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 • Ephemeroptera - Mayfly • Plecoptera – Stonefly • Trichoptera - Caddisfly
Means a healthy stream Macroinvertebrate Diversity
Macroinvertebrates common in clean- pollution-free waters Dobson Fly Water pennies Riffle beetles
Present in poor quality waters Low D.O. High Organic pollution Worms Tubifex worms Leeches Bloodworms Black flies Midge larvae
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 • Collectors- feed on decomposing matter • Gathering- benthic, consume organic matter- • 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