Geoscience Reference
In-Depth Information
s
Torminess
/W
aVe
e
nergy
Climate. change. will. intensify. storms. and. amplify. wave. energy. (IPCC. 2001). with.
several.consequences.for.beach.species..First,.there.may.be.a.greater.metabolic.cost.
of.maintaining.position.in.the.swash.zone,.with.low-on.effects.to.survival.and.repro-
duction.. However,. the. burrowing. anomuran. crab.
Emerita analoga
. showed. no. dif-
ference.in.oxygen.uptake.(a.measure.of.physiological.stress).across.a.range.of.wave.
exposures.on.the.same.beach.(Lastra.et.al..2004)..Either.the.premise.was.false.or.
acclimation.to.changes.in.wave.energy.occurred.
Second,.increased.wave.energy.may.change.the.morphodynamic.state.(grain.size.
and.slope).of.the.beach..If.beaches.were.to.become.more.relective,.their.macroben-
thic.assemblages.would.become.impoverished.as.explained.previously..In.addition,.
changes. in. grain. size. and. beach. slope. may. affect. settlement. and. recruitment.. For.
example,.the.South.African.wedge.clam.
D. serra
.settles.as.spat.in.the.surf.zone,.pre-
ferring.areas.with.ine.sediment..Juveniles.subsequently.recruit.into.the.adult.popu-
lation. on. the. intertidal. beach,. which. is. inluenced. by. the. beach. slope. (Schoeman.
and.Richardson.2002)..Furthermore,.if.a.changed.beach.slope.caused.the.abundance.
of.
Donax
.to.fall,.there.may.be.cascading.trophic.consequences.for.shorebirds..For.
example,. Peterson. et. al.. (2006). found. that. fewer. shorebirds. (e.g.,. sanderlings). for-
aged.on.beaches.after.a.reduction.in.the.density.of.their.prey,.
Donax
.spp..In.addition,.
a.change.in.sediment.composition.can.affect.the.foraging.eficiency.of.shorebirds.by.
reducing.their.ability.to.probe.with.their.bills.and.manipulate.prey.(Quammen.1982;.
Peterson.et.al..2006)..Other.climate-related.population.changes.involve.the.sandhop-
per.
Talitrus saltator
.on.the.Baltic.coast.(Weslawski.et.al..2000),.which.now.occurs.
in.fewer.localities.and.at.lower.densities.compared.with.previous.records—a.pattern.
correlated.with.increases.in.storm.frequency,.winter.severity,.and.sea.level.
Third,. storms. dislodge. kelp,. which. is. deposited. on. beaches. as. wrack. (Grifiths.
and.Stenton-Dozey.1981)..If.bigger.storms.produce.more.beach.wrack,.there.may.be.
contrasting.faunal.effects
(McGwynne.et.al..1988)..There.would.be.more.localized.
hypoxia.via.decomposition..If.the.redox.discontinuity.layer.rises,.or.if.“methane.gey-
sers”.develop.underneath.dense.wrack.accumulations,.infaunal.invertebrate.popula-
tions. would. decrease. (McLachlan. 1985;. Hacking,. unpublished. data).. In. addition,.
stranded.kelp.affects.both.the.feeding.and.burrowing.eficiency.of.the.wedge.clam,.
D. serra
.(Soares.et.al..1996)..However,.because.this.is.a.pulse.disturbance,.recovery.
should.occur.after.dispersal.of.the.wrack..In.contrast,.species.that.depend.on.wrack.
for.food.or.habitat.are.likely.to.beneit.from.denser.wrack..These.include.insect.lar-
vae,.amphipods,.and.their.predators.(Dugan.et.al..2003)..Furthermore,.wrack.piles.
insulate.the.underlying.sand.from.temperature.extremes.and.maintain.high.humidity..
Beach.fauna.that.have.no.active.mechanism.for.water.retention.such.as.the.amphipod.
Orchestia gammarellus
.are.favored.by.this.
Fourth,.increased.hydrodynamic.energy.may.cause.increased.near-shore.turbid-
ity.and.decreased.surf-zone.photosynthesis..If.so,.this.would.reduce.the.food.supply.
for.beach.fauna,.especially.on.dissipative.beaches..Increased.hydrodynamic.energy.
may.also.enhance.abrasion,.which.may.be.deleterious.for.some.species,.especially.
those.with.shells.weakened.by.acidity..Finally,.a.likely.consequence.of.larger.storms.
is.the.increased.risk.of.shipwrecks.and.oil.pollution.with.consequent.impacts.(Jones.
