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<br />~ <br /> <br />.~ <br /> <br />~ <br />" <br />~ <br /> <br />~ <br /> <br />9 <br /> <br />DISCUSSION <br /> <br />Macroinvertebrates <br /> <br />Species composition, abundance and diversity in the invertebrate <br /> <br />community showed some significant trends for the March sample. The <br />relatively high abundance and diversity of invertebrates immediately <br />below Flaming Gorge Dam can be attributed largely to the presence of <br /> <br />crustaceans entrained from Flaming Gorge Reservoir. Abundance and <br />diversity decreased steadily downstream as the influence of the <br /> <br />reservoir fauna decreased. Of primary importance- however~ was the <br />increase in species diversity and the actual species composition of <br /> <br />the Jensen station, located below the mouth of the Yampa River. Spe- <br />cies diversity more than doubled from the previous station (Table 2), <br /> <br />and a number of genera of Ephemeroptera, Plecoptera, and Trichoptera <br />were observed for the first time. This increase in abundance and <br /> <br />diversity is likely an indication of the moderating influence of the <br />Yampa River. <br />These preliminary results are roughly comparable to those obtained <br />by Pearson (1967) in both abundance and taxa. However, a more complete <br /> <br />taxa list is expected as sampling continues and more micro niches are <br />sampled in a qualitative, as well as quantitative, manner. <br /> <br />Fishes <br /> <br />Of major importance to this study is the increase in species <br />composition noted at Echo Park and the shift towards warm water species <br />