taxonomic key to benthic macroinvertebrates -...

83www.HoosierRiverwatch.com

GO BELOW TO:

The purpose of this taxonomic key is to assist volunteer monitors, who are not trained in taxonomy, with theidentification of benthic macroinvertebrates found in Indiana. This key is a simplified version of morecomplex keys. The taxonomic level of this key is intended for use by citizen monitoring groups. Whenusing this key please note that each couplet offers two or three options. Each couplet is numbered and thenumbers in bold refer to the next couplet (the next set of numbers that you proceed to).

Please be aware that some macroinvertebrates may have missing body partsso you should look at more than one organism!

(1)a Has a shell(s)2

(4)a Right-handed opening RIGHT-HANDED SNAIL

Right-Handed Snail

(4)b Left-hand opening LEFT-HANDED SNAIL

Left-Handed Snail

(1)b Has no shell 5

(2)a Has a hinged double shell

(2)b Has a single shell 4

(3)a Adult under 2 inches long 19

(3)b About 2-4 inches long MUSSEL

Taxonomic Key toBenthic Macroinvertebrates

CHOOSE ONE:

3

Mussel

84 www.HoosierRiverwatch.com

GO BELOW TO:6(5)a Has a segmented body or looks like a tiny tick

(5)b Has an unsegmented body and has an "arrowshaped" head; 2 pigment spots (eyes)

PLANARIA

Planaria

(6)a No obvious legs 7

(6)b Obvious legs

(7)a Has no obvious appendages (long, tubular body)

12

8

(7)b Has some appendages (small tubes, tiny bumps,or feathery structures)

9

LEECH(8)a Has a smooth body and suckers Leech

RAT-TAILED MAGGOTRat-Tailed Maggot

(8)b Has a round body and a rat tail

(8)c Has a rounded body AQUATIC WORMS

Aquatic Worms

CRANE FLY LARVA(9)a Body black or brown; more than 1/3 inch long;plump and catepillar-like

(9)b Has a distinct head 10

CHOOSE ONE:

BLACK FLY LARVA(10)a One end of body wider than otherend; two tiny feather structures on smaller end

Black Fly Larva

Crane Fly Larva


GO BELOW TO:CHOOSE ONE:

(10)b No difference in diameter along body 11

(11)a Bright red body BLOOD MIDGESBlood Midge

(11)b Grey Body OTHER MIDGES

(12)a Has four pairs of legs WATER MITE

Water Mite

(12)b Has three pairs of legs 13

(12)c Has many pairs of legs 26

(13)a Has no wings or short wing pads on back 14

(13)b Has two pairs of wings that cover the abdomen 23

WATER PENNY BEETLELARVA

(14)a Has a flat, round body with legsunderneath (wings are not obvious)

Water Penny

(14)b Not flat, has long body with legs 15

(15)a Lives in a tube or a case or has twohooks in its last segment and is greenwith 3 plates on back behind head.(The "green caddisfly" builds a net &tube, but will be washed into thekick net as "free living")

CADDISLY LARVA

Caddisfly Larva

(15)b Free-living 16


GO BELOW TO:CHOOSE ONE:(16)a Abdomen possesses lateral filaments

similar in size to legs21

(16)b Abdomen does not have "leg-like"filaments (may have feathery "gills")

17

(17)a Always with only twotail appendages and noabdominal gills

STONEFLY NYMPHStoneflyNymph

(17)b Usually has three tail appendages, andwith no lateral gills on abdominalsegments

18

(17)c Tail has no appendages 25

MAYFLY NYMPH(18)a Has long, bristle-like tail appendages,sometimes 2 or 3

Mayfly Nymph

(18)b Lower lip formed into extensible scoop-like structure and has leaf-like tailappendages

DAMSELFLY NYMPH

Damselfly Nymph

20

(19)b Small triangular shell with alternatingcream and dark brown bands

ZEBRA MUSSEL (EXOTIC)

