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• fish Creek <br /> A total of 30 taxa were collected from the stations on Fish Creek, with <br /> 50% found at both sites (Table 2). As with Middle Creek, aquatic insects <br /> dominated the benthos. Riffle invertebrate density was high at both sta- <br />1 tions, although pool invertebrate density was lower at Station 2. <br /> Riffle invertebrates were again dominated by net spinning caddisflies <br />( (Hydropsyche and Cheumatopsyche) and chironomids (especially Form 1) at both <br />I1 stations. The caddisflies were more abundant at Station 2, whereas chirono- <br /> mids were more abundant at Station 1. Mayflies were well represented at <br />1 both stations, while stoneflies (Plecoptera) were absent. <br /> Chironomidae Form 8 also dominated the pool fauna in Fish Creek, <br /> <br />l although it was much less abundant at Station 2. Limnodrilus exhibited <br /> large numbers at both stations and the elmid beetle Dubiraphia quadrinotata <br />f was abundant in pools at Station 1. <br />I The number of species was also similar at both stations (Table 2). The <br /> addition of a couple of beetles and dipterans accounted for the greater <br />I number of taxa at Station 2. Despite the greater number of taxa at Station <br /> 2, the Species Diversity Index (D) was lower at this station due to the <br /> dominance of a few species (especially Cheumatopsyche). <br /> As discussed for Middle Creek, pool habitat again proved to be less <br />1 diverse than the riffles. Station 2 had fewer taxa, due to fewer dipteran <br /> taxa at that site. D was low in the pools resulting from large densities of <br />1 a few taxa (i. e., Chironomidae Form 8). <br /> Station 2 on Fish Creek was previously sampled in 1975 and 1979. <br /> Comparison of results from all three years is presented in Table 3. Notably, <br /> benthic densities and number of taxa for the July sampling in 1975 and 1979 <br /> are well below those from the present study, (i. e., 307 org/m2 vs. 15228 <br />~ <br />i org/m2). This appears to be related to seasonal fluctuations common in <br /> these streams. The August sampling of the 1975 study did compare favorably <br /> with the present study in both bensity and numbers of taxa. Apparently, the <br /> early July sampling period hits the low period in invertebrate numbers due <br />~ to the effects of spring runoff and adult emergence. The one month recovery <br /> period obviously makes a great difference in both numbers of organisms and <br /> number of taxa that are collected in August. <br />• <br /> -14- <br />