LAUSR

It is important to explore the underlying mechanisms that cause triphasic species–area relationship (triphasic SAR) across different scales in order to understand the spatial patterns of biodiversity. Instead of theory establishment or field data derivation, I adopted a data simulation method that used the power function of SAR to fit log-normal distribution of species abundance. The results showed that one-step sampling caused biphasic SAR and n-step sampling could cause 2n-phasic SAR. Practical two-step sampling produced triphasic SAR due to the Preston and Pan effects in large areas. Furthermore, before exploring biological or ecological mechanisms for the nature phenomenon, we should identify or exclude potential mathematical, statistical or sampling reasons.