(20)a Numerous very fine concentric rowsof elevated lines, white or creamcolored, with smooth lateral teeth(ridge lines on inside near point)

FINGERNAIL CLAM

(19)a Small rounded shell (< 2 inches)

Fingernail Clam

Zebra Mussel

(20)b Numerous concentric elevated ridges,yellowish brown to black shell withserrated lateral teeth

ASIATIC CLAM (EXOTIC)

Asiatic Clam


CHOOSE ONE:

(21)a Head narrower than widest bodysegments

BEETLE LARVA

(21)b Head as wide or wider than other bodysegments

22

(22)a Abdomen with single long filament at end ALDERFLY

(22)b Abdomen ending with a pair of tinyhooked legs, large head with pincer-likejaws

DOBSONFLY OR FISHFLY

Dobsonfly Larva

(23)a Oval shaped body, legs with featheryswimming hairs

ADULT WATER BUGS ANDWATER BEETLES

(23)b All legs smooth, without hairs, crawling RIFFLE BEETLE ADULT

Riffle Beetle Adult

GO BELOW TO:

(25)a Lower lip formed into scoop like structure

Dragonfly Nymph

(25)b Looks like a tiny millipede RIFFLE BEETLE LARVA

Riffle Beetle Larva

DRAGONFLY NYMPH

Beetle larva

Alderfly

Water bug

(26)a Flattened top to bottom, crawling lookslike "roly-poly" or a "pill bug"

SOWBUG

(26)b Flattened side to side, swimming lookslike tiny shrimp

SCUD

Sowbug

Scud or Side-swimmer

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How to Complete theBiological Monitoring Data Sheet

The first portion of the Biological Monitoring Data Sheet is the information section. For instructionson how to complete this section, see pages 108-111 in Chapter 7 Data Reporting.

Sampling ProceduresEquipment: Check one or both of the nets used to collect macroinvertebrate sample.Habitat: Check each type of habitat sampled during this survey.

Pollution Tolerance IndexThe macroinvertebrate index is divided into Pollution Tolerance Groups (PT Group) 1,2,3 and 4.These PT groups represent the different levels of pollution tolerance. The higher the group number,the higher the pollution tolerance level. Record the number of macroinvertebrates you find here.

The next row is the # of Taxa. Insects that have the same body shape all belong to the same taxa (seethe back of your PTI macroinvertebrate data sheet for general body shape/taxa). To find the totalnumber of taxa for each PT Group you need to add the number of types of organisms. It is possible tohave a particular PT group without any numbers, therefore it will score a zero.

Do not make the mistake of adding the numbers of organisms together.

PT GROUP 1 PT GROUP 2 PT GROUP 3 PT GROUP 4 Intolerant Moderately Intolerant Fairly Tolerant Very Tolerant

Stonefly Nymph ________ Damselfly Nymph ________ Midge Larvae ________ Left-Handed Snail ________

Mayfly Nymph ________ Dragonfly Nymph ________ Black Fly Larvae ________ Aquatic Worms ________

Caddis Fly Larvae ________ Sowbug ________ Planaria ________ Blood Midge ________

Dobsonfly Larvae ________ Scud ________ Leech ________ Rat-tailed Maggot ________

Riffle Beetle ________ Crane Fly Larvae ________

Water Penny ________ Clams/Mussels ________

Right-Handed Snail ________ Crayfish ________

# of TAXA ______ # of TAXA ______ # of TAXA ______ # of TAXA ______

The next row is the group scores. Multiply each # of taxa by its weighting factor.

# of TAXA ______ # of TAXA ______ # of TAXA ______ # of TAXA ______

(x 4) ______ (x 3) ______ (x 2) ______ (x 1) ______

Note: The Volunteer Stream Monitoring Internet Database (described in Chapter 7) will perform thesecalculations for you when you submit data.

