Some species of plants which existed when Australia was part of Gondwanaland still live here - and it is the only place in the world you find them.
If the mists stop rolling in off the ocean and hitting the highlands then the biodiversity of the Daintree will diminish because the forest will change.
The upland species will disappear from the mountains which were part an ancient reef system before tectonic movement pushed them up leaving only the Great Barrier Reef.
These ancient mountains have been worn down by the millennia.
The possums, frogs and insects which are unable to live in warmer zones would move up the mountain if it went any higher, but it doesn't.
(I'm paraphrasing information from a technical tour of the Daintree hosted by James Cook University's Professor of Geography Steve Turton.)