I am a desert known for its unique, fog-dependent ecosystem, and I am not located in Africa, Asia, or Australia. My terrain includes vast sand dunes, but I'm more famous for a coastal stretch that supports diverse wildlife.

1. My name is derived from the word 'bare'.
2. I am found on the western edge of a continent.
3. I am one of the oldest deserts in the world.
4. The unique Welwitschia mirabilis plant is native to me.