A multiple index integrating different levels of organization

Area of Science:

• Environmental Science
• Ecology
• Aquatic Biology

Background:

• Current freshwater biomonitoring often uses limited biological organization levels.
• This restricts the assessment of cause-effect relationships from anthropogenic impacts.
• A more integrated approach is needed to capture a wider spectrum of ecological responses.

Purpose of the Study:

• To develop an integrated bioassessment tool for evaluating ecological status in rivers.
• To combine multiple levels of biological organization for a comprehensive assessment.
• To address limitations of current biomonitoring methods in detecting anthropogenic impacts.

Main Methods:

• Combined biological biomarkers (histopathology, biochemistry), community bioindicators (fish guilds, invertebrates, chironomids), and ecosystem functional indicators (decomposition rates).
• Assessed ecological status at Water Framework Directive (WFD) monitoring sites across a human impact gradient in northern Portugal.
• Utilized Random Forest analysis to rank indicator importance and establish class discrimination levels.

Main Results:

• A total of 59 Biological Quality Elements and functional indicators were determined.
• Random Forest effectively ranked variables and identified cut levels for ecological status classes.
• The integrated approach demonstrated potential for robust ecological status assessment.

Conclusions:

• The developed Multiple Ecological Level Index (MELI Index) offers a powerful bioassessment tool.
• Integrating diverse ecological levels enhances the sensitivity to anthropogenic impacts.
• This approach provides a more comprehensive understanding of riverine ecosystem health.