Riparian Herbivores and Predators

Arthropods limited to the riparian zone of mature and old-growth forests depend on either the cool, moist, shady conditions found in stream forests, stable or disturbed shore conditions along the edge of cool, clear watercourses.

The largest block of species listed above are ground beetles (Family Carabidae). All of these depend on the physical and biotic conditions found in old-growth or mature, old-growth, or riparian forests (Kavanaugh, personal communication). These beetles not only rely on the cool moist conditions found at ground level in riparian forests, but they also require coarse, woody debris and litter for shelter and to provide habitat for necessary food resources. Ground beetles in the genus Scaphinotus , called snail-hunters, eat snails as their principal food. Little information is available about the specific snail species that are eaten by the Scaphinotus species listed above, but some may rely in part on the mollusks considered elsewhere in this impact analysis. Promecognathus laevissimus is a specialist predator on the millipede, Harpaphe haydenana, an important comminutor in mature and old-growth forests.

Several herbivores eat the foliage of trees or understory plants that are found only or primarily in mature or old-growth riparian forests. Examples include the moth Autographa corusca whose caterpillars eat the foliage of red alder in such forests (Lafontaine and Poole, 1991). The butterfly Speyeria cybele pugetensis lives only in mature or old-growth riparian forests in western Oregon and Washington (Chermock and Frechin, 1947; Dornfeld, 19xx). Its caterpillars eat the leaves of violets, while the adults nectar at flowers in light gaps found in or adjacent to the forest (Hammond, personal communication). A closely related but unnamed subspecies is resident in a limited area near Kneeland, Humboldt County, and is presumably limited there to mature or old-growth riparian forest.

Two species of unique-headed bugs (Family Enicocephalidae, Order Heteroptera), Boreostolus americanus and Systelloderes grandes, are found along streams and rivers under rocks that are partially imbedded in moist sand. Although able to withstand periodic flooding, it is critical to these species that their streamside habitats remain fairly stable and that their habitats not be eroded or silted in by fluctuating river levels or flooding that might result from changes in upstream timber management or other impacts.

    Class Oligochaeta

        Order Haplotaxida

            Family Megascolecidae

    Arctiostrotus perieri

    Megascolides macelfreshi Smith, Oregon earthworm

    Class Insecta (insects)

        Order Heteroptera (true bugs)

            Family Enicocephalidae (gnat bugs)

       Boreostolus americanus Wygodzinsky and Stys

       Systelloderes grandes Kritsky

            Family Tingidae

        Physatocheila variegata Parshley

            Family Pentatomidae (stink bugs)

        Zicrona caerulea (L.)

        Order Coleoptera (beetles)

            Family Carabidae (ground beetles)

        Agonum belleri

        Agonum ovipennis Mannerheim

        Bembidion spectabile Mannerheim

        Cyphrus (Cychrus) tuberculatus Harris

        Harpalus cordifer Notman

        Nebria acuta quileute Kavanaugh

        Nebria gebleri siskiyouensis Kavanaugh, Siskiyou ground beetle

        Nebria kincaidi kincaidi Schwarz

        Nebria kincaidi balli Kavanaugh

        Nebria sahlbergii triad Kavanaugh, Trinity Alps ground beetle

        Notiophilus sylvaticum Escholtz

        Promecognathus crassus LeConte

        Promecognathus laevissimus (Dejean)

        Pterostichus (Anilloferonia) lanei (Hatch)

        Pterostichus (Anilloferonia) rothi Hatch,Roth's blind ground beetle

        Pterostichus (Hypherpes) amethystinus Menetries

        Pterostichus (Hypherpes) crenicollis LeConte

        Pterostichus (Hypherpes) lama Menetries

        Pterostichus (Hypherpes) nigrocaerulea Van Dyke Scaphinotus (Brennus) cristatus (Harris)

        Scaphinotus (Brennus) johnsoni Van Dyke

        Scaphinotus (Brennus) rugiceps rugiceps(Horn)

        Scaphinotus (Brennus) rugiceps incipiens (Casey)

        Scaphinotus (Neochrysus) angulatus (Harris)

        Scaphinotus (Neocychrus) behrensi behrensi Roeschke

        Scaphinotus (Neocychrus) behrensi malkini

        Scaphinotus (Neocychrus) longiceps Van Dyke, Humboldt ground beetle

        Scaphinotus (Stenocantharis) hatchi Beer

        Scaphinotus (Stenocantharis) velutinus (Menetries)

        Stomis termitiformis Van Dyke

        Tachyta falli Hayward

        Tachypachus holmbergi Motschulsky

        Trechus humboldti Van Dyke

        Zacotus matthewsi LeConte

        Order Mecoptera (scorpionflies)

            Family Panorpidae (common scorpionflies)

        Brachypanorpa oregonensis (MacLachan)

        Order Lepidoptera (butterflies and moths)

            Suborder Zeugloptera

            Family Micropterygidae

        Epimartyria pardella (Walsingham)

        Epimartyria sp. undescribed

            Family Nymphalidae (brush-footed butterflies)

        Polygonia progne oreas (W.H. Edwards)

        Polygonia progne silenus (W.H. Edwards)

        Speyeria cybele pugetensis F. Chermock and Frechin

        Speyeria hydaspe rhodope (W.H. Edwards)

            Family Thyatiridae

        Euthyatira lorata (Grote)

        Ceranemota improvisa (Henry Edwards)

        Ceranemota fasciata (Barnes and McDunnough)

        Ceranemota semifasciata Benjamin

            Family Noctuidae (owlet moths)

        Autographa corusca (Strecker)

        Order Hymenoptera (ants, bees, and wasps)

            Suborder Symphyta (sawflies and horntails)

            Family Tenthredinidae (common sawflies)

        Empria multicolor (Norton)


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