Final answer:
An area with at least 1500 endemic species of plants is called a biodiversity hotspot, a term introduced by Norman Myers in 1988. There are currently 34 recognized biodiversity hotspots that cover just 2.3% of the Earth but contain significant portions of the world's species.
Step-by-step explanation:
An area with at least 1500 endemic species of plants is known as a biodiversity hotspot. This concept was introduced by British environmentalist Norman Myers in 1988 to highlight regions with exceptional levels of plant endemism and significant threat from human activities.
The Cape Floristic Region in South Africa and the rainforests of the Amazon are examples of biodiversity hotspots. These areas often also have high numbers of endemic animal species and are conservation priorities because they have a large percentage of the world's flora and fauna that cannot be found anywhere else.
Conservation International has identified 34 biodiversity hotspots worldwide. Although they cover a mere 2.3 percent of the Earth's land surface, these hotspots are home to 42 percent of terrestrial vertebrate species and 50 percent of the world's plants. The designation of an area as a biodiversity hotspot helps to focus conservation efforts to protect a large number of species at risk.