Effects of interregional migration and regional connectivity on biodiversity in cyclic competition systems

Population migration is ubiquitous in real social and ecological systems, and specifically has been found to play a key role in shaping species biodiversity among cyclically competing mobile populations. While its crucial role in biodiversity has been widely studied, prior studies have usually considered a single habitat, and the effect of inter-patch migration, i.e., migration between two habitats, has been examined in a uniform environment structure. In this paper, to address gaps in realistic situations arising from different environments, we explore how population migration between two adjacent habitats can affect biodiversity in each system of cyclic competition. By using the classic spatial rock-paper-scissors game and constructing a connected network of two habitats, we investigate how asymmetry and connectivity between habitats can ultimately affect the evolution of populations. Through extensive simulations of the two considered scenarios of habitat asymmetry, we found that even if the mobility of one patch exceeds the single-patch critical mobility, the exchange-rate asymmetry drives the endangered patch to restore coexistence, accompanied by a change in collective behavior. Even when the density difference between two regions is large, robust coexistence can still be maintained if both patches exceed the critical mobility. We further find that connectivity between the two regions is important for biodiversity. Our findings may provide insight into the importance of population migration between adjacent regions for maintaining communities and can help inform urban/regional planning.