Forest-cover increase does not trigger forest-fragmentation decrease : case study from the Polish Carpathians

sustainability

Article

Forest-

CoverIncreaseDoesNotTriggerForest-

FragmentationDecrease:CaseStudyfromthePoli shCarpathians

JacekKozak^1,*^ID,Elz˙bietaZiółkowska²,PeterVogt³,MonikaDobosz¹,DominikKaim^{1I D,}NataliaKolec ka^1andKrzysztofOstafin^{1I D}

1 InstituteofGeographyandSpatialManagement,JagiellonianUniversityinKraków,Gronostajowa7,30- 387Kraków,Poland;monika.dobosz@uj.edu.pl(M.D.);dominik.kaim@uj.edu.pl(D.K.);natalia.kolecka@uj.edu.pl(N .K.);krzysztof.ostafin@uj.edu.pl(K.O.)

2 InstituteofEnvironmentalSciences,JagiellonianUniversityinKraków;Gronostajowa7,30-387Kraków, Poland;e.ziolkowska@uj.edu.pl

3 JointResearchCentre,EuropeanCommission;ViaEnricoFermi2749,I- 21027Ispra(VA),Italy,peter.vogt@ec.europa.eu

* Correspondence:jacek.kozak@uj.edu.pl;Tel.:+48-12-6645-299

Received:12April2018;Accepted:4May2018;Published:8May2018 ^{checkforupdates}

Abstract:Understandingthecausesandconsequencesofforest-

fragmentationchangesiscriticalforpreservingvariousecosystemservicesandtomaintainbiodiversit ylevels.Weusedlong-term(1860s–2010s)andlarge-

scaledataonhistoricalforestcoverinthePolishCarpathianstoidentifythetrajectoriesofforestfragmentation.Pastfore stcoverwasreconstructedforthe1860s,1930s,1970sand2010susinghistoricalmapsandthecontempo rarynationaldatabaseoftopographicobjects.Weanalyzedforest-

coverchangesin127randomlyselectedcirculartestareas.ForestfragmentationwasquantifiedwithGuidosT oolboxsoftwareusingmeasuresbasedonalandscapehypsometriccurve( L H C ) . D e s p i t e a g e n e r a l i n c reasei n f o restc o ve r,f o restf r a g m e n t a t i o n s h o w e d d i v e rgenttrajectories:adecreasebet weenthe1860sand1930s(in57%oftestareas),andanincreasebetweenthe1930sand1970sandbetweenthe1970sand201 0s(in58%and72%oftestareas,respectively).Althoughdeforestationtypicallyinvolvestheincreasingfrag mentationofforesthabitats,wefoundthatforestexpansionmaynotnecessarilyleadtomorehom ogenousforestedlandscape,duetocomplexland-ownershipandland-

uselegacypatterns.Thisisbothachallengeandanopportunityforpolicymakerstotunepoliciesinsuchawayastomaintainthedesi redfragmentationofforesthabitats.

Keywords:forest-coverchange;forestexpansion;forest-

fragmentationtrends;fragmentationindex;historicalmaps;landscapehypsometriccurve;mountainareas

1.I n t r o d u c t i o n

Thelossofforesthabitatsandforestfragmentationhavebeenextensivelyinvestigatedinthelastfewdecades[1]

.Studiescarriedoutatvariousscalesshowthatforestfragmentationiscriticalformaintainingbiodiversitylevels[2–

4]andthatdeforestationincreasesforestfragmentationbydissectingintactforestareas,isolatingforestpatche s,andeliminatingforestcorridors[5–18].Thevastevidencethatforest-

coverdecreaseislinkedtoincreasingforestfragmentationmayleadtoabeliefthatforestexpansion,onthecontra ry,decreasesforestfragmentation.Onlyfewstudieshavepresentedaquantitativeanalysisofforestfragm entationinthecontextofincreasingorrelativelystableforestcover,providing,however,inconclusiveevidenceforbothincre asing[19–

22]anddecreasingfragmentation[23,24].T h e lackofevidenceontherelationshipbetweenforestcover andforestfragmentationisremarkableinthecontextoftherecentlyproposedhabitatamounthypothesis[25]

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thatunderlinestheinfluenceofhabitatamountonspeciesrichness,questioningatthesametimetheroleofhabitatf ragmentation.

Forestexpansionhasbeenrecordedsincethe19thcenturyinanumberofcountriesalloverth eworld[26]asaresultofforesttransition,referredtoasthereversalofdecreasingforest-

covertrends[27–

29].Thereversal,however,doesnotneedtodenoteafullremovalofalltheconsequencesoft h e f o r m e r f o rest- coverreduction—

inp a r t i c u l a r t h o s e referringt o t h e i n c reasedf r a g m e n t a t i o n andl o s s o f c o n n e c t i v i t y o f f o r estedh a b i t a t s . I n E u rope,f o restt r a n s i t i o n i s m o s t l y relatedt o t h e releaseo f e x c e s s a g r i c u l t u r a l l a n d f roma g r i c u l t u r a l p roduction( l a n d a b a n d o n m e n t ) i n m a rginallocationsandnat uralsecondaryforestsuccessionorafforestation[30–36].L a n d -

u s e legaciesandpersistenceplayasignificantroleasforestexpansionoccursinareaswithhistori callyestablishedsettlements,i n f r a s t ructuraln e t w o r k s a n d l a n d o w n e r s h i p , p romotings o m e a reasa n d e x c l u d i n g othersf romfo restrecovery[37–39].Fo rest-

coverin creasefollo winglandabandon men tis t hu s aslowandgradualprocess,insomeaspectssi milartothesprawlofurbanareas,reproducinginitialdistributionofforestpatchespreservedinthelandscape andspatialpatternsofbiophysicalfeaturesinthelandscape[40–

42].Contrarytodeforestationthatmaydecreaseforestcoveroverlargeareasbytensofpercentinarelativelys horttime,forest-

coverincreasebysimilarvaluesoccursoveratleastseveraltensorhundredsofyears.Therefore,studyingfore st-

fragmentationchangesrelatedtoforestcoverincreaserequiresspatialdatasetsencompassingperiodsof50yearsor more.

