These are the biologically richest but most threatened areas on the planet. Each hotspot contains at least 1,500 plant species found nowhere else on the planet and has lost at least 70 percent of its original primary vegetation. Taken together, remaining natural habitats within the 35 biodiversity hotspots cover only 2.3 percent of the Earth’s land surface, yet they support nearly 60 percent of the world’s plant, bird, mammal, reptile and amphibian species.