Shannon’s Diversity Index, Simpson’s Diversity Index, and Richness are among the most popular diversity indices in ecology. We use those indices to quantify agrobiodiversity in the Mediterranean regions at Nuts 3 level. Both the Shannon’s Diversity Index and the Simpson’s Diversity Index measure the abundance and evenness of agricultural land covers. The Shannon’s Diversity Index is sensitive to rare land cover. The Simpson’s Diversity Index gives more weight to common or dominant land cover classes. Richness is a measure of abundance of agricultural land cover, it is defined as the number of agricultural land covers.
Shannon’s Diversity Index
Shannon’s Diversity Index= 
(abundance and evenness of agricultural land covers) where 
is the ratio of agricultural land cover i (for example the proportion of non-irrigated arable land).
Simpson’s Diversity Index
Simpson’s Diversity Index = 
(abundance and evenness of agricultural land covers) where is the ratio of agricultural land cover i (for example the proportion of non-irrigated arable land).
Richness
Richness = Number of agricultural land covers.