Wyoming

To meet state biocriteria, Wyoming uses an O/E index built in 2018. Index accuracy and precision differs across ecoregions. Therefore, separate benchmarks are used for each ecoregion. To apply this index, midges must be identified to genus (extra cost and time) and samples should be collected between August 1-October 31st for mountain ecoregions and July 15- October 31st for plains and basin ecoregions

Index # Reference Sites # Degraded Sites Index Mean Index SD Moderate departure from reference benchmark Major departure from reference benchmark Narrative Conditions
WY2018_VOLCANIC 17 NA 1.05 0.17 <= 0.8646 < 0.6456 Full-support, Indeterminate, Partial/non-support
WY2018_GRANITIC MNTS 13 NA 0.99 0.19 <= 0.8832 < 0.6468 Full-support, Indeterminate, Partial/non-support
WY2018_SEDIMENTARY MNTS 34 NA 1.04 0.15 <= 0.8234 < 0.6825 Full-support, Indeterminate, Partial/non-support
WY2018_SOUTHERN ROCKIES 12 NA 1.07 0.14 <= 0.8917 < 0.6208 Full-support, Indeterminate, Partial/non-support
WY2018_SOUTH FH LARAMIE RANGE 18 NA 1.09 0.16 <= 0.8818 < 0.6838 Full-support, Indeterminate, Partial/non-support
WY2018_BIGHORN BASIN FOOTHILLS 5 NA 0.88 0.14 <= 0.8445 < 0.6310 Full-support, Indeterminate, Partial/non-support
WY2018_BLACK HILLS 9 NA 0.95 0.2 <= 0.8813 < 0.5940 Full-support, Indeterminate, Partial/non-support
WY2018_HIGH VALLEYS 21 NA 1.03 0.14 <= 0.8599 < 0.6847 Full-support, Indeterminate, Partial/non-support
WY2018_SE PLAINS 4 NA 1.01 0.16 <= 0.7813 < 0.5144 Full-support, Indeterminate, Partial/non-support
WY2018_NE PLAINS 4 NA 0.88 0.15 <= 0.7500 < 0.5199 Full-support, Indeterminate, Partial/non-support
WY2018_WYOMING BASIN 15 NA 1.00 0.19 <= 0.8158 < 0.6351 Full-support, Indeterminate, Partial/non-support

Wyoming with various bioregions - Bighorn Basin Foothills in teal, Black hills in pink, granitic mountains in orange, high valleys indigo, northeast plains in yellow, south Wyoming foot hills and laramie range in green, southeast plains in pale pink, sedimentary mountains in purple, southern rockies in blue, volcanic mountains and valleys in dark green, WB bighorn basin in red, and Wyoming basin in orange and black dots representing MMI reference sites
Wyoming macroinvertebrate reference sites

Box plots of catch elevation(m) on a scale of 1000 to 3000 with a mean of 2250, mean annual precipitation (mm) on a scale of 200 to 1400 with a mean of 700, temperature (C) on a scale of -1 to 8 with a mean of 2 and log watershed area (km2) on a scale of -1 to 4 with a mean of 2
Environmental gradients of reference sites used for Wyoming and used for NAMC’s model applicability test

  • Method for accounting for natural environmental gradients: Discriminant function analysis predicting group membership
  • Predictors of reference assemblages or metrics: 
    • Mean lithological uniaxial compressive strength (megaPascals) content in surface or near surface geology within watershed
    • Mean watershed elevation (m)
    • Is the point within the High Valleys and Upper North Platte ecoregion
    • Latitude of the point
    • Longitude of the point
    • Is the point within the Black hills ecoregion
    • % of watershed area classified as evergreen forest land cover (NLCD 2006 class 42)
    • % of watershed area classified as shrub/scrub land cover (NLCD 2011 class 52)
    • % of watershed area classified as lithology type: silicic residual material
    • Mean permeability (cm/hour) of soils (STATSGO) within watershed
    • Mean pesticide use (kg/km2) in yr. 1997 within watershed
    • PRISM climate data - Mean precipitation (mm) within the watershed. Period: 2008
    • Mean % sand content of soils (STATSGO) within catchment
    • Is the point within the Southern Foothills and Laramie Range ecoregion
    • Is the point within the Southern Rockies and Bighorn Mountains ecoregion
    • PRISM climate data - 30-year normal maximum temperature (°C): Annual period: 1981-2010 within the watershed
    • PRISM climate data - Mean temperature (°C) within the watershed. Period: 2008
    • Log10 of watershed area
  • # of Macroinvertebrate groups obtained by hierarchical cluster analysis: 9
  • Fixed count: 300
  • Minimum count: unspecified
  • Operational Taxonomic Unit (OTU) applied: Yes
  • Rare taxa <0.5 probability of capture included: No
  • Documentation