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Chi ono mid species were relatively abundant in the North Fork during <br />• the sampling period. Table $-8 shoxs a phylogenetic listing of taxa <br /> found by station over the three sampling periods. Some 21 taxa xere <br /> identified over the year. More species are undoubtedly present, but <br />because of the time involved in separation and identification of chironomid <br />larvae, only representative samples were identified. These data showed <br />16 taxa present in October, 12 in March, and 10 in July. The number of tar.a <br />decline3 during the yeaz, as for a number of other insect groups and <br />probably was the result of poor environmental conditions related to low flows <br />ir. the river. <br />Similaz tctal numbers of species ~ 45 - 51 ) xere found during <br />the Octobe_•, 1976 and Mazch 1977 periods 4r.~t`there xas a marked decline in <br />species numbers to 3 0 ir. July 1977. All of the plecopterans xere gone <br />• an3 there was many fewer caddisfly and chironomid species Found. Normally <br />it would be expected that fewer species would be found in late summer be- <br />cause o° e:~gence, hoxever the greater number of species in October of the <br />previous year suggests that ether envL^onmental factors are involved. <br />The very low flows in the study area during the 1977 water year probably <br />negatively irrluenced the number of species found in the river. Of the <br />water duality parameters tested (see previous section) there did not <br />appear ~~.o Se ary consistent water quality factor that would negatively <br />affect the benthic organisms, hoxeve= there was evidence of irfreeuent <br />"dumps" or spills of materials that might reduce species present. <br />• <br />5-'+ <br />