Mountain Ecology: Organism Responses to Environmental Change, an Introduction Author(s): John R. Haslett Reviewed work(s): Source: Global Ecology and Biogeography Letters, Vol. 6, No. 1, Mountain Ecology: Organism Responses to Environmental Change (Jan., 1997), pp. 3-6 Published by: Blackwell Publishing Stable URL: http://www.jstor.org/stable/2997522 . Accessed: 18/01/2012 07:34 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Blackwell Publishing is collaborating with JSTOR to digitize, preserve and extend access to Global Ecology and Biogeography Letters. http://www.jstor.org
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8/2/2019 Mountain Ecology - Organism Responses to Environmental Change, An Introduction
Mountain Ecology: Organism Responses to Environmental Change, an IntroductionAuthor(s): John R. HaslettReviewed work(s):Source: Global Ecology and Biogeography Letters, Vol. 6, No. 1, Mountain Ecology: OrganismResponses to Environmental Change (Jan., 1997), pp. 3-6Published by: Blackwell PublishingStable URL: http://www.jstor.org/stable/2997522 .
Accessed: 18/01/2012 07:34
Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp
JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of
content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms
of scholarship. For more information about JSTOR, please contact [email protected].
Blackwell Publishing is collaborating with JSTOR to digitize, preserve and extend access to Global Ecology
interact vera wide rangeof spatial scales to create
complex,nestedmosaics of habitatconditions. hese
mosaics, n turn, ften ave considerable ffectspon
thespatialdistributionsf organisms nmountains s
well as on their morphologies, rowth,physiology,
life cycles, behaviouralpatterns nd the typesand
intensitiesf interactions etweenndividuals. uch a
highdegree fspatialheterogeneitynd itsdominating
influencesre majorways n whichmountain 'alpine')
environmentsre to be considered nique, set apart
from the equally harsh, but generally more
homogeneous olar ('arctic') areas (Haslett,1996a).
This 'landscape' approachto mountain cology s
underpinned y an awarenessof the importance f
scale-the size atwhich he and mosaic s interpreted.Traditionally, ountainshave been treated imply s
large scale landscapes-mosaics of habitats nd land
use that eflect umanperceptionsf the nvironment.
This way of thinking as been perpetuated o some
degree by those using modern GeographicalInformation ystems t larger scales (e.g. Price &
Heywood, 1994). An alternative s to consider
mountain or other) andmosaics from he organism
point of view'. Here a wide range of spatialscales is
included, rommillimetreso hundreds f kilometres,
depending pon whether eetles r birds re thefocus
of attentione.g. Wiens, 1995; Haslett, 1996b). This
multi-scale approach allows understanding of
ecologicalprocessessee Hansson, Fahrig& Merriam,
1995) rather hanmerely eflectinghewishesofland
managers nd planners Haslett,1996b).The papers n this Special Issue of Global Ecology
and Biogeography etters emonstrate learly he roleof spatial heterogeneityn creatingthe uniqueness
of mountainnvironmentsnd the communitiesforganismshat nhabit hem,whether heybe plants,
insects, mallmammals r indeedourselves. hey also
emphasizethe importanceof scale in any attempt
at determiningow organisms, rom ndividuals opopulations o communities,re likely o respondto
changes o mountain nvironments.
THE VULNERABILITY OFMOUNTAIN ENVIRONMENTS:CONFLICTING EVIDENCE FROMPLANTS AND ANIMALS?
Althoughmountain nvironmentsre subject ochangefrom widevariety f causes,bothnatural nd human(Hewitt,1995), changesrelated o a changing limateare presently major avenue of research nd are an
underlyingheme n thepapers of thisSpecial Issue.There is now a generalscientific onsensus that theglobal climate s likely ochangeover oming ecades,
at ratesunprecedentednmodernhumanhistorye.g.Schneider, 989). Mountainclimates re characterized
by marked diurnal and seasonal cycles,with highvariability ver wide range f spatial cales. Changesto these climatesmayaffectmountain cosystemsntwo general ways, although these are also closelyinterlinked.irst, heremaybe physiologicalesponses
arisingfrom the increased concentration f carbondioxide available for photosynthesisKorner, 1994;
? 1997Blackwell cienceLtd 3
8/2/2019 Mountain Ecology - Organism Responses to Environmental Change, An Introduction
Price& Haslett,1995). Second, heremayberesponsesoforganismso thephysical limatic hanges: hangesin the means, variances and spatial distributions fparameters uch as temperature, umiditynd lightintensity.oth of these sets of issues have importantconsequences ormountain rganismsta widevarietyof spatial scales and organisationalevels.
