Environmental flows: Water allocations delivered to achieve environmental outcomes

Transcription

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2 Environmental flows: Water allocations delivered to achieve environmental outcomes

3 Contentious management problem

4 Discharge Antecedent conditions: Water allocation Antecedent conditions Wetland inundation Day of year

5 Objectives: Influence of different periodicities of wetland inundation on wetland fish assemblages. Implications for flow policies?

6 Study design overview Fish Data ~ Flow Data

7 Study sites: 6 floodplain wetlands on the Murray River Cottadidda Banyandah Lake Mulwala YARRAWONGA Dairy Snake Island Golf Course Quatt Quatta MURRAY RIVER OVENS RIVER Albury: 36 04'56"S, '37"E

8 Fish sampling: 3 time per year for 5 years 2-5 fyke nets per wetland 2-6 seine hauls per wetland

9 Average Daily Discharge (ML/d) 60,000 50,000 Corowa Yarrawonga 40,000 30,000 20,000,000 0 Jun-02 Jun-03 Jun-04 Jun-05 Jun-06 Jun-07 Jun-08 Jun-09 Jun- Jun-11 Jun-12

10 Antecedent Flow Metrics: Fish sampling year-1 year-2 year-3 year-4 year-5 Long-term Medium-term Short-term 4 years 9 months 3 months

11 Data

12 How do we analyze this data?

13 Linear model (or glm)? Catch ~ Poisson(Mean) Important assumption: - Catch is proportional to abundance Catch = p * Abundance p = Catch/Abundance

14 Constant detection probability? Variables Systematically Reference Sampling gear Coggins et al. (2014), Lauretta et al. (2013), Korman et al. (2009) Current Coggins et al. (2014), Lyon et al. (2014) Temperature Danzmann et al. (1991) Species Hangsleben et al. (2011), Dodrill et al. (2014), Lyon et al. (2014), Lauretta et al. (2013) Season Hangsleben et al. (2011) Abundance McInery & Cross (2000), Schoenebeck & Hansen (2005), Habitat Simpson (1978), Bayley & Austen (2002), Price & Peterson (20), Dodrill et al. (2014), Lyon et al. (2014) Water clarity Kirkland (1965), Simpson (1978), Gilliland (1987), Coggins et al. (2014), Lyon et al. (2014) Randomly Water body Hangsleben et al. (2011) Time Dodrill et al. (2014), Coggins et al. (2006)

15 N-mixture model? Important assumption: Catch ~ Binomial(Abundance,p) - Independence among individual fish - Independence among replicate samples

16 N = 00 P =.01 Mean = NP = Variance = NP(1-P) =9.9 Catch ~ Catch ~ N = P =.999 Mean = NP ~ Variance = NP(1-P) ~

17 Extra-binomial variation N = 0 N = 0 N = 19 Catch Catch Catch

18 Extra-binomial variation N bias high N = 0 P bias low N = 0 N = 19 Type-I error rates up Type-II error ~ rates

19 Royle-Nichols model Important assumption: p inc = 1-(1-p ind ) N Catch ~ Binomial(replicates,p inc ) - Independence among individual fish - Independence among replicate samples

20 Detection probability (p) Royle-Nichols model p inc = 1-(1-p ind ) N p = 1-1 r N r = 0.1 r = Abundance

21 Extra-binomial variation N = 0 N = 0 N = 19 Catch Catch Catch

22 Extra-binomial variation N bias low N = 0 P bias high N = 0 Type-I error rates up ~ N = 19 Type-II error rates

23 Modeling choices Generalized Linear Model Assumes detection is constant N-mixture model Models catch with binomial assumption Royle-Nichols model Models detection/non-detection data with binomial assumption

24 N covariates Model: Long-term Medium-term Short-term Long:Short-term Medium:Short-term Season Wetland (rand effect) p covariates Gear Wetland area Gear:Wetland area Wetland (rand effect) Abundance model (N) N log( i, ~ Poisson ( i, i, j j j ) * Covariates Detection model (p) p i r, j 1 (1 i, j j ) N i, j logit ( ri, j ) j * Covariates Observed detections (y) yi j Binomial( replicates, pi,, j Hyper-distributions j j ~ ) Normal(, ) ~ Normal(, ) )

