What is the role of a pioneer species in primary succession? to destroy parasites to create shade to provide fruit to create the soil

The pioneer species grow on the surfaces, where no organsim has grown previously. This includes rocks, volcanoes, mountains etc. This leads to onset of the biotic conditions on that surface and development of ecological system. They utilize those abiotic conditions to normalize the conditions for growth of other species.

In a primary succession, the pioneer species are algae, fungi, lichen, etc. The pioneer specie also include the abiotic factors such as the water, wind, climate, etc. Primary successions begins on rock formations and other places even with no soil or other organisms.