Toward a trophic theory of species diversity.

摘要: Efforts to understand the ecological regulation of species diversity via bottom-up approaches have failed yield a consensus theory. Theories based on alternative top-down fared better. Paine’s discovery keystone predation demonstrated that forcing could be simple, strong, and direct, yet ecologists persistently perceive generality in result. Removing top predators destabilizes many systems drives transitions radically distinct states. These typically involve community reorganization loss diversity, implying is crucial maintenance. Contrary expectations theories, terrestrial herbivores mesopredators are capable sustained order-of-magnitude population increases following release from predation, negating assumption populations primary consumers resource limited at or near carrying capacity. Predation sensu lato (to include Janzen–Connell mortality agents) has been shown promote wide range ecosystems, including rocky intertidal shelves, coral reefs, nearshore ocean, streams, lakes, temperate tropical forests, arctic tundra. The compelling variety these ecosystems suggests plays universal role regulating diversity. This conclusion further supported by studies showing reduction absence leads and, more dramatic cases, catastrophic regime change. Here, I expand thesis maintained interaction between competition, such strong reduces allowing coexistence.