Macroinvertebrates
Little Creatures that tell us
If our natural waterways are healthy
Benthic Macroinvertebrates
• Benthic means: living at the bottom of a body of water (stream, river, pond)
• Macro- large
• Invertebrate- animal without backbone
• Macroinvertebrate- large water dwelling invertebrate able to be seen without a microscope
What are Macroinvertebrates?
• Abundant in surface waters
• Have short life-cycles• Are greatly affected
by water quality• Easy to collect• Leading indicators of
the health of a stream
Most are insects
• Insects spend part of their life cycle under the water as nymphs or larva
Water Quality
• A measure of the condition of water (physical, chemical or biological ) relative to the requirements of one or more biotic species.
Macroinvertebrates are the best indicators of water quality. They give an overall/ over time picture of water quality.
Macroinvertebrate Survey
Indicator of the health of a stream
• Organisms move slowly and cannot escape pollution
• The population of macroinvertebrates indicate stream quality over a long period of time.
Why are Macroinvertebrates Important?
• Some are clean-water organisms & sensitive to pollution.
• Some of pollution tolerant.
Index species- their presence in large numbers tell us whether a stream is clean or polluted.
Index Species
Large populations of these three species indicate very good water quality!
• Mayflies
• Stoneflies
• Caddisflies
EPT
System widely used to monitor water quality:
Biological monitoring of water quality
Orders of macroinvertebrates
1.Ephemeroptera - Mayfly
2.Plecoptera – Stonefly
3.Trichoptera - Caddisfly
MACROINVERTEBRATE DIVERSITY
Means a healthy stream
Macroinvertebrates common in clean- pollution-free waters
Dobson Fly
Water pennies
Riffle beetles
Macroinvertebrates sensitive to water pollution
Present in poor quality waters
Low D.O.
Midge larvae
High Organic pollution
Worms
Tubifex worms
Leeches
Bloodworms
Black flies
Where do Macroinvertebrates live?
• Bottom of a Stream
• Attached to rocks
• Attached to plants
• In fast moving water, need oxygen
• http://www.epa.gov/owow/nps/kids/masterbugtheater.html
Classified by Feeding Groups
1. Collectors- feed on decomposing mattera) Gathering- benthic, consume organic matter-
b) Filter feeders-
2. Scrapers- graze on algae
3. Shredders- feed on the algae, bacteria and fungi found on decomposing plants
4. Predators-
5 Parasites- consume fluids from hosts
Macroinvertebrates
http://wupcenter.mtu.edu/education/stream/Macroinvertebrate.pdf