Britannica Sources used in this answer

How does biodiversity loss differ from species extinction?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

biodiversity loss A sea turtle swimming over a bleached coral seascape near Heron Island, February 2016.

While biodiversity loss is often associated with species extinction, the two terms represent distinct ecological concepts.

Species extinction refers specifically to the permanent disappearance of a single species from the biosphere. It is the final outcome of a species' inability to survive environmental or ecological pressures.12

Biodiversity loss is a broader term that encompasses the decline in the variety of life at multiple levels, including:13

Genetic diversity: The loss of genetic variation within a species, which can increase inbreeding and reduce a species' ability to adapt.13
Population declines: The reduction in the number of individuals within a species, which can disrupt social structures and ecosystem functions even if the species itself does not go extinct.13
Community and ecosystem variety: The loss of the different biological communities and ecological assemblages within a geographic area.14

Essentially, while extinction is the total loss of a species, biodiversity loss includes the "subtle phenomena" that threaten ecosystem health long before a species is fully eliminated. Even if a species persists elsewhere, the loss of its local populations can degrade ecosystem services and reduce the overall complexity and resilience of the environment.135