Weighting

Factors:

4 2 2 2

4 2 2 216 6 4 2

6

10

30

15

2

>100

16

15 25


Other Biological IndicatorsCheck the appropriate box if you find native mussels, zebra mussels, rusty crayfish or submerged aquaticplants at your site. Estimate the percentage of rocks or the stream bottom covered by algae at your site. Writeyour Diversity Index score if you perform the procedures described on pages 95-96.

Then total all of the group scores to get the POLLUTION TOLERANCE INDEX RATING.

POLLUTION TOLERANCEINDEX RATING(Add the final index values for each group.)

23 + Excellent17 - 22 Good11 - 16 Fair10 or Less Poor

# of TAXA ______ # of TAXA ______ # of TAXA ______ # of TAXA _______

(x 4) ______ (x 3) ______ (x 2) ______ (x 1) ______

Other Biological Indicators

_______ % Algae Cover

_______ Diversity Index

NativeMussels

ZebraMussels

RustyCrayfish

Aquatic Plants

4 2 2 2

16 6 4 2

28

25 0.75


Stonefly Nymph ________ Damselfly Nymph ________ Midge Larvae ________ Left-Handed Snail ________


Caddis Fly Larvae________ Sowbug ________ Planaria ________ Blood Midge ________




Right-Handed Snail________ Crayfish ________

# of TAXA ________ # of TAXA ________ # of TAXA ________ # of TAXA ________

(x 4) ________ (x 3) ________ (x 2) ________ (x 1) ________

23 or More Excellent17 - 22 Good11 - 16 Fair10 or Less Poor

Weighting

Factors:


POLLUTION TOLERANCE INDEX (PTI)

Example of a complete Pollution Tolerance Index:

6

30

15

2

>100

16

15

1025

416

2 2 26 4 2

28


BIOLOGICAL MONITORING DATA SHEET

Date ____/____/____ Begin Time _____:_____ (am/pm) # Adults __________________

End Time _____:_____ (am/pm) # Students ________________

Certified Monitors' Names____________________________________ Volunteer ID_______________

Organization Name ___________________________________________________________________

Watershed Name _______________________________________ Watershed # __ __ __ __ __ __ __ __

Stream/River Name ____________________________________________ Site ID ________________

MM DD YY

(Above ID numbers are required.) (Please do not abbreviate.)

Riffles

Leaf Packs Snags/Vegetation

Undercut Banks Sediment

Other

Check Habitats Sampled

Kick Seine Net (3 times)

D-Net (20 jabs or scoops)

Check Methods Used


Stonefly Nymph ________ Damselfly Nymph ________ Midges ________ Left-Handed Snail ________


Caddis Fly Larvae________ Sowbug ________ Planaria ________ Blood Midge ________




Right-Handed Snail________ Crayfish ________

# Of TAXA ________ # Of TAXA ________ # Of TAXA ________ # Of TAXA ________

(x 4) ________ (x 3) ________ (x 2) ________ (x 1) ________

23 or More Excellent17 - 22 Good11 - 16 Fair10 or Less Poor

Weighting

Factors:


POLLUTION TOLERANCE INDEX (PTI)

Other Biological Indicators

_______ % Algae Cover

_______ Diversity Index

NativeMussels

ZebraMussels

RustyCrayfish

Aquatic Plants

GROUP 4 – Very Tolerant of Pollution

GROUP 3 – Fairly Tolerant of Pollution

GROUP 2 – Moderately Intolerant of Pollution

GROUP 1 – Very Intolerant of Pollution

Stonefly Nymph Mayfly NymphRiffle BeetleAdult & Larva Caddisfly Larva

DobsonflyLarva Water Penny Larva

Right-Handed

Snail

Damselfly Nymph

DragonflyNymph

Scud

SowbugCranefly

Clam/Mussel

MidgeLarva

Planaria

Black Fly Larva

Leech

Aquatic Worms

Rat-tailedMaggot Blood Midge

LarvaLeft-HandedSnail

Macroinvertebrate Identification Key

2 tailslongantennae

3 tails

3 paddle-like (feathery) tails

no tailslarge eyes

flattened top tobottom (lookslike a pill bug)

