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<br />., - <br />u,) , <br /> <br />Adult fish are present in the mainstem and some of the tributaries year.round. Adult trout and <br />other large species require large. deep pools and glides. The pools are used for resting and <br />cover throughout the range of flows. Glides and the deeper riffles provide feeding areas and <br />living space for less dominant or less competitive fish. Cover provided by boulders. rock <br />ledges, large wood debris and debris dams is also an imponant aspect of adult habitaE. <br /> <br />;o...facroinvenebrates are animals without backbones which can be seen wilh the naked eye. <br />Aquatic macroinvertebrate5 include annelids. crustaceans, flatworms. mollusks, and <br />insects. Aquatic insects play an important ecological role as the link between the sources <br />of primary production. such as algae, riparian vegetation. and other organic material, and <br />fish. Some species are filter feeders. and others are predators (MacDonald et aI, 1991). <br />Some species graze on algae and on terrestrial organic material which falls or is washed <br />into the stream. Deciduous riparian vegetation is an important component of their food <br />base. Alder leaves decompose faster than most other streamside vegetation and are easily <br />colonized by microorganisms that are themselves the food supply for some aquatic insects <br />(peterson and Cummins. 1974). Therefore. alder plays an important role in the primary <br />production of the ecosystem. <br /> <br />Based on systematic sampling done in 1988 and 1989 plus observations in 1991 by the <br />Forest Service. there is currently a wide variety of aquatic insects with a variety of feeding <br />habits and habitat requirements found in the Piedra River. Mayflies. caddisrlies. and <br />stonetlies are the primary food sources for aU the fish species in the Piedra River. The <br />Piedra River is quite productive from an aquatic insect and fisheries viev,rpoint (~1angum. <br />1990). $tonetlies such as the species Pteronarcys califomica and Claasenia sabulosa are <br />used as indicators of good water quality because they are intolerant of accumulations of <br />fine sediment and embedded substrates and of chemical contaminants. Both species are <br />present in the Piedra River. These two species are important in the trout diet because they <br />have twO to three year life cycles and provide a food source during the winter when other <br />insects are not available (Mangum. 1990). Accumulation of fine sedimentS in and on the <br />subsrrate would reduce the abundance of aquatic insectS thus affecting the entire food chain <br />(Meehan. 1991). <br /> <br />Within the context of CRS 37.92-102(3). the above discussion provides the basis for the <br />rinding that there is a natural environment within the proposed Piedra Wilderness that <br />requires instream flow protection. Although there are established water rights in the <br />upper portion of the watershed. these appropiations of water have not signiticantly altered <br />the environment of the Piedra River and its associated ecosystems within the proposed <br />wilderness. <br /> <br />Page 14 <br />