94 Pedodiversity
Much interest has been focused on the value of p, the slope of the log
S versus log A regression line when dealing with the power law model
under the assumption of the canonical lognormal distribution as a model
for the distribution of abundances. For islands (mainland data, in general,
give smaller p values than data from islands; e.g., see Rosenzweig 1995,
1998, 1999), linear regression leads to a slight overestimation of parameter
p (e.g., p = 0.262 in Preston (1962a and b), and p = 0.263 in McArthur and
Wilson (1967)) as compared to the asymptotically exact value of 0.25 (May
1975). Observed values often fall in the range 0.2–0.4 (Preston 1962a and b,
McArthur and Wilson 1963, May 1975, Connor and McCoy 1979, Sugihara ...