during primary succession lichen and mosses are the first species to arrive to the area, why are the lichen and mosses not needed in an area that is experiencing secondary succession?

Lichens are typically the first organisms to colonize bare rock. They are therefore the pioneer species in primary succession. Many organisms require soil before they can colonize an area. ... Mosses can then colonize the thin soil; as mosses die, the soil thickens more allowing other hardy species to colonize.

Explanation:

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.