Lichen is often the first organism to appear in an area that has been stripped of all life forms due to a large disturbance. what are organisms of these type called?

Lichen is often the first organism to appear in an area that has been stripped of all life forms due to a large disturbance. Lichens are hardy organisms that can survive extreme conditions of the environment that are not favourable to other organisms. Lichens tend to be the pioneer species in the primary succession of a newly created habitat. They help shape the barren environment such that other life forms may develop over there.