Which freshwater organisms are commonly used as bioindicators?

Macroinvertebrates, such as mayflies and caddisflies, are widely recognized as effective bioindicators of freshwater ecosystem health. These organisms are sensitive to changes in water quality and habitat conditions, making their presence and abundance indicative of the health of the aquatic environment.

When assessing water quality, scientists often look at the diversity and population levels of various macroinvertebrate species. Each species has specific tolerances to pollution and habitat alteration; for example, mayflies typically require clean, oxygen-rich water to thrive, while more pollution-tolerant species might be found in degraded environments. Consequently, a healthy population of sensitive macroinvertebrates suggests good water quality and a stable environment, while a decrease in their numbers can indicate habitat degradation or water pollution.

Other organisms like fish, worms, and amphibians can also provide information on ecosystem health, but they may not be as effective as macroinvertebrates in quickly indicating changes in environmental conditions. Macroinvertebrates are typically more numerous and are impacted by water quality changes more directly, making them particularly valuable in bioassessment programs. This makes their use as bioindicators paramount in freshwater ecology studies.