What role do decomposers play in primary and secondary ecological succession

They break down dead organisms and keep them from piling up and just being scattered around. They can also turn the dead organisms into fertilizer for other plants to consume.

The role that they play is they break down dead plants and animals and waste (poop). This allows for plants to get nutrients in the means of fertilizer from what the decomposes break down. It also prevents from dead plants and animals piling up.