Diversity - Biodiversity Under Threat

Biodiversity refers to the variety of life forms found in a particular region, including the diversity of species, genetic variations within species, and the variety of ecosystems.

Habitat Loss and Fragmentation: This is the primary threat to biodiversity. When large habitats are broken into smaller fragments due to human activities like urbanization or agriculture, species requiring large territories (like mammals and birds) are adversely affected.

Invasive Alien Species: When non-native species are introduced (intentionally or accidentally) into a new habitat, they may become invasive and cause the decline or extinction of indigenous species (e.g., Water Hyacinth in Indian water bodies).

Over-exploitation: Humans depend on nature for food and shelter, but when 'need' turns to 'greed', it leads to over-exploitation. Many species have become extinct in the last 500 years due to over-hunting (e.g., Steller's sea cow, Passenger pigeon).

Co-extinctions: When a species becomes extinct, the plant and animal species associated with it in an obligatory way also become extinct. For example, when a host fish species becomes extinct, its unique assemblage of parasites also meets the same fate.

Climate Change: Rapid changes in global temperatures caused by increased concentrations of greenhouse gases like $CO_2$ and $CH_4$ threaten the survival of species that cannot adapt or migrate quickly enough.

The IUCN (International Union for Conservation of Nature) maintains the 'Red List', which categorizes species based on their risk of extinction: Extinct, Extinct in the Wild, Critically Endangered, Endangered, and Vulnerable.

Conservation Strategies: These are divided into In-situ conservation (protecting species in their natural habitat, e.g., National Parks, Biosphere Reserves) and Ex-situ conservation (protecting species outside their natural habitat, e.g., Zoological Parks, Seed Banks).