Can lichen symbiosis be broken?

Symbiosis is a form of relationship between two living organisms in which one or both of them benefit from one another. Lichens are a symbiosis of fungus and green algae. If the symbiosis is broken, then the lichen dies. But the symbiosis of lichen is very difficult to break. It grows slowly, does not need soil, is able to survive in very cold and very hot seasons. One experiment showed that a lichen can live without air in a vacuum for several weeks, and this indicates a good survival of these organisms.