Table 1.
Indicators evaluated in the present study. Indicators with “NM” in the Origin column were measured following the NM method protocol [34], and indicators marked with “PNW” were measured following the PNW protocol [27]; other indicators were measured with protocols developed for this study, which are provided in Supplementary File S1, and come from sources reviewed in a study by McCune and Mazor [35]. Asterisks (*) indicate hydrologic indicators that are considered direct measures of water presence.
| Indicator | Description | Origin |
|---|---|---|
| Geomorphic Indicators | ||
| Sinuosity | Visual estimate of the curviness of the stream channel | NM |
| Bankfull width | Width of the channel at bankfull height | PNW |
| Floodplain channel dimensions | Visual estimate of the extent of channel entrenchment and connectivity to the floodplain | NM |
| Particle size/stream substrate sorting | Visual estimate of the extent of evidence of substrate sorting within the channel | NM |
| In-channel structure/riffle pool sequence | Visual estimate of the diversity and distinctiveness of riffles, pools, and other flow-based microhabitats | NM |
| Sediment deposition on plants and debris | Visual estimate of the extent of evidence of sediment deposition on plants and on debris within the floodplain | NM |
| Hydrologic indicators | ||
| Surface and subsurface flow * | Estimates of the percent of the reach-length with surface and subsurface flow | PNW |
| Isolated pools * | Number of pools in the channel without any connection to flowing surface water | PNW |
| Water in channel * | Visual estimate of the extent of surface flow in the channel | NM |
| Seeps and springs * | Presence/absence of springs or seeps within one-half channel width of the channel | NM |
| Hydric soils | Presence/absence of hydric soils within the channel, measured at up to 3 locations | NM |
| Soil moisture and texture * | Extent of soil saturation and texture measured at three locations in the channel | |
| Woody jams | Number of woody jams within the channel | |
| Biological indicators | ||
| Live and dead algal cover | Visual estimate of the percent of streambed covered by live or dead algal growth | |
| Filamentous algal abundance | Estimate of the overall abundance of filamentous algae within the channel | NM |
| Stream shading | Percent shade-providing cover above the streambed measured with a densiometer at three locations | |
| Hydrophytic plant species | Number of OBL or FACW-rated plants (as listed in [36]) growing within the channel or a half-channel width from the channel | PNW |
| Fish | Estimate of the overall abundance of fish (other than non-native mosquitofish) in the channel. | NM |
| Aquatic invertebrates | Abundance and richness of aquatic invertebrate families collected from the channel | PNW |
| Aquatic invertebrates | Estimate of the overall abundance of aquatic invertebrates within the channel | NM |
| Amphibians | Estimate of the overall abundance of amphibians within the channel | NM |
| Mosses and liverworts | Visual estimate of the percent of streambed and banks covered by live or dead bryophytes or liverworts | |
| Differences in vegetation (riparian corridor) | Visual estimate of the distinctiveness of vegetation in the riparian corridor compared to surrounding upland vegetation | NM |
| Absence of upland rooted plants in the streambed | Visual estimate of the extent of upland rooted plants growing within the streambed | NM |
| Presence of iron-oxidizing fungi or bacteria | Presence of oily sheens indicative of iron-oxidizing fungi or bacteria within the assessment reach | NM |
| Presence of aquatic or semi-aquatic snakes | Presence of aquatic or semi-aquatic snakes (e.g., most garter snake species) in the channel | PNW |
| Geospatial | ||
| Location and watershed characteristics | Latitude, longitude, elevation, and watershed area (watershed area retrieved from StreamCat database [37]) | |
| Long-term normal precipitation and temperature | 30-year normal mean annual and monthly precipitation, and 30-y normal mean, maximum, and minimum annual temperature (PRISM climate data; [38]). | |
| Soil type | Landscape metrics related to soil (such as erodibility, hydraulic conductivity, and bulk density) calculated at the watershed and catchment scale (StreamCat database [37]) | |
| Geology | Landscape metrics related to geology (such as geological nitrogen content in bedrock) calculated at the watershed and catchment scale (StreamCat database [37]) | |
| Ecoregion | Level 2 and 3 ecoregions for the Western United States [39] |