Tb. Mihuc et al., SPECIES-ENVIRONMENT RELATIONSHIPS AMONG FILTER-FEEDING CADDISFLIES (TRICHOPTERA, HYDROPSYCHIDAE) IN ROCKY-MOUNTAIN STREAMS, The Great Basin naturalist, 56(4), 1996, pp. 287-293
Species-environment relationships were determined for filter-feeding m
acroinvertebrates from 55 Rocky Mountain stream sites to establish spe
cies distribution patterns. Species abundance and 20 environmental var
iables were measured at each site with species-environment relationshi
ps determined using canonical correspondence analysis and stepwise mul
tiple regression. Results suggest that the distribution of several tax
a was strongly related to upstream-downstream environmental gradients.
Arctopsyche grandis abundance increased with stream size (width and d
epth) and decreased with increasing turbulence (Reynolds number). Brac
hycentrus abundance also increased with stream size (depth). Hydropsyc
he abundance increased with increasing baseflow. Parapsyche elsis abun
dance demonstrated negative correlation with depth, Froude number, and
conductivity. Taxa followed previously reported patterns, partitionin
g habitat according to stream size. Arctopsyche grandis, Brachycentrus
, and Hydropsyche were found in larger (3rd- to Gth-order) streams, wh
ile Parapsyche elsis was observed in small headwater (1st- and 2nd-ord
er) streams. Other filter-feeding taxa such as Simulium, Pisidium, and
ostracods exhibited little or no apparent habitat partitioning among
stream sites.