The condition of smaller alligators ranging in size from 182 to 304 cm TL from
all lakes was also compared because the proportion of alligators in each quartile was not
equally distributed among the lakes. This analysis was compared against the overall
condition analysis to see if the disproportionate sizes of the alligators caught among the
lakes affected the overall condition results.
Diversity and equitability
The Shannon-Wiener Diversity Index, H' (Krebs 1999) was used to compare the
diversity of alligator diets among the lakes. The formula for calculating the Shannon-
Wiener diversity index, H', was:
H' = C(Pi)(LNPi)
i= 1
where s = the number of taxonomic categories, Pi = the proportion of samples of the ith
taxon and the natural log of the proportions was used (Krebs 1999).
Sheldon's Equitability Index, E (Ludwig and Reynolds 1988), was used to
determine if the alligators were consuming prey evenly and to compare it among lakes.
The formula for calculating the Sheldon's Equitability Index, E, was:
E = H'/LNs
where H' = the Shannon-Wiener Diversity Index, s = the number of taxonomic
categories, and the natural log was used in the analysis (Ludwig and Reynolds 1988).
The Shannon-Wiener Diversity Index and the Sheldon's Equitability Index were
calculated using the minimum number of taxa (MNT) identified in the stomach samples
for each lake. MNT included all prey identified to species level and also included prey
identified to genus or family when no other members were identified to a lower taxa in
the same group. For example, if the prey identified included Dorosoma spp., Dorosoma