Right around this time of year, swarms of midges and mayflies take over Cleveland and surrounding areas. For some, this is the most annoying time of the year, but these bugs are fantastic news for water quality in the region! Midges and mayflies indicate that the water quality of Lake Erie and its tributaries is improving! Insect species exhibit varying tolerances to pollution, and thus the insect community fluctuates relative to water quality. Studying the insect community can provide insight into the short- and long-term effects of pollution as well as the cumulative impact of multiple pollution events. Macroinvertebrates like midges and mayflies have limited mobility and therefore reflect the localized environmental conditions. Environmental degradation like sedimentation, habitat loss, and chemical pollution can threaten these communities, causing the population to leave a waterbody.
So maybe those crazy bugs flying all around you are actually a very good thing! The pollution tolerance of midges varies depending on the species of midge, but for the most part, midges fall into Group 3 of macroinvertebrates: the pollution tolerant group. These invertebrates can survive in low oxygen environments with a wider pH range and warmer water. Thus, the presence of midges does not necessarily mean the water quality is improving. The presence of midges alone could be an indicator of poor water quality, as midges tolerate high pollutant loads and low oxygen levels, but in the Lake Erie region, we are lucky to have mayflies as well! Unlike midges, mayflies are sensitive to pollution and their presence is an indicator of improving water quality. Read more at https://tinkerscreek.org/get-buggy-water-quality-midges-mayflies/