A trophic cascade refers to a dramatic change in an ecosystem that occurs when a top predator is removed or reintroduced. This ecological phenomenon illustrates how alterations at the top of the food chain can impact multiple trophic levels below. For example, the removal of a top predator can lead to overpopulation of herbivores, which may then over-consume vegetation, resulting in decreased plant diversity and health. Conversely, reintroducing a predator can help control herbivore populations, allowing plant communities to thrive. Understanding trophic cascades is essential for managing wildlife and conserving ecosystems, as they underscore the interconnectedness of species within food webs.