Species diversity indices.
The diversity and relationships between species isolated in this study within the HDB community were evaluated by several species-diversity indices(Atlas and Bartha, 1998). We used the number of species (S); Simpson’s index (D ¼ sum [Pi2]),where Pi is the number of a given species divided by the total number of isolates observed; Simpson’s index of diversity (1 D); Simpson’s reciprocal index (1=D); the Shannon-Weaver index (H ¼sumðPiln ½PiÞ); the evenness index (E ¼ H=½ln S),and the equitability index (J ¼ H=Hmax), where Hmax is the theoretical maximal H for the population examined, assuming each species has only one number.