Ingeneral,howlong-term,gradualforest-

coverincreasetranslatesintoforestfragmentationisfarfromknown,aslarge- scalestudiesbasedonspatiallyexplicitlong-termforest-

coverdataarenotcommon.Inourstudyweaim,therefore,toassessrelationshipsbetweenforestareaandf orestfragmentation,underrealconditionsofthelong-term(1860–2010)forest-

coverincreaseinthePolishCarpathians(approximately20,000km²),basedonmap-derivedforest-

coverdata.Toassessforestfragmentation,weuseanewconceptofalandscapehypsometriccurve(LH C)basedondistancesdistributionwithinlandscapeelements.I n thepaper,weseektoaddressthefollowin gresearchquestions:

1. Howhasforestfragmentationchangedinthestudyregionsincethe1860s(rates,trajectories)?

Whatareregionaldifferencesandwhydidtheyoccur?

2. Whatistherelationbetweenchangesinforestfragmentationandratesofforest-coverchange?

3. Whichstructuralelementsofforestcover(patches,branches,corridors,perforations)havethestrong estinfluenceonforestfragmentationanditschanges?

2. MaterialsandMethods 2.1. StudyAreaandForestData

ThePolishCarpathiansarelocatedinthenorthernpartoftheCarpathianarcwithaltitudesrangingfr om300maslatthenorthernmarginoftheCarpathianfoothills,and2500maslinthePolishpartoftheTatraMountains[43].Forest transitionstartedintheregioninthemid-

19thcenturywhenforestcoveramountedto27%[44,45].AsinallCarpathiancountries,land-

usechangewasdrivenbyfrequentregimeshiftsrelatedtothecomplexhistoryoftheregion[46].Currently,typicallandscape sinthePolishCarpathiansconsistofamosaicofagriculturallandsandforests,withmostsettlementslocatedinvalleys,andforests cover47%ofthearea[45].Inthe1840s,almostallforestsbelongedtopropertiesoflargelandowners[47].AfterWo rldWarII,forestpropertieslargerthan25hawerenationalizedand,currently,approximately50%offorestsinth eCarpathiansareownedbytheStateForestsNationalHolding.A c c o rdingto[33],approximately14%ofthefar mlandshowssignsofsecondaryforestsuccession,andthereforeforest-

coverincreaseintheregionisexpectedinthenearfuture[48].

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Thepatternchangeofforestfragmentationanditsrelationshiptoforestareawereanalyzedinf o u r t i m e s t e p s : t h e 1 8 6 0 s , 1 9 3 0 s , 1 9 7 0 s a n d 2 0 1 0 s ( F i g u re1).The b o u n d a r i e s o f t h e for estedareasinthe1860sand1930sforestmapswereobtainedusingmanualvectorization

10

oftopographicmaps,theAustro-HungarianSecondMilitarySurveyMap(1:28,800;quicklooks

Sustainability2018,10,xFORPEERREVIEW 3of24

availablea th t t p : / / m a p i re.eu/),a n d theP o l i s h M i l i t a r y M a p ( 1 : 1 0 0 , 0 0 0 ; m a p s c a n b e c o n s u l t e d a t

http_h:_t/_tp/_:h_//g_mis_a._pc_ia_rr_et_.o_em_u/)a_,tic_a.p_nl_d/),_tr_he_espe_Pc_ot_li_iv_se_hly._MFo_ilr_itath_rye19_M70_apsw₍e_1:e 1x₀t₀r_,a₀c₀t₀e_;df_mor_ae_ps_st-co_cav_neri_bn_efor_cm_ona_sti_uo_ln_teu_dsin_ag_ta semhi_t-

ta_pu_:/t_/o_hm_gia_st_.ce_ad_rtf_oe_mat_au_tr_ie_c-_.pex_l/t₎r_,a_rc_et_si_pon_ecp_tir_vo_ec_lyed_.Fu_ore_rtb_ha_ese₁d₉₇o₀n_sc_wo_el o_er_xs_tre_ap_ca_tr_ea_dti_fo_on_rea_sn_t-d_com_veo_rrp_inh_fo_ol_ro_mg_aic_ta_iol_npr_uo_sc_ines_gsi_angfollsoewmei-

daubtyommaatenduaflecaoturre-

etixotrnac[t4i9o]nappproliceeddutorethbeaPseodlisohnTocpoologrraspehpiacraMtioanp(a1n:2d5,0m00 o;rpahvoaliolagbiclaelathttpr//o/cemssaipnyg.gfeoollpoowretadl.bgyovm.pal/n)u,aplucbolrirsehcetdion

by[4t9h]eaHpepalidedOftfioctehoefPGoeliosdheTsyopaongdraCpahritcogMraph(y1:

(2G5,ł0ó0w0;nyUrz^aa^v˛d^ailG^abe^lo^ede^az^tji^hi^tK^tpa^:r^//t^mog^ar^pa^yfi^.gi,^eG^opU^oG^rtI^aK^l.g).^oT^vh^.pe^l/2^),01^p 0^us^bf^lo^isr^hes^et^dm^ba^ypw^tha^eso^Hb^et^adine^Od^fftⁱh^cr^eou^og^fhGth^eoe^din^est^yegr^aaⁿt^dionofd^Ci^aff^re^tore^gn

