Species Richness
Species Richness is a count of how many different types of living things share one place.
Think of it this way
A kitchen spice rack with twenty different jars has high variety. Each jar holds a distinct flavor. A rack with only salt and pepper has low variety. Ecologists count species the same way: more distinct types in one place means higher species richness.
Explaining species richness by grade level
A park with many kinds of plants draws many kinds of bugs and birds. You can count them all to see how rich that spot is. A bare lawn has far fewer types of life. More plant types means more animal types show up.