How do you calculate biotic index?
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- Example of Biotic Index Calculation. Using Macroinvertebrate Information.
- If you find:
- Mayflies. Caddisflies. Stoneflies. Scuds. Midge larva.
- Multiply each by the Biotic Value:
- Biotic Value. Mayflies. 25 x 10 = 250. Caddisflies. 15 x 10 = 150.
- TOTAL = 820. Divide total by 10. This is the Biotic Index Value: 820/10 = 82.
How do you calculate the Hilsenhoff biotic index?
The FBI is calculated by multiplying the number in each family by the tolerance value for that family (Table 1), summing the products, and dividing by the total arthropods in the sample (Hilsenhoff 1988).
How is EPT calculated?
EPT Index is the total number of Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies) divided by the total number of individuals across all taxa. In general, the more EPT taxa, the better the water quality.
What are the biotic index ranges of macroinvertebrates for indication of a clean water?
TABLE 35.3. Water Quality Based on Family Biotic Index Values from Hilsenhoff (1988)….Data Analyses.
| Family Biotic Index | Water Quality |
|---|---|
| 0.00–3.75 | Excellent |
| 3.76–4.25 | Very good |
| 4.26–5.00 | Good |
| 5.01–5.75 | Fair |
How do you calculate BMWP?
The BMWP index is calculated by adding up the individual tolerance scores of aquatic macroinvertebrates at family taxonomic level present at a sample site.
What does a high biotic index mean?
A high biotic index indicates the presence of many pollution-sensitive organisms, denoting an unpolluted environment. A low biotic index indicates a polluted environment, due to a relative abundance of pollution-tolerant organisms.
What is the EPT test for water quality?
The EPT Richness Index estimates water quality by the relative abundance of three major orders of stream insects that have low tolerance to water pollution. EPT can be expressed as a percentage of the sensitive orders (E= Ephemeroptera, P= Plecoptera, T= Tricoptera) to the total taxa found.
What is the EPT index?
The EPT Index is the total number of distinct taxa within the groups, Trichoptera, Ephemeroptera, and Plecoptera. For example, if five species of Ephemeroptera (mayflies), five Plecoptera (stoneflies), and two Trichoptera (caddisflies) are found at a site, the total number of EPT taxa and Index would equal 12.
What Is percent EPT?
Percent EPT is the total number of EPT individuals divided by the total number of individuals in the sample. The HBI is based on an organism’s relative sensitivity to stream-quality conditions.
Could a pollution tolerant macroinvertebrate live in clean water?
If the water contains pollution sensitive macroinvertebrates, then it is a good indication that the water is clean enough and of high enough quality for these sensitive individuals to survive.
What are the 3 categories of macroinvertebrate pollution tolerance?
The classes of macroinvertebrates are low pollution tolerant, somewhat pollution tolerant, and high pollution tolerant (Primbas, 2005). Some macroinvertebrates that are low pollution tolerant are caddisflies, water pennies, stoneflies, and mayflies.