Coastal Ecosystems Revision

8/14/2019 Coastal Ecosystems Revision

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CoastaEcosvstems

What isan ecosvstem?A community f plants ndanimals nd he physical nvironmentn which hey ive.

Successiosuccessionccurr ingna sand une ystem:sammosere.Successionccurringna saltmarsh ystem: alosere.

What is he process f succession?Ecosystemsndergo hangehrough ime and over ime the sequence f vegetation n a sitechanges this scal led uccession.Successions he changesn vegetat ion ver ime n responseo the changing hysicalondit ioEcologicaluccessionn previously n-vegetated ites, uchas on sanddunes,mudflatsand saltmarshessknownasprimary uccession.

Whatare he componentsf anecosvstem?Non-l ivingnvironment:- Relief/slopef the and

Living nvironment:- Animals- Vegetation- Insects

- Water- Sunl ight- Air- Soil- Rock


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Theprocessf succession:

Init ial ly ondit ions reveryharsh onlycertainspecies urvivepioneer pecies).

Over ime he physical nvironment ecomesmorefavourableo plantgrowth withchangesn soi l ,wateravailabi l i tytc.)

As hisoccurs egetation ecomesmore diverse,tal lerandwoodier n character i th an ncreasenbiomass.

Eventual lyhe cl imax ommunitys reachedbestsuited o the condit ions) oftena part icular lantspecies ecomes ominant.

IMPORTANT-HEFOCUS FSUCCCESSIONSCHANGE VER IME.


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Sand une uccessionpsammoseres:

Howdo sanddunes evelop?Theyare an mportantdepositionaleature ormedby the wind (Aeolian rocesses).

Wheredo thevdevelop?o Where here sa strong n-shore ind.o Where here sa arge upply f sand.o Where here s a large nter-tidal angeso hat largeareasof sand egularly ry out.

A simple equence f sanddune ormation:1. Thewind movessanddriedout at low tide inlandby: saltation, trongsheer orceas

windblowsover he surface ndbal l ist icmpact rom othersand rains.2. An obstaclee.g. r i f twood)wi l l hal tsal tat ion nd esult n deposit ion nd he

accumulat ionf sandwil l p i leup around he obstacle.3. Pioneer lants e.g.marram rass) an olerate he harsh ondit ionsndwil l colonise

the area.Thisbreaks p the wind and encouragesurther deposition ndgrowthof theduneswhi le he rootsstabi l isehe dune.

4. Another une ormson the seaward ideof the or ig inal unewhichwil l sheltert andchangeshe environmental ondition ausing ther ypesof vegetation o colonise.

5. A sequence f dunes orm (oldestnland) nd he environmen talondit ionsontinueochange ue o the changen vegetation. ventual lyl imax ommunitys reached.

Tvpe f Dune Embryo Yellow Grey WastingDuneHeiehtm) t 5 8-10 6-8% of exposed and 80 20 Lesshan 10. Over40.Humus ndmoistureontent Little,

mixed altandfresh.

Some, eryl i t t lemoisture.

Increasedinland,decreasedwater.

big,brackiswater nslacks.PH Over8 Sl ight ly

alkal ine.6.5-7 5-6

Plantvpes Sand ouch,LymeGrass.

Marram,Xerophvtic. Fescue,Heather. Heather,Gorse.


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Modification f sandduneecosvstemsue o humanactivitv:L. Beachmanagement

Beach leaningmeasures an removeobstructionseducinghe l ikel ihood f embryodune ormation.

2. RecreationWalking,kite boarding,picnics,ires, ramplingcan all reducevegetationcover eadingto blowoutsandgully ormations.

3. GrazingRabbits ndotheranimals raze n dunes ndcancrate abbi tholes ndblowouts.

4. Mi l i tarvuseCauses oss of vegetationdue to militarytrainingand exercise.EXAMPLE: COTLANDANDDEVON.

lmpactof vegetationoss:o Novegetationmeans t'seasy or wind to blowawaysand.o Creates lowouts.o Most ikelynear he beach,ess hel terrom prevai l ing inds.o Resultsn overall ossof biodiversity.

