Dr Ben Gawne Murray Darling Freshwater Research Centre. 30 May 2012

Transcription

1 Dr Ben Gawne Murray Darling Freshwater Research Centre 30 May 2012

2 1993 Walker, K. F. and M. C. Thoms (1993). "Environmental effects of flow regulation on the River Murray, South Australia,." Regulated Rivers: Research and Management 8: Sheldon, F. and K. F. Walker (1993). "Pipelines as a refuge for freshwater snails." Regulated Rivers Research & Management 8(3): Boulton, A. J. (1993). "Stream ecology and surface hyporheic hydrologic exchange: Implications, techniques and limitations." Australian Journal of Marine and Freshwater Research 44: Downes, B. J., P. S. Lake, et al. (1993). "Spatial variation in the distribution of stream invertebrates: implications of patchiness for models of community organization." Freshwater Biology 30: McComb, A. J. and J. A. Davis (1993). "Eutrophic waters of southwestern Australia. Fertilizer Research 36(2): James, K. R. and B. T. Hart (1993). "Effect of salinity on 4 freshwater macrophytes." Australian Journal of Marine and Freshwater Research 44(5):

3 Freshwater Ecology Development Data Analysis Patterns Hypotheses Model Conceptualization Prediction

4 <1970s Paul Humphries

5 Freshwater Ecology Development Data Analysis Patterns Hypotheses Model Conceptualization Prediction

6 How have we done? Chemicals Bacteria Algae Plants Birds Invertebrates Fish Reptiles Mammals

7 Blue Green Algae Phytoplankton Biomass ƒ(n) Internal Nitrogen r ƒ(p) ƒ(c) Internal Phosphorus Internal Carbon DYRESM CAEDYM ƒ(l), ƒ(t) ƒ(cuso4) CuSO4 Dose Vertical Migration Lewis et al. (2004) J App. Phyc.

8 Blackwater Photo: Alison King Discharge Aeration Algae Photo: Kerry Whitworth Water Column Dissolved Oxygen Floodplain Carbon Dissolved Organic Carbon Bacteria Temperature

9 Wetland acidification Carbon source Nutrients Oxygen Sulfides Acid Fertiliser Groundwater SO 4 2 (oxidized electron acceptor) Water Residence Time

10 Bird Breeding Total number of successful nests /01 Release of the Barmah Millewa Forest Environmental Water Allocation / / / / / / / / /91 R 2 = Discharge (GL/month) 1993/ / /97 David Leslie

11 Ok, so how are we doing? Chemicals Bacteria Algae Plants Birds Invertebrates Fish Reptiles Mammals

12 So, what s the next step?

13 Redgum response RRG at Hattah 2009 to Foliage abundance (%) Response variable Response reliant on condition Response not linear Individual trees Cond score 2009 Cond score 2010 Cherie Campbell

14 Influence of Flow in Context Multiple limitations Flow Geomorphology Physical Structure Food Water Quality Competitors Predators Response Cues Condition of Individuals Environmental characteristics

15 Variable response Quantitative predictions have low reliability Probabilistic predictions provide an alternative Stochastic Models Bayesian models

16 Model structure Wetland Characteristics Management Levers Recruitment Mortality Dispersal Larvae Juvenile Adult Population Structure Abundance Fish Condition Population Health

17 Current (pre-wetting) area of wetland? zero - dry < 10 ha ha ha ha ha ha > 5000 ha Likely nutrient status of wetland? Extreme nutrient/algae nutrient/algae Average nutrient/algae nutrient/algae Extreme nutrient/algae % newly inundated area with ASS? 0% 1-10 % % % % > 75% Current (pre-wetting) Max wetland depth less than 30cm thirty cm to 60 cm more than 60 cm Max Newly Inundated Shallow (<50cm)... zero - dry < 10 ha ha ha ha ha ha > 5000 ha Likely Piscivorous bird Abundance % decomposable veg cover in newly we... 0% 1-10 % % % % > 75% Predatory Fish abundance Max % inundated veg cover during sprin... 0% 1-10 % % % % > 75% Wetland depth (min thalweg) in summer? < 30 cm cm cm > 100 cm Source water River channel Large permanent channel large temporary channel temporary spur Predatory Fish efficiency Predatory bird efficiency Predation Pressure Spawning habitat quality/quantity Poor Average Good Spawning intensity YOY Gain YOY abundance YOY Immigration Time Inundation commenced January to February March to April May to June July to August September to October November to December Starting YOY abundance Likelihood YOY are present in the sourc P(YOY fish in sourcewater enter wetland) high proportion med proportion low proportion high proportion med proportion low proportion YOY Mortality YOY Loss Immature (>0+) abundance YOY emigration high proportion med proportion low proportion zero Adult abundance Duration_of_connection < 3 days 3 days to 2 weeks 2 weeks to 1 month > 1 month Immature (>0+) immigration Likelihood Immatures are present in sou... Immature (>0+) emigration high proportion med proportion low proportion zero Immature (>0+) Mortality high proportion med proportion low proportion Immature (>0+) Loss high proportion med proportion low proportion P(Immature fish in sourcewater enter w... Starting immature (>0+) abundance Food abundance/availability Extreme Extreme Method_of_wetland_filling Pumping - small Pumping - med Pumping - large Regulator controlled channel Unregulated channel Overbank flows Do all inflows come through carp screen... Yes No Likelihood adults are present in source P(Adult fish in sourcewater enter wetland) Adult immigration L of M due to Water Temperature Extreme Extreme Starting Adult abundance high proportion med proportion low proportion high proportion med proportion low proportion Adult emigration high proportion med proportion low proportion zero Adult Mortality Adult Loss L of M due to Dissolved Oxygen Extreme Extreme Blackwater likelihood Extreme Extreme Threat from blackwater and ASS Extreme Extreme L of M due to Water Quality Extreme Extreme CARP population structure Poor Moderate Good Total CARP abundance CARP Population Health Very poor 5.11 Poor 28.2 Moderate 21.5 Good 32.7 Excellent 12.5 Very poor Poor Moderate Good Excellent Fish Condition

18 Model structure Wetland Characteristics Management Levers Gudgeon Health Golden Perch Health Carp Health Smelt Health

19 Response and Condition Condition Intervention Characteristics Ecological Response Character Ecosystem Characteristics Nested Systems Requisite Variety Connectivity Iteration Co evolution Simple Rules Self Organising Edge of Chaos Emergence Sub Optimal

20 Generating the knowledge Iterative nature of complex systems makes understanding starting conditions important. Interaction among 3 high level components (intervention, character & condition) requires long term examination of replicate watering events to identify drivers of response.

21 So Predictive capacity has improved Improved conceptual understanding provides solid foundation for further improvement Need to develop; Modeling frameworks Ecological modeling capacity Important to link predictions more closely with condition assessments

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