CORANGAMITE CATCHMENT MANAGEMENT AUTHORITY OTWAYS BASIN BIOLOGICAL MONITORING December 2008 CCMA Otways Basin Bio-monitoring CERTIFICATE OF APPROVAL FOR ISSUE OF DOCUMENTS Report Title: Otways Basin Biological Monitoring Document Status: Final Date of Issue: 22 December 2008 Document No: 1054-2008-030 Project Title: Otways Basin Bio-monitoring Client: CCMA Comments: Position Name Signature Date Prepared by: Principal Ecologist Alistair Cameron 26/8/08 Internal Review by: Peer Review by: CCMA Approved by: Principal Ecologist Alistair Cameron 23/12/08 For further information on this report, contact: Name: Alistair Cameron Title: Principal Ecologist Address: 22 Dalmore Drive, Scoresby Phone: (03) 8756 8000 E-mail: [email protected] Document Revision Control Version Description of Revision Person Making Issue Date Approval 1 Final Editing Alistair Cameron 26/11/08 AC © Ecowise Environmental Pty Ltd This proposal and the information, ideas, concepts, methodologies, technologies and other material remain the intellectual property of Ecowise Environmental Pty Ltd. It is provided to prospective clients on a strict commercial- in-confidence basis, and at no time should any information about our proposal be divulged to other parties. Disclaimer This document has been prepared for the Client named above and is to be used only for the purposes for which it was commissioned. No warranty is given as to its suitability for any other purpose. Ecowise Environmental Pty Ltd ABN 68 074 205 780 Ecowise Environmental (Victoria) Pty Ltd ABN 94 105 060 320 Enviro-Managers Pty Ltd ABN 18 072 428 810 1054-2008-030 i Final CCMA Otways Basin Bio-monitoring TABLE OF CONTENTS 1 Introduction 1 2 Methods 1 2.1 Site Selection 1 2.2 Water quality Monitoring 2 2.3 Macroinvertebrate Monitoring 2 3 Results 4 3.1 Water Quality 4 3.2 Macroinvertebrates 5 4 Conclusions 6 5 References 7 Appendices Appendix A – Site Photos Appendix B – Macroinvertebrate Riffle Data Appendix C – Macroinvertebrate Edge Data Table of Figures Figure 1 Site Locations ........................................................................................................... 2 List of Tables Table 1 Sampling Sites in the Otways – Latitudes and Longitudes ........................................ 1 Table 2 Water quality measurements on each sampling event .............................................. 4 Table 3 Macroinvertebrate Indices – combined season data .................................................. 5 1054-2008-030 Final CCMA Otways Basin Bio-monitoring 1 Introduction Macroinvertebrates are common to all freshwater systems and play a major role in the functioning of the ecosystem. They comprise a variety of trophic groups, including filter feeders, algal grazers, leaf shredders, wood miners, predators and deposit feeders. In addition, they are an important food source for other animals and their well being is reflected in the health of other animals higher in the food chain. Aquatic macroinvertebrates are sensitive to changes in water quality and quantity and certain taxa are absent or depleted from rivers that are affected by human activities. Macroinvertebrates are recommended for the general assessment of the ecological health of a system and are particularly useful for detecting toxic effects and oxygen stress (EPA 2003a). Ecowise Environmental (Victoria) was engaged by the Corangamite Catchment Management Authority (CCMA) to examine the macroinvertebrate communities in six streams in the Otways Basin. The assessment of the streams was based on requirements of the Victorian River Health Strategy (DNRE 2002) for CMA to ensure the natural values of these highly valued streams are maintained. Sites were selected as the streams were deemed to have high biological integrity, show little anthropogenic impact and that the areas are of high statewide and natural value. The health of the waterways was determined by comparing the community structure against inst Environmental Protection Authority (EPA) State Environmental Protection Policy (SEPP) objectives. This report also includes interpretation of the data against measured habitat and water quality parameters. 