en:rda_cca_r
Section: Ordination analysis
RDA, tb-RDA, CCA & db-RDA (constrained ordination)
R functions
rda
- this function calculates RDA if matrix of environmental variables is supplied (if not, it calculates PCA). Two types of syntax are available:- matrix syntax -
RDA = rda (Y, X, W)
, whereY
is the response matrix (species composition),X
is the explanatory matrix (environmental factors) andW
is the matrix of covariables - formula syntax -
RDA = rda (Y ~ var1 + factorA + var2*var3 + Condition (var4), data = XW)
- as explanatory are used: quantitative variablevar1
, categorical variablefactorA
, interaction term betweenvar2
andvar3
, whereasvar4
is used as covariable and hence partialled out.
cca
- this function calculates CCA if matrix of environmental variables is supplied (if not, it calculates CA).RsquareAdj
- in case of CCA, it extracts only the value of R2, while values of adjusted R2 are not available (these need to be calculated by permutations and it is not available in R yet).anova.cca
- tests the significance of the variation in species composition explained by explanatory variables, using Monte Carlo permutation test.
en/rda_cca_r.txt · Last modified: 2021/03/03 19:53 by David Zelený