1. Sampling Biodiversity Using macroinvertebrates
Assessing Aquatic Biodiversity

2. What is a Macroinvertebrate?
“Macro” – big enough to see with the naked eye
“Invertebrate” – no backbone
These organisms represent the foundation of freshwater aquatic ecosystems
Food sources for-
Fish
Birds
Reptiles and Amphibians
Diversity of Macroinvertebrate Life is an indicator of STREAM HEALTH

3. Benthic Macroinvertebrates?
“Benthic” = Bottom
Most Macros are in the LARVAL or Nymph stage of life cycle
Egg  Larva/Nymph  Adult

4. Dragonfly Life cycle
Dragonfly
NYMPH

6. Tolerance to Pollution
Different orders of macros have different levels of tolerance to water pollution:
Pollution Intolerant- macros cannot tolerate any level of pollution- will die if Exposed
Examples: Mayfly, stonefly, caddisfly
Pollution Sensitive- can stand some pollution
Scuds, Dragonfly Larvae
Pollution tolerant- can live in very polluted waters
Aquatic Worms, Leeches, Black Flies

7. Why Does biodiversity matter?
The more types of macros we find 
the higher the biodiversity 
the healthier the aquatic ecosystem is
What can we infer if we only found pollution Tolerant bugs in our stream?

8. Identifying Macros dichotomous key
Use physical characteristics to narrow down choices
You will get better the more you practice

9. PRACTICE Identifying Macros
Number your Journal #1-5
For each photo- use the dichotomous Key to Determine Macro
READY?

10. #1

11. #1-
Stonefly
Pollution Intolerant

12. #2

13. #2-
Amphipod (Scud)
Pollution Sensitive

14. #3

15. #3-
Black Fly
Pollution Tolerant

16. #4

17. #4-
Crane Fly
Pollution Sensitive

18. Adult Crane Fly-
They DON’T Bite!

19. #5

20. #5-
Dragonfly
Pollution Sensitive

21. Sampling Method- Kick Net
Find a riffle of a stream
One Partner faces upstream with net poles in streambed, Net outstretched
Other partner stands in front of net, upstream
Disturb streambed- Rub rocks off in Water, Kick, Twist feet, dance
The point is to dislodge macros from their home into the net
Carefully lift net out of water with debris inside, bring to stream bank and layout flat
Sort through your sample, place similar Macros in Ice cube tray w/ Water- ID and count macros

22. Where do the Macros live?
Riffles
Packets of clumped dead leaves (Leaf Packs)
Under and On Rocks
Stream bed Sediments (Sand, Clay, Silt)
Try to sample sites where these habitats are available for best results

23. What do Macros eat?
Shredders- eat decomposing organic matter (detritivores)
Crayfish, caddisflies, stoneflies
Collectors- filter-feeders and gatherers
Net-building caddisflies, black fly larva, mayflies
Grazers- algae on rocks or vegetation
Snails, waterpennies
Predators- eat other macros, tadpoles
hellgrammites, dragonflies, damselflies

24. Why Sample the Riffles?
Oxygen enters Water
Macros have gills – need oxygenated water

25. Other data we will collect
Air temperature (deg. C)
Water temperature (deg. C)
Stream depth (cm)
Stream width (m)
Current and Recent Weather- Rainfall
Types of macro habitat present (check) – leaf packs, submerged logs, etc.

26. When is a good time to Sample?
Spring and fall are optimal
Be careful of private property and hunting season
Be safe when working in water

27. Assessing Water Quality
Identify different macros (scuds, mayflies, black flies, etc.)
Tally how many of each type of macro there are- 6 scuds, 2 mayflies, 1 crane fly
Using the biotic index assign a Number (1, 2, 3) based on pollution tolerance
Pollution Intolerant = 3
Somewhat Sensitive= 2
Pollution tolerant = 1
add up all the biotic index numbers to get stream health score

28. Practice stations at lab tables
calculating stream health score based on Sample Streams