steppe {ade4} | R Documentation

## Transect in the Vegetation

### Description

This data set gives the presence-absence of 37 species on 515 sites.

### Usage

    data(steppe)

### Format

`steppe` is a list of 2 components.

tab
  is a data frame with 512 rows (sites) and 37 variables (species) in presence-absence.
esp.names
  is a vector of the species names.

### Source

Estève, J. (1978) Les méthodes d'ordination : éléments pour une discussion. in J. M. Legay and R. Tomassone, editors. Biométrie et Ecologie, Société Française de Biométrie, Paris, 223–250.

### Examples

    par(mfrow = c(3,1))
    data(steppe)
    w1 <- col(as.matrix(steppe$tab[,1:15]))
    w1 <- as.numeric(w1[steppe$tab[,1:15] > 0])
    w2 <- row(as.matrix(steppe$tab[,1:15]))
    w2 <- as.numeric(w2[steppe$tab[,1:15] > 0])
    plot(w2, w1, pch = 20)
    plot(dudi.pca(steppe$tab, scan = FALSE, scale = FALSE)$li[,1],
        pch = 20, ylab = "PCA", xlab = "", type = "b")
    plot(dudi.coa(steppe$tab, scan = FALSE)$li[,1], pch = 20,
        ylab = "COA", xlab = "", type = "b")
    par(mfrow = c(1,1))

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