20-23 May 2025
To foster international participation, this course will be held online
Multivariate analysis of ecological communities is often performed with a set of loosely connected methods that rely on distance measures (e.g., C(C)A, NMDS, PCoA). In the last decade,
Generalized Linear Latent Variable Models (GLLVMs) have been proposed as an alternative, unifying framework, for performing ordination, and for jointly analysing the occurrence patterns of
multiple species as Joint Species Distribution Models do. GLLVMs can be seen as a multivariate extension of GL(M)Ms, so that they inherit many of the useful properties of both statistical models
and ordination methods. The explicit statistical model formulation makes GLLVMs more flexible than classical ordination methods, and provide many useful tools for inference on species
associations, and for model diagnostics.
The course is aimed at PhD candidates, postdoctoral researchers and researchers with basic statistical knowledge, that have multivariate data (which can be experimental or observational) and want
to learn how to analyse it in a statistically appropriate manner. Familiarity with concepts in generalised linear models (e.g., distribution, link function, mean-variance relationship,
uncertainty quantification) for different response types is required, whereas familiarity with generalised linear mixed models (e.g., variance parameters, quirks that come with mixed models) or
with the basics of ordination (e.g., biplots, latent variables) is an advantage. Basic knowledge in the R programming language is required.
Monday – Classes from 2-8 PM Berlin time
Recap of related methods including generalised linear models, generalised linear mixed models, and concepts in classical multivariate analysis (i.e., ordination).
Introduction to the gllvm R-package.
Tuesday – Classes from 2-8 PM Berlin time
Background on GLLVMs with ecological examples.
Introduction to ecological gradient theory: what are latent variables?
Species co-occurrence patterns: Joint Species Distribution Models or ordination?
Benefits of GLLVMs over classical ordination methods, with practical demonstration.
Wednesday – Classes from 2-8 PM Berlin time
Fitting an ordination with covariates.
Model checking and selection.
Some suggestions on visualizing results, drawing inference from GLLVMs.
Thursday– Classes from 2-8 PM Berlin time
Going beyond vanilla GLLVMs: a brief look at hierarchical ordination and other hierarchical GLLVMs.
Opportunity for fitting GLLVMs to your own data.
Cancellation Policy:
> 30 days before the start date = 30% cancellation fee
< 30 days before the start date= No Refund.
Physalia-courses cannot be held responsible for any travel fees, accommodation or other expenses incurred to you as a result of the cancellation.