The research, funded in part by the National Science Foundation (NSF), "highlights the unanticipated effects of trophic cascades on Earth systems, including far-reaching processes such as biogeochemical cycles," said David Garrison, director of NSF's Biological Oceanography Program. The loss of apex consumers from an ecosystem triggers an ecological phenomenon known as a "trophic cascade," a chain of effects moving down through lower levels of the food chain. There also are dramatic declines in populations of many large herbivores, such as elephants and bison. Plummeting numbers of apex consumers are most pronounced among the big predators, such as wolves on land, sharks in the oceans, and large fish in freshwater ecosystems. Their decline, largely caused by humans through hunting and habitat fragmentation, has far-reaching and often surprising consequences, including changes in vegetation, wildfire frequency, infectious diseases, invasive species, water quality and nutrient cycles. They shaped the structure and dynamics of ecosystems. The study looked at research results from a wide range of terrestrial, freshwater and marine ecosystems and concluded "the loss of apex consumers is arguably humankind's most pervasive influence on the natural world."Īccording to lead author James Estes, a marine ecologist and evolutionary biologist at the University of California, Santa Cruz, large animals were once ubiquitous across the globe. The finding is reported by an international team of scientists in a paper in this week's issue of the journal Science.
The decline of large predators and other "apex consumers" at the top of the food chain has disrupted ecosystems across the planet. Telephone numbers or other contact information mayīe out of date please see current contact information at media This material is available primarily for archival
Fishing alters predator patterns when large fish are removed, corals don't fare as well.