Coexistence in Periodic Environments

Abstract

Theoretical knowledge on the ecological significance of periodic environments is still underdeveloped. Despite this, many global periodicities, on a variety of timescales, are changing due to climate change and other anthropogenic impacts. Thus, alterations in these periodicities may fundamentally restructure species interactions and future competitive outcomes, with clear implications for the maintenance of biodiversity under global change. We extend a two-species Lotka-Volterra competition model that incorporates periodic forcing between two seasons of high and low productivity to investigate the effects of changing environmental patterns on species coexistence. Towards this, we define coexistence criteria for periodic environments by approximating isocline solutions akin to classical coexistence outcomes. This analytical approach illustrates that seasonality can mediate different competitive outcomes, and that our numerical results and bifurcation patterns are quite general. Importantly, species coexistence may be incredibly sensitive to changing periodicities, and therefore, climate change has the potential to drastically impact the maintenance of biodiversity in the future.