Responsesofmountain lants o changes nclimate,or indeed to variations in any aspect of theenvironment,re of fundamentalmportance, ecausealterations o the form nd/or ontent f vegetationmosaics also constitutehanges o habitatmosaicsforbothplants nd animals. n a study f thevegetationofthe OlympicMountains USA), Peterson, chreiner& Buckingham (1997) use palaeontological and
biogeographicaldata to identify esponses of thevegetation o previous limatic hanges, nd use this
informationogainan insights to howthevegetationwill react to future limates.They argue that thediversityf habitatsnmountainss a majorsourceofresilience o climate hange and that theexceptional
variety f habitat onditions ithinelativelymalldistances facilitates survival of plant species byproviding dynamicmosaicthat sually ncludes ome'safe sites'. These sites are the sources of laterrecolonization. oing a stagefurther,he authors lsomake the point hatmostforms f human and use inmountain environments end to reduce spatialheterogeneity nd thus also reduce the inherentresilience f the system.
Some support or hisview sprovided ytheresultsof a study f the forest ypes f the SwissAlps. Thiswork mploys very ifferent,ndeed lmostoppositeapproach to thepreviousone. Fischlin & Gyalistras(1997) take Global ClimateModels as their tartingpoint,down-scalinghepredictionso local levels onreal mountain errainsnpre-definedlimate cenariosthat also includeseasonal changes.Theyhave foundthatup to a certain imit heirmodelpredictshat heforests re robust in the face of changingclimatic
parameters. ndeed,at one of their ites, venmajorchangesdid not result n any greatalteration o theforest ype.However, esults ffurtherimulations tother sitesdo suggest hat a whole rangeof forestresponses s possible, from no change to completecollapseof theforest anopy, epending pon the ocalsituation.
Contrary o theabovevegetational tudies, he twoinvestigationsncluded nthisSpecial Issue thatfocusupon insects uggest hatspatial heterogeneitys animportant actor hatcontributeso the fragility f
mountain ecosystems n the face of environmentalchange. This is despite the fact that animals aregenerallymuch more mobile than plants, so thatintuitivelynimalpopulationsmight e expected o be
more obust. oggs & Murphy 1997),using utterflies,showthatalthough he morevagilemountain pecieshave the ability o move theirdistributions,rackingthe changes n vegetation nd conditions aused byglobal warming, he ess mobile species are at riskofextinctionn such circumstances.mportantly,heseauthorsnote that changes n the variance alterationsto thefrequency f occurrence), ot ustthemeansofthe climatic conditions, are sufficient o cause
population extinctions.A similar argument isdevelopedby Haslett 1997) in relation o flies f the
family yrphidaentheAlps. Here,numbers fspeciesand individualshave been correlatedwith the form
and complexity f the habitatmosaic (taken as adynamicentity f its own, not just a collectionofpatches) at relevant patial scales. Changes to themicroclimatic osaic,particularlyhedegree fmixing
between atches, re likely o have significantffectson population izes and species ssemblage tructure.
One ofthe mostwidespread onsequences fglobalwarmingon mountain environmentss an overallreduction n area, with the total loss of particularhabitats. As the differentltitudinal ones migrate
upwards, he islands'ofmountain abitats re reducedin size, and the uppermost implydisappearwhen
there s no longer any land surfacehigh enoughtoaccommodate hem.This leads ultimatelyo changesin population densities, pecies rangesand regionalspecies distribution patterns of biogeographicdimensions nd significance,s illustratedythe tudy
of North Americanbutterfliesy Boggs & Murphy(1997). Indeed,the characteristicsf mountains ndmountainrangescan be sufficientlynsular to allowspeciesdistributionso be analysedusingthe theoriesand ideas of island biogeography. n an island
biogeographical tudyof the non-volantmammals
occurringnthemountainsnwestern orthAmerica,Lomolino & Davis (1997) suggest hat our ability operceive atternsnd assess causalitynbiogeographymay be strongly nfluencedby our own limitedperception f spatial scale (here ntra-archipelagoolarge-scale egional) n combinationwith the use ofdifferentarameters f ecological descriptionspeciesrichness, community nestedness and distributionpatterns fsingle pecies). One importantmplicationis that a limitedperception f scale is also likely oaffectur understandingfextinction ates n islands,
and thereforelso our udgement f thevulnerabilityor robustness f mountain abitat islands' nresponseto environmental hange. (Note that the botanicalpaper by Peterson t al. (1997), in which mountainswere argued to be resilient, nvolves a parallelmethodology; heuse of information ased upon the
past as an aid to explaining resentnd future atternsof speciesdistributions).
