Using Aquatic Macroinvertebrates as Indicators of Stream Flow ...

Appendix A. Representative photographs of indicator taxaThe photographs below are intended only as a quick guide to provide context and a visualreference to individuals who may be unfamiliar with the recommended indicator taxa. As statedearlier, we recommend that a guide be developed specifically for practitioners in the field thatcould be targeted at issues users of the stream assessment protocol are likely to encounter, suchas recognizing and identifying pupae, exuviae, and cases, and differentiating between familieswhose members may closely resemble one another. Unless otherwise indicated, all photos beloware credited to The Xerces Society (Jeff Adams).Mollusca (snails, mussels)• Juga spp. (pluerocerid snail): Perennial indicator; shells are dark reddish-brown to black,may be smooth or ridged; may have lighter colored lines spiraling with the coils; 10-30 mm(0.4-1.2 in.) in length• Freshwater mussels (Margaritiferidae , Unionidae ): Perennial indicator; bivalved shell with two oblong halves; can live for 100years and reach >15 cm (6 in.) in length; more common in larger rivers with softer substrate;larvae (glochidia) must attach to a fish host for development and dispersal before droppingoff and burrowing into the substrate. For a detailed guide, see “Freshwater Mussels of thePacific Northwest”, published by the Pacific Northwest Native Freshwater Mussel Group.Anodonta nuttalliana Margaritifera falcata Gonidea angulata(winged floater) (western pearlshell) (western ridged mussel)Trichoptera (caddisflies)• Philopotamidae (finger-net caddisfly): perennial indicator;yellowish-white fleshy body; reach up to 16 mm (0.6 in.); 1 stthoracic segment is sclerotized (hardened) on top and hasprominent black band around posterior rim; long anal prolegs(arrow); build finger-like nets on the underside of rocks forMacroinvertebrates as indicators of stream flow duration,The Xerces Society for Invertebrate Conservation29