Comparing Allee effect-based and dispersal-based neutral models for species abundance distribution patterns

Dispersal is important for biodiversity maintenance in both neutral and niche theories. However, little is known about the potential role of Allee effect at the community level. In the present study, we developed neutral models for quantifying the separate and joint influences of the Allee effect and dispersal process, respectively, on species abundance distribution (SAD) patterns. Tree census data from Barro Colorado Island (BCI), Panama were used as the case to compare different neutral SAD models. Results showed that Allee effects were not detected in the BCI tree SAD curve. By contrast, the neutral models with the incorporation of dispersal process (including both immigration and emigration) can remarkably improve the fitting power of neutral models on the BCI tree SAD curve. Finally, even though the influence is not detectable, the Allee effect-based SAD models still might be alternative SAD models for model comparison and null hypothesis testing.