Competition enhances coexistence and support biodiversity

Abstract

A few studies on simple food chain suggest that competition has a strong dampening ability till some degrees and play a vital role to stabilize the food chain dynamics in the ecosystems. Still, much work is needed to understand the complex role played by competition in the food chains and food webs with higher trophic. We have studied the effect of competition on the (i) Combination of two food chain model and (ii) Combination of a food chain with a food web model, having individually various stability conditions (point stability and instability (or chaos)). In most of these cases, we have observed that low competition favors chaotic dynamics exhibited by one of the original models but as competition increases, system come into stability (limit cycles to point stability) and extinction of some species occurred as high competition is not favorable for the coexistence of species. Also from our various combinations of model dynamics, we have observed a negative effect of competition on the stable systems as high competition brings point stability to oscillations with higher trophic species extinction. The threshold values of the competition for each models may vary with original model's stability conditions. With competition in these models, a bigger parameter stability domain is observed which increases along with competition (below to upper threshold). Such bigger stability domain enhances the species coexistence and reduces the probability of extinction as system has high probability to have stable solutions and far away from the extinction. Based on our observations, we hypothesize that competition may sustain coexistence and support biodiveristy of the ecosystem.