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ic^Kov^ae^rtr^os^gp^raa^ftⁱiⁱa^,lGd^Ua^Gta^Ib^Ka⁾s^.eTs^h.^eA²⁰p¹r⁰i^sm^fa^or^ry^esd^tamta^apso^wu^ar^sce^obo^tn^aifⁿo^er^d estbou^thn^rd^oa^ur^gie^hs^thw^eaⁱs^ntt^eh^ge^rac^to^ionⁿte^om^fdpⁱo^ffr^ea^rr^ey^ntP^ao^vl^ais^ilh^abn^leat^li^aoⁿn^da^-

l^usto^ep^aoⁿg^dr^la^apⁿh^di^-

c^cov^ve^ec^rto^spr^ad^tia^at^la^db^aa^ts^ae^bai^sn^ess^.c^Aale^pr1^im:10^ar,0^y00(BD^dO^atT^a1^s0^ok^u,^ra^ceva^oiⁿla^fb^ol^re esa^tt^bhotutpn:d/a/rmiesawpya.sgtehoepcoorntatel.mgopvo.rpalr/y),^Pf^ou^lir^st^hheⁿr^av^tie^orⁿi^afi^le^td^opu^os

gin^rag^pd^hia^cta^vefr^co^tom^rdth^ate^abF^ao^sr^eest

Nuⁱmⁿe^sr^ci^ac^la^el1M^:1a⁰p^,0,⁰t⁰he^(BF^Do^Ore^Tst¹⁰D^ka^,t^avB^aa^iln^ak^bl(^eh^at^thss^t:^t/^p/^:/w^/mw^aw^p.^yb^.gd^el.^ola^p s^oy^r.^tg^ao^l.v^g.^op^vl/^.pp^lo^/)r^,t^fa^ul/^rt)^h,eth^re^veP^ro^ifl^ies^dhT^uo^spⁱⁿo^gg^dra^ap^tahic

Ma^fp^rof^mor1^th9^e70^Fs^o(^r1^e:^s2^t5,^N00^u0^m)a^ernⁱd^caa^leMri^apa^,nthd^esa^Ft^oe^rl^eli^st^te^Dim^aa^tage^Br^ayⁿa^kc q^(hu^ti^tr^pe^sd^:/b^/wet^ww^wee^.bn^d2^l.0^la0^s9^ya^.gn^od^v2^.p0^l1^/p5^o(^ra^tv^aa^l/i⁾l^,ab^thle^eathttp^P:^o/^li/^sm^hTap^opy.

og^ge^ro^ap^po^hr^icta^Ml.g^ao^pv^f.^op^rl/¹)⁹.⁷F⁰o^sr⁽e¹s^:2t⁵m^,0a⁰p⁰⁾s^afoⁿr^da^al^el^rtⁱi^am^laeⁿs^dte^sp^as^tew^llie^tr^eeⁱ mco^an^gv^ee^ryrt^ae^cd^qt^uo^irr^ea^dst^be^er^tf^wo^er^emⁿa²t⁰w⁰⁹ithand2015(availableathtp://mapy.geoportal.go

v.pl/).Forestmapsforalltimestepswereconverted mspatialresolution.

torasterformatwith10mspatialresolution.

Figure1.Forestcoverinthestudyareaanditslocation.

Figure1.Forestcoverinthestudyareaanditslocation.

2.2.LandscapeHypsometricCurveandForest-FragmentationIndex 2.2. LandscapeHypsometricCurveandForest-FragmentationIndex

ForestfragmentationwasquantifiedwiththesoftwareG uidosToolbox,version2.6[50]using

mFeaosruersetsfbraagsemdeonntathtieonLHwCas(sqeeuAanptpifienedixwAithfotrhaedseotfatiwlea drdeeGscuripdtoiosTno).oPlbrionxc,ipvaellrys,iothno2se.6m[5e0a]suurseisngmeaseubreassebdasoen

in

ddoinstathneceLsHtoCfo(sresetAedpgpeesnwdihxicAhfaorreamdoestalyileudsedeisncrliapntdioscna)p. ePrfirnacgimpaenlltya,ttihonossetumdeieassutoresare^ab^ssa^es^se^sd^fon^esd^t,is^ota^rn^lc^aeⁿs^dsto^caf^po^ere^d sⁱt^sse^ed^cg^tie^osⁿw^bh^yic^rh^oaa^dr^se⁽m^roo^as^dt^ll^ey^ssus^ve^od^lui^mn^el⁾an^[9d^,5sc¹a^–

p⁵³e^].fr^Aag^smimen^pt^la^emtio^en^ts^et^dudⁱⁿiestoa^Gs^use^ids^os^sf^To^or^oes^lbt,^oo^x,r^Lla^Hn^Cdsc^ua^mp^me^ad^riⁱ s^zs^ee^sct^hio^en^Eb^uy^clir^do^ea^adⁿs^d(ⁱr^so^taⁿd^cles^dsⁱv^sto^ril^bu^um^tie^o)ⁿ[9fo,5r1a–

5g3iv].^enA^bsⁱⁿim^arp^yl^le^am^nde^sn^ct^ae^pd^einGu^mid^ao^ps^,Tⁱoⁿo^wlb^hoⁱx^ch,L^tH^heC^fos^ru^em^grm^ouaⁿr^diz^c e^ls^at^sh^se^reE^pu^rec^sli^edⁿe^tsan^thd^eis^latⁿan^dc^-

ce^od^vi^es^rtr^ci^lb^au^ssti^oo^fnⁱⁿfo^ter^rea^sg^ti⁽v^he^en^reb^fi^on^ra^er^sy^t),lands^tc^ha^epema^bp^a,^ci^kn^gw^roh^uiⁿc^dht^ch^la e^ssforeg^rr^eo^su^en^td^sctl^ha^ess^cr^oe^mp^pre^les^men^etⁿs^tath^ryel^ca^ln^asd^s-c⁽o^hv^ere^erⁿcl^oaⁿs^-

s^fof^ei^sn^t)t^.er^Ee^us^ct^l(^idhereⁿfdoⁱr^se^ts^atⁿ)^c,^ea^snd^art^ehebac^ck^ag^lcr^uo^lu^an^ted^dcal^sas^ps^osrⁱe^tp^ivr^ees^ve^a n^luts^esthⁱⁿe^tc^ho^em^fop^rlem^roe^unⁿta^dry^anc^dlaⁿss^eg(^ah^te^ivre^vn^ao^ln^u-

ef^sorⁱⁿes^tt^h).^ebE^au^cc^kl^gid^roe^uan^dd^li^asⁿta^dn^-cc^oe^vs^ea^rre

calc^cu^lal^sa^st^.e^Ld^Has^Cp^isos^fi^ut^riv^the^ev^raⁿl^ou^re^msi^an^lizth^ede^,fo^i.r^ee^.,g^sr^co^au^len^dd^ba^yn^td^hn^ee^thga^eoti^rv ee^tiv^calu^me^as^xiⁱn^mt^uh^meb^daⁱc^sk^tagⁿr^co^eunⁱⁿd^thla^en^fd^o-^rc^eo^gv^re^or^ucⁿl^dass.

