Benthic  Macroinvertebrate  Ecology  &  Identification

Susan  F.  CushmanHobart  &  William  Smith  Colleges

Geneva,  NYcushman@hws.edu

315-­‐781-­‐3599

Outline

I. Reason  to  study,  definition,  identifying  characteristics

II. Sampling  protocolIII. Identification  of  major  groupsIV. Tier  2  analysisV. Stream  habitat  for  macroinvertebratesVI. Aquatic  food  webs

Outline

I. Reason  to  study,  definition,  identifying  characteristics

II. Sampling  protocolIII. Identification  of  major  groupsIV. Tier  2  analysisV. Stream  habitat  for  macroinvertebratesVI. Aquatic  food  webs

Why  Macroinvertebrates?

• Provide  an  integrated  picture  of  stream  chemistry  (water  quality),  physical  habitat,  and  environmental  change

• Easy  to  collect  and  identify  to  determine  potential  impact

• Inexpensive  equipment• Assessment  models  are  easy  to  understand• Great  activity  to  get  kids  involved  with!

Definition

A  macroinvertebrate is  the  term  used  for  invertebrate  fauna  that  can  be  captured  by  a  500-­‐ m  net  or  sieve.  

This  includes  arthropods (insects,  mites,  scuds  and  crayfish),  molluscs (snails,  limpets,  mussels  and  clams),  annelids (segmented  worms),  nematodes(roundworms),  and  platyhelminthes (flatworms).

(Hauer and  Resh,  1996.  Methods  in  Stream  Ecology,  Academic  Press,  San  Diego,  CA.)

BMI  Lifecycles

• Larval  aquatic  forms– Spend  most  of  their  juvenile  life  underwater

• Live  multiple  years  in  water

Incomplete  Metamorphosis Complete  Metamorphosis

Basic  Anatomy

Outline

I. Reason  to  study,  definition,  identifying  characteristics

II. Sampling  protocolIII. Identification  of  major  groupsIV. Tier  2  analysisV. Stream  habitat  for  macroinvertebratesVI. Aquatic  food  webs

Macroinvertebrate  Protocol

• Take  one  benthic  sample  per  visit– Disturb  debris  along  diagonal  transect  for  5  mins– Place  contents  of  net  in  pan  for  inspection

D-­‐net  sampling

Outline

I. Reason  to  study,  definition,  identifying  characteristics

II. Sampling  protocolIII. Identification  of  major  groupsIV. Tier  2  analysisV. Stream  habitat  for  macroinvertebratesVI. Aquatic  food  webs

Major  Group  Analysis

Major  Group:  EphemeropteraCommon  name:  Mayflies

Tier  2  – Major  Group

Major  Group:  PlecopteraCommon  name:  Stoneflies

Tier  2  – Major  Group

Major  Group:  TrichopteraCommon  name:  Caddisflies

Tier  2  – Major  Group

Major  Group:  Diptera -­‐ ChironomidaeCommon  name:  Midges

Tier  2  – Major  Group

Major  Group:  ColeopteraCommon  name:  Beetles

Tier  2  – Major  Group

Major  Group:  OligochaetaCommon  name:  Aquatic  worms

Tier  2  – Major  Group

Biotic  Index  Analysis

Tier  2  – Biotic  Index

Net  spinning  Caddisflies

Non  -­‐ Net  spinning  Caddisflies

7 10

Tier  Two  – Biotic  Index

Major  Group:  MegalopteraCommon  name:  Dobsonfly

Tier  Two  – Biotic  Index

Major  Group:  ColeopteraMinor  Group:  ElmidaeCommon  name:  Riffle  Beetle

Tier  Two  – Biotic  Index

Major  Group:  ColeopteraMinor  Group:  PsephenidaeCommon  name:  Water  Penny  Beetle

