Land-use change and climate change effects on the in-stream animals of Westernport streams and rivers, and potential mitigating management actions

Transcription

1 Land-use change and climate change effects on the in-stream animals of Westernport streams and rivers, and potential mitigating management actions Chris Walsh, Yung En Chee (University of Melbourne), Rhys Coleman (Melbourne Water), and Nick Bond (Latrobe University) Melbourne Waterway Research-Practice Partnership

2 My brief today The nature of rivers and their catchments Drivers of habitat suitability in rivers and streams Predicting distributions of instream animal species The effects of urbanization and climate change (and their interaction) on habitat suitability and distributions Potential management actions to mitigate those effects Melbourne Waterway Research-Practice Partnership

3 What makes a healthy stream? Lightwood Creek, Mornington Peninsula National Park

4 Adapted from Roberts D. (1985). 'From swampland to farmland: a history of the Koo- Wee-Rup flood protection district.' (Rural Water Commission of Victoria: Melbourne.)

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6 Map showing rivers, creeks and drains for Westernport catchment as used in the model

7 Red lines on the map are showing urban stormwater drains

8 20+ years of biological data The models use data from Melbourne Water s biological monitoring programs

9 Environmental Data: carefully selected variables (e.g. ) Mean annual discharge depth Mean annual air temperature Effective imperviousness Weighted forest cover

10 Overview of the Habitat Suitability Modelling Process Biological data Model fitting MODELLING Model selection Model evaluation DATA Environmental predictors understand predict SDM OUTPUTS Applications

11 Habitat Suitability Models (HSMs) 59 macroinvertebrate families 23 fish species Total Platypus & Female-only Platypus Today, a focus on 53 macroinvertebrate families

12 Mean annual air temperature ( o C)

13 Mean annual discharge depth (mm)

14 Connected imperviousness (stormwater drainage impacts)

15 Weighted forest cover (riparian forest most important)

16 Manipulating predictor variables to simulate scenarios of human actions and climate change. The example of 53 sensitive macroinvertebrate families

17 1. What it once was. Number of sensitive macroinvertebrate families in the absence of human impacts

18 2. What it is today. Number of sensitive macroinvertebrate families in 2016

19 3. (BAU) urban growth in a warmer, drier climate Number of sensitive macroinvertebrate families following urban expansion o warmer climate + 25% less river flow (urban growth area fully developed, assuming business-as-usual stormwater management, no change in forest cover)

20 Instream habitat suitability for instream biota (animals) Business as usual Future BAU FUTURE

21 What we can do in the face of expected future changes? Warmer temperatures Drier conditions Increasing urbanisation (increasing stormwater runoff from impervious land cover) Management Interventions Effectively manage SW (stormwater) in Future Urban Areas Reveg riparian areas Remove instream barriers

22 LUMaR macroinvertebrate index BAU urban growth in a warmer, drier climate (The base case)

23 Difference in LUMaR from BAU future if All future urban development retains urban stormwater adequately

24 Difference in LUMaR from BAU future if All future and existing urban development retains urban stormwater adequately

25 Difference in LUMaR from BAU future if 20-m revegetation along reaches

26 Difference in LUMaR from BAU future if 20-m revegetation along reaches and all future urban development retains urban stormwater adequately

27 Difference in native fish index from BAU future if All barriers removed

28 Difference in native fish index from BAU future if Primary barriers removed and 20-m revegetation along reaches and all future urban development retains urban stormwater adequately

29 Female platypus 2016

30 Female platypus (BAU) urban growth in a warmer, drier climate

31 Difference in female platypus from BAU future if 20-m revegetation along reaches and all future urban development retains urban stormwater adequately

32 Difference in female platypus from BAU future if Future climate is not drier + 20-m revegetation along reaches and all future urban development retains urban stormwater adequately