Saving rare plants, scientists stress, means saving the rare places, like Tater Hill, where they live. It's the habitat, stupid. Plants on the endangered species are usually there because their habitat has been destroyed. The destruction comes in many forms. Virginia spiraea, for instance, grows along flood-scoured riverbanks.
Flooding seems essential to the plant's survival because the scouring eliminates competition.
Build a dam or a stabilize the stream bank with rocks, the floods stop and the plant disappears. Rock gnome lichen, on the other hand, grow on humid , exposed, high - elevation outcroppings where it is constantly bathed in fog. As with the spruce and fir forest that surrounds it, the lichen is being done in by acid deposition and ozone. Only seven of the 32 remaining populations cover more tha n 2.4 square yards. A lot of them we don't know enough to know if we should list them.