Module 4 Stream Invertebrate Survey Interpretation
Lizard Creek, Oct 05, 2014 | Survey ID: 79
A) ABUNDANCE AND DENSITY
ABUNDANCE total number of organisms from Column B: 561
DENSITY invertebrate density per square meter
# of 30cm x 30cm samples: 3
(total # counted 561) / (# of 30cm x 30cm samples x.09m2 3 / (Area: 0.27)) : 2,077.78
B) PREDOMINANT TAXON: Mayfly, (223)
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) = 12
2 x (# of category 2) = 0
(# of category 3) = 5
Pollution Tolerant Index = 17
EPT INDEX
Good Acceptable Marginal Poor
greater than 8 5 - 8 2 - 5 0 - 2
Total number of EPT taxa from Column C = 16
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 369 / total 561 = 0.66
D) DIVERSITY ASSESSMENT
Total Number of Taxa: 25
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:
223 / 561 = 0.3975
SITE ASSESMENT RATING
Good Acceptable Marginal Poor
4 3 2 1
Pollution Tolerance Index: 3
EPT Index: 4
EPT to Total Ratio: 3
Predominant Taxon Ratio:
Total: 2.5

Field Data as Collected
Polution Tolerance
Number Counted
Number of Taxa
Common Name
Category 1 - Polution Intolerant 30 5 Caddisfly
Dobsonfly
Gilled Snail
223 6 Mayfly
62 1 Riffle Beetle
116 5 Stonefly
Water Penny
Sub Total: 431 17
Category 2 - Somewhat Pollution Tolerant Alderfly larva
Aquatic Beetle
Aquatic Sowbug
Clam, Mussel
Cranefly Larva
Crayfish
Damselfy Larva
Dragonfly Larva
Fishfly Larva
Scud
Watersnipe Larva
Sub Total: 0 0
Category 3 - Pollution Tolerant 4 1 Aquatic Worm
1 1 Blackfly Larva
Leech
81 3 Midge Larva (chironomid)
11 1 Planarian
Pouch Snail
Truebug Adult
33 2 Water Mite
Sub Total: 130 8