piecewiseSEM: Piecewise structural equation modelling in r for ecology, evolution, and systematics

piecewiseSEM provides a practical R implementation of confirmatory path analysis, a form of structural equation modeling used to resolve complex multivariate relationships among interrelated variables in the biological sciences. Traditional SEM evaluates models through covariances among variables, which supports many model forms but limits detailed specification. Local estimation instead allows non-normal distributions, random effects, and different correlation structures, and this package automates that previously manual process.

The package extends piecewise SEM to all current generalized linear, phylogenetic least-squares, and mixed effects models while relying on familiar R syntax, making the method accessible and tractable. The author demonstrates it with two worked examples, one involving random effects and temporal autocorrelation and another involving phylogenetically independent contrasts, aiming to reflect the ecological and methodological processes that generate data.