Geoscience Reference
In-Depth Information
sheet.volume.in.both.the.northern.(Clark.et.al..1999).and.southern.(Rignot.and.Thomas.
2002). hemispheres,. and. global. phenology. changes. (Badeck. et. al.. 2004),. as. well. as.
other.changes.in.the.Earth's.biota.(Root.et.al..2003).
Regardless.of.the.reasons.for.climatic.change,.the.reality.of.such.changes.and.the.
need.to.understand.their.effect.on.the.Earth.system.is.one.of.the.most.pressing.chal-
lenges.facing.the.scientiic.community..The.potential.impacts.of.climate.change.will.
manifest.in.both.the.biotic.and.abiotic.components.of.the.Earth.system,.in.ways.that.
may.not.be.readily.predictable.based.on.past.analogs.(Williams.and.Jackson.2007)..
In.this.context,.even.consideration.of.the.terminology.used.to.describe.the.problem.
is.illustrative..Although.frequently.framed.in.both.the.scientiic.and.popular.media.
as. “global. warming,”. the. actual. impacts. of. climate. change. are. likely. to. be. more.
complex.and.geographically.heterogeneous.than.the.simple.hypothesis.of.tempera-
ture.increase.would.suggest..Results.for.similar.emissions.scenarios.simulated.using.
different.climate.models.show.widely.varying.patterns.of.temperature.and.precipita-
tion.in.a.greenhouse-enhanced.world.(Watson.et.al..1997)..Geographic.and.temporal.
variations.in.the.distribution.of.precipitation.are.expected..Some.areas.might.have.
little.or.no.change.in.total.interannual.precipitation,.but.with.the.timing.altered.to.
include. less. frequent. but. larger. events.. Other. areas. could. see. changes. in. both. the.
amount.and.timing.of.precipitation,.as.well.as.changes.in.the.relative.amounts.of.rain.
and.snow..These.global.alterations.in.temperature.and.hydrology.represent.changes.
in.the.distribution.of.energy.through.the.surface-atmospheric.system,.which.in.turn.
may.feed.back.to.force.the.system.in.unforeseen.ways.
Changes.in.the.distribution.of.precipitation.and.temperature.are.important.in.their.
own.right,.but.also.because.of.their.role.in.regulating.the.Earth's.biosphere..Across.spa-
tial.scale,.climate.(operationally.deined.here.as.the.mean.and.variability.of.tempera-
ture.and.precipitation).is.a.major.ecological.control.of.terrestrial.biota..At.larger.spatial.
scales,.aggregate.patterns.of.climate.control.the.location.and.distribution.of.major.ter-
restrial.biomes.(Holdridge.1967)..Vegetation.assemblies.and.species.distribution.can.
often.be.related.to.climatic.conditions,.even.at.scales.as.ine.as.a.few.square.centime-
ters..Understanding.the.interaction.of.climate.and.the.biosphere.is.a.major.theme.in.
ecological.and.biogeographic.research.(Stenseth.et.al..2003)..Relating.them.remains.
the.subject.of.intense.investigation,.made.all.the.more.signiicant.because.of.the.poten-
tial.need.to.understand.climate-biosphere.interactions.under.changing.conditions.
C
limaTe
and
e
Cology
r
esearCh
in
The
lTer p
rogram
As.with.many.problems.in.ecology,.comprehensive.understanding.of.climate-bio-
sphere.interactions.requires.systematic.observation.at.time.scales.appropriate.to.the.
problem.. The. Long. Term. Ecological. Research. (LTER). program. was. established.
in. 1980. in. order. to. address. these. needs. within. the. ecological. research. commu-
nity..LTER.consists.of.a.network.of.26.research.sites.distributed.throughout.North.
America,.Antarctica,.and.the.Paciic.Islands..The.sites.were.chosen.to.represent.a.
wide.variety.of.ecosystem.types,.including.agricultural,.forest,.grassland,.arctic.and.
alpine.tundra,.hot.and.cold.desert,.estuarine,.urban,.and.marine..Since.its.inception,.
LTER.research.has.concentrated.on.ive.core.areas:.primary.productivity.(patterns.
and.control),.trophic.structures,.organic.matter.accumulation,.nutrient.cycling,.and.
