Overexploitation, also called overharvesting, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource. The term applies to natural resources such as: wild medicinal plants, grazing pastures, game animals, fish stocks, forests, and water aquifers. In ecology, overexploitation describes one of the five main activities threatening global biodiversity. Ecologists use the term to describe populations that are harvested at an unsustainable rate, given their natural rates of mortality and capacities for reproduction. This can result in extinction at the population level and even extinction of whole species. In conservation biology, the term is usually used in the context of human economic activity that involves the taking of biological resources, or organisms, in larger numbers than their populations can withstand. The term is also used and defined somewhat differently in fisheries, hydrology and natural resource management. Read all..


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In more recent times, overexploitation has resulted in the gradual emergence of the concepts of sustainability and sustainable development, which has built on other concepts, such as sustainable yield,[8] eco-development,[9][10] and deep ecology.[11][12]



Tragedy of the commons


In 1968, the journal Science published an article by Garrett Hardin entitled "The Tragedy of the Commons".[13] It was based on a parable that William Forster Lloyd published in 1833 to explain how individuals innocently acting in their own self interest can overexploit, and destroy, a resource that they all share.[14][pages needed] Lloyd described a simplified hypothetical situation based on medieval land tenure in Europe. Herders share common land on which they are each entitled to graze their cows. In Hardin's article, it is in each herder's individual interest to graze each new cow that the herder acquires on the common land, even if the carrying capacity of the common is exceeded, which damages the common for all the herders. The self-interested herder receives all of the benefits of having the additional cow, while all the herders share the damage to the common. However, all herders reach the same rational decision to buy additional cows and graze them on the common, which eventually destroys the common. Hardin concludes:



The tragedy of the commons has intellectual roots tracing back to Aristotle, who noted that "what is common to the greatest number has the least care bestowed upon it",[16] as well as to Hobbes and his Leviathan.[17] The opposite situation to a tragedy of the commons is sometimes referred to as a tragedy of the anticommons: a situation in which rational individuals, acting separately, collectively waste a given resource by underutilizing it.



The Atlantic bluefin tuna is currently overexploited. Scientists say 7,500 tons annually is the sustainable limit, yet the fishing industry continue to harvest 60,000 tons.

In wild fisheries, overexploitation or overfishing occurs when a fish stock has been fished down "below the size that, on average, would support the long-term maximum sustainable yield of the fishery".[19] However, overexploitation can be sustainable.[20]




About 25% of world fisheries are now overexploited to the point where their current biomass is less than the level that maximizes their sustainable yield.[22] These depleted fisheries can often recover if fishing pressure is reduced until the stock biomass returns to the optimal biomass. At this point, harvesting can be resumed near the maximum sustainable yield.[23]

The tragedy of the commons can be avoided within the context of fisheries if fishing effort and practices are regulated appropriately by fisheries management. One effective approach may be assigning some measure of ownership in the form of individual transferable quotas (ITQs) to fishermen. In 2008, a large scale study of fisheries that used ITQs, and ones that did not, provided strong evidence that ITQs help prevent collapses and restore fisheries that appear to be in decline.[24][25]

Water resources

Overexploitation of groundwater from an aquifer can result in a peak water curve.[26]

Water resources, such as lakes and aquifers, are usually renewable resources which naturally recharge (the term fossil water is sometimes used to describe aquifers which do not recharge). Overexploitation occurs if a water resource, such as the Ogallala Aquifer, is mined or extracted at a rate that exceeds the recharge rate, that is, at a rate that exceeds the practical sustained yield. Recharge usually comes from area streams, rivers and lakes. An aquifer which has been overexploited is said to be overdrafted or depleted. Forests enhance the recharge of aquifers in some locales, although generally forests are a major source of aquifer depletion.[27][28] Depleted aquifers can become polluted with contaminants such as nitrates, or permanently damaged through subsidence or through saline intrusion from the ocean.

This turns much of the world's underground water and lakes into finite resources with peak usage debates similar to oil.[29][30] These debates usually centre around agriculture and suburban water usage but generation of electricity from nuclear energy or coal and tar sands mining is also water resource intensive.[31] A modified Hubbert curve applies to any resource that can be harvested faster than it can be replaced.[26] Though Hubbert's original analysis did not apply to renewable resources, their overexploitation can result in a Hubbert-like peak. This has led to the concept of peak water.

Forest resources

Clear cutting of old growth forests in Canada.




Overexploitation is one of the main threats to global biodiversity.[2] Other threats include pollution, introduced and invasive species, habitat fragmentation, habitat destruction,[2] uncontrolled hybridization,[34] climate change,[35] ocean acidification[36] and the driver behind many of these, human overpopulation.[37]

One of the key health issues associated with biodiversity is drug discovery and the availability of medicinal resources.[38] A significant proportion of drugs are natural products derived, directly or indirectly, from biological sources. Marine ecosystems are of particular interest in this regard.[39] However, unregulated and inappropriate bioprospecting could potentially lead to overexploitation, ecosystem degradation and loss of biodiversity.[40][41][42]

Endangered species

It is not just humans that overexploit resources. Overgrazing can be caused by native fauna, as shown in the upper right. However, past human overexploitation (leading to elimination of some predators) may be behind the situation.



The Carolina parakeet was hunted to extinction.

