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Jul 20, 2023 284 likes •525 views

Potential impacts of climate change and irrigation development on fish refugia in the ephemeral rivers of Northern Australia. Jim Wallace 1 , Nathan

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SLIDE 1

Potential ¡impacts ¡of ¡climate ¡change ¡and ¡ irrigation ¡development ¡on ¡fish ¡refugia ¡in ¡the ¡ ephemeral ¡rivers ¡of ¡Northern ¡Australia. ¡ ¡ . ¡

¡ ¡

¡

Jim ¡Wallace1, ¡Nathan ¡Waltham1, ¡Damien ¡Burrows1 ¡and ¡David ¡McJannet2 ¡

¡

1Centre ¡for ¡Tropical ¡Water ¡& ¡Aquatic ¡Ecosystem ¡Research ¡(TropWATER), ¡

James ¡Cook ¡University, ¡Townsville, ¡QLD ¡4811, ¡Australia. ¡ ¡

2CSIRO ¡Land ¡and ¡Water, ¡EcoSciences ¡Precinct, ¡Dutton ¡Park, ¡QLD ¡4120, ¡Australia. ¡

¡

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SLIDE 2
  • ¡Rivers ¡in ¡northern ¡Australia ¡
  • Study ¡locations ¡in ¡the ¡Flinders ¡and ¡Gilbert ¡catchments ¡
  • Importance ¡of ¡dry ¡season ¡waterholes ¡
  • Waterhole ¡temperature ¡
  • Measurements ¡
  • Optimum ¡and ¡lethal ¡thresholds ¡for ¡fish ¡
  • Modelling ¡
  • Potential ¡impacts ¡of ¡climate ¡change ¡& ¡irrigation ¡

development ¡

  • Conclusions ¡

¡

Outline ¡

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SLIDE 3

Climate ¡& ¡waterhole ¡locations ¡

ASFB & ASL Joint Congress, Cairns, 30 June – 4 July 2014

Climate

  • Flinders mean rainfall: 492 mm
  • Gilbert mean rainfall: 775 mm
  • Potential evaporation: 1866 mm

River flow Waterholes

  • 10 waterholes in each catchment
  • All in-channel (except 3 Flinders)
  • Flinders: 5 ephemeral, 5 permanent
  • Gilbert: 10 permanent
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SLIDE 4

Dry ¡season ¡waterholes ¡

F07: 9 September 2012 F07: 20 December 2012 F03:19 December 2012 F03: 18 September 2012

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SLIDE 5

Water ¡temperature ¡measurements ¡

  • Hobo sensors (Onset

Corporation) attached to large float

  • Top sensor 20 cms below

surface

  • Bottom sensor 15 cms

above bottom

  • Data recorded every 20

mins

  • September 2013 to May

2014

Continuous temperature rig in the Gilbert catchment. The larger float has the surface probe fixed to the bottom of the float to remain in the water column and shield from direct sunlight. The smaller float tether is a locator buoy. Reproduced from Waltham et al., (2013).

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SLIDE 6

Water ¡& ¡air ¡temperature ¡data ¡

ASFB & ASL Joint Congress, Cairns, 30 June – 4 July 2014

  • Surface (blue) & bottom (green) temperature. Air temperature (red) & daily rainfall (black).

0" 10" 20" 30" 40" 50" 60" 70" 80" 5" 10" 15" 20" 25" 30" 35" 40" 45"

14/12/2012" 15/12/2012" 16/12/2012" 17/12/2012" 18/12/2012" 19/12/2012" 20/12/2012" 21/12/2012" 22/12/2012" 23/12/2012" 24/12/2012" 25/12/2012" 26/12/2012" 27/12/2012"

Rainfall'(mm)' Temperature'(oC)'

Flinders catchment waterhole F05 during December 2012

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SLIDE 7

Water ¡& ¡air ¡temperature ¡data ¡

ASFB & ASL Joint Congress, Cairns, 30 June – 4 July 2014

  • Surface (blue) & bottom (green) temperature. Air temperature (red) & daily rainfall (black).
  • Preferred temperature, Tpref (- - - - ) 31oC Bony bream (Nematalosa erebi) Pusey et al., (2004).

Flinders catchment waterhole F05 during December 2012

0" 10" 20" 30" 40" 50" 60" 70" 80" 5" 10" 15" 20" 25" 30" 35" 40" 45"

14/12/2012" 15/12/2012" 16/12/2012" 17/12/2012" 18/12/2012" 19/12/2012" 20/12/2012" 21/12/2012" 22/12/2012" 23/12/2012" 24/12/2012" 25/12/2012" 26/12/2012" 27/12/2012"

Rainfall'(mm)' Temperature'(oC)'

Flinders catchment waterhole F05 during December 2012

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SLIDE 8

Water ¡& ¡air ¡temperature ¡data ¡

ASFB & ASL Joint Congress, Cairns, 30 June – 4 July 2014

  • Surface (blue) & bottom (green) temperature. Air temperature (red) & daily rainfall (black).
  • Preferred temperature, Tpref (- - - - ) 31oC Bony bream (Nematalosa erebi) Pusey et al., (2004).
  • Critical thermal maximum, CTmax (ŸŸŸŸŸ) 33.5 oC Fly speckled hardyhead (Craterocephalus stercusmuscarum)

Burrows and Butler, (2012).

