Using Aquatic Macroinvertebrates as Indicators of Stream Flow ...

and other physico-chemical variables are less suited to the presence of these organisms. Thus,even though several taxa in Oregon streams can be strong indicators of perennial flow, membersof these families will not always be present in every perennial stream, depending on theecoregion, elevation, substrate, canopy, types of surrounding landscape uses, etc.Existing modelsIntermittent and especially ephemeral streams are often overlooked and undervalued as habitatfor aquatic invertebrates and other organisms, and few biological assessment techniques takeinhabitants of temporary flowing waters into account. Rapid field-based tools that distinguishreliably between ephemeral, intermittent, and perennial streams are critically needed butchallenging to develop. For example, different rapid habitat assessment protocols used inforested headwater streams in several eastern and Midwestern states consistently identifiedephemeral channels, but were significantly less accurate at distinguishing between intermittentand perennial streams (Fritz et al., 2008).OhioDetailed invertebrate sampling and sample preservation techniques for use in headwater streampermanence assessment have been developed by the EPA (Fitz et al., 2006). Aquaticmacroinvertebrate metrics have been created as part of a rapid assessment protocol for primaryheadwater streams in Ohio, which are generally small, have shallow pools (generally