Geoscience Reference
In-Depth Information
will.occur.suficiently.slowly.for.natural.acclimation.and/or.evolutionary.adaptation.
to.occur.
In. general,. the. resilience. of. an. impacted. beach. will. be. enhanced. if. protected,.
unaffected.beaches.exist.suficiently.close.to.provide.dispersive,.colonizing.larvae..
Protected.beaches.should.be.selected.according.to.the.comprehensive/adequate/rep-
resentative. criteria. used. elsewhere.. In. particular,. different. morphodynamic. beach.
types.should.be.included.in.different.biogeographic.zones..Dissipative.beaches.are.
particularly.rich.in.biota.and.may.also.provide.planktonic,.larval.colonists.to.dep-
auperate.relective.beaches,.i.e.,.the.source-sink.hypothesis.(Defeo.and.McLachlan.
2005)..Moreover,.adjacent.terrestrial.and.marine.areas.should.also.be.protected.in.
order.to.accommodate.the.ecosystem.linkages.described.previously.
SUMMARY
Sandy.beaches.are.immensely.important.economically.and.culturally..Contrary.to.
popular.opinion,.they.provide.numerous.ecological.services.and.support.diverse.eco-
logical.assemblages.whose.species.are.mostly.small.and.buried,.and.evade.attention..
Beaches.vary.morphodynamically.and.this.affects.their.biotic.diversity.(dissipative.
beaches. are. biologically. richer. than. relective. beaches). as. does. tidal. height. (more.
species. live. low. on. the. beach).. Biotic. assemblages. appear. to. be. largely. physically.
controlled,. especially. on. steep,. relective. beaches,. but. biological. relationships. can.
also. be. present.. In. addition,. beach. ecosystems. have. strong. linkages. with. adjacent.
ecosystems,.especially.dunes.and.the.surf.zone,.concerning.their.sand.budget,.pri-
mary.production,.life.histories,.and.migratory.species..These.linkages.have.strong.
implications.for.the.scales.at.which.management.should.operate.
Concern.about.beaches.is.increasing.because.of.their.vulnerability.to.burgeoning.
human.terrestrial.pressures.and.climate-related.marine.pressures..The.latter.include.
rises.in.temperature,.sea.level,.storminess,.and.oceanic.acidity..Most.are.large-scale.
press.disturbances.from.which.recovery.will.depend.on.acclimation.or.evolutionary.
adaptation..These.disturbances.may.affect.the.biota.singly.or.in.combination.and.may.
be.synergistic.with.existing.stresses.such.as.pollution.and.ORVs..Effects.may.be.direct.
(e.g.,.reduced.calciication).or.indirect.(e.g.,.changes.to.planktonic.food.supply).
Of.particular.concern.is.acidiication.because.it.is.a.press.disturbance.affecting.all.
beaches,.and.many.beach.species.are.calcium.dependent..Also.important.is.the.com-
bination.of.storm.surges.and.sea-level.rise,.which.will.exacerbate.erosion.rates..The.
most.extreme.effect.can.be.the.total.loss.of.the.beach.habitat,.especially.if.seawalls.
are.deployed.to.protect.urban.coastal.assets..Alternatively,.in.other.areas,.there.may.
be.a.slow.retreat.of.the.coastline.with.few.effects.on.beach.ecosystems.
Concerning.management,.a.perspective.that.seeks.to.promote.resilience.is.appro-
priate..Resilience.is.a.concept.with.both.ecological.and.social.components.and.treats.
these. in. an. integrated. manner.. In. terms. of. broad. strategies,. both. mitigation. and.
adaptation. are. needed.. The. former. would. seek. to. constrain. the. increase. in. atmo-
spheric.greenhouse.gases.by.addressing.the.underlying.causes.(i.e.,.population.and.
economic.growth).and.by.applying.appropriate.low-carbon.technologies..Adaptation.
strategies. would. recognize. the. linkages. between. beaches,. dunes,. and. surf. zones;.
maintain. sand. movement. and. storage;. and. allow. for. the. landward. migration. of.
