Laserfiche WebLink
INTRODUCTION <br />In the early sixties, Flaming Gorge Dam was built across the Green River in <br />northeastern Utah. This, in addition to dikes constructed along the rivers course and the <br />introduction of non-native fishes, has altered natural conditions such that many native <br />fishes have reached the brink of extinction. Many are now on the list of endangered <br />species. Grabowski and Hiebert (1989) studied the Green River and noted the <br />importance of backwaters as nursery habitats to introduced and native fishes. They found <br />the most important food items to be benthic macroinvertebrates, namely chironomid <br />larvae. Grabowski and Hiebert's investigation of benthic invertebrates was confined to <br />two habitats, the main channel and river backwaters. We feel that along with the river <br />channel and backwaters, two habitats not previously quantified could be of importance <br />to fishes in the Green and merit study. These are the seasonally inundated wetland and <br />ephemeral side channel. For the Green River, no information exists about shifts in <br />densities or community structure of benthic macroinvertebrates for these habitat types. <br />Benthic invertebrates of large rivers worldwide are poorly known. Difficulty in <br />sampling, the amount of time needed to process samples and the identification of <br />specimens after collection make study difficult and most often expensive. Added to this <br />is the fact that, obviously, rivers are not homogenous entities. Benthic invertebrate <br />communities in riffles, pools, and backwaters are among many that interact to make the <br />large river as a whole very complex. This, perhaps, is why benthic macroinvertebrates <br />in large rivers have been largely ignored. However, work has been done on lotic <br />systems with some on large rivers. Some studies randomly sample an entire crossection <br />2