richness {glmtoolbox}

Species richness

Description

In these data the response is species richness represented by a count of the number of plant species on plots with different biomass and three different soil pH levels: low, mid, and high.

Usage

data(richness)

Format

A data frame with 90 rows and 3 variables:

Biomass

a numeric vector giving the value of the biomass in the plots.

pH

a factor giving the soil pH level in the plots: "low", "mid", and "high".

Species

a numeric vector giving the number of plant species in the plots.

References

Crawley M.J. (2007) The R Book. John Wiley & Sons, Chichester.

Examples

data(richness)
dev.new()
with(richness,plot(Biomass,Species,col=as.numeric(pH),pch=16))
legend("topright", legend=c("low","mid","high"), col=c(1:3), pch=16,
       title="pH level", bty="n")