add plotting symbol in CCA plot in R

I want to generate canonical correspondence analysis(CCA) plot, to show the influence of environmental parameters on species distribution using this code:

spe <- read.csv("spe.csv", row.names=1, sep=";")
env <- read.csv("env.csv", row.names=1, sep=";")
ccamodel <- cca(spe~., env)
plot(ccamodel, xlim=c(-1.5,2), ylim=c(-1,1.5), display=c("sp","cn"))

Here is the output generated where the environmental variables and species name are highlighted in blue and red respectively. My questions: How I can put the same symbol as a filled circle or a filled square before or after each species name in the plot?

Thanks in advance