How can lichens survive in habitats so seemingly devoid of nutrients and under harsh physical condition?

Lichens are one of the first organisms to colonise a newly disturbed area and are a part of the first stage in plant succession.
Like mosses lichens have a number of adaptations which allow them to survive seemingly nutrient free habitats.
Lichens, unlike vascular plants can grow with very little nutrients. There are enough nutrients carried in rain water and dust to allow lichens to grow on rock faces etc.