andinthebackground.ThedegreeoffragmentationcorrespondstotheareaundertheLHCcoveredLHCisfurth ernormalized,i.e.,scaledbythetheoreticalmaximumdistanceintheforegroundandinbetweenminimump

ossiblef ragmentation( fora landscapewiththes ameforegroundareabut

thebackground.ThedegreeoffragmentationcorrespondstotheareaundertheLHCcoveredbetween clumpedina s inglecircle)a ndmaximumfragmentation( f ora chessboard-likelandscape minimumpossiblefragmentation(foralandscapewiththesameforegroundareabutclumped

configurationofforegroundpatchesandforegroundcoverageof5 0 %).Fragmentationisthen as i n g l e c i rcle)a n d m a x i m u m f r a g m e n t a t i o n ( f o r a c h e s s b o a rd-

likel a n d s c a p e c o n f i g u r a t i o n o f

calculatedseparatelyfortheforegroundandbackgroundclass,aswellassummarizedforthewhole landscape(AppendixA,Equations(A1)–(A3)).

4

foregroundpatchesandforegroundcoverageof50%).Fragmentationisthencalculatedseparatelyfortheforegrounda ndbackgroundclass,aswellassummarizedforthewholelandscape(AppendixA,Equations(A1)–(A3)).

TheLHCapproachallowsforasimultaneousaccountofdifferentfragmentationaspects,includingperforations,amount, divisionanddispersionofhabitatpatches,andprovidesonesinglevaluerangingfrom0%to100%referringtofragmentati on,inthissensebeinganoverallfragmentationmeasure.BasedontheLHCconcept,wedefinedtheforest- fragmentationindexasthedegreeoffragmentationofforegroundareaforaforest/non-forestbinarymap.

2.3. QuantifyingForestFragmentationandItsChange s

Wea n a l y ze d f o rest-fragmentationa n d f o rest-

coverch a n g e s b a s e d o n L H C i n 1 2 7 r a n d o m l y selectedcirculartestareaswith5-

kmradii(anareaofapproximately80km²,closetotheareaofatypicalcommuneinthestudyarea)andwith minimumdistancebetweencentersofcirclesequalto5km(that,ispartialoverlapwasallowed).Toensure anevencoverageoftheentirestudyarea,thePolishCarpathianswerecoveredbytheregulargridof20×2 0kmsquareunits,andatleastonecirclecenter-

pointwaslocatedineachunit.Foreachcirculartestareaandtimestep,wecalculatedtheLHC-basedforest- fragmentationindex(asdescribedabove),aswellasforest-coverarea.Foreachofthetimeperiods(1860s–

1930s,1930s–1970sand1970s–

2010s),thechangeratesofforestfragmentationandthechangeratesofforestcoverwerecalculatedasarelativedifferen cebetweentheend-andtheinitialv a l u e s .

Finally,foreachtestareaweassesseditsforest-

fragmentationtrajectory(FFT).AnFFTwasoneof27possiblesequencesofstable,increasingordecreasingforestfragme ntationinthreeanalyzedtimeperiods(forinstance,atestareacouldhavedecreasingforestfragmentationintheperiod1860s–

1930s,astableforestfragmentationintheperiod1930s–

1970s,andanincreasingforestfragmentationintheperiod1970s–

2010s).F r a g m e n t a t i o n foragivenperiodwaslabelledasstableifthefragmentation changeratewaslowerthan^{1 of}thestandarddeviationofchangeratesforallanalyzedtestareas:

below1.45%fortheperiod1860s–1930s,below1.81%fortheperiod1930s–1970s,andbelow1.18%fortheperiod1970s–

2010s.

2.4. QuantifyingP o t e n t i a l D e t e r m i n a n t s o f F o restF r a g m e n t a t i o n

Foreachcirculartestareawecalculatedthepercentageofforeststructuralcomponents.Toassessforeststructure,w eusedmorphologicalimagesegmentationavailableinGuidosToolbox[50].Following[54],e a c h f o rest p i x e l w a s c a t e g o r i z e d a s e i t h e r c o ref o rest( n o n o n -

f o restn e i g h b o r s ) , edgeforest(attheoutsideoflargerforestpatches),loop/bridge/branchforest(thin,elo ngatedforeststructureswithnocoreforest,attachedtolargeforestpatches),perforatedforest(edgesalongopeningsinsidela rgerforestpatches),andisletforests(patchestoosmalltocontaincoreforest),usingtheforestedgewidthof30m(3pixels).C hangeratesofforeststructuralcomponentsforeachtimeperiodwerethencalculatedinthesamewayasforforestfragm entationandforestcover,i.e.,asarelativedifferencebetweentheend-andtheinitialvalues.

3. Result s

3.1. PatternsofForestFragmentationandItsRelationtoForestArea

AverageforestfragmentationinthePolishCarpathiansremainedstablebetweenthe1860sand2010s,atan approximatelevelof55%

(Figure2).However,wefoundfluctuationsinspecificperiods:ageneraldecreaseofforestfragmentationbetweenth e1860sand1930s(in57%oftestareas),andageneralincreasebetweenthe1930sand1970sandbetweenthe1970sand2010s(in 58%and72%oftestareas,respectively).Thistrajectoryofforestfragmentationwasobservedinthecontextofasignificanti ncreaseofforestareaintheregionovertheentirestudyperiod,from27%to47%

(Figure2).Mostofthetestareasexperiencedforest-coverincreasethroughthewholeanalyzedperiod(61%).Forest-cover

decreasewasfoundin34%ofthetestareasbetweenthe1860sand1930s,andinonly7%ofthetestareasbetweenthe19 30sand1970s.Betweenthe1970sand2010s,forestcoverwasincreasinginalltes^St^ua^str^aeⁱⁿa^as^b.ility2018,10,xFORPEER REVIEW5of24

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FigFuigreur2e.2C.hCahnagnegsesininfofroersetstcocovveerraannddffrraaggmeentationiintthheePPool il_sis_hh_CC_aa_rprp_ata_hth_iai_na_sns_beb_te_wtw_eee_nen_tht_eh₁e₈1₆8₀6_s0_as_ndand201_2F0_is_g10ufo_srr_efot₂h_r.e_Ct hs_he_at_nso_gef_ett_soe_is_fnt_tfa_eosr_re_tea_ass_tr._ecT_aosh_v.eTrb_hao_enx_debs_ofrxs_ah_egso_mw_sehntoh_twae_tiu_tohp nep_ineur_pth(pQ_eer1_P)_o(a_Qlin_s1hd)Clao_naw_drpe_alr_otq_hwu_ieaa_rnr_stqi_bule_eas_trwt(iQ_elee3_sn).

