Introduction
Theory, R functions & Examples
Section: Ordination analysis
RsquareAdj
(library vegan
) - extracts the value of R2 and adjusted R2 from results of ordination (and also regression). For linear constrained ordinations (RDA, tb-RDA), the adjusted R2 is calculated using Ezekiel's formula, while for unimodal constrained ordinations (CCA) the calculation is based on permutation model introduced by Peres-Neto et al. (2006).anova.cca
(library vegan
) - tests the significance of the variation in species composition explained by explanatory variables in constrained ordination (RDA, CCA), using Monte Carlo permutation test. It can test the significance of first = TRUE
);by = “axis”
), sequentially from the first to the last (this is done by using samples scores on the n-th axis as explanatory variables, while using scores of the axis 1, 2, ... n as covariables);by = “terms”
; note that this variation depends on the order of variables in which they enter the model);by = “margin”
; here the variation does not depend on the order of variables in the model).