Geoscience Reference
In-Depth Information
however,.this.assumption.does.not.often.hold,.due.to.biological.reasons.or.artifacts.
of.the.analytical.process..For.example,.species.with.limited.dispersal.capabilities.or.
that.are.in.the.process.of.range.expansion.do.not.ill.all.their.potential.distributions;.
for.instance,.herptiles.consistently.show.lower.degrees.of.equilibrium.with.climate.
compared.to.other.vertebrates.such.as.birds.(Araújo.and.Pearson.2005)..Furthermore,.
failing.to.include.critical.environmental.variables.during.the.modeling.process.may.
also. produce. models. falsely. appearing. to. be. at. disequilibrium. (Dormann. 2007)..
Failing.to.meet.the.equilibrium.assumption.overestimates.the.distributional.potential.
of.species.in.altered.scenarios.(e.g.,.due.to.contemporary.climate.change)..However,.
implementation.of.distance.constraints.obtained.from.calculating.distances.among.
neighboring.occurrences.and.spatial.autocorrelation.data.typically.improves.model.
performance.(Allouche.et.al..2008).
Another. assumption. used. when. projecting. ENMs. through. time. is. that. of. niche.
stability. (Nogués-Bravo. 2009),. also. referred. to. as. niche. conservatism.. Projected.
models. assume. that. species. will. not. adapt. to. novel. conditions. present. in. changed.
climates;.rather,.species.will.maintain.evolutionary.stability.and.thus.they.will.track.
the. environmental. conditions. suitable. for. them. across. space.. In. other. words,. the.
quantitative.relationships.to.climatic.variables.that.a.species'.distribution.has.exhib-
ited.recently.are.assumed.to.remain.unchanged.through.time.(and.through.altered.
climates)..This.seems.a.reasonable.assumption.for.most.species.with.relatively.low.
evolutionary. rates. (e.g.,. higher. plants. and. vertebrates),. given. that. the. duration. of.
climate.change.in.this.warming.episode.covers.only.a.few.generations..However,.for.
fast-evolving. (e.g.,. insects. and. microorganisms). or. genetically. plastic. species. this.
may. not. be. the. case,. and. adaptation. can. occur. (Rodríguez-Trelles. and. Rodríguez.
1998;.Rodríguez-Trelles.2010)..In.the.latter.cases,.ENMs.will.underestimate.species'.
potential.distributions.
s
TrengThs
and
l
imiTaTions
of
enm
The.conceptual.simplicity.of.ENMs.plus.the.growing.availability.of.source.data.(i.e.,.
species. records. and. climate. time. series). and. software. for. analysis. have. made. this.
approach.very.popular.in.recent.years,.and.the.literature.is.replete.with.the.use.of.
such.models.for.addressing.a.wide.variety.of.questions,.for.many.taxonomic.groups,.
and.in.virtually.all.regions.of.the.world..Evidence.of.this.can.be.found.by.reviewing.
the.contents.of.recent.issues.of.
Ecography
,.the.
Journal of Biogeography
,.and.
Global
Ecology and Biogeography
..Ironically,.the.features.that.make.ENM.appealing.con-
stitute,.at.the.same.time,.both.strengths.and.weaknesses.
Owing.to.their.need.for.only.relatively.basic.input.data,.ENMs.have.been.used.
to. analyze. the. response. of. large. numbers. of. species. to. climate. change. in. differ-
ent. regions. of. the. world,. allowing. detection. of. regional. and. global. patterns.. For.
example,.Peterson.et.al..(2002).modeled.the.potential.impacts.of.two.climate-change.
scenarios.out.to.the.year.2055—a.conservative-emission.and.a.liberal-emission.sce-
nario—for.1870.species.across.México,.including.butterlies,.birds,.and.mammals..
The.authors.found.that.levels.of.species.turnover,.rather.than.extinctions.or.massive.
range.reductions,.may.be.the.most.important.ecological.consequence.of.contempo-
rary.climate.change.for.this.region..In.another.study,.Thuiller.et.al..(2005).modeled.