25 Results Natives Carp gudgeon Unspecked hardyhead Australian smelt Flathead gudgeon Murray-Darling rainbowfish Golden perch Flat-headed glaxias River black fish N0n-Natives Eastern gambusia Common carp Goldfish Oriental weatherloach European perch

26 Results Natives Carp gudgeon Unspecked hardyhead Australian smelt Flathead gudgeon Murray-Darling rainbowfish Golden perch Flat-headed glaxias River black fish N0n-Natives Eastern gambusia Common carp Goldfish Oriental weatherloach European perch

27 Species-specific response: Species Short-term Medium-term Long-term LT:ST MT:ST Native species Australian smelt + Flathead gudgeon + + Carp gudgeon Unspecked hardyhead - Non-native species European perch Oriental weatherloach Gambusia + - Common carp Goldfish + -

28 Species-specific response: Species Short-term Medium-term Long-term LT:ST MT:ST Native species Australian smelt + Flathead gudgeon + + Carp gudgeon Unspecked hardyhead - Non-native species European perch Oriental weatherloach Gambusia + - Common carp Goldfish + -

29 Species-specific response: Species Short-term Medium-term Long-term LT:ST MT:ST Native species Australian smelt + Flathead gudgeon + + Carp gudgeon Unspecked hardyhead - Non-native species European perch Oriental weatherloach Gambusia + - Common carp Goldfish + -

30 Species-specific response: Species Short-term Medium-term Long-term LT:ST MT:ST Native species Australian smelt + Flathead gudgeon + + Carp gudgeon Unspecked hardyhead - Non-native species European perch Oriental weatherloach Gambusia + - Common carp Goldfish + -

31 Species-specific response: Species Short-term Medium-term Long-term LT:ST MT:ST Native species Australian smelt + Flathead gudgeon + + Carp gudgeon Unspecked hardyhead - Non-native species European perch Oriental weatherloach Gambusia + - Common carp Goldfish + -

32 Species-specific response: Species Short-term Medium-term Long-term LT:ST MT:ST Native species Australian smelt + Flathead gudgeon + + Carp gudgeon Unspecked hardyhead - Non-native species European perch Oriental weatherloach Gambusia + - Common carp Goldfish + -

33 Hypothetical flow policies: year-1 year-2 year-3 year-4 year-5 60 days of inundation Once every 5 years Once every year Once every 6 months Once every 3 months

34 Antecedent Flow Metrics: Fish sampling year-1 year-2 year-3 year-4 year-5 Long-term Medium-term Short-term 4 years 9 months 3 months

35 Hypothetical flow policies: year-1 year-2 year-3 year-4 year-5 Predicted ratio of native/non-native

36 River stage What did we learn? Western Carp Gudgeons Wetland inundation Fish assemblage? Australian Smelt Rudie Kuiter Flatheaded Gudgeon Year Ron Felix

37 River stage What did we learn? Gambusia Wetland inundation Fish assemblage? Carp Weatherloach Goldfish Year

38 Detection probability (r) What did we learn about sampling Fyke (a) Goldfish Common carp Gambusia Oriental weatherloach Seine European perch (b) Unspecked hardyhead Carp gudgeon Flathead gudgeon Australian smelt Wetland area

39 River stage River stage Implications for policy - Wetlands need water to be wetlands - Moderate expectations of managers and public - A call for more creative solutions - Validation Year Year

40 Detection probability (r) Implications for e-flow/fish research - Raise our consciousness of the detection process - Mine existing data sets - Directed flow experiments - A call for more creative solutions - Do not expect perfection Fyke Goldfish (a) Common carp Gambusia Oriental weatherloach Seine European perch (b) Unspecked hardyhead Carp gudgeon Flathead gudgeon Australian smelt Wetland area

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