(tQM_he3e₎₁d.8i_M6a₀n_esdv_aia_anl_nduesare_v2s_a0h_l1uo_0eswsfn_aorrien_tshth_eoic_swk_entb_oilna_fc_ttk_ehsil_tcin kae_rbs_el._aD_sc.ko_Ttls_hineree_sbp_.orDe_xs_eoe_stn_sst_rhs_eopv_warelu_sthee_nestb_sue_pvy_pao_leun_red_(sQtbh_1ee )ye_aox_nt_dre_tlm_ohwes_erxotf_qrt_euh_mae_retw_silh_eosfis_t(k_hQe_e3rs_)w.,hi_M.ies._ek,_db_eire_asl_n,owQ1_iv.

−_ea.l,u1_be.e5_slo×_awre(Q_Qsh3_1o−−_w1nQ.51_i×n),

(tQohri3cak−b_Qbolv_1ae_)c,kQ_orl3ian+_beos1.v.5De×oQt3s(Q_+re3_1p.−r5e×sQe(nQ1t)_3s.

−vaQlu1e).sbeyondtheextremesofthewhiskers, i.e.,belowQ1−1.5×(Q3−Q1),oraboveQ3+1.5×(Q3−Q1).

Wefoundnoclearpaternwhenanalyzingforestfragmentationinrelationtoforestareaforthe Wefoundnoclearpatternwhenanalyzingforestfragmentationinrelationtoforestareaforthe

1860sWanedfo1u9n3d0sn(oFcigleuarrep3a).ttAernewghateinveanreallaytzioinngbfeotrwesetefnrafogrmesetn-tfraatigomneintraetliaotnioanntdoffoorreesstt- caorevaerfoarrethase1860sand1930s(Figure3).Anegativerelationbetweenforest-fragmentationandforest- coverareasw18a6s0fsoaunndd1f9o3r0tsh(eF1ig9u7r0es3a)n.dA2n0e1g0ast,iwvehreerleatfioornesbteatrw

eeaeenxpfolraeinste-dfra3g8m%eanntdati6o1n%anodfvfaorrieastti-ocnovinerfaoreasts wasfoundforthe1970sand2010s,whereforestareaexplained38%and61%ofvariationinforest fwraagsmfoeunntadtifoonr,trheesp1e9c7t0ivsealynd(F2ig0u10res,3w).hereforestareaexplained38%and61%

ofvariationinforest fragmentation,respectively(Figure3).

fragmentation,respectively(Figure3).

Figure3.Forestfragmentationvs.forestcoverforeachtimestep.

Figure3.Forestfragmentationvs.forestcoverforeachtimestep.

Changesinfor^Feⁱs^gt^uf^rr^ea³g^.m^Foe^rn^et^sa^tti^fo^ran^gmdi^efⁿfe^tr^ae^tid^onal^vs^so^.fr^oe^rg^ei^so^tn^coal^vl^ey^r.^fL^oo ro^ek^acin^hg^timat^et^sh^tepe^.ntirestudyperiod,

1860sC–

h20a1n0gse,sfoinresfotrfersatgmfraegnmtaetinotnatdioencrdeaifsferemdoaslstosirgengiifoicnaanllt yly.Linoothkeinsgouatththanedenstoiureths-teuadsyterpnerpioadrt,o1f86t0hse–

2r0e1g0ios,nfo(rBeisetszfrcazgamdyenatnatdioBnedskecidreaNseisdkimMosotusnigtaniinfisc)a,ncto lyrrienspthonedsionugthwainthdtshoeuthi-gehasetsetrnfopreasrttionfcrtehaeserergaitoens,

(wBhieislezcfzoardesytfarnadgmBeenstkaitdioNniisnkcireMasoeudnmtaoinsstl)y,cinortrheespnoon rdthinegrnwainthdcthenetrhailgphaerstofofrtehsetincreaserates,whileforestfragmentationincreased mostlyinthenorthernandcentralpartofthe

Figure4.Forest-coverandforest-fragmentationchangeratesintheperiod1860s–2010s.

Figure5.Forest-fragmentationchangeratevs.forest-coverchangerateforeachtimeperiod.

a changerateforallanalyzedtimeperiodsaswellasforthewholestudiedperiod(R²≤0.1),≤

w0

it.1),w

eiththe

weaklynegativefortheperiod1930s–1970s,andweaklypositivefortheperiod1970s–92010s(Figure5.

signo f therelationv ariableintime:neutralf ortheperiod1 860s–1930s(andoverall,1 860s–2016₀0_s),

Changesi n f o restf r a g m e n t a t i o n d i ffereda l s o regionally.L o o k i n g a t t h e e n t ires t u d y p e r i o d , 1860s–2010s,forestfragmentationdecreasedmostsignificantlyinthesouthandsouth-

easternpartoftheregion(BieszczadyandBeskidNiskiMountains),correspondingwiththehighestforestincre aserates,w h i l e f o restf r a g m e n t a t i o n i n c reasedm o s t l y i n t h e n o r t h e r n a n d c e n t r a l p a r t o f t h e s t u d y

Sustainability2018,10,xFORPEERREVIEW 6of24

area.Severalareaswithhighforest-coverincreaseratesshoweddecreasesoffragmentation,yetin

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someca^ss^te^us^dyw^ae^reo^ab^.Ss^evv^ere^ad^lah^rei^ag^sh^wfⁱo^thre^hsⁱt^g-^hco^fov^rest-

i^cn^oc^vr^ee^raⁱsⁿe^crr^eases^raa^telo^sn^shg^os^wid^ededfr^ea^cg^rem^asest^oa^ft^fi^ro^agn^min^enc^tr^ae^ta^iosⁿe^,y(F^etigure4).