Given the evidencepresentedn the papers citedabove, and including oth plant nd animalstudies,t
maybe suggested hat oo muchreliance pon humanscales of study' s the main source of manyof thepresent ncertaintiesurroundinghedegree f mpactof environmentalhangeon mountain cosystems.
HUMAN INTERPRETATIONS:
MOUNTAIN ECOLOGY MEETSCULTURAL THEORY
If it is necessary o be waryof overly nthropogenic
interpretationsf nature nmountain ituations,t iscertainlyronic hat cosystemynamics nmountainsseem to have a lot in common with human socio-cultural ystemsn the same areas. Classical viewsofboth types of system assume some unidirectionalchangefrom n initial o a final tate. n ecology, hisis exemplified y successional rogressionsowards'climax'community, hile nthe social sciences inearchangesfrom raditional omodern, r capitalism ocommunism, re examples of 'grand theories' thatinfer hange n a singledirection.
Recent experiencehas shown that in ecology,successions not a simple inearprogression,ather tis a complex, dynamic, nd oftencyclic, ystem fmosaic patches e.g. Remmert, 991) very imilar othose of mountain andscapes discussed within hisSpecialIssue. Similarly, odern ultural heory iewssocial systems s non-linear,nvolvingneverendingsequencesof transitionaltates e.g. Holling, 1986).
In an exploration f the parallelsand interactionsbetween ecology and human culture, Price &Thompson 1997)examine heresponses fthehumaninhabitants of mountain regions to the changingenvironmentsnwhich heyive, s shownbythewaysinwhich hey manage'their esources. sing xamplesof Himalayan nd a Swiss lpinevillage, hese uthorsargue that mountainsocio-cultural ystems annotoperateas straightforwardlys implied by 'simple'theories such as presented n 'the tragedy of thecommons' (Hardin, 1968, 1994). Instead of simple
linear rogressions,he ystems espond o being ulledin many different ays at once by exhibiting highdegree f flexibility,nwhich trategiesmay change o
allow thesystem o absorb the effects f unforeseen'surprise' vents.As putforward y Price& Thompson(1997), the similarities etween cultural theory nd
ecological theory n mountains re striking,nd theapproach should not be ignored.
TAILPIECE
This brief ntroductoryaperhasattemptedoprovidea perspectivef some of the critical ssues nvolvedn
understandinglantand animalresponses o changesin mountain environments, articularly hanges in
climate. Spatial complexity nd scale have come
stronglyo the ore, ogether ith hedynamic ature fspatialmosaicsoverdifferentemporal cales.Whether
'top down' or 'bottomup' researchapproaches toecological questionsof climate hangeare preferable
remains subject ordebate Root & Schneider, 995),
but it may be suggested hat because of the widerangeof spatial and temporal cales nvolved, closerintegration f the two types of strategywould beparticularly ruitfulnmountain ituations.
Mountain ecosystems are argued here to haveimportance s special, functional omponents f ourplanet, nd also to have value as model' systems ithinthe realms of ecological and biogeographical heory.Thismeansthey re worth reserving. espitethefact
thatmanymountain reas have been designated sNational Parks,orhave been affordedther orms fprotected tatus, the presently ccepted large-scale,
patch ontentpproaches oconservationmanagementare likelyto prove inappropriate n situationsofenvironmental hange. If the characteristicspatialbiodiversity'f mountains s to be maintained,hen twill be necessary o alter and use, managementnd
conservationtrategieso place muchmoreemphasis
on the mportance f complexity nd scale-the veryaspects of mountainecologythat make mountains
unique.
ACKNOWLEDGMENTS
I thankJohn ee and Hazel Normanfor heir riendlysupport before and during the VI InternationalCongress fEcology nManchester, here he uthorsof thismountain cologySpecial Issue came together.
Hewitt,K. (1995) Hazards and disaster n mountainenvironments:roblems n the geography f risk.Mountainst risk: urrentssuesn nvironmentaltudies(ed. byJ.R.Allan),pp.98-128.Manohar,New Delhi.
Holling, .S. 1986)Theresiliencef errestrialcosystems:local surprise and global change. Sustainabledevelopmentf thebiosphereed. by W. C. Clark andR.E. Munn), p.292-320.Cambridge niversityress,Cambridge.
Korner, . (1994) mpact f tmospherichanges n highaltitude egetation. ountain nvironmentsn changingclimatesed. byM. Beniston). outledge, ondon.
