Bayesian trophic position models using stan (pronounced trips) by leveraging {brms}. Equations for trophic position models are derived from Post 2002 and Heuvel et al. 2024 and are to be used with stable isotope data for different species.
Trophic Models in {trps}
Currently {trps} supports the following models:
One Source Model -
one_source_model()
Two Source Model -
two_source_model()
Two Source Model - corrected () using Heuvel et al. 2024 -
two_source_model_ar()
Two Source Model - corrected () - with carbon mixing model -
two_source_model_arc()
Installation
You can install the R-Universe version of {trps} using the following:
install.packages("trps",
repos = c("https://benjaminhlina.r-universe.dev",
"https://cloud.r-project.org"))
You can install the development version of {trps} using the following:
devtools::install_github("benjaminhlina/trps")
To view the overall progress of the package please see news.
Vignettes
I highly suggest going through the vignettes as they will walk you through how to use create each trophic position model using {trps} and {brms}.
vignette("estimate_trophic_position_one_source_model")
You can also use the following to see vignettes:
browseVignettes("trps")
The vignettes are currently available online under the articles section of the website. See the following links, Estimate trophic position - one source.
Citations
To cite this package please cite the following publications
Post, D.M. 2002. Using Stable Isotopes to Estimate Trophic Position: Models, Methods, and Assumptions. Ecology 83(3): 703-718. doi: 10.2307/3071875.
Heuvel, C., Zhao, Y., and Fisk, A.T. 2025. Food web structure across basins in Lake Erie, a large freshwater ecosystem. Canadian Journal of Fisheries and Aquatic Sciences 82:1-16. doi: 10.1139/cjfas-2024-0028.
Hlina B.L. 2025. trps: Bayesian trophic position models using stan. R package version 0.1.0 (‘one-skate’). https://benjaminhlina.github.io/trps/