In natural ecosystems, animals play dual roles as both predators and prey, facing predation risk throughout their life cycles. The cascading effects of predators within ecosystems primarily impact prey through both consumptive and non-consumptive interactions. Predators can indirectly enhance plant performance by suppressing small herbivores, with both direct consumption and indirect changes in prey traits (e.g., alterations in foraging behavior) contributing to a reduction in small herbivore population density. We conducted two field experiments to assess the extent of these non-consumptive effects, simulating predation risk and comparing it with a no-predation risk control. We systematically evaluated the impacts of non-consumptive effects at the behavioral, population, and food web levels in experimental mesocosms. At the behavioral level, non-consumptive effects significantly reduced foraging time in low-density populations and increased concealment behavior but had no significant effect on high-density populations. At the population level, the density of the low-density population exposed to non-consumptive effects was significantly lower than that of the non-predation risk group. At the food web level, non-consumptive effects significantly reduced the impact of plateau pikas on plant dominance, diversity, and biomass in low-density areas. Additionally, the vegetation’s response to non-consumptive effects varied significantly with different population densities of plateau pikas. We conclude that through trophic and behavioral cascades, non-consumptive effects limit low population density of plateau pikas, reducing their consumption of vegetation and thereby increasing vegetation biomass.