Water Action Volunteers in the field


Tips for teaching Biotic Index


Pre-training thoughts:

  • Read through the biotic index fact sheet in the Volunteer Stream Monitoring Factsheet Series carefully. There are a lot of directions in the fact sheet and a thorough reading is necessary even if you are familiar with macroinvertebrate sampling.

  • Remember the biotic index we use is a presence-absence measure. Even if you find 100 of a certain organism and only 1 of another, they both will get circled on the data sheet just one time (no need to count how many of each kind of critter people find).

  • You might want to consider going to the stream site prior to training so that you have an idea of the types and percentages of habitat types at the site (because directions ask that you get a representative sample of the variety of habitats at a site), to see what your monitoring site is like in regards to safety, access, etc., and to create a voucher collection of specimens found at the site (which may be useful if training day weather keeps monitors from the field or to assist them with identification of organisms they find in their samples).
  • If you have resources to do this, laminating Keys to Macroinvertebrate Life in the River for use during the training can be very helpful.
  • For rainy day or cold weather training sessions you can use the training video for biotic index from the WAV website which demonstrates the sampling procedures. If you know the weather will be inclement, you might also consider sampling some macroinvertebrates in advance of the training so that participants can practice searching for, identifying and determining a biotic index score. (These could come from any stream-does not have to be the one where training will occur, but DO NOT put them back into any stream after teaching. They must be disposed of on the ground away from natural waterways.)

  • Be sure to give monitors a copy of the data sheet for use at the training as well as for use at their own sites. All data sheets can be printed from the WAV website at: ¬†


Teaching tips:

Discuss the biotic index and how it works:

    1. A Biotic Index (BI) is a rating of water quality based on organisms (in our case, macroinvertebrates) living in the stream.
    2. Macroinvertebrates are primarily immature aquatic insects, crustaceans, and other invertebrates that can be seen without magnification.
    3. Biotic Index scores can only be determined for streams and cannot be determined for ponds or lakes. This is because BI scores are related to dissolved oxygen levels in streams which are affected by inputs to streams. Dissolved oxygen levels in lakes and ponds are not affected in the same manner as dissolved oxygen levels in streams.
    4. The Biotic Index is based on grouping macroinvertebrates into four different categories, each group of animals requires differing concentrations of dissolved oxygen to survive. The organisms in the Group 1 "Sensitive to Pollution" group require the highest concentration of dissolved oxygen, and the organism in the Group 4 "Tolerant to Pollution" require the least amount of oxygen to survive. Tolerant organisms can be found in streams with lower concentrations of oxygen but they are usually not dominant. Pollution sensitive organisms are not found in streams with low dissolved oxygen concentrations.
    5. The BI is different than most of the other parameters we measure because it represents stream health over time, not just at one moment in time, like D.O. or temperature or transparency. It also gives a picture of watershed health since organisms within the stream will ultimately react to the environmental changes caused by watershed land uses.


  • NOTE: Caddisflies have three different pictures on the data sheet, but only count them as one when tallying circled bugs even if people find two or three different kinds of caddisflies. The same thing is true for riffle beetles - since both adults and larvae are shown on the data form.

  • Make extra effort to show trainees the netting in the d-frame net, as it's easy to hide when showing the net and how it is used. This will help them get a better picture of how the sampling works.

  • Always work downstream to upstream so as not to disturb your sampling area before you're ready.

  • Remember that one riffle sample consists of a total of 4 minutes of kicking, two at the downstream and two at the upstream portion of a riffle.
  • Three samples combined equal one sample for the Biotic Index WAV uses.
  • Because we want people to be aware that macroinvertebrates live in various habitats of the stream, monitors should collect from at least two habitat types.

  • A snag or vegetative sample consists of about 20 jabs of the net into the materials being sampled.

  • Do have monitors combine snag and riffle samples. For example, if a site is partially riffle and partially snags, have them do 8 minutes of riffle kicking and 20 jabs in snags. Combine all of these to get one biotic index sample.

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