Today, overexploitation and misuse of natural resources is an ever-present threat for species richness. This is more prevalent when looking at island ecology and the species that inhabit them, as islands can be viewed as the world in miniature. Island endemic populations are more prone to extinction from overexploitation, as they often exist at low densities with reduced reproductive rates.[47] A good example of this are island snails, such as the Hawaiian Achatinella and the French Polynesian Partula. Achatinelline snails have 15 species listed as extinct and 24 critically endangered[48] while 60 species of partulidae are considered extinct with 14 listed as critically endangered.[49] The WCMC have attributed over-collecting and very low lifetime fecundity for the extreme vulnerability exhibited among these species.[50]


Where there is substantial human migration, civil unrest, or war, controls may no longer exist. With civil unrest, for example in the Congo and Rwanda, firearms have become common and the breakdown of food distribution networks in such countries leaves the resources of the natural environment vulnerable.[52] Animals are even killed as target practice, or simply to spite the government. Populations of large primates, such as gorillas and chimpanzees, ungulates and other mammals, may be reduced by 80% or more by hunting, and certain species may be eliminated altogether.[53] This decline has been called the bushmeat crisis.

Overall, 50 bird species that have become extinct since 1500 (approximately 40% of the total) have been subject to overexploitation,[54] including:


Other species affected by overexploitation include:

  • Insect collectors: butterflies
  • Shell collectors: Marine molluscs
  • Aquarium hobbyists: tropical fish
  • Chinese medicine: bears, tigers, rhinos, seahorses, Asian black bear and saiga antelope[55]
  • Novelty pets: snakes, parrots, primates and big cats

Cascade effects






See also


  2. 1 2 3 4 Wilcove, D. S.; Rothstein, D.; Dubow, J.; Phillips, A.; Losos, E. (1998). "Quantifying threats to imperiled species in the United States" (PDF). BioScience. 48 (8): 607–615. doi:10.2307/1313420. JSTOR 1313420.
  3. Oxford. (1996). Oxford Dictionary of Biology. Oxford University Press.
  7. Paul S. Martin
  9. Lubchenco, J. (1991). "The Sustainable Biosphere Initiative: An ecological research agenda". Ecology. 72 (2): 371–412. doi:10.2307/2937183. JSTOR 2937183. S2CID 53389188.
  10. Lee, K. N. (2001). "Sustainability, concept and practice of". In Levin, S. A. (ed.). Encyclopedia of Biodiversity. 5. San Diego, CA: Academic Press. pp. 553–568. ISBN 978-0-12-226864-9.
  11. Naess, A. (1986). "Intrinsic value: Will the defenders of nature please rise?". In Soulé, M. E. (ed.). Conservation Biology: The Science of Scarcity and Diversity. Sunderland, MA: Sinauer Associates. pp. 153–181. ISBN 978-0-87893-794-3.
  12. Sessions, G., ed. (1995). Deep Ecology for the 21st Century: Readings on the Philosophy and Practice of the New Environmentalism. Boston: Shambala Books. ISBN 978-1-57062-049-2.
  13. 1 2 Hardin, Garrett (1968). "The Tragedy of the Commons". Science. 162 (3859): 1243–1248. Bibcode:1968Sci...162.1243H. doi:10.1126/science.162.3859.1243. PMID 5699198. Also available at http://www.garretthardinsociety.org/articles/art_tragedy_of_the_commons.html.
  14. Lloyd, William Forster (1833). Two Lectures on the Checks to Population. Oxford University. Retrieved 2016-03-13.
  15. Bowles, Samuel (2004). Microeconomics: Behavior, Institutions, and Evolution. Princeton University Press. pp. 27–29. ISBN 978-0-691-09163-1.
  16. Ostrom, E. (1992). "The rudiments of a theory of the origins, survival, and performance of common-property institutions". In Bromley, D. W. (ed.). Making the Commons Work: Theory, Practice and Policy. San Francisco: ICS Press.
  19. "NOAA fisheries glossary". repository.library.noaa.gov. Retrieved 2021-06-13.
  20. [Source?]
  24. New Scientist: Guaranteed fish quotas halt commercial free-for-all
  31. http://www.epa.gov/cleanrgy/water_resource.htm%5B%5D
  32. http://atlas.aaas.org/pdf/63-66.pdf Archived 2011-07-24 at the Wayback Machine Forest Products
  33. "Destruction of Renewable Resources".
  36. Mora, C.; et al. (2013). "Biotic and Human Vulnerability to Projected Changes in Ocean Biogeochemistry over the 21st Century". PLOS Biology. 11 (10): e1001682. doi:10.1371/journal.pbio.1001682. PMC 3797030. PMID 24143135.
  37. Dumont, E. (2012). "Estimated impact of global population growth on future wilderness extent". Earth System Dynamics Discussions. 3 (1): 433–452. Bibcode:2012ESDD....3..433D. doi:10.5194/esdd-3-433-2012.
  38. (2006) "Molecular Pharming" GMO Compass Retrieved November 5, 2009, From "Archived copy". Archived from the original on 2013-05-03. Retrieved 2010-02-04.CS1 maint: archived copy as title (link)
  42. "COHAB Initiative - on Natural Products and Medicinal Resources". Cohabnet.org. Archived from the original on 2017-10-25. Retrieved 2009-06-21.
  43. Hemley 1994.
  44. Primack, R. B. (2002). Essentials of Conservation Biology (3rd ed.). Sunderland: Sinauer Associates. ISBN 978-0-87893-719-6.
  45. Redford 1992, Fitzgibon et al. 1995, Cuarón 2001.
  46. Frankham, R.; Ballou, J. D.; Briscoe, D. A. (2002). Introduction to Conservation Genetics. New York: Cambridge University Press. ISBN 978-0-521-63014-6.
  48. "IUCN Red List". 2003b.
  49. "IUCN Red List". 2003c. Retrieved 9 December 2003.
  54. The LUCN Red List of Threatened Species (2009).
  55. Collins, Nick (2012-04-12). "Chinese medicines contain traces of endangered animals". Telegraph.
  58. Krebs, C. J. (2001). Ecology (5th ed.). San Francisco: Benjamin Cummings. ISBN 978-0-321-04289-7.

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