Macroinvertebrate Monitoring in the GYE

YERC Field Techs Sample Macros on the Yellowstone Mainstem

This summer our RiverNET team began the implementation of additional diagnostics for the program with the addition of monitoring for benthic macroinvertebrates on both the Upper Yellowstone and Upper Madison watersheds. Benthic macroinvertebrates are “bottom-dwelling” aquatic animals and larva stages of insects that do not have a backbone and are large enough to be seen with the naked eye. Macroinvertebrates spend significant portions of their life spans living under water in streams and lakes. These critters are often found hiding under rocks, attached to woody debris, or burrowed in sediments in aquatic environments. Common examples of macroinvertebrates found in streams in the Greater Yellowstone Ecosystem include stoneflies, mayflies, and caddisflies. 

Macroinvertebrates are important for researchers to monitor as they serve as “biological indicators” for water quality. This means that the types and numbers of macroinvertebrates observed in a waterbody are reflective of the biological condition of that waterbody. The key to this is that different species of macroinvertebrates can tolerate different levels of pollution in water. For example, stonefly larvae are very sensitive to pollution so they can only live in very pristine, clean streams while leeches are pollution tolerant species so they can live in dirty and polluted water bodies. If researchers observe that there are high numbers of pollution sensitive macroinvertebrates living in a water body, this is a good indicator that the biology of that waterbody is healthy and that the water quality is high. 

To monitor macroinvertebrate populations, researchers commonly use a technique known as “kick sampling.” For this technique, one researcher uses their feet to disturb the streambed and dislodge any macroinvertebrates that may be attached to the substrate while another researcher stands with a net downstream to collect them. Macroinvertebrates collected in the net can then be easily identified and counted. At YERC, we are now collecting kick samples at all of our RiverNET sensor station locations on tributaries to both the Yellowstone and Madison Rivers. Additionally, we are collecting samples from select fishing access sites along the mainstems of both rivers. We are using this data to gain insight into the biological condition of these watersheds and to train our Macroinvertebrates Mobile App. The mobile app was designed by our technology team with the help of students at Montana State University. It allows users to upload pictures to identify macroinvertebrates they have observed in the field. Our team is currently working on training the app using photos taken during our sampling events to ensure it can properly identify a variety of species, the app will be available soon to the public! Stay tuned for more updates on our research with macroinvertebrates and our mobile on our website!