Obtaining the final model and Interpretation of the results - Step 5/6

According to these four maps the probability to find P. krameri in its native range will be lower in many areas in the future. By contrast, new potential suitable area will be present outside its native range.
 
Now we can graphically evaluate the effect of climate change on the potential distribution of the species making a histogram of the values of the probability maps for the current and future climates:

> library(scales)
> par(mfrow=c(1,3))
> hist(values(current_final), xlim=c(0,1000), xlab="Probability of presence*1000", col="darkblue", main="Predicted probabilies of presence")
> hist(values(future_final), xlim=c(0,1000), xlab="Probability of presence*1000", col=alpha("red",0.7), main="Future climate", add=T)

In addition, it is possible to compare the number of cells of predicted presence for the current and future climates, in order to evaluate if the species is predicted to colonize new areas.

> barplot(c(table(values(b_current))[2], table(values(b_future))[2]), col="darkgreen", main="Area of predicted presence",
+names=c("Current", "Future"), ylab="number of cells")