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Shannon Diversity and Evenness Indexes- Micro
Abundance is based on counts of 'Adult' life stage records.
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Bedrock Geology ** indirectly affects moth distribution by influencing the type of habitat and food plants available in an area. In turn, this may affect the types of moths that can thrive, or where they can most likely be found.
In the Derbyshire/VC57 recording area, the Shannon-Weiner Diversity Index measures the diversity and richness of moth communities by counting the distinct species found within each tetrad and assessing how evenly individuals are distributed among them. A higher Shannon Index value indicates a more diverse community with many species present and balanced abundances. The Evenness Index, ranging from 0 to 1, reflects how balanced the community is: a value close to 1 means species are recorded in similar numbers, while a value near 0 suggests that a few species dominate the records, with many others recorded rarely or not at all.
Approximate formulas:
Shannon Diversity Index (H) = -∑i=1S pi × ln(pi)
where S = total species count, pi = proportion of individuals of species i.
Evenness Index (E) = H / ln(S)
where H = Shannon Diversity Index, S = total species count.