Spatial patterns and diversity in multi-species models of succession

SARAVIA, LEONARDO A.; MOMO, FERNANDO R.

Santiago de Chile

Congreso; 11th International Symposium on Mathematical and Computational Biology; 2011

BIOMAT Consortium

p, li { white-space: pre-wrap; } Neutral models has been very successful in explaining patterns of diversity like species abundance distributions and species-area relationships (SARs). Two areas that have not been explored in these models are the spatial patterns (other than SARs) and the temporal dynamics as produced by ecological succession. We explored the temporal pattern with regard to the richness (R), the Shannon diversity index (H) and with respect to spatial pattern with fractal information dimension (D1). We used a spatial explicit stochastic model where space is discretized and each position represents an individual, these kind of models have been called stochastic cellular automata or interactive particle systems. We built 4 slightly different models: a classic neutral model, a neutral model without the saturation or zero-sum assumption and a hierarchical model with and without saturation. We analyze the first 100 time steps of colonization of an empty site. Neutral models reach an equilibrium before than the hierarchical ones and no major differences were found between saturated and not saturated kinds of models. Two parameters of the models were more important in all cases: the colonization rate and the dispersal distance. Both have a positive influence in D1 , H and R. We observed in the hierarchical models a clear negative relationship between D1 and H. In contrast we found in the neutral models a triangular relationship: there is a negative relationship between H and the minimum D1. This negative relationship was also found in experimental ecosystems and this implies that D1 could be used as an index to identify probable areas of high diversity.