The trophic basis of reference and post-fire stream food webs 10 years after wildfire in Yellowstone National Park

Wildfire disturbance can alter stream ecosystems in numerous ways including loss of riparian litter inputs, altered flow regimes, shifts in resource allocations, and changes in biotic community structure. While some information exists on long-term recovery of streams following wildfire, patterns in trophic dynamics are poorly understood. This study involved comparison of trophic pathways in reference and post-fire streams in Yellowstone National Park (YNP) in 1998, ten years after wildfire. 2^nd and 3^rd order post-fire catchments in Cache Creek, YNP showed an increase in autochthonous grazing pathways compared to reference streams. The shift from detrital to grazing pathways, however, was less pronounced in 1998 (10-yrs post-fire) than it was in 1990 (2-yrs post-fire). Post-fire stream energy pathways showed an initial shift to autochthonous resources followed by recovery toward pre-fire allochthonous pathways over the first post-fire decade. Increasing energy derived from allochthonous resource pathways is expected to continue until it reaches pre-fire conditions in Yellowstone streams.