Flinders catchment waterhole F05 during December 2012

0" 10" 20" 30" 40" 50" 60" 70" 80" 5" 10" 15" 20" 25" 30" 35" 40" 45"

14/12/2012" 15/12/2012" 16/12/2012" 17/12/2012" 18/12/2012" 19/12/2012" 20/12/2012" 21/12/2012" 22/12/2012" 23/12/2012" 24/12/2012" 25/12/2012" 26/12/2012" 27/12/2012"

Rainfall'(mm)' Temperature'(oC)'

Flinders catchment waterhole F05 during December 2012

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SLIDE 9

Threshold ¡temperature ¡exceedance ¡

0" 10" 20" 30" 40" 50" 60" 70" 80" 90" 100" 20" 22" 24" 26" 28" 30" 32" 34" 36" 38" 40"

%"#me"above"threshold"temperature" Threshold"temperature"(oC)"

G10 (clear/well mixed – solid lines)

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SLIDE 10

Threshold ¡temperature ¡exceedance ¡

0" 10" 20" 30" 40" 50" 60" 70" 80" 90" 100" 20" 22" 24" 26" 28" 30" 32" 34" 36" 38" 40"

%"#me"above"threshold"temperature" Threshold"temperature"(oC)"

G10 (clear/well mixed – solid lines)

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SLIDE 11

Threshold ¡temperature ¡exceedance ¡

0" 10" 20" 30" 40" 50" 60" 70" 80" 90" 100" 20" 22" 24" 26" 28" 30" 32" 34" 36" 38" 40"

%"#me"above"threshold"temperature" Threshold"temperature"(oC)"

G10 (clear/well mixed – solid lines)

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SLIDE 12

Threshold ¡temperature ¡exceedance ¡

0" 10" 20" 30" 40" 50" 60" 70" 80" 90" 100" 20" 22" 24" 26" 28" 30" 32" 34" 36" 38" 40"

%"#me"above"threshold"temperature" Threshold"temperature"(oC)"

G10 (clear/well mixed – solid lines)

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SLIDE 13

Threshold ¡temperature ¡exceedance ¡

0" 10" 20" 30" 40" 50" 60" 70" 80" 90" 100" 20" 22" 24" 26" 28" 30" 32" 34" 36" 38" 40"

%"#me"above"threshold"temperature" Threshold"temperature"(oC)"

G10 (clear/well mixed – solid lines)

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SLIDE 14

Threshold ¡temperature ¡exceedance ¡

0" 10" 20" 30" 40" 50" 60" 70" 80" 90" 100" 20" 22" 24" 26" 28" 30" 32" 34" 36" 38" 40"

%"#me"above"threshold"temperature" Threshold"temperature"(oC)"

G10 (clear/well mixed – solid lines)

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SLIDE 15

Threshold ¡temperature ¡exceedance ¡

0" 10" 20" 30" 40" 50" 60" 70" 80" 90" 100" 20" 22" 24" 26" 28" 30" 32" 34" 36" 38" 40"

%"#me"above"threshold"temperature" Threshold"temperature"(oC)"

G10 (clear/well mixed – solid lines) F07 (turbid/stratified– dashed lines)

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SLIDE 16

Threshold ¡temperature ¡exceedance ¡

0" 10" 20" 30" 40" 50" 60" 70" 80" 90" 100" 20" 22" 24" 26" 28" 30" 32" 34" 36" 38" 40"

%"#me"above"threshold"temperature" Threshold"temperature"(oC)"

G10 (clear/well mixed – solid lines) F07 (turbid/stratified– dashed lines)

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SLIDE 17

Waterhole ¡temperature ¡modelling ¡

0" 5" 10" 15" 20" 25" 30" 35" 40"

25/08/2012" 08/09/2012" 22/09/2012" 06/10/2012" 20/10/2012" 03/11/2012" 17/11/2012" 01/12/2012" 15/12/2012" 29/12/2012" 12/01/2013" 26/01/2013" 09/02/2013" 23/02/2013" 09/03/2013"

Daily&average&temperature&(oC)&

  • Energy balance model (Wallace et al., 2015); Rn ± δHw = Ha + E {daily time step}
  • Inputs; solar radiation, air temperature, relative humidity (SILO) and wind speed (2 m s-1)
  • Outputs; daily mean water temperature & evaporation

Flinders waterhole F05 {clear / well mixed}

20# 22# 24# 26# 28# 30# 32# 34# 20# 22# 24# 26# 28# 30# 32# 34#

Model&daily&average&temperature&(oC)& Measured&daily&average&temperature&(oC)&

&

Tmodel = 0.93 Tmeasured + 2.2 (r2 = 0.96)

