Salt marsh Outline of this talk

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Salt marshSalt marshSalt marshSalt marsh

Ecosystem engineering by coastal vegetations:Ecosystem engineering by coastal vegetations:Ecosystem engineering by coastal vegetations:Ecosystem engineering by coastal vegetations:

BioBioBioBio----Physical interactions & BioPhysical interactions & BioPhysical interactions & BioPhysical interactions & Bio----GeoGeoGeoGeo----morphology morphology morphology morphology

Tjeerd J Bouma, Stijn Temmerman, Tjeerd J Bouma, Stijn Temmerman, Tjeerd J Bouma, Stijn Temmerman, Tjeerd J Bouma, Stijn Temmerman, et al.et al.et al.et al.

[email protected]@[email protected]@nioo.knaw.nl

Spatial ecology

• Salt marshes Salt marshes Salt marshes Salt marshes –––– some basicssome basicssome basicssome basics

• Principle of ecosystem engineeringPrinciple of ecosystem engineeringPrinciple of ecosystem engineeringPrinciple of ecosystem engineering

• Modelling bioModelling bioModelling bioModelling bio----geomorfological feedback loopgeomorfological feedback loopgeomorfological feedback loopgeomorfological feedback loop

• shortshortshortshort----term interactions (1 tide)term interactions (1 tide)term interactions (1 tide)term interactions (1 tide)

• longlonglonglong----term development & selfterm development & selfterm development & selfterm development & self----organisationorganisationorganisationorganisation

• effects of species traitseffects of species traitseffects of species traitseffects of species traits

• Underlaying mechanismsUnderlaying mechanismsUnderlaying mechanismsUnderlaying mechanisms

• SmallSmallSmallSmall----scale flume studiesscale flume studiesscale flume studiesscale flume studies

• LargeLargeLargeLarge----scale basin experimentsscale basin experimentsscale basin experimentsscale basin experiments

• Management applicationsManagement applicationsManagement applicationsManagement applications

Outline of this talk


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Global distribution of salt marshesGlobal distribution of salt marshesGlobal distribution of salt marshesGlobal distribution of salt marshes

after Long & Mason (1983)after Long & Mason (1983)after Long & Mason (1983)after Long & Mason (1983)

WaddenseaWaddenseaWaddenseaWaddensea

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Why do marsh plants live where they do ?Why do marsh plants live where they do ?Why do marsh plants live where they do ?Why do marsh plants live where they do ?

ColdeweyColdeweyColdeweyColdewey & & & & ErchingerErchingerErchingerErchinger (1992)(1992)(1992)(1992)

Elevation gradient

Inundation gradientHalimione ElymusSalicornia

Vegetation zonation

Stress gradient structures marsh communityStress gradient structures marsh communityStress gradient structures marsh communityStress gradient structures marsh community

HIGH marsh

LOW marsh

mud flat

---- above groundabove groundabove groundabove ground---- hydrodynamicshydrodynamicshydrodynamicshydrodynamics

---- below groundbelow groundbelow groundbelow ground---- anoxic sedimentanoxic sedimentanoxic sedimentanoxic sediment

Bouma et al. RCEM 2008Bouma et al. RCEM 2008Bouma et al. RCEM 2008Bouma et al. RCEM 2008

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Ecosystem engineering:Ecosystem engineering:Ecosystem engineering:Ecosystem engineering:

modification of the abiotic environment by biological activity (Jones 1994)

STRONGSTRONGhydrodynamicshydrodynamics

REDUCEDREDUCEDhydrodynamicshydrodynamics

enhanced elevation = reduction inundation stress

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Example: Example: Example: Example: SpartinaSpartinaSpartinaSpartina anglicaanglicaanglicaanglica tussockstussockstussockstussocks

50 100 150 200 250 300 350

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100

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tussock13

Bouma et al. RCEM 2008Bouma et al. RCEM 2008Bouma et al. RCEM 2008Bouma et al. RCEM 2008

Salt marshSalt marshSalt marshSalt marsh

can ecosystem engineering lead to

landscape development?

SpartinaSpartinaSpartinaSpartina tussockstussockstussockstussocks

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• longlonglonglong----term developmentterm developmentterm developmentterm development








Spatial ecology

Modeling shortModeling shortModeling shortModeling short----term interactions: 1 tideterm interactions: 1 tideterm interactions: 1 tideterm interactions: 1 tide

Vegetation

FlowGeomorphology

Temmerman et al. JGR 2005Temmerman et al. JGR 2005Temmerman et al. JGR 2005Temmerman et al. JGR 2005

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Temmerman et al. JGR 2005Temmerman et al. JGR 2005Temmerman et al. JGR 2005Temmerman et al. JGR 2005

vegetation (marsh)

no vegetation(mudflat)

