Module 4 Stream Invertebrate Survey Interpretation
ALEXANDER CREEK | Survey ID: 75
A) Abundance and density
ABUNDANCE: 989 / NUMBER OF SAMPLES: (3 *.09) = DENSITY: 3,662.96
B) PREDOMINANT TAXON
Mayfly Larva
C) WATER QUALITY ASSESSMENTS
POLLUTION TOLERANT INDEX
Good
Acceptable
Marginal
Poor
greater than 22
22 - 17
16 - 11
less than 11
3 x (# of category 1) = 12
2 x (# of category 2) = 4
(# of category 3) = 5
= 21
EPT INDEX
Good
Acceptable
Marginal
Poor
greater than 8
5 - 8
2 - 5
0 - 1
Total number of EPT taxa from Column C = 14
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
934 / total
989 =
0.94
D) DIVERSITY ASSESSMENT
TOTAL NUMBER OF TAXA: 23
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: Predominant Taxa 454 / 989 = 0.4590
SITE ASSESMENT RATING
Good
Acceptable
Marginal
Poor
4
3
2
1
Pollution Tolerance Index: 3
EPT Index: 4
EPT to Total Ratio: 4
Predominant Taxon Ratio: 3
Total: 3.5
POLLUTION TOLERANT INDEX | |||
---|---|---|---|
Good | Acceptable | Marginal | Poor |
greater than 22 | 22 - 17 | 16 - 11 | less than 11 |
3 x (# of category 1) = 12
2 x (# of category 2) = 4
(# of category 3) = 5
= 21
2 x (# of category 2) = 4
(# of category 3) = 5
= 21
EPT INDEX | |||
---|---|---|---|
Good | Acceptable | Marginal | Poor |
greater than 8 | 5 - 8 | 2 - 5 | 0 - 1 |
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
934 / total
989 =
0.94
PREDOMINANT TAXON RATIO | |||
---|---|---|---|
Good | Acceptable | Marginal | Poor |
0 - 0.40 | 0.40 - 0.60 | 0.60 - 0.80 | 0.80 - 1.0 |
SITE ASSESMENT RATING | |||
---|---|---|---|
Good | Acceptable | Marginal | Poor |
4 | 3 | 2 | 1 |
Pollution Tolerance Index: 3
EPT Index: 4
EPT to Total Ratio: 4
Predominant Taxon Ratio: 3
Total: 3.5
EPT Index: 4
EPT to Total Ratio: 4
Predominant Taxon Ratio: 3
Total: 3.5
Field Data as Collected
Polution Tolerance |
Number Counted | Number of Taxa | Common Name |
Category 1 - Polution Intolerant | 88 | 4 | Caddisfly |
Dobsonfly | |||
Gilled Snail | |||
454 | 6 | Mayfly | |
4 | 1 | Riffle Beetle | |
392 | 4 | Stonefly | |
Water Penny | |||
Sub Total: | 938 | 15 | 4 |
Category 2 - Somewhat Pollution Tolerant | Alderfly larva | ||
1 | 1 | Aquatic Beetle | |
Aquatic Sowbug | |||
Clam, Mussel | |||
2 | 1 | Cranefly Larva | |
Crayfish | |||
Damselfy Larva | |||
Dragonfly Larva | |||
Fishfly Larva | |||
Scud | |||
Watersnipe Larva | |||
Sub Total: | 3 | 2 | 2 |
Category 3 - Pollution Tolerant | 6 | 1 | Aquatic Worm |
2 | 1 | Blackfly Larva | |
Leech | |||
15 | 2 | Midge Larva (chironomid) | |
17 | 1 | Planarian | |
Pouch Snail | |||
Truebug Adult | |||
8 | 1 | Water Mite | |
Sub Total: | 48 | 6 | 5 |
Total: | 989 | 23 | 11 |