flattenedside-ways& swimson side

caterpillar-shaped, ringed

large head &2 pinchers

lookslike a

suctioncup

makes a case fromtwigs, rocks, leaves

flattened &segmented

one end isswollen

bright red

2 eye spots& very small

top bottom

www.HoosierRiverwatch.com

verysmall

&hardshell

must bealive tocount



small, butvisible head

intense wiggler

segmented“earthwormy”

92

Crayfish

looks likea mini-lobster

fluttering gills


Metric Your Metric Result

2 1 0

A) Mayflies + Stoneflies + Most Caddisflies

Greater than 32.2

16.1-32.2 Less than 16.1

B) Common Netspinner Caddisflies

Less than 19.7 19.7-34.5 Greater than 34.5

C) Lunged Snails Less than 0.3 0.3-1.5 Greater than 1.5

D) Riffle Beetles + Water Pennies

Greater than 6.4

3.2-6.4 Less than 3.2

E) % Tolerant Less than 46.7 46.7-61.5 Greater than 61.5

F) % Non-Insects Less than 5.4 5.4-20.8 Greater than 20.8

Total # of 2s: Total # of 1s: Total # of 0s:

subtotals:Multiply by 2: Multiply by 1: Multiply by 0:

Add the 3 subtotals to get the Final Multimetric Index Score:

Acceptable Ecological Condition (7-12)Unacceptable Ecological Condition (0-6)

Virginia Save Our Streams Multimetric Index

Other Macroinvertebrate IndicesOnce you have identified the macroinvertebrates in your river or stream samples and noted the numberof each taxa, the data can easily be applied to more than one index. The metrics shown below weredeveloped for the Virginia Save OurStreams program through an extensiveresearch project by Sarah Engel and J.Reese Voshell at Virginia Tech. Theseexamples are provided for Riverwatchvolunteers purely for educational use.They provide an example of additionalinformation that can be obtained fromsamples properly collected and countedfor the Pollution Tolerance Index (PTI).

Since the final multimetric index ratingvalues or "scores" were based on ecologicalconditions in Virginia streams, they do notapply in Indiana. The final metric is only validfor shallow, rocky-bottom streams in the mid-Atlantic region of the U.S. However, we hopeto someday complete the research to develop amultimetric index for use in Indiana. If youwant to "try out" this index with your data,your sample must contain at least 200organisms for these metrics to be valid.

Metric A scores better when higher, since these are Group 1 organisms.

Metric B scores better when lower, since net spinners are more tolerant of pollution.

Metric C scores better when lower, since these are Group 4 organisms.

Metric D scores better when higher, since these are in Group 1.

Metrics E & F score better when lower, since these are more tolerant organisms (mostly Group 3 & 4).

The final index combines the resultsof the six individual metrics andweights them accordingly. Themultimetric index's final assessmentof ecological condition in Virginiastreams matched those of theprofessional biologist 95.5% of thetime. (Information on this page modifiedfrom Engel and Voshell, 2002.)

Taxon NumberDamselflies

Dragonflies Taxon NumberSowbugs Right-handed snailsScuds SowbugsClams ScudsAll Midges ClamsBlack Flies CrayfishPlanaria PlanariaLeeches LeechesLunged Snails Lunged SnailsAquatic Worms Aquatic WormsTotal Tolerant Total Non-InsectsTotal Tolerant divided by the total number of organisms in the sample

Total Non-Insects divided by the total number of organisms in the sample

Multiply by 100 (E) Multiply by 100 (F)