Tier  Two  – Biotic  Index

Major  Group:  ColeopteraCommon  name:  Other…

Tier  Two  – Biotic  Index

Major  Group:  DipteraMinor  Group:  TipulidaeCommon  name:  Crane  Fly

Tier  Two  – Biotic  Index

Major  Group:  GastropodaCommon  name:  Gilled  Snail

Major  Group:  GastropodaCommon  name:  Lunged  Snail

Tier  Two  – Biotic  Index

Major  Group:  AmphipodaCommon  name:  Scud

Tier  Two  – Biotic  Index

Major  Group:  MegalopteraCommon  name:  Alderfly

Tier  Two  – Biotic  Index

Major  Group:  OdonataCommon  name:  Damselfy

Dragonfly

Tier  Two  – Biotic  Index

Major  Group:  DipteraMinor  Group:  SimuliidaeCommon  name:  Black  Fly

Tier  Two  – Biotic  Index

Major  Group:  IsopodaCommon  name:  Sow  Bug

Outline

I. Reason  to  study,  definition,  identifying  characteristics

II. Sampling  protocolIII. Identification  of  major  groupsIV. Tier  2  analysis  -­‐ PMAV. Stream  habitat  for  macroinvertebratesVI. Aquatic  food  webs  

PMA

PMA

41

03

28

19

06

03

00

100

100

100

100

100

100

100

41%

0%

28%

19%

6%

3%

3%

Outline

I. Reason  to  study,  definition,  identifying  characteristics

II. Sampling  protocolIII. Identification  of  major  groupsIV. Tier  2  analysisV. Stream  habitat  for  macroinvertebratesVI. Aquatic  food  webs

Hierarchical classification of stream habitats

Habitat is made more complex by: Organic matter• Large woody debris• Rootwads• Leaf packs/debris jamsChannel morphology• Geologic formations• Forces of erosion (undercutting)• Slope of the stream• Pools, riffles, runs, glides

Landscape influences• Slope of the land adjacent to stream• Landuse near the stream• Low extent of upstream environmental impacts

Habitat  Complexity

Large  woody  debris

-­‐Non-­‐living  logs  that  are  found  near,  hangingover,  or  in  the  stream  channel  

Rootwads

-­‐Living  trees  that  line  the  streambank,  whichprovide  streambank stability  and  habitat  forfish  and  macroinvertebrates

Undercut  and  eroded  banks

Undercut  banks  are  stabilized  by  roots  and  provide  habitat  for  fish  and  macroinvertebrates,  while    eroded  banks  have  exposed,  bare  soil  that  are  susceptible  to  future  erosion  from  storm  events  and  will  release  sediment  into  the  stream  channel.

Pool/Riffle System-Depth-Sediment size-Flow rate

BMI  HabitatPreferred  habitat  varies• Lithophilous taxa:  stony  

substrates– Ex.  Water  penny  

(Psephenidae)• Sammophilous taxa:  

sandy  substrate– Ex.  Tube-­‐building  

caddisflies(hydropsychidae)

• Burrowing  taxa:– Ex.  Amelytidae mayflies

• Xylophilous taxa:  wood  dwelling  – Ex.  Some  beetle  larvae

• Phytophilous taxa:  aquatic  plants– Ex.  Rhyacophila caddisflies

(free-­‐living)

Outline

I. Reason  to  study,  definition,  identifying  characteristics

II. Sampling  protocolIII. Identification  of  major  groupsIV. Tier  2  analysisV. Stream  habitat  for  macroinvertebratesVI. Aquatic  food  webs

Invertebrate  consumers

Feeding  Role• Shredders

• Suspension– Filter– Collector

• Deposit  – Gatherer

• Grazer

• Predator

Food  Resources,  Examples• Non-­‐woody  CPOM,  leaves,  fungi,  microbiota

– Trichoptera,  plecoptera,  crustacea• FPOM,  bacteria,  sloghed periphyton

– Net  spinning  trich,  simuliidae (diptera),  ephemeroptera

• FPOM,  bacteria– Ephemeroptera,  chironomidae (diptera)

• Periphyton,  diatoms,  biofilms– Many  ephem,  trich;  some  diptera,  

coleoptera• Animal  prey

– Odonata,  megaloptera,  some  Plec,  Trich,  Dip,  Colep

Vertebrate inhabitants of stream ecosystems

Leopard  Frog

Green  Frog

No.  Water  snake

Box  Turtle

No.  two  linedsalamander

BlacknoseDace

CreekChub

Rosyside Dace

White Sucker

GreenSunfish

BluegillSunfish

Stream fish: minnows, sunfish, suckers, sculpins

Mottled Sculpin