2.5. Epifauna diversity indices
Epifaunal community structure was described using the diversity indices
related to the number and abundance of species recorded. Abundance was
determined as the total number of individuals (N ) recorded across
all sites and seasons. Species richness was defined using the Margalef
index (d) that calculates the average number of species per unit number
of organisms collected (Margalef, 1989). Species diversity was first
determined after the Shannon-Wiener index (H’) (Shannon 1963), and
thereafter converted to “effective number of species” by calculating
the exponential (exp (H)) of each diversity value after Hill (1973).
This transforms the non-linear H’ to a linear form that permits
statistical comparisons that are intuitive, while the unit “number of
species” allows for diversity comparisons across metrics (Jost et al.
2006, Jost et al. 2010).