Poorer correlations;

  • Flowing streams
  • Turbid / stratified waterholes
  • Windier sites
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SLIDE 18

Climate ¡change ¡impacts ¡

ASFB & ASL Joint Congress, Cairns, 30 June – 4 July 2014

  • Simulations;
  • Mid-Flinders 2m waterhole
  • Zero flow starts 1 May 2012
  • Green – current climate
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SLIDE 19

Climate ¡change ¡impacts ¡

ASFB & ASL Joint Congress, Cairns, 30 June – 4 July 2014

  • Simulations;
  • Mid-Flinders 2m waterhole
  • Zero flow starts 1 May 2012
  • Green – current climate
  • Red – air 2 oC warmer
  • Climate scenario;
  • Petheram and Yang (2013)
  • Air Temperature + 2 oC
  • Rainfall – no change
  • Climate impacts;
  • Depth; - 90 mm
  • Evaporation; + 0.4 mm d-1
  • Temperature; + 1.1 OC

0.5$ 1.0$ 1.5$ 2.0$ 2.5$ 01/05/2012$ 01/06/2012$ 01/07/2012$ 01/08/2012$ 01/09/2012$ 01/10/2012$ 01/11/2012$ 01/12/2012$

Depth$(m)$

(A)$

$current$climate$+$2$K$ $current$climate$ 15$ 20$ 25$ 30$ 35$ 01/05/2012$ 01/06/2012$ 01/07/2012$ 01/08/2012$ 01/09/2012$ 01/10/2012$ 01/11/2012$ 01/12/2012$

Temperature!(oC)!

(B)$

0$ 2$ 4$ 6$ 8$ 10$ 12$ 01/05/2012$ 01/06/2012$ 01/07/2012$ 01/08/2012$ 01/09/2012$ 01/10/2012$ 01/11/2012$ 01/12/2012$

EvaporaEon$(mm$dG1)$

(C)$

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SLIDE 20

Climate ¡impact ¡on ¡exceedance ¡of ¡Tpref ¡& ¡ ¡CTmax

¡

0" 10" 20" 30" 40" 50" 60" 70" 80" 90" 100" 20" 22" 24" 26" 28" 30" 32" 34" 36" 38" 40"

%"#me"above"threshold"temperature" Threshold"temperature"(oC)"

Surface Tpref ; from 51% to 73% CTmax ; from 14% to 26% Bottom Tpref ; from 30% to 56% CTmax ; from 0% to 2% G10 (clear/well mixed)

  • Current climate – solid lines
  • Future climate – dashed lines
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SLIDE 21

Conclusions ¡– ¡temperature ¡data ¡

ASFB & ASL Joint Congress, Cairns, 30 June – 4 July 2014

  • High time resolution waterhole temperature measurements;
  • Reveal important aspects of the thermal regime in waterholes and help

assess their suitability as aquatic habitats.

  • Thermal frequency curves; provide an estimation of how long the

waterhole temperature is above optimal and lethal thresholds for fish (& other aquatic species).

  • In Flinders & Gilbert waterholes surface temperature often exceeds

these thresholds; water near the bottom does so on fewer/shorter

  • ccasions.
  • Turbid (and/or deep) waterholes can sustain bottom water

temperatures below the lethal threshold throughout the entire summer

  • period. These waterholes are therefore more thermally suited for fish; if

they can remain close to the bottom of the waterhole ( - oxygen ??).

  • Conclusions hold for any temperature thresholds between ~ 28 – 35oC

(due to steep slope of the frequency curve).

  • Urgent need for more acute and chronic thermal thresholds for a range of

aquatic species in tropical rivers (ongoing work in TropWATER).

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SLIDE 22

Conclusions ¡– ¡climate ¡impacts ¡

  • Daily mean water temperatures can be modelled using readily available

weather data with reasonable accuracy in waterholes that are well mixed (accuracy declines in stratified waterholes & windy sites).

  • The model predicts a ~ 1 oC rise in waterhole temperature under a 2 oC

warmer climate.

  • This increase ~ doubles the amount of time water temperatures exceed
  • ptimal and potentially lethal thresholds for fish.
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SLIDE 23

Thank you – questions ?

Jim Wallace TropWATER European Office 4 Fairfield House Rectory Close Newbury United Kingdom Phone UK: +44 1635 770634 Mobile UK: +44 7928 625200 Mobile Australia: 0415 221750 Email: jim.wallace@mail.com Phone: +61 7 4781 4262 Email: Damien.Burrows@jcu.edu.au Web: www.jcu.edu.au/tropwater Contact: TropWATER, Australia

Further details of this research in: Wallace, J., Waltham, N., Burrows, B and McJannet, D.

  • 2015. The temperature regimes of dry-season waterholes in

tropical northern Australia: potential effects on fish refugia. Freshwater Science 34(2). DOI:10.1086/681278.