the intrinsic value of coastal wetlands - Amazon Simple Storage ...

Report 1 Downloads 44 Views
THE INTRINSIC VALUE OF COASTAL WETLANDS Gerardo M. E. Perillo CONICET-Instituto Argentino de Oceanografía Universidad Nacional del Sur

COASTAL WETLANDS are ecosystems t that th t are found f d within ithi an elevation gradient that ranges between subtidal btid l depths d th to t which hi h light li ht penetrates t t to t support photosynthesis of benthic plants and th landward the l d d edge d where h the th sea passes its it hydrologic influence to groundwater and atmospheric t h i processes. (Wolanski et al., 2009)

MAIN TYPES OF COASTAL WETLANDS • • • • •

Seagrasses Tidal flats Salt marshes Mangroves Freshwater marshes

GEOGRAPHIC DISTRIBUTION • • • •

Seagrasses = 165.000-500.000 km2 Marshes > 1.000.000 km2 Tidal Flats > 1.000.000 km2 Mangroves = 230 230.000 000 km2

(Wolanski et al., 2009)

Why are coastal wetlands important? • Buffer between sea and continent • Sediment traps • Areas A off reproduction d ti and d grow off many commercial species • Source of nutrients to the coast • Resting g places p for migratory g y birds • Fisheries and aquaculture • Etc. Etc

Definitions •

Tidal flats – Areas of low relative relief associated to the intertidal zone,, with unconsolidated sediments and without herbaceous vegetation



Marshes – Areas of low relative relief associated to the intertidal zone, with unconsolidated sediments and with herbaceous vegetation – They y can be either salt/brackish or fresh

Mangroves

Forest ecosystems

Clasification of Tidal Courses • Cavas de marea = Tidal rills • Surcos de marea = Tidal grooves

• Cárcavas de marea = Tidal gullies • Arroyos de marea = Tidal creeks • Canales de marea = Tidal channels Perillo, 2009

ENVIRONMENTAL IMPACTS Change vs Variability

Perillo & Piccolo, Piccolo in press

MAJOR ISSUES

• SEA LEVEL VARIATIONS • SEDIMENT BALANCE • WAVE ATTENUATION

Variaciones del NMM a lo largo de la Historia Geológica de la Tierra

Variaciones del NMM - Pleistoceno

MSL – LAST POSTGLACIAL

MSL Changes - Southern H.

Isla, 1989

EXAMPLE OF MSL VARIATION BAHIA BLANCA ESTUARY 10

Eleva ación (m m)

5

-1.4 mm/yr 0

1.6 mm/yr

9.4 mm/yr

-5

-10

-15 0

2000

4000

Años AP

6000

8000

Gómez & Perillo, 1995

FUTURE OF MSL Historical Evolution

Predicted Evolution

-Extreme prediction from IPCC (2007) = 88 cm -Flexure effect up to 2x predicted (Syvistki and Saito, 2009)

Punta Piedras

35° 30´ S

Level I = 0-1.5 m Level II = 1.5-2.5 m Level III < 5 m

Bahía de Samborombón

Flooded Area 624 k km2

Nivel II

Punta Rasa

Nivel I 36° 22´ S

Nivel III

R. Sau c

eC hi c

o

Level I = 0-1.5 m Level II = 1.5 1.5-2.5 2.5 m Level III > 2.5 m

BahíaBlanca

Punta Alta Ca na lP rin

cip al

Flooded Area 1611 km2

SEDIMENT BALANCE • Imported by – Rivers – Wind – Tides – Waves – Biological input

• Exported – Tides – Waves – Winds

Rivers - Changes in pp. pp cycles - Dams Winds g in storminess - Changes Tides - Changes in geomorphology - Changes in winds - Changes Ch i rivers in i Waves - Changes in winds - Changes in geomorphology Biological Input - Changes in climatic conditions - Geomorphologic changes - Species modifications

Teledetección para evaluar cambios

Pratolongo et al., 2008

Retraction of shrubs S. perennis marshes

Pratolongo et al., 2008

Expansion S. alterniflora marshes

Pratolongo et al., 2008

CHANGES IN MANGROVE VEGETATION BETWEEN 1976 AND 2001 IN THE ESTUARY OF PARAÍBA DO SUL RIVER

Water Transition Avicennia e Laguncularia Avicennia e Rhizophora Landscape Urban Area

