Packaged: | 2026-01-20 00:05:15 UTC; Donald McKnight |
| Author: | Donald T. McKnight [aut, cre] (affiliation: Savanna Field Station) |
| Repository: | CRAN |
| Date/Publication: | 2026-01-23 15:50:02 UTC |
Calculate Constant Temperature Equivalent (CTE)
Description
Calculate movements in a stream network for multiple individuals
Usage
CTE(M, R, T0 = 0, t = pi, max.it = 10000)
Arguments
M |
(integer) Mean temperature for a given day in degrees centigrade |
R |
(integer) Maximum deviation of temperatures from M for a given day in degrees centigrade (e.g., if the range of temperatures is 14‒16 and M = 20, then R = 6) |
T0 |
(integer) Temperature in degrees centigrade below which no development will occur. Default = 0. |
t |
(integer; 0 < t < 2pi) Starting seed for calculating the point along the curve above which half of development occurs. Any value > 0 and < 2pi will work. Default = pi. |
max.it |
(numeric) Maximum number of times the function will try to find a solution for a given day. In rare cases, no stable solution exists, in which case it will attempt to find a solution max.it number of times before returning NA. Default = 10000 |
Details
CTE takes input values for a given day and returns the CTE using the formulas in Georges (1989). It automatically selects the appropriate formula based on whether the minimum temperature (M-R) is less than T0. T0 may not be precisely known in all cases, but should be estimated based on knowledge of the species being studied. If you think your nest never dropped below T0 (i.e., there was not point at which development was not occurring) then set T0 lower than your minimum temperature. If M+R < T0 (i.e., all temps on a given day were less than T0, then T0 is returned as CTE). Because this function operates on data from a single day, in most cases you will want to run it within a looping function. See Vignette for details on the formulas and examples.
Value
Numeric value of the CTE for a given day (in degrees centigrade)
References
Georges, A. (1989). *Female turtles from hot nests: is it duration of incubation or proportion of development at high temperatures that matters?*. Oecologia, **81**, 323-328
Examples
CTE(M=20, R = 6, T0=10)
Example temperature data
Description
Example data set for two nests over one or two days.
Usage
data(example_temp_data)
Format
A data frame with 144 rows and 3 variables:
- nest
Nest ID
- date
Date (YYYY-MM-DD)
- time
Time (HH:MM:SS)
- temp
Temperature (degrees centigrade)
Source
Hypothetical data of two nests over 1 or 2 days