Publications

The impact of predator dormancy on the population dynamics of phytoplankton-zooplankton in freshwater ecosystems is investigated using a simple model including dormancy, a strategy to avoid extinction. In addition to recently reported chaos-mediated mixed-mode oscillations, as the carrying capacity grows, we find surprisingly wide phases of nonchaos-mediated mixed-mode oscillations to be present well before the onset of chaos in the system. Nonchaos-mediated cascades display spike-adding sequences, while chaos-mediated cascades show spike-doubling. A host of braided periodic phases with exotic shapes is found embedded in a region of control parameters dominated by chaotic oscillations. We describe the organization of these complicated phases and show how they are interconnected and how their complexity unfolds as control parameters change. The novel nonchaos-mediated phases are found to be large and stable, even for low carrying capacity. This paper reports a systematic investigation of the control parameter space of a model system incorporating effects of predator dormancy on the population dynamics of phytoplankton-zooplankton in freshwater ecosystems. Such a model was recently found to support chaos-mediated mixed-mode oscillations. In contrast, the present paper reports the discovery of surprisingly wide regular phases of nonchaos-mediated mixed-mode oscillations found to precede the onset of chaos in the system as the carrying capacity grows. Nonchaos-mediated cascades were observed only recently in distinct systems. They are characterized by spike-adding sequences of oscillations, while chaos-mediated cascades display the more common spike-doubling sequences of oscillations. Abundant periodic phases with exotic shapes are found embedded in a region of control parameters dominated by chaotic oscillations. The organization of all these complicated stability phases is described in detail. Furthermore, we show how phases of complex oscillations are interconnected and how their complexity unfolds as control parameters vary. Even at relatively low carrying capacity, nonchaos-mediated phases are found to be large and stable.