Area (ha)

1976

1986

2001

%

Atafona

147.5

108.6

26.5

-81 -

Gargaú

912.6

431.3

528.9

-42

Graça

37 7 37.7

27 2.7

--

-100 100

Ilha do Lima

191.7

306.2

285.5

+33

Total

1289.5

848.8

841.9

-35 35

Specific Loss: 6,55 ton-Corg.ha-1.yr-1 US$ 447 447,600 600 up to 1 1,342,800 342 800 per year as disruption of general functions US$ 41 million as C sinks for total hectare deforested (US$ 2,000/kg of C) courtesy of C. Rezende (2011)

courtesy of C. Rezende (2011)

Bioestabilization Lister Dybs y Tidal lagoon g

8 July 1996

16 September 1996

courtesy M. Perjup

27 July 1996

28 November 1996

Spatial Varaition of the Surface

20

Bed leve el (cm)

15

20 m fra marsk

10 5 0 -5 -10 J 97 Jan-97

1997

J 98 Jan-98

1998

J 99 Jan-99

1999

J 00 Jan-00

2000

J 01 Jan-01

2001

2002

J 02 Jan-02

2003

J 03 Jan-03

2004

J 04 Jan-04

2005

D 04 Dec-04

D 05 Dec-05

20

Bed level (cm)

15

500m fra marsk

10 5 0 -5 -10 Jan-97

1997

Jan-98

1998

Jan-99

1999

Jan-00

2000

Jan-01

2001

Jan-02

2002

2003

Jan-03

2004

Jan-04

2005

Dec-04

Dec-05

courtesy M. Perjup

BIODESTABILIZATION

5.1 x 106 m3 SSC up p to 5 g/l g

HUMAN DESTABILIZATION

CANOPY PROFILE

Nef (2004)

Marsh

Mud flat

D Depression i and d Shoulder Sh ld att Front F t Edge Ed off the th Spartina S ti anglica li Saltmarsh S lt h Horizontal distance (m) 0

2

4

6

8

10

-300

E lee v a tio n (m m )

-350

Spartina salt marsh

Mudflat

-400 -450 -500

80 mm -550

?

-600 600

Example from the Tavy Estuary (Courtesy of Reg Uncles & John Widd Widdows) )

12

14

•2 Sontek ADV’s deployed for a neap-spring cycle •3 components of velocity measured in 10 min bursts at 10 Hz every 20 min •Pressure measured in 10 minutes bursts at 2 Hz • Bed level measured at the beginning of each burst •SSC based with accoustic backscatter MUDFLAT

SALTMARSH Sediment critical shear stress measured with a Cohesive Shear Meter during exposure

Tidal level

Corrected Bed Elevation

Zero-crossing wave parameters (non-directional) from the pressure time series T Si ifi Significant t period i d (s) ( ) (s) NNW 11 m/s

NW 25 m/s

E - NE 15 m/s

Significant wave height (m) H (m)

N 3 m/s

SE 24 m/s

Spectral wave parameters after correction of the pressure attenuation (Tucker and Pitt 2001) Wave energy gy ((J m-2)

Peak period (s)

(High pass- filtered time series) Normal conditions

Mud deposition event

Normal conditions

Mud d deposition iti event

EFFECT OF THE TIDE AND PLANT CHARACTERISTICS ON WAVE ATTENUATION

WAVE ATTENUATION

Koch et al., 2009 FEE

Proxies for Wave W tt Wattenuation ti

Direct Measurements Spatial

Modeling

Variations as f(species)

Seasonal Variation as f(biomass)

Aereal Cover

Koch et al., 2009 FEE

Koch et al., 2009 FEE

Barbier et al., 2008, Science

CONCLUSIONS • CW are an essential part of the coastal zone • Even in areas with little direct human interaction, they are highly impacted • Ecosystem cosyste se services ces a are e tthe e highest g est o of a all other coastal environments • They overcome the values of most human activities that replace them • Preservation and restoration of CW are key to maintain most of these ecosystem value

MUITO OBRIGADO THANK YOU