Apex predator

From Wikipedia, the free encyclopedia
The lion is Africa's apex land predator.

An apex predator, also known as an alpha predator or top predator, is a predator residing at the top of a food chain upon which no other creatures prey.[n 1][1][2] Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic levels and serve as keystone species, vital to their ecosystems. One study of marine food webs defined apex predators as those feeding at trophic levels above four.[3] The apex predator concept is commonly applied in wildlife management, conservation and ecotourism.

Food chains are often far shorter on land, with their apices usually limited to the third trophic level – for example, giant constrictor snakes, hyenas, varanid lizards, wolves, humans, or big cats preying mostly upon large herbivores. Most apex predators are hypercarnivores.

Ecological roles

Effect on prey population dynamics

Apex predators affect prey species' population dynamics. Where two competing species are in an ecologically unstable relationship, apex predators tend to create stability if they prey upon both. Inter-predator relationships are also affected by apex status. Non-native fish, for example, have been known to devastate formerly dominant predators. One lake manipulation study found that when the non-native smallmouth bass was removed, lake trout, the suppressed native apex predator, diversified its prey selection and increased its trophic level.[4]

Effects on wider ecosystem

Effects on wider ecosystem characteristics such as plant ecology have been debated, but there is evidence of a significant impact by apex predators. When introduced to subarctic islands, for example, Arctic foxes' predation of seabirds has been shown to turn grassland into tundra.[5] Such wide-ranging effects on lower levels of an ecosystem are termed trophic cascades. The removal of top-level predators, often – and, especially, recently – through human agency, can radically cause or disrupt trophic cascades.[6][7]

A now commonly cited example of the effect of apex predators on an ecosystem is the dramatic changes in the Greater Yellowstone Ecosystem recorded after the gray wolf was reintroduced to Yellowstone National Park in 1995. Elk, the wolves' primary prey, became less abundant and changed their behavior, freeing riparian zones from constant grazing and allowing willows, aspens and cottonwoods to flourish, creating habitats for beaver, moose and scores of other species.[8] In addition to their effect on prey species, the wolves' presence also affected one of the park's vulnerable species, the grizzly bear: emerging from hibernation, having fasted for months, the bears chose to scavenge wolf kills,[9][10]:56 especially during the autumn as they prepared to hibernate once again.[10]:90 The grizzly bear gives birth during hibernation, so the increased food supply is expected to produce an increase in the numbers of cubs observed.[11] Dozens of other species, including eagles, ravens, magpies, coyotes and black bears have also been documented as scavenging from wolf kills within the park.[12]

Keystone species

Keystone species are often apex predators, though there may be other species at the same trophic level. The first example to be described (by Robert Paine) was the relationship between the starfish Pisaster ochraceus and the mussel Mytilus californianus,[13]

Keystone species thus do not have to be at the highest trophic level, but may have their own predators. Thus, sea stars are prey for sharks, rays, and sea anemones, while sea otters are prey for orca.[14]

In humans

The status of homo sapiens as an apex predator has a complexity subject to various analyses for years.[quantify] The highly varied environments that human beings have lived in (and continue to live in) coupled with the similarly highly varied behaviors of human cultures towards animals make generalizations particularly difficult; though as omnivores that consume more plant matter than meat, humans have the organized ability to drive other species into extinction as well as threatened status vastly unlike any other animal. The topic has been explored in publications such as the Proceedings of the National Academy of Sciences[15][16] and Scientific American,[17] with disputed results.

Human tool use (especially firearms, but also clubs, spears, nets, and fishing gear) and collaboration with dogs make humans among the deadliest predators on Earth.[citation needed]


See also


  1. ^ Zoologists generally define predation as the non-parasitical or non-bacterial killing and consumption of organisms.[citation needed]


