Evaluating the relationship between biotic and sediment metrics using mesocosms and field studies

Area of Science:

• Aquatic ecology
• Environmental science
• Ecotoxicology

Background:

• Elevated sediment poses a significant challenge in detecting biological responses.
• Developing sediment-specific bioassessment metrics is essential for evaluating ecological impacts.

Purpose of the Study:

• To evaluate the relationship between biological and sediment metrics.
• To identify the most effective bioassessment metrics for discerning sediment effects on macroinvertebrates.

Main Methods:

• Laboratory mesocosm experiments and field observations in Irish rivers.
• Assessed macroinvertebrate responses to varying sediment levels.
• Correlated biological metrics (e.g., % EPT, PSI) with sediment metrics (% surface cover, turbidity).

Main Results:

• Decreased sensitive taxa abundance with increased sediment surface cover in mesocosms.
• % EPT abundance showed the strongest negative correlation with sediment surface cover in both studies.
• % Sediment surface cover was a more effective sediment metric than turbidity or re-suspendable sediment.

Conclusions:

• % Sediment surface cover and % EPT abundance are potentially useful metrics for assessing sediment impacts on macroinvertebrates.
• EPT metrics may require combination with sediment cover data in multi-pressure riverine environments.