Macroinvertebrate Monitoring
Macroinvertebrates are water creatures big enough to see with your naked eye but with no backbone. Macroinvertebrates are known as bioindicators, because they can tell us how healthy a waterway is. Some macroinvertebrates are tolerant to pollution and will be able to live in fairly polluted waters, while others are sensitive to changes in environmental conditions and will either die or move away. So by measuring the abundance and diversity of macroinvertebrates, we can get a fairly accurate indication of water health.
Sampling procedures
Macroinvertebrates are collected using fine-mesh nets which are “swept” through the water. It is important that all freshwater habitat types including plants, algae, rocks, sediment and varying water depths are sampled in order to gather a variety of all animals from each monitoring site. All samples are studied on site with macroinvertebrates identified using identification books. Representative samples of macroinvertebrates not easily identified are preserved and taken back to the office for further study using a microscope.
Ratings = indicators
Macroinvertebrates can be given a SIGNAL2 pollution sensitivity score from 1 – 10. SIGNAL2 refers to “Stream Invertebrate Grade Number – Average Level”. This is a simple scaling system used to differentiate between the animals that are sensitive or tolerant to poor water quality and allows for a quick environmental assessment of the site. However, it is important to remember that it is all aspects of the habitat that influence what animals are found, such as the amount of water present, water flow, plant communities, and substrates, not just the quality of the water. But the types, numbers and communities of macroinvertebrates found at a site definitely help us to gain a better understanding of the environment that they come from and the health and quality of the water, because most of them would not be there if the water was polluted!
Results
Have a look at our maps and posters by CLICKING HERE for monitoring results.
Want to know more?
Learn all about aquatic macroinvertebrates, where they live, our local invertebrates, how to sample and catch them and other activities by visiting Macroinvertebrates.
Get involved
For more information, please contact your local NRM Education office.
or
Enter your details in our Biological Monitoring Expression of Interest Form