Aquatic Herbivores, Detritivores, and Predators
Not only do many aquatic insects serve as food for fish, they play major roles in nutrient cycling, feeding on primary producers, converting organic matter to higher trophic levels. The aquatic insects listed as sensitive are dependent on a limited range of physical conditions for suitable habitat and their sensitivity to forest management practices is least as great as that of the soil and litter dwelling species.
There are aquatic species adapted to all segments of streams and rivers ranging from small headwater springs and seeps, waterfalls, small streams, to larger, slow-flowing rivers.
Examples of headwaters species include the nymphs of the primitive dragonfly Tanypteryx hageni live in spring-fed bogs or seeps in old-growth or riparian forest (Meyer and Clement, 1978; Clement and Meyer, 1980), while nymphs of the spring stonefly Ostrocerca dimicki live in spring-fed rivulets that lead into small, meandering streams (Young et al., 1989). Several other stoneflies of the genus Soliperla have nymphs that are found only in seeps in the headwaters of small streams (Stark, 1983). These springs and seeps are very sensitive to activities such as the construction of roads, ditches, or rights- of-way that might interfere with their flow. Similarly, other logging or construction activities must be planned so that the thermal regimes or flows of these habitats is not interfered with.
Other aquatic species are dependent on cool clear, flowing rivers with sandy, gravelly, or rocky substrates. Two dobsonflies (Dysmicohermes dijunctus and Orohermes crepusculus) rely on cold, clear, fast-flowing streams with unsilted bottoms (Chandler, 19xx). The mountain midge (Deuterophlebia shasta) is found in only three clear, cool streams in northwesterm California and southwestern Oregon (Courtney, 1989).
Two crustaceans on the U.S. List of Endangered Species (USDI, 1988a, 1988b) have stream habitats within the range of the northern spotted owl. The Shasta crayfish (Pacifastacus fortis) is endemic to several rivers in Shasta County, California, where it is principally threatened by introduction of crayfish from other regions. The Shasta crayfish also relies on the presence of cool, clear water in its stream habitats (Bouchard, 1977; Erman, 1993). The California freshwater shrimp (Syncaris pacifica) dwells in low gradient streams in Marin, Napa, and Sonoma counties, California, where it relies on relatively clear streams with sandy and gravelly bottoms, although some mud, silt, and organic debris is tolerated (Eng, 1981; Serpa, 1991). Suitable stream habitats are almost completely shaded by overarching tree canopies. The habitats of both species are downstream from northern spotted owl habitats and conceivably could be affected by stream siltation or changed flows from any changes in forestry management practices upstream.
A number of caddisflies within the range of the northern spotted owl are considered candidates for listing under protection of the U.S. Endangered Species Act (USDI, 199x), and most of these rely on cool, clear streams with unsilted bottom conditions.
Class Crustacea (crustaceans) (Malacostraca)
Order Decapoda (shrimp and crayfish)
Family Astacidae
Pacifastacus fortis (Faxon), Shasta Crayfish
Syncaris pacifica (Holmes), California freshwater shrimp
Class Insecta (insects)
Order Ephemeroptera (mayflies)
Family Ephemerellidae
Drunella doddsi (Needham)
Ephemerella infrequens McDunnough
Order Odonata (damselflies and dragonflies)
Suborder Anisoptera (dragonflies)
Family Petaluridae (graybacks)
Tanypteryx hageni (Selys)
Family Gomphidae (clubtails)
Octogomphus specularis Hagen
Order Plecoptera (stoneflies)
Family Nemouridae (spring stoneflies)
Ostrocerca dimicki (Frison)
Ostrocerca foersteri (Ricker)
Nemoura (Zapada) wahkeena Jewett, Wahkeena Falls flightless stonefly
Family Capniidae (small winter stoneflies)
Paracapnia oswegaptera (Jewett)
Family Leuctridae (rolled-winged stoneflies)
Paraleuctra andersoni Harper and Wildman
Family Peltoperlidae
Soliperla fenderi (Jewett), Fender's soliperlan stonefly
Soliperla campanula (Jewett)
Soliperla quadrispinula (Jewett)
Soliperla thyra (Needham and Smith)
Soliperla tilamook Stark
Order Megaloptera (dobsonflies, fishflies, and alderflies)
Family Corydalidae (dobson flies)
Dysmicohermes disjunctus (Walker)
Orohermes crepusculus (Chandler)
Order Coleoptera (beetles)
Family Psephenidae (water-penny beetles)
Acneus beeri, Beer's false water penny (beetle)
Acneus burnelli, Burnell's false water penny (beetle)
Family Hydrophilidae
Chaetarthria leechi, Leech's chaetarthria water scavenger beetle
Order Trichoptera (caddisflies)
Family Philopotamidae (finger-net caddisflies)
Dolophilodes novusamerica (Ling)
Family Rhyacophilidae (primitive caddisflies)
Himalopsyche phryganea (Ross)
Rhyacophila amabilis Denning
Rhyacophila colonus Schmid, O'Brien rhyacophila caddisfly
Rhyacophila fenderi Ross, Fender's rhyacophilan caddisfly
Rhyacophila haddocki Denning, Haddock's rhyacophilan caddisfly
Rhyacophila lineata Denning, Castle Crags rhyacophilan caddisfly
Rhyacophila mosana Denning, Bilobed rhyacophilan caddisfly
Rhyacophila willametta Ross
Family Phryganeidae (large caddisflies)
Yphria californica (Banks)
Family Uenoidae (northern caddisflies)
Apatania sorex (Ross)
Farula jewetti Denning, Mt. Hood farulan caddisfly
Neothremma andersoni Wiggins, Columbia Gorge neothremman caddisfly
Neothremma siskiyou Denning
Oligophlebodes sierra Ross
Family Psychomyiidae (trumpet-net caddisflies)
Tinodes siskiyou Denning, Siskiyou caddisfly
Family Hydropsychidae (net-spinning caddisflies)
Homoplectra alsea Ross
Homoplectra schuhi Denning, Schuh's homoplectran caddisfly
Abellan hydropsyche
Family Lepidostomatidae (lepidostomatids)
Lepidostoma cascadense (Milne)
Family Brachycentridae (brachycentrids)
Eobrachycentrus gelidae Wiggins, Mt. Hood primitive brachycentrid caddisfly
Family Goeridae
Goera archaon Ross
Family Hydroptilidae
Ochrotrichia vertreesi Denning and Blickle, Vertrees' ochroctrichian micro caddisfly
Family Limnephilidae
Apatania tavala (Denning), Cascades apatanian caddisfly
Cryptochia shasta Denning, Confusion caddisfly
Desmona bethula Denning, Amphibious caddisfly
Philocasca demita Ross
Philocasca oron Ross, Clatsop philocascan caddisfly
Order Diptera (true flies)
Suborder Nematocera (primitive flies)
Family Psychodidae (moth flies)
Maurina sp.
Family Simuliidae (black flies)
Parasimulium undescribed species
Family Deuterophlebiidae (mountain midges)
Deuterophlebia shasta Wirth