Methods and Indicators

Assessments for the Freshwater EHMP are based on 5 indicators: physical/chemical, nutrient cycling, ecosystem processes, aquatic macroinvertebrates, and fish. Click on the indicators to the right for more detailed information.
  • pH
  • Conductivity
  • Diel (24hr) range and maximum temperature
  • Diel range and minimum dissolved oxygen
  • Ratio of 15N to 14N stable isotopes
  • Growth rate of algae
  • Ratio of 13C to 12C stable isotopes
  • Respiration (R24)
  • Gross Primary Production (GPP)
  • Number of macroinvertebrate taxa
  • PET richness (number of stonefly, mayfly and caddisfly families)
  • Average SIGNAL score
  • Proportion of native species expected
  • Ratio of observed to expected species
  • Proportion of alien fish 
Report card calculations