2 Methods 2.1 Site Selection Six sites were examined in streams across the Basin in November 2007 and May 2008. Streams examined include the Aire River, Carisbrook Creek, Elliot River, Grey River, Parker River and Smythes Creek. The exact locations of sites were provided by the CCMA and are presented in Table 1 and Figure 1. Site photos are presented in Appendix A. Table 1 Sampling Sites in the Otways – Latitudes and Longitudes Reach Location Latitude Longitude Aire Crossing, Wait-a While Road- Aire River 38.70317 o 143.47878 o 100m upstream Carisbrook Creek 100m upstream from coast 38.69185 o 143.80948 o Elliot River Elliot Road crossing- 20 m upstream 38.78231 o 143.61653 o Grey River Road crossing, 20m Grey River 38.65969 o 143.81607 o downstream of Grey River Picnic Area Cape Otway – Blanket Bay Road, 20m Parker River 38.84216 o 143.54222 o upstream Smythes Creek 100m upstream from coast 38.70339 o 143.76167 o 1054-2008-030 Final 1 CCMA Otways Basin Bio-monitoring Figure 1 Site Locations 2.2 Water quality Monitoring In-situ measurements of water temperature, dissolved oxygen concentration, pH, and electrical conductivity were made at each site on each sampling period using a calibrated multiprobe (HydroLab ‘Quanta’ or Horiba multiprobes). One water sample per site was collected for laboratory analysis of turbidity. Alkalinity was also measured during the macroinvertebrate sampling events, primarily to use as an input into AusRivAS macroinvertebrate predictive models. 2.3 Macroinvertebrate Monitoring A rapid bioassessment (RBA) methodology for the sampling of the macroinvertebrates was is conducted in the present study, where the main aim is to collect the greatest diversity of animals within a set time period (EPA, 1998a). For the purposes of consistency samples were taken over a 10 metre stretch although the distance was not necessarily continuous. A 10 metre stretch of edge habitat was sampled using sweep nets with a 250 μm mesh size. Edge habitat is defined as the bank area of pool areas where little or no current is evident. Sampling involved vigorously sweeping the net through the water column and above the substrate resulting in macroinvertebrates being suspended in the water column before being collected with the net. Any aquatic vegetation in edge habitats were sampled in a similar manner. The benthic habitat was sampled using a kick net and involves holding a net on the bottom of the river and disturbing the substrate immediately upstream of the net with ones feet so that dislodged animals are carried by the current into the net. Approximately 10 metres of substrate in riffle habitat (area of fast flowing, shallow water) was sampled per kick sample. Benthic samples could not be collected from Elliot Creek or Parker River as there was not sufficient flow to wash the macroinvertebrates into the collecting net. 1054-2008-030 Final 2 CCMA Otways Basin Bio-monitoring The contents of each net were spread out onto large trays and live sorted in the field for a standard time of 30 minutes. An extra 10 minutes of live sorting was conducted if there were less than 200 animals. Additionally another extra 10 minutes of live sorting was conducted if new taxa were collected in the last 5 minutes. Live sorting was undertaken for a maximum of one hour. Animals captured with the aid of forceps and pipettes were preserved in 80% ethanol and retained for identification in the laboratory. With the aid of a stereomicroscope, macroinvertebrates were identified to family taxonomic resolution with the exception of Chironomids (Diptera) which were identified to sub-family in accordance with EPA protocols. 2.3.1 SEPP Guidelines SEPP’s have been developed by EPA Victoria (EPA 2003b) to provide objectives for monitoring of creeks and rivers in the state. Water quality guidelines also exist except they are based upon percentile data that requires a minimum of 11 sampling events. Water quality is therefore not compared against the SEPP however results are interpreted against the guidelines. All waterways in this project fall within the ‘Forests B’ bioregion (B3) which also encompasses the Otways Basin. All following results will be discussed in comparison to these objectives. Objectives can be found at the top of the data tables. Calculation of preliminary macroinvertebrate indices was performed using Ecowise’s database program. The SEPP objectives developed for macroinvertebrate data are based on two season’s data and therefore macroinvertebrates were combined at the site level from each sampling event. Apart from the index Key Number of Families, where habitats are combined, all other indices are based on the habitat sampled. SIGNAL (Stream Invertebrate Grade Number - Average Level) is an index of water quality based on the known tolerances of macroinvertebrate families to pollution. Families have been assigned pollution sensitivity grades from 1 (very tolerant) to 10 (very sensitive) based on their known tolerances to a variety of pollution types (Chessman 1995). Macroinvertebrate families were assigned SIGNAL scores from the RBA manual (EPA 2003a). If all families found at a site are tolerant of pollution (have low tolerance grades) it is reasonable to conclude that this site is polluted, and, conversely, if many families sensitive to pollution are present at a site then it may be assumed that this site is not polluted. The average