Ingenerⁱsnatul^s,dowym

ae^eref^coa.su^eSn^sevd^weenrao lb

ac^srlee^raa^vsr^ewdcioth

hr^igrhheigl^fahot^rife os

rt e-

scbto -

e^vctoew^rveieⁿre^cinre cafro^see

arse^reas^tre a-

sfter^asa^logshnmog

wseⁱn^dedetadft^rieaocg

rn^meac^esnhet sa^anoti

fg^ofnerairgnamct^reenaa^stnae tdi(

oF

nf^igo,uryr ee

tt -coverchange⁴irⁿa^).t^sIe^nomf^go^er^ncea^arl^sal^els,a^wn^wea^el^fy^oubz^sne^edrvnt^eoi^dm^clheiagp^rhce^ofr^ori^rro^ed^slats^-

tci

a^oosⁿvew^bre

e^tiw nllce

ra^een

sasf eor

re as

ttt

he- sf

e^raw^lgomnh^go^esnlⁱe^tdaetsⁱt^ofu^rnad^gci^hme^ad^enngp^teae^trir^aoi^tno^ed^ainn(^cdR^{ref2aosres(tF-cigouvreer} signoft⁴h^).e^Inre^gelaⁿt^ei^ro^an^l,wv^ea^fr^oia^unb^dleⁿi^on^clt^earce^o:^rrn^ee^lau^tit^orⁿal^bef^to^wr^et^eh^nforesr^ti^-

o^frd^ag1^m8^e6ⁿ0^tas^t–^io1ⁿ93^ch0^asⁿ(^ga^en^rad^teo^avⁿe^dr^fa^ol^rl^e,^s1^t-8^chovthes^r–2010s), weaklyn^che^agⁿa^gt^eiv^re^atefo^fr^orth^ae^llp^ane^ar^li^yo^zd^ed19^ti3^m0^es–

p1^e9^ri7^o0^ds,^aasigno f therelationv ariableintime:neutralf ortheperiod1 860s–1930s(andoverl,1 860s–2010s),^sn^wd^ellask^fol^ry^thp^eos^wit^hi^ov^le^esfo^tur^dtⁱh^edepee^rr^ioio^dd^(R1^2≤70⁰s^.1–⁾2^,0^w1ⁱ0^thst(^hF^eigure5).

weaklynegativefortheperiod1930s–1970s,andweaklypositivefortheperiod1970s–2010s(Figure5).

Figure4.Forest-coverandforest-fragmentationchangeratesintheperiod1860s–2010s.

Figure4.Forest-coverandforest-fragmentationchangeratesintheperiod1860s–2010s.

Figure5.Forest-fragmentationchangeratevs.forest-coverchangerateforeachtimeperiod.

Figure5.Forest-fragmentationchangeratevs.forest-coverchangerateforeachtimeperiod.

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33..22..Forreesstt--FFrraaggmennttaattiioonnTTrreennddss

IInnoouurrssttuuddyyaarreeaaweffoouund22iindiividuallFFTss((oouuttooff2277ttheoorreettiicc aallllyypossssiibleeoneess))..Weeffoundiimpoorrttaannttrergeigoinoanladlifdfeifrfeenrecensceinstih nedthisetridbiustrioibnuotifotnrajoecftotraiejescitnotrhieesstiundythaeresatu(Fdiyguarere6a):

(dFeicgrueraesin6g):fdraecgrmeaesnitnagtiofrnawgmasenfotuatniodnmwosatslyfoinunthdemsooustt hly-eainstetrhnepsaoruttohf-

ethaestPeronlisphaCrtaropfatthheiaPnso,liwshhiCleairnpcartehaisaings,fwrahgimleeinntcarteioansi nwgasfrpargemvaelnetnattionthweansorptrheevranlepnatrtinoftthheensoturdthyearnrepa.aTrthoeft wthoemstousdtycoamrema.oTnhteretnwdoswmeorset:dcoecmremasoenintrfeonredsstfwraegrme:e dnteactrieoansebeitnwefeonretshtef1r8a6g0mseantdat1i9o3n0sbaentwdethenentihnecr1e8as6e0sin afnodres1t9f3ra0gsmaenndtatthioenbinectwreeaesnetihnef1o9r3es0tsfarnadgm20e1n0tsat(i2o4n

%boeftwteesetnartehaes)1,9a3n0dsianncrdea2s0e1i0nsf(o2r4e

%stforfagtemstenartaetaiso)n,athnrdouingchroeuastethinewfohroesletfarnagalmyzeendtaptieornioth dr(o2u4g%hooufttethsteawrehaosl)e.aTneasltyazreedaspewriohdt(h2e4s

%etorfatjescttoarrieeassw).Tereestcahraeraasctweritihzetdhebsyetthraejeloctwoerisetsfowreerset- cchoavrearcaterreiazeindablylttihmeeloswteepsst(fFoirgeustr-

eco7vAe)r.aDrearienasaellotfimfoerestsetpfrsa(gFmigeunreta7tiAo)n.Dbeetcwreeaesnetohfefo18re6 s0tsfarangdm20en10tastaionndbinetcwreeaesneitnhefo1r8e6s0tsfraangdm2e0n1t0astiaondininthcre efiasrestinpefroiroedst(1fr8a6g0ms–e1n9t3a0tsio)nfoilnlotwhefibrsytdpeecrrioeadse(1i8n6f0osr–

e1s9t3f0ras)gmfoellnotwateiodnbiyndtheecrseeacsoenidnafnodretshtirfrdagpmereiondtast(i1o9n3i0 ns–t1h9e7s0escaonndd1a9n7d0st–h2i0rd10ps)erwioedresf(o1u93n0ds–

in191710%sannd169%70osf–t2e0s1t0asr)ewase,rreesfopuecntdivienly1.1T%esatnadre6a

%swofitthestthaerseatsr,arjestpoerciteisvwelyer.eTcehstaararecatesrwizeitdhbthyetsheethraigjehceto strifeosrewste-rceovcheraraarcetaerinizeadlltbiymtehsetehpisg,hwesithfomreesatn-cfoovreersta- creoaveirnpaelrlcteimnteagseteepxsc,eweditihngm6e0a%nafolrreeasdt-

ycoinvetrhepe1r9c7e0nsta(Fgieguexrece7eBd)i.ng60%alreadyinthe1970s(Figure7B).

