BIOINDICATORS

WHAT ARE BIOINDICATORS? Living things sensitive to changes in their environment. They indicate or show how changes are taking place and are used to monitor the overall health of an ecosystem. (bio means life)

HOW ARE THEY USED? Different bioindicators are sensitive to different types of changes. Scientists study changes in the populations of animal and plant bioindicators to see if an environment is healthy.

Macroinvertebrates Macroinvertebrates are aquatic organisms that are quite small but can be seen with the naked eye This diverse group of organisms such as worms, insects, and crustaceans play key roles in aquatic ecosystems: predators, filter feeders, scrapers, shredders, and collectors. (macro = big invertebrate = no backbone)

Macroinvertebrates Macroinvertebrates are often used as bioindicators because: They are very sensitive to pollution, excess nutrients, increased turbidity, chlorine, etc. They do not easily escape the changes They can be collected very quickly and easily

Macroinvertebrates A variety of environmental stressors can impact macroinvertebrate populations: Sewage and fertilizers can cause eutrophication consuming their oxygen Excess sediment from construction smothers where they live killing them off Pollution changes pH and temperature of their water

Some examples of macroinvertebrates and what it might mean in terms of health of an aquatic ecosystem… Group A: Very sensitive to Environmental Stresses (Healthy ecosystem) Stoneflies Mayflies Caddisflies Dobsonflies Water penny Group B: Somewhat sensitive to Environmental Stresses (Ecosystem has some pollutants/stressors…monitor frequently) Dragonflies Craneflies Damselflies Crayfish Scuds Group C: Tolerant to Environmental Stresses (Ecosystem is in harm/not healthy…needs intervention) Midges Leeches Snails Pouch Snails Blackfly larva

Bioindicators Even though macro-invertebrates are most commonly used, other bioindicators such as large varieties of plants, fish, ducks, crabs, frogs, birds and much more can be used to monitor water systems. If the animals aren’t around or are born with mutations…the water has your reason why!!

http://www.watersheds.org/stream_movie.htm