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Biological trait analysis: application to the Waikato Regional Council Monitoring Programme

On this page: Abstract, table of contents

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.

Biological trait analysis: application to the Waikato Regional Council Monitoring Programme (2 mb)

Table of contents

  Executive summary v
1 Introduction 1
2 Methods 3
2.1 Data preparation 3
2.2 Biological trait data 4
2.3 Environmental data 5
2.4 A priori predictions for trait responses 6
2.5 Statistical analysis 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
4.2 Landuse impacts 14
5 Ability to differentiate levels of impact 27
5.1 Introduction 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
6.1 Introduction 49
6.2 Variation in metrics 49
6.3 Variation in traits 52
7 Diagnostic value of traits 58
8 Discussion 61
9 Conclusion and recommendations 66
10 Glossary of abbreviations and terms 68
11 References 70
  Appendix A - Biological traits and trait categories and their codes 74