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Assessing biological integrity using freshwater fish and decapod habitat selection functions
Michael K Joy1, Russell G Death
1Institute of Natural Resources-Ecology, Massey University, Private Bag 11 222 Palmerston North, New Zealand. mikejoy@clear.net.nz
Environmental Management
|May 27, 2004
Summary
This study introduces a new method for assessing river health using fish and decapod data, adapting the RIVPACS approach. The developed models effectively predict expected species assemblages to measure biological integrity in flowing waters.
Area of Science:
- Freshwater ecology
- Environmental monitoring
- Bioassessment
Background:
- Biological integrity assessment using observed vs. expected taxa is ecologically meaningful.
- The River Invertebrate and Classification System (RIVPACS) is a successful model for macroinvertebrate-based assessments.
- Extending this approach to fish and decapod assemblages offers a novel bioassessment tool for flowing waters.
Purpose of the Study:
- To develop a predictive model for assessing biological integrity in flowing waters using freshwater fish and decapod assemblages.
- To adapt and extend the RIVPACS predictive model approach for fish and decapod bioassessment.
- To evaluate the model's performance using internal validation tests and comparisons between reference and impacted sites.
Main Methods:
- Developed discriminant models for the 12 most common fish and decapod species based on presence/absence data from 118 reference sites in Auckland, New Zealand.
- Modeled individual species separately, avoiding the biotic classification step of traditional RIVPACS.
- Predicted expected species assemblages at new sites using environmental data and calculated Observed/Expected (O/E) ratios for biological integrity assessment.
Main Results:
- Successfully developed individual discriminant models for 12 key fish and decapod species.
- The models predicted expected species assemblages, enabling O/E ratio calculation for biological integrity assessment.
- Internal validation tests (jackknifing, data partitioning) and comparisons with impacted sites demonstrated model robustness and efficacy.
Conclusions:
- The developed method provides a robust and adaptable approach for assessing biological integrity in flowing waters using fish and decapod assemblages.
- This fish and decapod-based model offers a valuable extension to existing bioassessment tools like RIVPACS.
- The approach is effective in distinguishing between reference and human-impacted sites, supporting environmental management decisions.