Nature of species diversity in stochastic ecological systems

Coexistence of species in multi-species competition is a complex dynamics in ecosystem driven by various internal and external mechanisms to maintain species diversity and enriched species society. Demographic stochasticity, arising from intrinsic random individual birth and death, intra-species and inter-species interaction, and species resource interaction, is one important parameter which can drive competing multi-species for a single resource to coexist in the regime where species coexistence in its deterministic counterpart is not possible. The distribution of mean abundances of single or competing species in various parameter spaces of the ecosystem exhibit patterns of species group formation with varied sizes and distributions. The species correlation with resources forecasts the prediction of endangered, strongly competing and comparatively stable species depending on its values. The emergence of number of positively correlated species with resource or a reference species indicates the possibility of inter-species group formation in the ecosystem. However, the distributions of these numbers of positively correlated species follow negatively skewed Poisson distributions indicating the patterns of inter-species group formation breaks down at long run.