NCERT Notes for UPSC Geography Exam l


NCERT notes on Causes of Biodiversity Loss and other important topics are crucial assets for the IAS exam. These notes will also be useful for other competitive exams like banking PO, SSC, state civil services exams and so on.

This article talks about the causes of biodiversity losses. The article will be very helpful for candidates who are aspiring to preparation for UPSC 2023.

To know more about Biodiversity in general, visit the linked article.

Causes for Loss of Biodiversity

The accelerated rates of species extinctions that the world is facing now are largely due to human activities. There are four major causes

  • Habitat loss and fragmentation
  • Over-exploitation
  • Alien species invasions
  • Co-extinctions

Aspirants must check the Importance of Biodiversity on the page linked here.

Habitat loss and fragmentation

  • Habitat loss and fragmentation is the most important cause of driving animals and plants to extinction.
  • The most intense examples of habitat loss come from tropical rainforests.
  • The Amazon rain forests protecting probably millions of species are being cut and cleared for agricultural purposes or for conversion to grasslands for raising beef cattle.
  • In addition to the total loss, the degradation of several habitats by pollution also threatens the existence of many species.
  • When large habitats are broken up into small fragments due to anthropogenic activities, mammals and birds necessitating large territories and certain animals with migratory habits are severely affected, leading to population regressions.

Candidates can check the given links to prepare comprehensively on various topics-


  • Humans have always depended on nature for food and shelter, etc.
  • The population explosion is the major reason for the over-exploitation of available resources.
  • Many species extinctions in the last 500 years such as Steller’s sea cow, passenger pigeon were due to overexploitation by humans.
  • Currently, several marine fish populations around the world are over-harvested, threatening the sustained existence of certain commercially important species. Read the detailed information on National Fisheries Policy 2020 on the linked page.

Aspirants can check the IUCN Red List of Endangered Species for information on species threatened with extinction.

Alien species invasions

  • When alien species are introduced by chance or deliberately, some of them turn aggressive and cause the extinction of local species.
  • The Nile perch introduced into Lake Victoria in East Africa led ultimately to the extinction of a naturally unique group of more than 200 species of cichlid fish in the lake. Read in detail about Fishermen in India on the given link.
  • The illegal introduction of the African catfish, Clarias gariepinus for aquaculture purposes is posing a danger to the local catfishes. Further information on Alien Invasive Species is available on the linked page.

To know more about the biodiversity hotspots in India, candidates can refer to the linked article.


  • When a species becomes extinct, the flora and fauna related to it in an essential way also become extinct.
  • When a host fish species becomes extinct, its unique assemblage of parasites also meets the same destiny.

Causes of biodiversity loss (UPSC Notes):- Download PDF Here

Candidates must read about the Conservation of Biodiversity on the given link.

Aspirants of Civil Services Exams can check out the relevant links related to Biodiversity that will be helpful in their exam preparation-

For more UPSC-related preparation materials and articles, visit the links given in the table below. You can also find out more about the UPSC Syllabus by visiting the linked article.

Related Links

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