Climate Change and mangrove/saltmarsh communities

Neil Saintilan Head, Rivers and Wetlands Unit NSW Department of Environment and Climate Change

Endangered Ecological Community Endangered species Wilsonia backhousei Figure courtesy of AWSG

Bat Foraging

 Anabat detector installed in seven sites in NSW and Victoria.

 Threatened bat species detected at Kooragang Island on the Hunter River Nightly activity of bats

70 60 50 40 30 20 No. of passes 10 0

1:00 2:00 3:00 4:00 5:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00:00 Time

V. vulturnus M. norfolkensis C. morio M. australis Zooplankton abundance in different locations towards the Bay

10000 9000 Other zooplankton 8000 7000 6000 Crab larva 5000 4000 3000 2000 1000 0

Saltm. (A) Mang. (B) Seagr.(C) Bay (D) Zooplankton density Zooplankton cubic per metre water Larval export through mangrove to estuary Mangrove Encroachment

Saltmarsh decline Saltmarsh Region Location Timescale Reduction* Reference Queensland Hinchinbrook Chan. 1943-1991 78% Duke, 1995 Oyster Point 1944-1983 75% MacTainsh et al., 1988 Coolangatta- 1974-1987 10.5% Hyland & Butler, 1988 Caloundra Northern NSW Tweed River 1943-1991 72% West, 1993 Clarence River 1942-1986 86% Macleay River 1942-1986 35% Central NSW Lake Macquarie 1954-1986 25% Winning, 1990 Hunter River 1954-1994 67% Williams et al., 1998 Hawkesbury River 1946-1996 80% Wilton, 1998 Sydney Region Homebush Bay 1930-1983 80% Clarke & Benson, 1987 Botany Bay 1942-1986 30% Mitchell & Adam, 1989 Southern, NSW Minnamurra River 1938-1997 49% Chafer, 1998 Merimbula Lake 1948-1994 30% Meehan, 1997 Pambula Lake 1948-1994 40% Meehan, 1997 Southern Aust. Corner Inlet, Vic 1941-1985 ‘extensive’ Vanderzee, 1988 Gulf St Vincent, SA 1935-1979 865 ha Burton, 1982 Mangrove proliferation: north

LOCATION Mangrove Period Source increase (percent) Queensland Johnstone River 15 1943-1991 Duke 1995 Hinchinbrook Channel 6 1943-1991 Duke 1995 Coolangatta to Caloundra -8 1974-1987 Hyland and Butler 1988 Oyster Point 119 1944-1983 McTainsh et al. 1988 Moreton Bay 10 1944-1983 Morton 1994 New South Wales Tweed River 86 1930-1994 Saintilan 1998 Hunter estuary (overall) 31 1954-1994 Williams et al. 1999 -Kooragang Is. 20 1954-1994 Williams et al. 1999 -Tomago/Fullerton/Stockton 46 1954-1994 Williams et al. 1999 - South Bank 41 1954-1994 Williams et al. 1999 -Throsby Creek -91 1954-1994 Williams et al. 1999 -Hexham Swamp -95 1938-2000 Morrison 2000 Couranga Point, Hawkesbury 30 1954-1994 Saintilan & Hashimoto Berowra Creek, Hawkebury 30 1941-1994 Williams & Watford 1997b Careel Bay 551 1940-1996 Wilton 2001 Homebush Bay 65 1930-2000 Rogers & Saintilan 2001 Port Jackson/Parramatta R. -19 1930-1985 Thorogood 1985 Sea-level Rise

1050

1000

950

900 Mean Sea Level (mm) Level Sea Mean 850 1915 1925 1935 1945 1955 1965 1975 1985 1995 Year

Fort Denison Linear Trend (+0.86mm/yr)

Surface Elevation Analysis SET Vertical Accretion

Feldspar Marker Horizon

SET sites: Australia

CurrambeneUkerebagh Creek Island,Cararma Tweed RiverInlet Jervis Bay Jervis Bay

Quaill Island Rhyll Kooweerup French Island

Kooragang Island, Hunter River BerowraMinnamurra Creek River and MarramarraHomebush Creek Bay Tweed River Sydney Harbour Hunter River JervisMinnamurraSydneyHawkesbury Bay Harbour RiverRiver Westernport Bay No relationship between sedimentation and surface elevation trends

