<u>Vulnerable</u> is the status used to refer the conservation status of a species if it declines by 45% over a period of 10 years according to IUCN’s Red List.
Explanation:
“The International Union for Conservation of Nature (IUCN) Red List of threatened species” provides comprehensive information about the conservation status of various organisms like animals, plants, and fungi present globally.
The Red List directly indicates the health or status of biodiversity in an ecological system or the world’s biodiversity.
The Red List classifies threatened species into – “Data deficient, least concern, near threatened, vulnerable, endangered, critically endangered, extinct in the wild, and extinct”.
The criteria followed by IUCN for classification are – “population reduction rate, the geographic extent of occurrence, population size, population restriction”.
Accordingly, if the number of species or population of species reduces or declines from 30% to 50 % or ≥50% then that species is classified as a vulnerable species. Vulnerable species are at high risk and protective measures have to be taken to protect them to prevent from becoming endangered species.
