Geoscience Reference
In-Depth Information
the. spread. of. tundra. shrubs. in. neighboring. Ivvavik. NP. or. other. parks. as. one. in. a.
suite.of.EI.measures.for.assessing.the.Tundra.EI.Indicator..The.recent.terrestrial.eco-
logical.inventory.can.be.used.to.identify.where.shrub.communities.presently.occur.
in.the.park..Knowledge.of.the.ecological.factors.that.determine.the.different.types.
of.shrub.ecotypes.can.help.focus.the.analysis.to.those.tundra-shrub.ecotypes.most.
vulnerable.to.spreading.out..This.analysis.can.be.supported.by.ground.measures.to.
conirm.the.spreading,.and.by.back-casting.aerial.imagery.or.remote-sensing.data.to.
understand.the.scope.and.scale.of.the.issue.
Once.we.have.identiied.the.target.(focal).ecotypes.where.shrub.change.is.occur-
ring,.we.can.conduct.monitoring.at.two.scales:.local.ground-based.measures.of.rate.
of.spread,.and.associated.ecological.effects.on.snow.accumulation,.soil.temperature,.
active-layer. depth. and. species. effects.. We. can. also. link. these. ground. measures. to.
a. broader. landscape. scale. using. remote-sensing. tools.. Five-year. resampling. using.
high-resolution.satellites.would.provide.a.cost-effective.method.at.a.useful.scale.to.
follow. the. potential. spread. of. tundra. shrubs.. The. tundra-shrub. monitoring. results.
would. then. be. used. to. reine. the. shrub-spread. model. and. provide. more. precise.
estimates. for. subsequent. model. iterations.. Such. ecological. models. focused. on. key.
management. issues. will. be. the. key. to. proactively. managing. park. ecosystems. and.
anticipating.ecological.change.
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The.key.objectives.for.management-focused.research.will.be.to.measure,.interpret,.
and.communicate.the.biological.mechanisms.and.environmental.control.factors.that.
determine.the.most.important.aspects.of.ecological.change.in.the.park,.as.identiied.
through.EI.monitoring..Models.will.need.to.be.developed.that.relate.climate.drivers.
to.the.environmental.control.factors.that.determine.the.rate.and.direction.of.ecologi-
cal.change.
Using. the. spread. of. erect. tundra. shrubs. as. an. example,. the. rate. of. spread. can.
be. predicted. based. on. the. autecological. characteristics. of. the. shrub. species. (e.g.,.
seed-dispersal.potential,.germination.requirements,.time.to.sexual.maturity,.poten-
tial.for.vegetative.propagation).and.the.environmental.factors.that.limit.the.rate.of.
spread. such. as. exposure. to. winter. wind,. soil. temperature. and. nutrient. levels,. and.
snow.accumulations..Given.that.shrubs.are.already.expanding,.we.can.use.historical.
rates.of.spread.to.test.the.models.developed..There.is.also.potential.for.synergistic.
interactions,. so. that. more. erect. shrubs. will. trap. more. snow,. possibly. resulting. in.
warmer. ground. temperatures. and. higher. germination. and. rates. of. growth. (Sturm.
et. al.. 2005).. More. winter. snowfall. with. warming. climates. could. also. add. to. this.
synergy.and.further.increase.the.rate.of.spread..These.factors.can.be.modeled.and.
a.rate.of.spread.predicted..As.described.previously,.the.actual.rate.of.spread.is.then.
measured.through.the.EI.monitoring.program,.and.the.model.is.reined.within.the.
5-year.iterations.of.the.park.planning.cycle..Other.important.areas.of.climate-driven.
ecological.change.that.may.be.modeled.to.inform.management.include.changes.in.
the.interactions.among.active-layer.depth,.annual.soil.temperature,.and.soil.decom-
position.(ACIA.2005,.Callaghan.et.al..2005),.with.resulting.changes.in.vegetation.
