When a shortage of prey causes a decrease of predators, what is this phenomenon called?

The phenomenon described relates to how the availability of resources in an ecosystem influences the populations of organisms within it. When there is a shortage of prey, it directly impacts the predators that rely on that prey for survival. This ripple effect is characteristic of bottom-up regulation, a concept in ecology that describes how the abundance of lower trophic levels (like prey) controls the population dynamics of higher trophic levels (like predators).

In bottom-up regulation, if the prey population decreases, it can lead to a subsequent decline in the predator population because there are fewer resources available to sustain them. This relationship highlights the importance of primary producers and consumers in maintaining the balance of ecosystems.

In contrast, top-down regulation would involve the impact of predators on the prey populations, illustrating how apex predators can control the size of prey populations through predation. Thus, when prey shortages lead to fewer predators, it exemplifies bottom-up regulation in ecosystem dynamics.