7

6

5

4

3

2

1 (mm/yr) 0 0 1 2 3 4 5 6 7 8 9 10 -1

-2

-3 Mean Mean Rate of Elevation surface Change -4

Mean RateMean Rateof ofSediment Sediment Accretion accretion (mm/yr) (mm/yr)

mm/yr)

Mean Rate of Rate Mean Elevation Change ( 40 35 30 * 25 20 15 10 * 5 *

0 Average Trend (mm/yr) -5 Caribbean Australia Australia Pacific Micronesia (NSW) (Vic) Central America

Accretion Elevation Change

* Significant Shallow Subsidence at the P ≤ 0.10 level Other factors in addition to sedimentation rate influence surface elevation over inter- annual timescales 3.5 0

3 50 2.5 Groundwater 100 2

1.5 150

1 200 0.5

0 250

17-Jan 1-Feb 16-Feb 2-Mar 17-Mar 1-Apr 16-Apr 1-May 16-May 31-May 15-Jun Groundwater Depth (mm) Depth Groundwater -0.5 300

Surface Elevation Change (mm) Elevation Surface -1 350 -1.5 Surface elevation

-2 400 Sample No.

SET GW

140

120 100 Rainfall 80

60

40 Recorded rainfall (mm)Recorded 20

0 January February March April May

Rogers K., and Saintilan N. (in press). Relationships between groundwater and surface elevation in SE Australian wetlands. Journal of Coastal Research Quail Island

Drought & Reduced 0 -2Sep-00 Apr-01 Nov-01 Jun-02 Jan-03 Aug-03 Groundwater -4 -6 -8 -10 -12

Surface Elevation (mm) Mangrove -14 Surface Elevation Decrease Time

25 Rhyll SOI 20 5-month 6 15 mean 10 4 5 2

SOI 0 0 -5Sep-00 Apr-01 Nov-01 Jun-02 Jan-03 Aug-03 -2Sep-00 Apr-01 Nov-01 Jun-02 Jan-03 Aug-03 -10 -4 -15

Surface Elevation (mm) Mangrove -20 -6 Time Time

French Island Kooweerup

10 20 8 15 6 4 10 2 5 0 0 -2Sep-00 Apr-01 Nov-01 Jun-02 Jan-03 Aug-03 -4 -5Sep-00 Apr-01 Nov-01 Jun-02 Jan-03 Aug-03 -6 -10

-8 Surface Elevation (mm)

Surface Elevation (mm) Mangrove Mangrove -10 -15 Time Time 6.0 Currambene Creek

5.0 French Island Cararma 4.0 Inlet Kooweerup

3.0 y = 0.8771x + 3.1114 r2 = 0.6757 2.0 Rhyll p=0.0233 Ukerebagh Island 1.0

Mangrove Encroachment Mangrove (mm/yr) Minnamurra River 0.0 -4 -3 -2 -1 0 1 2 3 Relative Sea-level Rise (mm/yr)

Mangrove encroachment (vertical) mm/yr (vertical) encroachment Mangrove Relative Sea-level Rise (mm/yr)

Rogers K., Saintilan N. and Wilton K. 2006. Vegetation change and surface elevation dynamics of the estuarine wetlands of southeast Australia. Estuarine Coastal and Shelf Science. 66. 559-569. Planning for climate change

 Landward buffers should consider the potential of 40cm sea-level rise by 2100.  Groundwater removal may be detrimental to coastal wetlands LiDAR survey will provide an opportunity for detailed elevation modelling.

SET data turns static models into dynamic models Acknowledgements  Don Cahoon, Jim Lynch & Phillipe Hensel (USGS), Ron West (UoW), Kylee Wilton (DIPNR) and Fieldwork Assistants  Australian Research Council (ARC)  Australian Institute of Nuclear Science Education (AINSE)  Coasts and Clean Seas Initiative  Dept. of Infrastructure Planning & Natural Resources (DIPNR)  Vic. Dept. of Natural Resources and Environment (DNRE)  Sydney Olympic Park Authority (SOPA)  Jervis Bay Marine Park Authority (JBMPA)  Kooragang Wetland Rehabilitation Project  Hornsby Shire Council, Tweed Shire Council, Kiama Municipal Council, Shoalhaven City Council