Biological trait analysis: application to the Waikato Regional Council Monitoring Programme
Report: TR 2012/04
Author: N Phillips, D Reid (NIWA)
As part of the Waikato Regional Council’s Regional Ecological Monitoring of Streams (REMS) programme, metrics based on macroinvertebrate taxonomic composition are used to describe the ecological health of the region’s aquatic resources.
An alternative approach is to use the biological traits of macroinvertebrates, as these reflect changes in ecosystem function rather than just changes in macroinvertebrate composition.
In this project, the response of both metrics and traits to a gradient of pastoral development (% pastoral) for Waikato streams was determined:
- A priori hypotheses were developed of likely responses of traits to these stressors.
- The effectiveness of metric and trait measures were compared for differentiating levels of impact.
- The potential influence of regional variation in taxonomy on the ability of metrics and traits to detect the impacts of rural development was examined by combining Waikato data with Auckland stream data.
- Finally, the potential use of traits as a mechanistic tool was investigated.
|2.2||Biological trait data||4|
|2.4||A priori predictions for trait responses||6|
|3||Variability associated with stream type||8|
|3.1||Reference site variability||8|
|4||Comparison of metric and trait responses to pastoral development||12|
|4.1||Stream type versus landuse||12|
|5||Ability to differentiate levels of impact||27|
|5.2||Metrics - all stream types||28|
|5.3||Traits - all streams||31|
|5.4||Metrics - Hard-bottomed stream||35|
|5.5||Traits - Hard-bottomed stream||38|
|5.6||Metrics - Soft-bottomed stream||42|
|5.7||Traits - Soft-bottomed stream||44|
|6||Combined analysis - Auckland Council and Waikato Regional Council||49|
|6.2||Variation in metrics||49|
|6.3||Variation in traits||52|
|7||Diagnostic value of traits||58|
|9||Conclusion and recommendations||66|
|10||Glossary of abbreviations and terms||68|
|Appendix A - Biological traits and trait categories and their codes||74|