Abiotic autumnal organic matter deposition and grazing disturbance effects biofilm succession

Community assembly of stream epilithic biofilms is frequently described by successional patterns with disturbances being an important factor in defining the successional trajectory. Autumn leaf senescence is an annual resource subsidy to streams, but the physical effects (e.g., shading and reduced flow) of leaves settling on epilithic biofilms has not been investigated. We used an in situ experimental manipulation to investigate abiotic effects of leaf deposition (light and flow) and biotic (snail grazing) disturbances governing community assembly of epilithic biofilms.