Search for: [Abstract = "A FORTRAN program is developed that generates model assemblages on the basis of three basic features of animal communities\: the species weight relationship, the density\-weight relationship, and the minimal density. Samplings from random placed individuals of such assemblages revealed the influence of the sampling method \(sequential adding, nested and non\-nested\), the scale, and the underlying relative abundance distribution on resulting species\-area relationships \(SPARs\). It is concluded that the type of the species\-area relationship is not an intrinsic factor of an assemblage but depends especially on the sampling method and the unit of area. The fraction of species found only once in the sample \(singletons\) was the major factor influencing the model that fitted the SPAR best \(at low fractions the exponential, at higher fractions the power function model\). All sampling and structural factors that influence the fraction of singletons also influence the fit of the SPAR model. A mathematical derivation showed that at a certain fraction of singletons in the sample a shift from the power function to the exponential model is expected independent of assemblage type. This shift will occur between 20 and 30% singletons."]

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