The species richness is how much species there are in an area. the species evenness is who equal the relative number of species are.
If you have only a few species in an habitats the species richness will be low and if there are a lot the species richness will be hight.
But independently of the richness the eveneness is comparing the number of individuals between species. If thare are a lot of individuals in a few species and just a little number of individuals in the others species the evenness will be low.
For instance the two community they have the same number of species therefore the same species richness. In the other hand the first have a hight species evenness ( since every species bear numbers of individuals closes from eachother) and the second one have a low evenness.
the second example show two communitys with a different number of species ( i.e. a different species richness) but a similare evenness ( witch is high here since the number individuals in each species are very similar )