The diversity index is calculated using the Shannon-Wiener index. The Shannon-Wiener index is a measure of ecological diversity. The index uses the number of species and their abundance as input. The lowest value of the index is 0 (meaning only one species is present), and the maximum value depends on the number of species when they are all present in the same quantity. In Soil Life Monitor, the Shannon-Wiener index is based on the six groups measured (gram+ bacteria, gram- bacteria, actinomycetes, arbuscular mycorrhiza, other fungi and protozoa). Higher diversity is often related to better stability and resilience. Disturbances, lack of diverse input from food sources, and poor crop rotation can decrease the diversity.