Diversity behavior in a community model with spatial heterogeneity

Abstract

Habitat heterogeneity plays an essential role in the processes of generating diversity. Another critical factor is the resource distribution in a community. Here we investigate the diversity patterns by introducing a computational model with spatial structure. Spatial heterogeneity is introduced through the distribution of resources, which is made using a fractal landscape constructed using fractional Brownian motion. In this way, we can adjust the landscape roughness by varying the Hurst exponent. In our model, a species is characterized by a set of half-saturation constants, so each species uses each resource differently. We investigate the evolution of the species number over time. We observed that the species-area relationship has two power-law regimes. The diversity relation with the Hurst exponent depends on the mutation rate and distribution of half-saturation constants. Species diversity does not depend on spatial heterogeneity for high mutation rate. However, a positive relationship is verified for low mutation probability.