1. Developing methodology for assessing pressures on estuaries: relationships with catchment condition Jan Barton, Gerry Quinn, John Sherwood (Deakin University, Warrnambool)

2. Project background Estuaries major foci of human activity –easily degraded Major drivers of estuarine condition –upstream catchment modification –freshwater extraction –urban and coastal development –opening and closing of estuary mouths Little information on relative importance of different drivers to estuarine condition

3. Project background Restoration –environmental flows –longitudinal (upstream) & lateral (floodplain) connectivity Restoration targets –commonly water quality, algal blooms, recreational fishing, waterbirds –other targets, such as ecological condition?

4. Project background Two years NHT-funds through DSE –Deakin University to provide science underpinning management of estuaries Jan Barton, Gerry Quinn, John Sherwood –only initial funding yet approved –commenced October 05

5. Aims Identifying relationship between key pressures and rehabilitation tools and measures of ecological condition of estuarine environments –summarising measures (indicators) of both pressures on estuaries and condition or health of estuaries –assessment of effectiveness of relevant estuarine indicators –available datasets for Victoria’s estuaries GIS-referenced database –validate cause-effect relationships between pressures and estuarine condition responses

6. Project overview Literature review Conceptual models Data collation and analysis Indicator development analysis Testing cause-effect relationships

7. Literature review Focus on links between estuaries and pressures & rehabilitation Local, national and international literature Build on Barton (2003) and Barton PhD Strategic review (e.g. Lloyd et al. 2003): –directions of response to drivers –quantitative effect (response) sizes –methods (e.g. spatial comparisons, experimental) –indicators used

8. Relevant recent literature USA –many recent papers relating biological & chemical characteristics of estuaries to surrounding watersheds (e.g. land-use) –estuaries different to Vic (generally permanently open, predictable flows) South Africa –links between flow changes and biological condition of estuaries (focus on fish) –more comparable to Vic (size, flows)

9. Relevant recent literature Australian –estuary classifications, estuarine fish (life cycles), nutrient cycling –little work linking estuaries to catchments, except Edgar et al. (Tasmania) Focused on large estuaries (e.g. Chesapeake, Moreton, Port Phillip Bays) –little data on smaller, typical, representative, estuaries

10. Conceptual models Ozestuaries (NLWRA) database –different models for different estuary types –models descriptive (pictorial), focus on materials rather than biota and interactions Simple Estuarine Response Model (SERM) –generic (national?) allowing quantitative relationships –less applicable to smaller, intermittently open, estuaries Little data available to populate or validate models Requirement for models for local, smaller, estuaries –targeted data collection to fill key knowledge gaps

11. Data collation and analysis Find and collate available data on Victorian estuaries –methodology for GIS-referenced database –summary measures of catchment, estuary and nearby coastal environment using most appropriate indicators Classification of Victoria’s estuaries (again!?....) –following Edgar et al. (1999) for Tasmanian estuaries

12. Available data Previous local summaries: –collations/theses by Deakin (Arundel, Matthews, Mondon, Pope, Sherwood) and Flinders (Barton, Fairweather, Hirst) Other data –NLWRA habitat mapping (large-scale) –species lists within management plans –little on biota except fish (ARI, PIRVic) –EPA WQ monitoring –Barton PhD

13. Barton PhD Data and field sampling for 31 estuaries in central and west Victoria –previously sampled for WQ by Vic EPA Fine-scale geographic data collated Some limited hydrology and mouth data available Physico-chemical, nutrients, metals measured Biota sampled –microbial, macroinverts, macroalga, microflora

14. Indicator development Pressure indicators –amended Annual Proportional Flow Deviation –GIS mapping vegetation change land-use change metrics Estuary response indicators –Barton PhD (following talk) Cost-effectiveness of indicators? Causal links between pressure and response indicators?

15. Cause-effect 1 Spatial comparison across estuaries with different catchment characteristics, mouth opening/closing regimes etc. –broad-scale correlation –probably inadequate data available (esp. estuarine response) except….. Barton PhD –31 estuaries ranging from degraded (e.g. Curdies) through “pristine” (e.g. St George, Tidal Rivers)

16. Cause-effect 2 Estuary responses to natural “pulse” disturbances –floods, droughts, mouth opening/closing, deoxygenation events Targeted sampling before and after Spatial comparison to “control” estuaries –too much-between estuary variation –comparable estuaries close so similar disturbances Match mouth opening and catchment size across estuaries Maybe east-facing estuaries along GOR

17. Cause-effect 3 Evaluate response of estuaries to specific management actions –environmental flow releases (e.g. Coorong and Murray flows) –nutrient management schemes (e.g. regularly monitoring algal blooms) –estuary mouths artificially opened or closed (e.g. non-management action in Surry) Management (ecosystem) experiments

18. Decision tools for managers Estuary open/close decision support tool –Deakin (Arundel & Sherwood) Risk assessment Bayesian Decision Networks VPSIRR –vulnerability – pressure – state – impact - risk and response –experience from DIPNR NSW, ANU (ICAM) and Coastal CRC (MODSIM conference)