Tutorial for adding nonstationarity, nonlinearity, and statistical interactions to dynamic structural equation models
James Thorson, NOAA Northwest Fisheries Science Center
Tuesday, January 13th, 2025, 9:30AM
FISH 203
Webinar Link: https://attendee.gotowebinar.com/register/8831598901906187862
Dynamic structural equation models (DSEM) provide a fast and general approach to incorporate ecological knowledge in multivariate time-series analysis, e.g., when linking covariates to stock-assessment models. However, DSEM has previously been restricted to stationary, linear, and additive relationships, whereas many ecological systems are nonstationary, nonlinear, and include statistical interactions.
In this workshop, we introduce “moderated SEM” and quickly summarize how moderated DSEM can incorporate nonstationarity, nonlinearity, and statistical interactions. We will then walk through three R-package vignettes in package dsem, showing (1) random slopes linking the Pacific Decadal Oscillation to local temperature, (2) nonlinear (Lotka-Volterra) predator-prey interactions for Wolf-Moose or Paramecium-Didinium systems, and (3) quadratic temperature-
dependence in zooplankton dynamics for Lake Washington. We encourage participants to have a laptop with R and Rtools installed, and/or pre-installing the dsem@dev branch using `remotes::install_github(“james-thorson-NOAA/dsem@dev”)`.
In this workshop, we introduce “moderated SEM” and quickly summarize how moderated DSEM can incorporate nonstationarity, nonlinearity, and statistical interactions. We will then walk through three R-package vignettes in package dsem, showing (1) random slopes linking the Pacific Decadal Oscillation to local temperature, (2) nonlinear (Lotka-Volterra) predator-prey interactions for Wolf-Moose or Paramecium-Didinium systems, and (3) quadratic temperature-
dependence in zooplankton dynamics for Lake Washington. We encourage participants to have a laptop with R and Rtools installed, and/or pre-installing the dsem@dev branch using `remotes::install_github(“james-thorson-NOAA/dsem@dev”)`.