Data and code for: The role of indirect interspecific effects in the stochastic dynamics of a simple trophic system

Understanding indirect interspecific effects (IIEs) on population dynamics is key for predicting community dynamics. Yet, empirically teasing apart IIEs from other interactions and population drivers is data-demanding. We used stochastic population models parameterized with long-term vital rate time series to simulate population trajectories and examine IIEs in a high-arctic vertebrate trophic chain: Svalbard reindeer, its scavenger (Arctic fox), and a migratory fox prey (barnacle goose). Reindeer carcass supply shaped fox abundance fluctuations, subsequently affecting goose fluctuations. Yet reindeer and goose population growth rates were only weakly correlated, probably due to stochasticity, density dependence, and life history traits. However, by isolating the effects of individual processes within our simulation model, we demonstrate the presence of strong IIEs on goose population fluctuations and extinction probability. Thus, we highlight the long-term impact of species interaction..., , , # Data and code for: The role of indirect interspecific effects in the stochastic dynamics of a simple trophic system

## Bartra-Cabré L; Hansen BB; Lee A; Layton-Matthews K; Loonen M; Fuglei E; Loe LE, Grøtan V.

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R version used for the scripts: R version 4.3.1 (2023-06-16 ucrt).

We recommend opening the scripts in Rstudio as this will allow to automatically install the packages used.

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CONTENT

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\- A.Simulations.R: main R code that runs simulations for the three species.

\- B.SimFunctions.R: R code with simulation functions needed to run script A.

\- C.FoxModelEstimations.R: R code running survival and reproduction models for the arctic fox, using the posterior samples from Nater et al. (2021).

\- D.GooseModelEstimations.R: R code running survival and reproduction models for the barnacle goose, using (slightly modified) models from Layton-Matthews et al. 2019; 2020.

\- E.Figure2_code.R: R code for reproducing Figure 2. Note that figure wa...