Geoscience Reference
In-Depth Information
IMPORTANCE OF MECHANISTIC UNDERSTANDING
Throughout.the.topic,.authors.consistently.made.an.effort.to.discuss,.propose,.and.
highlight.known.or.suspected.mechanisms.that.account.for.biotic.responses.to.cli-
mate.change..Although.great.rigor.in.experimental.and.monitoring.design.is.needed.
to.acquire.a.mechanistic.understanding,.it.is.only.with.such.understanding.that.con-
servation.and.management.actions.will.be.best.informed.(Hallett.et.al..2004;.Beever.
et.al..2010)..The.longer.that.one.ponders.a.particular.type.of.wildlife-climate.rela-
tionship,.the.more.demanding.that.a.
full
.mechanistic.understanding.seems..That.is,.
complete.understanding.of.the.mechanisms.by.which.climate.affects.an.ecological.
phenomenon.would.ideally.include.relatively.long-term.data.on.(a).macroclimate.and.
microclimates.relevant.for.the.target.species.or.process;.(b).distribution.of.the.target.
species. through. time,. at. ine. spatial. resolutions. and. broad. extent;. (c). demography,.
including.reproductive.success.or.knowing.which.genders.and.age.classes.are.being.
positively.or.negatively.affected;.(d).physiology.of.each.individual.being.affected;.(e).
behavior.of.affected.and.unaffected.individuals.or.populations.(e.g.,.how.much.plas-
ticity.exists.in.diel.behavior.patterns?);.and.(f).sympatric.species.or.other.alternative.
sources.of.inluence.on.the.target.species..Given.that.the.full.complement.of.these.
data.sources.are.rarely.present.in.an.entire.research.program.(let.alone.in.any.indi-
vidual.investigation),.understanding.will.usually.have.to.be.constructed.piecemeal,.
and.at.least.occasionally.via.proxies.of.the.variables.truly.affecting.biotas.
Even.in.cases.where.an.aspect.of.climate.is.suspected.to.affect.an.ecosystem.com-
ponent. or. ecological. process,. our. understanding. of. biotic. responses. will. be. much.
improved.if.greater.speciicity.is.achieved..For.example,.consider.the.hypothetical.
assertion.that.“increasing.temperatures”.are.reducing.survivorship.of.juveniles.of.a.
particular.species.of.plethodontid.salamander..First,.are.temperature.maxima,.min-
ima,.or.means.increasing?.Second,.in.which.season(s).of.the.year.are.temperatures.
rising. in. a. manner. that. is. biologically. relevant?. Alternatively,. is. season. even. the.
right. time. period. to. investigate?. In. some. cases,. month,. week,. day,. or. even. single.
extreme.events.may.be.more.informative.(Gutschick.and.BassiriRad.2010)..Third,.
over.what.spatial.extents.and.resolutions.are.temperatures.increasing?.Fourth,.can.
you. distinguish. whether. the. effects. are. not. from. increasing. temperatures,. but. are.
instead.from.increased.variability.in.temperatures?.Careful.and.thoughtful.study.of.
those.portions.of.a.species'.distribution.in.which.it.is.being.lost.can.provide.addi-
tional. insight. (
sensu
. Wilson.et. al.. 2005).. Such. focused. study. may. alternatively. be.
performed. across. important. biophysical. gradients. within. a. species'. distribution.
(Breshears.et.al..2008).
SOME THINGS WE KNOW, AND THINGS WE HAVE LEARNED
As. evidenced. in. this. topic,. work. on. biotic. responses. to. contemporary. climate.
change. is. burgeoning,. and. scientists. are. achieving. new. milestones. of. understand-
ing. every. month.. As. also. seen. in. this. topic,. biotic. responses. relect. inluence. not.
only. of. climate,. but. also. of. other. factors—interacting. in. nuanced. and. sometimes.
nonintuitive. ways. (Post. and. Stenseth. 1999;. Jones.
this volume
;. Peterson. et. al..
this
volume
;. Blaustein. et. al.
this volume
;. Fleishman. and. Murphy
this volume
;. Wilson.
