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