Macroinvertebrate Monitoring Reveals River Health Trends

Volunteers Ryan Redmond, Jim Waldinger and Audrey Waldinger sampling macroinvertebrates in Boston Brook in Middleton.  Macroinvertebrates (bugs and other small creatures) are good indicators of water and habitat quality. Despite a rainy summer, more frequent droughts can have long-term impacts on river life.  

Macroinvertebrates include many different types of insects and other small creatures. Good places to look for these organisms are riffle areas. At riffles, water becomes oxygen-enriched by churning over rocky streambeds. The rocks also provide convenient hiding places for macroinvertebrates and small fish. Shallow by nature, riffles are often the first parts of a river to dry up. 

Under these conditions, organisms become stressed. Those organisms that can move to more suitable areas will do so, but unlike fish, macroinvertebrates cannot seek refuge in deeper pools. Once habitats dry up, macroinvertebrate communities may not recover even after flows return. This decline can have long-term impacts on the food web.  Macroinvertebrate sampling is a good way to study trends in the impact of river flow on aquatic life.

Despite abundant rain this summer, droughts are becoming common occurrences in our region. Severe droughts occurred in 2016 and again in 2020. The 2016 drought was especially destructive to macroinvertebrates. Water advocates statewide believe frequent and severe droughts will have long-term impacts on river health. But there’s hope.

Streams in protected areas show signs of recovery following drought. This highlights the effectiveness of protected riparian forests and wetlands. While we cannot control droughts, we can control how we use the river and its surroundings. To reduce your impact on the river, cut your water usage and grow lush, native plant landscapes. Stay tuned on our social media channels to learn about what goes bump in the night–if you’re a watershed.@ipswich_river

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