Most members of Deuteromycetes play a crucial ecological role primarily as:
While some members of Deuteromycetes are indeed saprophytes or parasites (causing diseases like early blight of potato), the NCERT text emphasizes their broader ecological importance. It states that a large majority of them function as vital 'decomposers of litter'. By breaking down fallen leaves, dead wood, and organic debris, they significantly help in essential mineral cycling within terrestrial ecosystems.
Ref: NCERT Class 11 Biology > Chapter 2: Biological Classification > 2.3 Kingdom Fungi