Figure6 . Forest-

fragmentationtrajectoriesbetweenthe1860sa nd2 0 1 0s.C i rcleoutlinesdenotetheFigure6.Forest- fragmentationtrajectoriesbetweenthe1860sand2010s.Circleoutlinesdenotetheyyeeaarrwwhheennffoorr eessttccoovveerreexxcceeeeddeedd6600%%ffoorrtthheefifrirssttttimimee..

3.3.DynamicsofForestFragmentationandStructuralComponents 3.3.D yn am i c s ofForestFragmentationandStructuralComponents

Fortheentirestudiedperiod(1860s–

2010s),forestfragmentationchangerateswerenegativelyFortheentirestudiedperiod(1860s–

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2

2010s),forestfragmentationchangerateswerenegativelyrelatedtoforestcorechangerate,andpositivelyrel atedtoforestedgeandforestloop/bridge/branchrelatedtoforestcorechangerate,andpositivelyrelatedtofor estedgeandforestloop/bridge/branchchangerates( Figure8).We f o undnos ignificantrelationo f forestfra gmentationtothechangingchanger a t e s ( F i g u re8).Wefo un d n o sign if ica nt relationo f f o restf ra g m e nt a t io n t o t he ch a n g in g amountofforestisletsandperforations(R^2≤0.01).

amountofforestisletsandperforations(R≤ 0.01).

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Figure7 . Changeso f f o rest-

covera rea[ % ] w i t h i n t e s t a reasw i t h d i fferentf o restf r a g m e n t a t i o n trFaijegcutroerie7s.:C(Aha) ntrgaejesctoofrifeosrewsti-tchomveorstalyreianc[r

%e]aswinigthfionretsetstfragremasenwtaitihond;i(fBfe)rternatjefcotroersietsfrwaigtmhemnotastliyond etrcarejeacstionrgiefso:r(eAst)ftrraagjmecetonrtiaetsiown.itChomloorestdlyreicntcarnegalseisnagsfion rFesigtufreg6m.Reendtaltiinoeni;n(dBi)catrteasjefcotroersitescowveitrh=m60o

%st.lydecreasingforestfragmentation.C oloredrectanglesasinFigure6.Redlineindicatesforestcover=60

%.

4.Discussion

Wemappedf o restcoverf orf o urtimesteps( 1860s,1930s,1 9 70s,2 010s)f ortheentirePolishCarpathi ans,andanalyzedforestfragmentationusingtheLHCmethod.Forestfragmentationwasthenrelatedtoch angesinforestcoverandtheamountofforeststructuralcomponents.Ourstudythusspans150years,provi dinginsightsintolong-

termforestfragmentationtrendsoveralargearea.Onlyaf e w studiesprovidea comparabletemporalfram ework[ 2 3,55],a s manys tudieso n f orestincreaseandfragmentationchangeuseremotelysenseddatacov eringrelativelyshortperiodsof10–

20years.Duetothelengthofthestudiedperiod,andarelativelygradualchangeinforestcoverovermoretha n150years,toassessandcompareforestfragmentationinspaceandtimeweusedtheLHCmethod,offering auniformmorphometricconcepttomeasuretheactualdegreeoffragmentationinagenericway.

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Figure8 . F^Fo^igr^ue^rs^et-⁸f^.r^Fa^og^rem^ste^-

fn^rat^ga^mti^eoⁿn^tac^tih^onan^chg^ae^ngr^eat^re^atevs^v.^s.c^ch^han^gg^ee^rar^ta^este^os^fofo

f^ref^so^tr^se^trs^ut^cs^tutr^au^lc^ct^ou^mr^pa^olⁿc^eoⁿm^tsp

foo^rn^the^entsf o r t h e

period1860s–2010s.

period1860s–2010s.

Althoughnotexplicitlytestedinthisstudy,itisexpectedthatLHCissensitivetospatialdata 4. Discuss^gi^eoⁿneralization,similartomanyotherfragmentationmeasures[56,57].Thismay,inparticular,applyt

othemaps eto f the1 9 30swiththescale1:100,000,theonlyava ilablef orthestudyareaf orthe

Weminatperpweadrpfeorrioeds,tacnodvtheerAfourstrfoo-

uHruntgimarieansStecposnd(1M8i6li0tasr,y1S9u3rv0esy,M19a7p,0tsh,e2o0ld1e0sst)mfaoprdtahtaeuesendtireP olishCarpathianⁱⁿs,^oua^rnd^stua^dn^ya^.lOy^uz^red^pref^voⁱr^oe^us^st^tf^er^sa^tsg^rm^ele^atn^edtat^oio^tn^heu^cs^oiⁿn^sg^istt^ehⁿe^cyL

oH^fCthem^he^ist^th^oro^icd^a.^lFmo^ar^pe^ss^ot^ffr^tha^egm^Poe^lin^shtationw a s

Carpathiansinthecontextofland-coverchangeanalysis[58]showed,however,thatspatialdetail

elatedtochangesinforestcoverandtheamountofforeststructuralcomponents.O u r study thenr forthemapsetofthe1930swiththescale1:100,000iscomparablewithmapsinmuchhigherscale.

thusspans_Si1_m5_i0_lay_rle_y,ar_ths_e,p_Ar_uo_sv_tri_od_-Hin_ug_ngin_ars_iaig_nh_St_es_coint_do_Mlo_iln_itg_ar-

yte_Sr_um_rvf_eo_yr_Mes_at_pfr_wa_ag_sm_gen_et_ra_at_li_zo_en_dtfr_re_on_md_ts_ho_ev1e_:2r₈₈a₀largearea.

