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Regional Guidelines for Ecological Assessments of Freshwater Environments: Aquatic Plant Cover in Wadeable Streams

TR 2006/47
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Report: TR 2006/47

Author: Kevin Collier, Johlene Kelly (Environment Waikato), Paul Champion (NIWA)

Abstract

Environment Waikato is developing a series of guidelines to assist those involved in assessment and monitoring of freshwater ecosystems in the region. The guidelines are intended to establish a regionally consistent set of approaches for sample collection, analysis and reporting, and to set a minimum level of effort that workers are welcome to exceed. This set of guidelines describes the procedures used in Environment Waikato’s Regional Ecological Monitoring of Streams (REMS) programme to monitor cover by aquatic plants (typically periphyton and rooted macrophytes). The periphyton protocol uses an adaptation of Rapid Assessment Method 2 (RAM-2) from the Stream Periphyton Monitoring Manual (Biggs & Kilroy 2000), and a new rapid macrophyte assessment protocol has been developed. Both methods allow indices to be calculated for nutrient enrichment (periphyton), proliferation (periphyton and macrophytes) and naturalness (macrophytes).

Periphyton and macrophyte assessments are done in all streams irrespective of dominant substrate types. As these are rapid assessment approaches, they are recommended for broadscale surveys such as SOE monitoring, but may not be appropriate for targeted assessments aimed at addressing specific questions, such as compliance monitoring where more detailed analyses may be required. The protocols can be used for wadeable streams with adequate water clarity, but are not suitable for non-wadeable streams and rivers. Rivers should not be surveyed for aquatic plants if visibility is insufficient to enable a reliable assessment. Surveys should be conducted at baseflow as water levels much higher than this could affect assessments of macrophyte height. Both macrophyte and periphyton assessments are carried out over January to March to match the expected peak plant biomass times and precede macrophyte senescence.

Note: This report was originally published in February 2007. This new edition corrects a minor data error which appeared in Equation 1 on page 6 of the original report.

Regional Guidelines for Ecological Assessments of Freshwater Environments: Aquatic Plant Cover in Wadeable Streams [PDF, 989 KB]

Contents
  Acknowledgements i
1 Introduction 1
2 Periphyton cover rapid assessment 2
2.1 Protocol 2
2.2 Indices 4
2.2.1 Nutrient enrichment index 4
2.2.2 Biomass indices 4
2.3 Example 6
3 Macrophyte cover rapid assessment 8
3.1 Protocol 8
3.2 Indices 9
3.3 Example 9
  References 12
Appendix 1: Datasheet for periphyton rapid assessment. 13
Appendix 2: Datasheet for macrophyte rapid assessment. 14
  Channel and wetted widths are recorded here for convenience but are not used in the calculation of indices 14
  Total emergent 15
Appendix 3: Pictorial guide to some macrophyte species found in Waikato streams and rivers 16
Appendix 4: Pictorial guide to some macrophyte species that are considered biosecurity threats and
may be found in Waikato streams and rivers (report these to the Biosecurity officer)		 22