Geoscience Reference
In-Depth Information
to.the.scant.attention.ecologists.have.afforded.beaches.in.contrast.with.other.coastal.
systems.such.as.rocky.shores,.sea.grasses,.mangroves,.and.coral.reefs.(Fairweather.
1990).
This.knowledge.deicit.is.unfortunate.because.beaches.are.highly.vulnerable.to.
a.“coastal.squeeze”.between.burgeoning.human.populations.on.the.terrestrial.side.
and. growing. marine. environmental. changes. engendered. by. climate. change.. The.
former.imposes.numerous.developmental,.recreational,.and.pollution.pressures.on.
beach.ecosystems.(Brown.and.McLachlan.2002;.Schlacher.et.al..2008;.Defeo.et.
al..2009);.the.latter.threatens.environmental.challenges.including.habitat.changes.
(e.g.,.sand.erosion).and.the.overlying.water.(e.g.,.temperature,.pH,.and.circulation).
(Jones. et. al.. 2007).. In. some. circumstances,. the. combination. of. climate-induced.
sea-level.rise,.erosion,.and.engineering.solutions.(e.g.,.seawalls).has.the.potential.
to.remove.sandy.beaches.entirely..This.would.be.most.unfortunate.from.both.eco-
centric.and.anthropocentric.points.of.view..Consequently,.the.need.for.informed,.
scientiically. based. management. is. clear. if. the. worst. consequences. of. climate.
change.are.to.be.avoided.
This.chapter.briely.introduces.sandy-beach.habitats,.their.biota.and.ecology,.and.
linkages.to.adjacent.marine,.terrestrial,.and.estuarine.ecosystems.(see.McLachlan.
and.Brown.2006.for.a.recent.comprehensive.ecological.text)..Attention.is.then.given.
to.the.vulnerability.of.beaches.to.pressures.imposed.by.climate.change,.the.likely.
effects.of.these.pressures,.the.concept.of.resilience.(Walker.and.Salt.2006),.and.eco-
system-based.approaches.(Curtin.and.Prellezo.2010).to.the.management.and.conser-
vation.of.sandy.shores..Herein,.the.term.“beach”.is.used.synonymously.with.“beach.
face,”.deined.as.“the.intertidal.slope.of.the.beach.between.the.high-.and.low-tide.
marks”.by.McLachlan.and.Brown.(2006,.p..325).
SANDY BEACHES AS HABITATS
Sandy. beaches. are. unstable,. three-dimensional. habitats. dominated. by. sand-sized.
sediments.that.are.strongly.inluenced.by.tides,.waves,.currents,.biogenesis,.and.geo-
logical.inheritance.(Short.1999)..Because.sedimentary.instability.excludes.attached.
plants,. beach. animals. are. partly. dependent. on. adjacent. ecosystems. for. primary.
production. (see. text. under. Linkages). and. lack. the. secondary. habitat. options. pro-
vided.by.vegetation.in.other.ecosystems..However,.as.beach.sediments.are.relatively.
coarse,.interstitial.spaces.occur.between.the.sand.particles,.and.these.are.inhabited.
by.numerous.species.of.meiofauna.and.photosynthesizing.microlora.
Another. habitat. feature. of. beaches. is. that. spatial. and. temporal. abiotic. vari-
ability. can. be. large.. In. particular,. the. effects. of. season. and. tide. on. patterns. of.
desiccation. and. temperature. are. important. and. many. species. display. seasonally.
and.tidally.related.behavioral.adaptations.(Brown.and.McLachlan.1990)..Temporal.
variation. is. enhanced. by. the. erosive. and. abrasive. power. of. periodic. storms,. and.
spatial.variability.occurs.both.within.and.among.beaches..For.example,.individual.
beaches. exhibit. both. horizontal. (across-. and. along-shore). and. vertical. physico-
chemical.gradients.in.factors.such.as.temperature,.moisture.content,.dissolved.oxy-
gen,.and.sediment.grade.
