Transient patterns and delayed herbivore response in plant-herbivore systems

Natural ecological systems typically exhibit transient dynamics, driven by various ecological and environmental factors. Understanding the root causes of transient behaviour and the associated regime shifts is of central importance for the sustainable management of ecosystems. Here, we develop and analyse a process-based model to describe the interaction between plants and their herbivore predators and to elucidate the mechanisms underlying transient patterns in plant-herbivore systems. Our model involves key components including seed-reproduction rates, plant dispersal abilities, the germination probabilities of seeds surviving predation, local interactions among plants, seed-predation rates, and herbivore conversion efficiencies. The plant-herbivore system has exhibited short-term and long-term transient behaviour and strong dependence of plant demography and predation pressure on abrupt transient shifts and duration of transients. Our results have demonstrated that high seed-reproduction rates obstruct long transients and can lead to extinctions of plants with low dispersal abilities. Herbivore predators have also exhibited delayed response to abrupt increases in plant density, even if their seed-predation rate is high. Taken together, our findings suggest that transient patterns are predominantly driven by the ecological and environmental pressure that plants experience.