Blakeny oint hasbeen modifiedasa resultof: management f tourism mpactand protectionof theecosystem sa nature eserve. hesanddunesare ownedby the national rustand t is aconservation reawith a uniqueecosystem it h greyseals ndbreedingmarinebirds.Humanuse ncludes oat rips or touristsand students protectionof the dunes s hereforeneeded:

o Regulate oat rips(reducing ollutionand waveerosion).o Fencing f particularlyragileareas.o Creating oardwalks n the dues controllingwhere walkersaregoing.o Educatehe publicwith signs ndposters e.g. keep o the paths")o Plantingmarramgrass or otherspecies)o anchordune andencourage egetation.

Thesanddunes realsoat increasediskof f looding ue o globalwarming nd he predicted mmrise n sea evelperannum.


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Saltmarsh uccessionhaloseres

Howaresaltmarshesormed?o Siltandmud rom ivers, liffs nd heseabed sdepositedy he riseand al lof the ide.o Mostdepositionccurs hen hevelocitiesre ownear he owandhigh ide evels.o Where reshwaterndsaltwater eet locculationccurs. his swhere ineparticlestick

togethero form arger articlesndare hendepositedo formmudflats ndeventuallynvegetatedaltmarshes.

Wherearesaltmarshesormed?o Where inesedimentsavai lable.o They orm in sheltered reasof the coastlinewhere here s ow energyand deposition an

occur.

A simplesequence f how salt marshes re ormed:Stage1:

o Pioneer pecies uchassal icorniandeelgrassrowhereon the baremudflats s heycantolerate he sal ine ondit ionshalophytic)ndcanalso olerate requent nd engthysubmergentsf up o 11 hours n a 12hourcycle.

. Vegetation lowsdown the movementof water and sediment s depositedncreasingheheight f the marsh.Stase2:

o As he heightof mudflats ncreaseshe seadoesn't each hem for as ongand submergentare shorter, educingo 6-8hours.

o Speciesuchasspart inia annowgrow heir oots o helpbind he mudandencouragemoredeposit ion.

Stase3:o A discontinuous at of vegetation ormswith species uchassea avender ndseaastero No need o be as olerant ssubmergentsonly ubmerged t high ide)and herefore on't

need o be halophytic.o Deadorganicmatter sadded o the mud increasinghe heightand ertility.o Saltpansorm here; hey are smallhollows n whichwater s rappedwhen the tide falls.As


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Stage4:o Mud evels ont inueo rise nundat ion ccurs nlyat the highestides.o A widevarietyof species an hereforebegin o grow e.g. eedsand rushes.o Creek ystemsorm acrosshe marshchannelling ater o the sea.

Stase5:o Themarsh s now high, ry and ert i leenough or treeswhicharenon-halophyt ic.g.ash

andalder o dominate.o Thisarea s seldom f eversubmerged y tidalwater.o As reesnow dominatedue o competition pecies iversity s now reduced.o This swherewe f ind he cl imax ommunity.

Modification f saltmarsh vstems ue o humanactivitv:L Grazing

The highmarsh uppersword) s oftengrazedby sheepand cattle. n order or this ohappenmanypartshavebeendrained nd eseeded .g.wel ls.RecreationBoat rips ead o pollutionof the shelteredwatersdue to dieseland itter.Overcrowdinandnoisedisturbswildlifeand mooringneeds areful ontrol.GlobalwarmingA rise n sea evel s a problemdue o theseareasbeingat an ncreasingisk o flooding.Coastal rotectionSaltmarshes n for exampleBrancaster avebeen e-establishedssoft seadefences.lmoactof vegetationoss:

o Saltmarshes reuniqueecosystemsrovidingeedingoverwinter for wadersanwild fowl suchasoystercatcher o herefore ossof habitat s a realproblem.

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Coastal Ecosystems Revision