Abstract:Higher-Order Interactions usually refer to the influence of one species on the strength of interactions between two other species. Although both theoretical and experimental studies have shown evidence of its significance, their role in ecosystems is often underestimated. In recent years, Higher-Order Interactions between organisms have become a hot spot in ecological research and have been shown to have important effects on species coexistence, community building and biodiversity. Higher-Order Interactions exist between plants, pollinators and herbivores:herbivores can have an impact on the reciprocal relationship between plants and pollinators, which includes both effects on the pollination effectiveness of pollinators on plants and the pollination returns of plants to pollinators. At the metapopulation level, the habitats of pollinators and herbivores are assumed to be plants distributed on different patches, and the local populations of the three are at risk of stochastic extinction. Then, Higher-Order Interactions resulting from herbivores altering reciprocal relationships between plants and pollinators, and indirect interactions resulting from herbivore-induced plant extinctions leading to pollinator extinctions, are considered on this basis. By analyzing the basic ecological processes among the three species of plants, pollinators and herbivores, a plant-pollinator-herbivore metacommunity model was developed from the interconversion of patch types and used to study their effects on metacommunity stability and persistence. To simplify the model, the mutual independence of pollinator and herbivore encroaching patches was assumed, and higher order terms containing Higher-Order Interactions and indirect interactions were derived, with which the formation of Higher-Order Interactions and indirect interactions are clearly demonstrated. Then, a simple analysis and computer simulation of the plant-pollinator-herbivore metacommunity model was conducted. The results show that (1) the reciprocal relationships can be bi-stable at the metacommunity scale (metapopulation occupancy shifts between two steady states and causes species extinction when it falls below the extinction threshold), which shows the ability of species to coexist depends on initial conditions, illustrating the dependence of community dynamics on initial conditions; (2) the positive Higher-Order Interactions can expand the range of parameters (plant extinction rates) over which bi-stable phenomena can occur in metacommunities, and the negative Higher-Order Interactions and indirect interactions narrow it, but neither changes the nature of metacommunities capable of bi-stable phenomena; (3) the positive Higher-Order Interactions can reduce the extinction threshold of metacommunities and increase the occupancy rate of metacommunities when they reach stable equilibrium, which is conducive to metacommunity survival, while the negative Higher-Order Interactions and indirect interactions are not conducive to metacommunity survival. The results suggest that Higher-Order Interactions and indirect interactions play an important role in regulating the dynamics of multispecies systems and species coexistence.