Simulations: plants have crucial impact on flow and sedimentation

Example 1

elevationmap

Detail of marsh-mudflat edge

10 m


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0.1

0.15

0.05

0

vegetation (marsh)

no vegetation(mudflat)

simulated flow patternwith vegetation


Example 1 flow velocity (m/s) at beginning flood

elevationmap

Flowreduction

Flowconcentration

10 m


0.1

0.15

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No vegetation


Example 1 flow velocity (m/s) at beginning flood

elevationmap

simulated flow patternwithout vegetation

no vegetation

Uniform flow

10 m


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vegetation

no vegetation

Sedimentation (g/m²) after 1 tide


Example 1

elevationmap

simulated sedimentationpattern with vegetation

sedimentation

channel formation

10 m


No vegetation

no vegetation


Example 1 Sedimentation (g/m²) after 1 tide

simulated sedimentationpattern without vegetation

elevationmap

Uniform sedimentation

10 m


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Spatial ecology

Modeling longModeling longModeling longModeling long----term self term self term self term self organisationorganisationorganisationorganisation ((((~100 yr)100 yr)100 yr)100 yr)

Vegetation

FlowGeomorphology

Temmerman et al. Geology 2007

dynamic changes in plant cover

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Model descriptionModel descriptionModel descriptionModel description

Delft-3D flow + sediment on line + vegetation module

Matlab plant-growth model

1 tide flow => ∆ bed-level x 1 yr

1 year vegetation growth

Plant growth module Plant growth module Plant growth module Plant growth module –––– S. TemmermanS. TemmermanS. TemmermanS. Temmerman

Vegetation development:

• Random seeding

• Veg. density = logistic growth

• Lateral growth = diffusion function

• Mortality = f (elevation+ bed shear stress)

Spatial ecology

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Vegetation module Vegetation module Vegetation module Vegetation module –––– R. UittenbogaardR. UittenbogaardR. UittenbogaardR. Uittenbogaard

Effect of rigid cylindrical structures on

• drag

• turbulence generation, transport & dissipation

• vertical momentum transfer

Preliminary model results: plant colonization initiates channel formation

Idealisedmudflat

Flo

oddi

rect

ion1 year time

step forveg. & morph.

Hydrodynamics: 1 tide

600m

Modeling longModeling longModeling longModeling long----term self term self term self term self organisationorganisationorganisationorganisation ((((~100 yr)100 yr)100 yr)100 yr)

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Plant density (stems.m-2)

Depth-averaged flow velocity during flood (m.s-1)

Elevation (m)

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100 200 300 400 500 600Distance (m)




Elevation (m)

100 200 300 400 500 600

100 200 300 400 500 600

100 200 300 400 500 600Distance (m)


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Elevation (m)

100 200 300 400 500 600

100 200 300 400 500 600

100 200 300 400 500 600Distance (m)




Elevation (m)

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100 200 300 400 500 600

100 200 300 400 500 600Distance (m)


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Elevation (m)

100 200 300 400 500 600

100 200 300 400 500 600

100 200 300 400 500 600Distance (m)




Elevation (m)

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100 200 300 400 500 600

100 200 300 400 500 600Distance (m)


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Elevation (m)

100 200 300 400 500 600

100 200 300 400 500 600

100 200 300 400 500 600Distance (m)




Elevation (m)

100 200 300 400 500 600

100 200 300 400 500 600

100 200 300 400 500 600Distance (m)


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Elevation (m)

100 200 300 400 500 600

100 200 300 400 500 600

100 200 300 400 500 600Distance (m)




Elevation (m)

100 200 300 400 500 600

100 200 300 400 500 600

100 200 300 400 500 600Distance (m)


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Elevation (m)

100 200 300 400 500 600

100 200 300 400 500 600

100 200 300 400 500 600Distance (m)




Elevation (m)

100 200 300 400 500 600

100 200 300 400 500 600

100 200 300 400 500 600Distance (m)


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Field observations














Spatial ecologySpatial ecology

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erosion

sedimentation

shoot density

erosion

sedimentation

shoot density

Bouma et al. OIKOS 2009Bouma et al. OIKOS 2009Bouma et al. OIKOS 2009Bouma et al. OIKOS 2009

Spatial ecology

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Conclusions:Conclusions:Conclusions:Conclusions:

� Bio-physical interactions & bio-geomorphology can be modeled well

• short-term => hydrodyn. & sedimentary processes• long-term => self organized landscapes

� Plant traits => directly affect landscape development:• lower stiffness => less/no creeks

less sed. accum.higher density => more creeks

=> FITS GROWTH STRATEGIES !!!

� Flume exps. => basic principles• plant traits => scale dependent feedbacks

� Modeling => needed for up-scaling in space & time

Tjeerd J. Bouma (Tjeerd J. Bouma (Tjeerd J. Bouma (Tjeerd J. Bouma ([email protected]@[email protected]@nioo.knaw.nl ))))

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Thank you for your attention Thank you for your attention Thank you for your attention Thank you for your attention ☺☺☺☺

Questions ?

[email protected]

Spatial ecology

T.J. BoumaP.M.J. Hermanet al.

M. FriedrichsG. Graf

B.K. van WesenbeeckM.B de VriesL.A. Van DurenE. Martini

et al.

J.T. Dijkstra

S. TemmermanW. Vandenbruwaene

Salt marsh Outline of this talk

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