  A pair of ecological tables is made of one table containing environmental
variables (in columns) and another table containing species data (in columns).
The rows of these two tables are identical and correspond to the sites where
environmental variables and species data have been measured. Such data are used
to analyze the relationships between species and their environment. If sampling
is repeated over time for both tables, one obtains a sequence of pairs of
ecological tables. Analyzing this type of data is a way to assess changes in
species-environment relationships, which can be important for conservation
Ecology or for global change studies. We present a new data analysis method
adapted to the study of this type of data, and we compare it with two other
methods on the same data set. All three methods are implemented in the ade4
package for the R environment.