Onlyafewcadsatsutrdailemsapprsoavniddreetaaincsomavpearyrahbiglehtlevmelpoofrdaeltafirlainmperwesoenr

tkin[g2l3a,n5d5]c,ovaesrm[59a]n.yItswtausdailesosonforestincreaseandfragmentationchangeuse re motelysenseddatacov eringrelativelyshortperiodsof 10–

20years.Duetothelengthofthestudiedperiod,andarelativelygradualchangeinforestcoverovermorethan1 50years,toassessandcompareforestfragmentationinspaceandtimeweusedtheLHCmethod,offeringauniformmorp hometricconcepttomeasuretheactualdegreeoffragmentationinagenericway.

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Althoughnotexplicitlytestedinthisstudy,itisexpectedthatLHCissensitivetospatialdata generalization,similartomanyotherfragmentationmeasures[56,57].Thismay,inparticular,applytothemapsetofth e1930swiththescale1:100,000,theonlyavailableforthestudyareafortheinterwar

period,andtheAustro-

HungarianSecondMilitarySurveyMap,theoldestmapdatausedinourstudy.Ourprevioustestsrelatedtot heconsistencyofthehistoricalmapsofthePolishCarpathiansinthecontextofland-

coverchangeanalysis[58]showed,however,thatspatialdetailforthemapsetofthe1930swiththescale1:100,000iscomparable withmapsinmuchhigherscale.Similarly,theAustro-

HungarianSecondMilitarySurveyMapwasgeneralizedfromthe1:2880cadastralmapsandretainsaveryhighlevelofdetailinprese ntinglandcover[59].Itwasalsosuccessfullyusedinotherland-useandland-

coverchangestudiesintheregion[60].Weconclude,therefore,thatthesetofmapsusedtoanalyzelong-

termforestfragmentationchangeshassufficientconsistencyinspiteofvariousspatialscales’generalizationlevels,yettheresultsneed tobeinterpretedwithcaution.

Contrarytotheexpectations—

thatincreasingforestcovercausesdecreasingforestfragmentation—

wereceivedseveralresultsshowinglackofstraightforwardrelationbetweenforestcoverandforestfragmentation.F i r s t , inspiteofasignificantforest-

coverincreaseintheentirestudyarea,forestfragmentationwasfoundtobestable.Next,forthefirst(1 860s)andsecond(1930s)timesteps,thecorrelationbetweenforestcoverandforestfragmentationwasfoundto beinsignificant.Finally,weobservednosignificantcorrelationbetweenforest-coverchangeratesandforest-

fragmentationchangeratesforallanalyzedperiods(1860s–1930s,1930s–1970s,1970s–2010s,1860s–

2010s).Theseresults,however,donotsignifyalackofrelationshipbetweenforestareaandforestfragmentation,butr atherimplyitscomplexity.Inthenorthernandnorth-

westernpartofthestudyarea,characterizedmainlybylowforestcoverandslowforestincrease,wefoundforest- coverincreaserelatedtoincreasingforestfragmentation.Insuchlandscapeswithinitiallylowfore stcoveraddingmoreforestislikelytohappenintheformofisolatedpatchesorirregularbranches,thustriggeri nganincreaseinfragmentation.O n theotherhand,inthesouth-

easternpartofthestudyarea,whereresettlementsafterWorldWarIItriggeredlandabandonmentandqui ckforestexpansion[40,61],weobserveddecreasingfragmentation(Figure7).W h e n forestcoverishigh,a ddingmoreforestislikelytohappenthroughthemergingofalreadyexistingforestpatchesortheclosure ofperforationsinsideforests,bothresultinginadecreaseoffragmentation.Inourcase,decreasingfragmentationinthestudy areawasclearlyvisiblewhenforestcoverexceeded60%,andthisobservationisinlinewithvariousstudieswhichhaveshown therelationbetweentheamountofcoverandthepatternstructuresandthesignificantchangeofthisrelationclosetotheper colationthresholdof59.3%[62–64].Importantly,randomlandscapeanalysiswithLHC-

basedfragmentationindexshowedasimilareffectalreadyabove50%offoreground(AppendixA),althoughthisslightlylow erthresholdislessevidentinthereal-

worlddata.Thetransitionofforestcoveroverthepercolationthresholdoccurredinmanytestareasonlyinthelasttwotimest eps(1970sand2010s).Thisiswhytheinsignificantcorrelationbetweenforestcoverandforestfragmentationwasnote dinthe1860sand1930s(mosttestareashadforestcoverwithvaluesbelow60%andhighfragmentationlevels)andwhyittur nedtoasignificantnegativecorrelationinthe1970sand2010s(testareashadeitherhighfragmentationlevelsforforestco verbelow60%orlowfragmentationwithforestcoverabove60%,Figure3).Ourresultsshowthatthehabitat(e.g.,for ests)fragmentationdoesnotneedtobecloselycorrelatedwiththeamountofhabitat(forinstance,

[65]),thusofferingspacetotestempiricallyhabitatamount–

speciesrichnessrelationshipsinlandscapeswithvariablefragmentationofhabitatsassuggestedby[25].

Theincreaseofforestfragmentationinareaswithincreasingforestcoverreflectsthefactthatforest - coveri n c reasei n t h e P o l i s h C a r p a t h i a n s h a s o c c u r redm o s t l y t h roughl a n d a b a n d o n m e n t andsecondaryforestsuccession onprivatefarmland,c o m p o s e d ofahugenumberofver ysmallparcelsmakingupfarmsofindividuallandowners[33].In thisway,severalnewstructuraleleme ntsappearinthelandscape,contributingtochangesoffragmentation. O u r resultsindicateth atwhileloops,b r i d g e s , b r a n c h e s a n d e d g esw e rep o s i t i v e lyc o r relatedw i t h a n d c o n t r i b u t e d t o i n c reasedforestf r a g m e n t a t i o n , i s l e t s a n d p e r f o r a t i o n s h a d n o s i g n i f i c a n t i n f l u e n c e . Weh y p o t h e s i z e t h a t althoughforestperforations—forinstance,formerpastures—

arelikelytodisappearfromthemountainlandscapes[66,67]t h u s d e c reasingf o restf r a g m e n t a t i o n , t h i s c h a n g e i s n o t c o u n t e r b a l a n c i n g t h e