E) % Tolerant Organisms

F) % Non-Insects

Metric Number Counted

Total # of Organisms in the Sample

Final Percent

A) Mayflies + Stoneflies + Most Caddisflies

Divide by

Multiply by 100

B) Common Netspinner Caddisflies

Divide by

Multiply by 100

C) Lunged Snails - Orb + Left-handed + Limpets

Divide by

Multiply by 100

D) Riffle Beetles + Water Pennies

Divide by

Multiply by 100

Individual Macroinvertebrate Metrics

15

16

5

1

30

210 7.62

210

210

210

0.48

2.38

14.29

>10016125

157 157

210

74.76 20.95

210

16125

7.62

0.482.38

14.2974.7620.95

1 1 42 1 0

3

2


Met

ric

Your

Met

ric

Resu

lt2

10

A) M

ayfl

ies

+ St

onef

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ost C

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ater

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ater

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ater

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Non

-Ins

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20.8

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ater

than

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8

Tota

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Tota

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:

subtotals:

Mul

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Mul

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Add

the

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ubto

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Inde

x Sc

ore:

Acce

ptab

le E

colo

gica

l Con

ditio

n (7

-12)

Una

ccep

tabl

e Ec

olog

ical

Con

ditio

n (0

-6)

Virg

inia S

ave

Our

Str

eams

Multimet

ric

Inde

x

Met

ric

Num

ber

Coun

ted

Tota

l # o

f Org

anisms

in

the

Sample

Fina

l Pe

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t

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ayfl

ies

+ S

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Macroinvertebrate Diversity IndexThe Diversity Index does not require benthic macroinvertebrate identification. This index measuresstream water quality by distinguishing organisms by color, size and shape. The only distinction ismade between the number of runs, and the number of different types (taxa) of organisms.

1. Collect macroinvertebrates using the Kick Seine or Dip Net sampling procedures and place them ina jar with water or a preservative and randomize them by swirling.

2. Make a grid of 4-6 cm squares on the bottom of a white tray.

3. Pour the sample from the jar into the white tray, spreadingthe macroinvertebrates evenly over the tray.

4. Randomly select a starting grid and begin picking outorganisms in a random sequence. Pick out all the specimensfrom one square before moving to the next square. If youpicked all of the specimens from one square and there were less than 50 organisms in the square,move to the next square and pick all of the organisms from that square to add to the first. You musthave at least 50 organisms to complete the test procedures.

5. Place the selected organisms in another tray and compare them two at a time. You will bedetermining if the next insect is like or different from the previous organism. To complete the"Organism" row, place an "X" in the box if the organism you are comparing is like the previousorganism and a "O" if it is different from the previous organism. Fill in the X and O boxes untilyou have compared 50 organisms.

6. To complete the "Run" row, record a number each time a change from "X" to "O", or "O" to "X"occurs. An example is shown below. Note: Always place an "X "in the first box for your firstorganism, and always begin with the number one for your first run.

CalculationsDetermine the total number of runs and the total number of organisms (usually 50). Divide the numberof runs by the number of organisms to determine the Diversity Index. (Note: The diversity index is thesame as the Sequential Comparison Index printed in the first edition of this manual).

Diversity = Number of runs = 7 = .78 = GoodIndex Number of organisms 9

Diversity Index Results

0.0 - 0.3 Poor0.3 - 0.6 Fair0.6 - 1.0 Good

X O X O O X O X X

1 2 3 4 5 6 7 Run

Organism



0.0 - 0.3 Poor0.3 - 0.6 Fair0.6 - 1.0 Good

Sample 1

Run

Organism

Run

Organism

Run

Organism

Total Number of Runs: __________

Total Number of Organisms: __________

Divide # Runs to get Diversity Index Results: __________


0.0 - 0.3 Poor0.3 - 0.6 Fair0.6 - 1.0 Good

# Organisms

Sample 2

Run

Organism

Run

Organism

Run

Organism

Total Number of Runs: __________

Total Number of Organisms: __________

Divide # Runs to get Diversity Index Results: __________ # Organisms

taxonomic key to benthic macroinvertebrates -...

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