World Library  
Flag as Inappropriate
Email this Article

Apex predator

Article Id: WHEBN0001872736
Reproduction Date:

Title: Apex predator  
Author: World Heritage Encyclopedia
Language: English
Subject: Food web, Megafauna, Paleontology/Natural world articles, Predation, Intraguild predation
Collection: Predation
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Apex predator

The lion is Africa's apex predator.

An apex predator, also known as an alpha predator, super predator, top predator or top-level predator, is a predator residing at the top of a food chain on which no other creatures predate.[n 1][1][2] Apex predators are usually defined in terms of trophic dynamics, meaning that apex-predator species occupy the highest trophic level or levels and play a crucial role in maintaining the health of their ecosystems. One study of marine food webs defined apex predators as greater than trophic level 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, crocodilians, hyenas, wolves or big cats preying mostly upon large herbivores. Apex predators do not need to be hypercarnivores.

Contents

  • Ecological role 1
  • Gallery 2
  • See also 3
  • Notes 4
  • References 5

Ecological role

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 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, a concept first described by zoologist Robert Paine to explain the relationship between the starfish species Pisaster ochraceus and mussel species Mytilus californianus, are apex predators within functional groups.[13]

Gallery

See also

Notes

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

References

  1. ^ "predator". Online Etymological Dictionary. Retrieved 2010-01-25. 
  2. ^ "apex predator". PBS. 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.  
  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" (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".  
  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.  
  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.  
  8. ^ Bystroff, Chris, "The wolves of Yellowstone" (2006-04-17), p. 2. Retrieved 2010-01-25.
  9. ^ Levy, Sharon (November 2002). "Top Dogs". Retrieved 2010-01-25. 
  10. ^ a b Wilmers, Christopher C. (2004). "The gray wolf – scavenger complex in Yellowstone National Park" (PDF). Retrieved 2010-01-25. 
  11. ^ Robbins, Jim (May–June 1998). "Weaving a new web: wolves change an ecosystem". Smithsonian Zoogoer ( 
  12. ^ Wilmers, Christopher C.; Getz, Wayne M. (April 2005). "Gray wolves as climate change buffers in Yellowstone". PLoS Biology 3 (4): e92. doi: 10.1371/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". Conservation Ecology 7 (1): r11. Retrieved 2010-01-25.
  14. ^ "Saltwater Crocodile." National Geographic. Retrieved 2010-01-25.
  15. ^ Whiting, Frances. "Terri fights to halt croc eggs harvest." Australia Zoo. 2007-06-11. Retrieved 2010-01-25.
  16. ^ – Orca (Killer Whale)"Orcinus orca". Marinebio.org. Retrieved 2012-03-04. 
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.