Gw. Minshall et al., BENTHIC COMMUNITY STRUCTURE IN 2 ADJACENT STREAMS IN YELLOWSTONE-NATIONAL-PARK 5 YEARS AFTER THE 1988 WILDFIRES, The Great Basin naturalist, 55(3), 1995, pp. 193-200
Physical characteristics, benthic macroinvertebrates, and periphyton a
ssemblages in two adjacent headwater streams in Yellowstone National P
ark were evaluated five years after the 1988 wildfires. The catchment
of one stream was burned by wildfire (burned stream) while the other c
atchment was unburned (unburned stream). Physical measures revealed ch
annel alteration in the burned stream relative to the unburned stream.
Periphyton biomass was lower in the burned than the unburned stream (
29.2 vs. 50.5 g/m(3) AFDM, respectively), further demonstrating the un
stable physical conditions of that system. Kendall's coefficient of co
ncordance (an index of similarity) between diatom assemblages was 0.22
, indicating distinct assemblage composition between streams. Navicula
permitis Hust. was the most abundant diatom in the burned stream whil
e Hannaea arcus (Ehr.) Patr. was dominant in the unburned stream. Macr
oinvertebrate taxa richness, density, and biomass were all greater in
the unburned stream, although Chironomidae was the most abundant taxon
in both streams. Results suggest the removal of terrestrial/riparian
vegetation by wildfire can directly influence stream benthic assemblag
es by altering the inherent disturbance regime of the physical habitat
templet.