
44 Pedodiversity
Where S is the number of different habitats of the species and R is the
average similarity between the habitats. In this formula the p
i
, namely
the “probability” to fi nd the species in the ith habitat is not considered,
however the formula may be changed considering the following:
max
)1(
)(
H
RH
SOD
−
=
26)
Where H is obtained by formula 4) or 6) and Hmax is lnS or respectively
1-1/S. The idea of using a power function of the type y=x
φ
, where y is
the diversity, x is the number of classes S and φ is a number ranging
between 0 and 1, is appealing since in case of φ=1, the diversity is equal
to S, namely the N
0
of Hill (1973) and in ...