Module 4 Stream Invertebrate Survey Interpretation
Nile Creek, Jul 17, 2013 | Survey ID: 55
A) ABUNDANCE AND DENSITY
ABUNDANCE total number of organisms from Column B: 75
DENSITY invertebrate density per square meter
# of 30cm x 30cm samples: 1
(total # counted 75) / (# of 30cm x 30cm samples x.09m2 1 / (Area: 0.09)) : 833.33
DENSITY invertebrate density per square meter
# of 30cm x 30cm samples: 1
(total # counted 75) / (# of 30cm x 30cm samples x.09m2 1 / (Area: 0.09)) : 833.33
B) PREDOMINANT TAXON: Mayfly, (47)
C) WATER QUALITY ASSESSMENTS
| POLLUTION TOLERANT INDEX | |||
| Good | Acceptable | Marginal | Poor |
| greater than 22 | 22 - 17 | 17 -11 | less than 11 |
3 x (# of category 1) = 9
2 x (# of category 2) = 4
(# of category 3) = 2
Pollution Tolerant Index = 15
2 x (# of category 2) = 4
(# of category 3) = 2
Pollution Tolerant Index = 15
| EPT INDEX | |||
| Good | Acceptable | Marginal | Poor |
| greater than 8 | 5 - 8 | 2 - 5 | 0 - 2 |
Total number of EPT taxa from Column C = 8
| EPT TO TOTAL RATIO | |||
| Good | Acceptable | Marginal | Poor |
| 0.75 - 1.00 | 0.50 - 0.75 | 0.25 - 0.50 | 0 - 0.25 |
# of EPT 67 / total 75 = 0.89
D) DIVERSITY ASSESSMENT
Total Number of Taxa: 12
| PREDOMINANT TAXON RATIO | |||
| Good | Acceptable | Marginal | Poor |
| 0 - 0.40 | 0.40 - 0.60 | 0.60 - 0.80 | 0.80 - 1.0 |
PREDOMINANT TAXON RATIO:
47 / 75 = 0.6267
47 / 75 = 0.6267
| SITE ASSESMENT RATING | |||
| Good | Acceptable | Marginal | Poor |
| 4 | 3 | 2 | 1 |
| Pollution Tolerance Index: | 2 |
| EPT Index: | 3 |
| EPT to Total Ratio: | 4 |
| Predominant Taxon Ratio: | 2 |
| Total: | 2.75 |
Field Data as Collected
Polution Tolerance |
Number Counted | Number of Taxa | Common Name |
| Category 1 - Polution Intolerant | 10 | 2 | Caddisfly |
| Dobsonfly | |||
| Gilled Snail | |||
| 47 | 5 | Mayfly | |
| Riffle Beetle | |||
| 10 | 1 | Stonefly | |
| Water Penny | |||
| Sub Total: | 67 | 8 | |
| Category 2 - Somewhat Pollution Tolerant | Alderfly larva | ||
| Aquatic Beetle | |||
| Aquatic Sowbug | |||
| Clam, Mussel | |||
| 1 | 1 | Cranefly Larva | |
| Crayfish | |||
| Damselfy Larva | |||
| Dragonfly Larva | |||
| Fishfly Larva | |||
| Scud | |||
| 3 | 1 | Watersnipe Larva | |
| Sub Total: | 4 | 2 | |
| Category 3 - Pollution Tolerant | Aquatic Worm | ||
| Blackfly Larva | |||
| Leech | |||
| Midge Larva (chironomid) | |||
| 1 | 1 | Planarian | |
| Pouch Snail | |||
| Truebug Adult | |||
| 3 | 1 | Water Mite | |
| Sub Total: | 4 | 2 |