Plants act as important indicators of the health of our natural environment. Assessments on plants are carried out to determine their local, national and global conservation status. This indicator is based on an evaluation of whether the results of the most recent assessment (made in 2018) determine whether the species are endangered, or are projected, inferred or suspected to be becoming endangered. Factors that indicate whether a species is considered endangered are scored under set criteria and guided under the International Union for Conservation of Nature's 'red list' criteria of critically endangered and vulnerable species.

This is a new indicator developed from a full assessment undertaken in 2018. It tracks the number of threatened plants species requiring full legal protection. The indicator will see a decrease in figures when species become more widespread and increase should more species become endangered.