TEMPORAL VARIATION IN MICROHABITAT USE AND SPATIAL RELATIONS IN THE BENTHIC FISH COMMUNITY OF A STREAM

Patterns of microhabitat use and overlap among five benthic fish speci es in a fifth-order stream were investigated during two same-year samp ling periods characterized by high vs. low discharges. Microhabitat us e patterns for Cottus carolinae (banded sculpin), Etheostoma bellum (o rangefin darter), E. blennioides (greenside darter), E. maculatum (spo tted darter) and E. zonale (banded darter) were similar to literature reports. During high flow most segregation occurred along a depth/subs trate roughness gradient while in low flows segregation was more commo n along a velocity gradient. Less segregation in microhabitat use duri ng low flow was probably due to differences in spatial overlap. Five s pecies pairs exhibited high spatial overlap (>0.60) during high flow w hereas one pair exhibited this pattern during low flow. Overall, there was a decrease in spatial breadth (13.91 vs. 10.57) and overlap (0.52 vs. 0.36) of microhabitat use during the low flow period.