  1. ^ "predator". Online Etymological Dictionary. Archived from the original on 2009-07-01. Retrieved 2010-01-25. 
  2. ^ "apex predator". PBS. Archived from the original on 2009-07-22. Retrieved 2010-01-25. 
  3. ^ Essington, Timothy E.; Beaudreau, Anne H.; Wiedenmann, John (December 2005). "Fishing through marine food webs" (PDF). Proceedings of the National Academy of Sciences. 103 (9): 3171–3175. doi:10.1073/pnas.0510964103. PMC 1413903Freely accessible. PMID 16481614. Archived (PDF) from the original on 2015-09-24. Retrieved 2010-01-25. 
  4. ^ Lepak, Jesse M.; Kraft, Clifford E., Weidel, Brian C. (March 2006). "Rapid food web recovery in response to removal of an introduced apex predator" Archived September 11, 2008, at the Wayback Machine. (PDF). Canadian Journal of Fisheries and Aquatic Sciences 63 (3): 569–575. ISSN 0706-652X. Retrieved 2010-01-25.
  5. ^ Croll, D. A.; Maron, J. L.; et al. (March 2005). "Introduced predators transform subarctic islands from grassland to tundra". Science. 307 (5717): 1959–1961. doi:10.1126/science.1108485. PMID 15790855. Archived from the original on 2009-10-28. Retrieved 2010-01-25. 
  6. ^ Egan, Logan Zane; Téllez, Jesús Javier (June 2005). "Effects of preferential primary consumer fishing on lower trophic level herbivores in the Line Islands" (PDF). Stanford at Sea. Stanford University. Archived (PDF) from the original on 2010-07-12. Retrieved 2010-01-25. 
  7. ^ Pace, M. L.; Cole, J. J.; et al. (December 1999). "Trophic cascades revealed in diverse ecosystems". Trends in Ecology and Evolution. 14 (12): 483–488. doi:10.1016/S0169-5347(99)01723-1. PMID 10542455. 
  8. ^ Bystroff, Chris, "The wolves of Yellowstone" Archived 2011-07-20 at the Wayback Machine. (2006-04-17), p. 2. Retrieved 2010-01-25.
  9. ^ Levy, Sharon (November 2002). "Top Dogs". Archived from the original on 2009-06-06. Retrieved 2010-01-25. 
  10. ^ a b Wilmers, Christopher C. (2004). "The gray wolf – scavenger complex in Yellowstone National Park" (PDF). Archived (PDF) from the original on 2010-07-12. Retrieved 2010-01-25. 
  11. ^ Robbins, Jim (May–June 1998). "Weaving a new web: wolves change an ecosystem". Smithsonian Zoogoer. Smithsonian Institution. 27 (3). Archived from the original on 10 February 2010. Retrieved 2010-01-25. 
  12. ^ Wilmers, Christopher C.; Getz, Wayne M. (April 2005). "Gray wolves as climate change buffers in Yellowstone". PLoS Biology 3 (4): e92. doi10.1371/journal.pbio.0030092. Retrieved 2010-01-25.
  13. ^ Davic, Robert D. (2003). "Linking keystone species and functional groups: a new operational definition of the keystone species concept" Archived 2007-09-28 at the Wayback Machine.. Conservation Ecology 7 (1): r11. Retrieved 2010-01-25.
  14. ^ Estes, J.A.; Tinker, M.T.; Williams, T.M.; Doak, D.F. (1998-10-16). "Killer whale predation on sea otters linking oceanic and nearshore ecosystems". Science. 282 (5388): 473–476. Bibcode:1998Sci...282..473E. doi:10.1126/science.282.5388.473. PMID 9774274. 
  15. ^ Eating up the world’s food web and the human trophic level Archived 2017-04-06 at the Wayback Machine.
  16. ^ Humans are apex predators Archived 2014-12-20 at the Wayback Machine.
  17. ^ Are Humans Apex Predators or Genome Conservers? Archived 2016-01-11 at the Wayback Machine.
  18. ^ "Saltwater Crocodile." Archived 2013-09-06 at the Wayback Machine. National Geographic. Retrieved 2010-01-25.
  19. ^ Whiting, Frances. "Terri fights to halt croc eggs harvest." Archived 2010-10-28 at the Wayback Machine. Australia Zoo. 2007-06-11. Retrieved 2010-01-25.
  20. ^ "Orcinus orca – Orca (Killer Whale)". Marinebio.org. Archived from the original on 2012-01-19. Retrieved 2012-03-04. 
Retrieved from "https://en.wikipedia.org/w/index.php?title=Apex_predator&oldid=826935663"
This content was retrieved from Wikipedia : http://en.wikipedia.org/wiki/Apex_predator
This page is based on the copyrighted Wikipedia article "Apex predator"; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA