The
trophic cascade
hypothesis was introduced in 1985 by Stephen Carpenter (
University of Wisconsin, Madison), and since has become one of the principal
paradigms in
ecology. It states that
nutrient input sets the limits to the potential
productivity of a system, and the deviations from this potential are due to
food web effects. In plain english, the biological component of an
ecosystem is governed by both the nutrients that are put into the system and the
animals and
plants that live within it. Essentially, the nutrients determine the total energy available to the system, and the
behaviour of the
organisms determine how (and how efficiently) this energy is distributed.
The trophic cascade hypothesis was introduced as a potential solution to the dispute between two camps in ecology: those that supported the bottom-up perspective, and those that supported the top-down perspective. The bottom-up hypothesis suggested that the major influences determining the structure and production of an ecosystem were determined by the composition and supply of nutrients. The top-down hypothesis suggested that the major influences on an ecosystem were determined by the predators and their effects on the prey. For years, both camps uncovered information and data which, while supporting their view, contained hints of discord with the theory. The trophic cascade was an attempt at a synthesis of the two perspectives, and has generally been credited with harmonizing the research community and providing more powerful explanations and predictions.