Biased vegetation patterns and detection of vegetation changes using phytosociological databases. A...

Phytocoenologia 35 (1) 1ETH18 BerlinETHStuttgart April 11 2005

Biased vegetation patterns and detection of vegetationchanges using phytosociological databases A case studyin the forests of the Babia Gora National Park(the West Carpathians Poland)

by Jan Holeksa Krakow and Gabriela Wozniak Katowice Poland

with 5 figures and 1 table

Abstract A huge number of phytosociological releves which have been collected inEurope during the last century seems to be a useful point of reference for analyses oftemporal changes in vegetation The high degree of subjectivity during data collectionhowever makes difficult the comparison between data sets collected at different time bydifferent authors Being aware of this we attempted to reveal 30-year changes in strictlyprotected old-growth mountain forests We compared two sets of releves a subjectivephytosociological sample collected in the 60s and a systematic random one from the 90sof the XX centuryStandard phytosociological data gave distinct vegetation units with transitional patchespoorly represented This was observed both in the gradient between beech and coniferousforests in the montane belt and in the altitudinal gradient including two forests belts Onthe contrary the random sample did not indicate discontinuity in any of these gradientsWe suggest that in spite of better representation of rare plant communities in the sub-jective sample a considerable part of vegetation variability was omitted to emphasizedifferences between associationsMost species positively distinguishing syntaxa were more frequent in the subjective sam-ple because of preferential sampling in patches with a high number of such species Therewere few diagnostic species with higher frequency in the random sample or with similarfrequencies in both samples Such results were interpreted as an evidence of spreading ofthese species Comparisons between samples revealed the expansion of heliophilous spe-cies typical for communities of Betulo-Adenostyletea and dramatic regeneration de-cline of Abies alba Acer pseudoplatanus and Picea abies

Keywords phytosociology sampling method vegetation change West Carpathians

Introduction

The phytosociological method wrestle with some basic problems at thestage of the field data collection that make difficult the comparisons be-tween sets of releves collected by different authors Leps amp Hadincova(1992) stressed the problem of the estimation of species cover Anotherproblem and probably the most important lies in the subjective locationof releves There is a substantial awareness concerning shortages of thecollection of phytosociological data and it is broadly accepted that prefer-

DOI 1011270340-269X20050035-0001 0340-269X050035-0001 $ 450rdquo 2005 Gebruumlder Borntraeger D-14129 Berlin middot D-70176 Stuttgart

2 J Holeksa amp G Wozniak

ential sampling most likely causes underestimation of the true vegetationvariability and emphasizes differences between communities Neverthelessthe knowledge of this aspect of phytosociology is still insufficient andneeds further investigations (Orloci 1988 Mucina 1997)

The non-random distribution of releves can even be accepted as virtueof the method from the classification point of view It makes easier thedistinction between syntaxa and eliminates a large area of doubts relatedto the occurrence of transitional vegetation patches that are difficult forunambiguous classification The results of phytosociological investigationshowever are not only used for vegetation classification During the lastcentury in European countries a huge number of releves has been collectedThere are more than 12000 releves from Polish forests (Matuszkiewicz2001) Czech National Phytosociological Data Basis contained in 1997about 40000 releves (Chytry 2001) It has been estimated that over 1 mil-lion releves were collected in Europe (Rodwell 1995) It is no wonder thatbotanists look at them as a useful point of reference for analyses of tempo-ral changes in vegetation (Wildi 1989 Duckworth et al 2000 Schamineeet al 2002 Swierkosz 2003) The comparison of archival and contemporarydata sets however should take into consideration the peculiarity of sam-pling method in phytosociology Otherwise the obtained results can beeasily misinterpreted

Our investigation attempted to reveal changes in unmanaged forests dur-ing more than 30 years They were also aimed at identifying the limitationsfor analyses of vegetation dynamics that arise from the non-random phyto-sociological sampling In particular we asked the following questions (1)Is the phytosociological sampling oriented on diagnostic species (2) Aretransitional patches underrepresented in phytosociological collectionsFurther we attempted to assess the amount of these biases

The investigations were carried out in forests of the Babia Gora NationalPark in the Polish West Carpathians This choice was made according tothe presence of a detailed phytosociological study based on data collectedat the turn of the 50s and 60s of the XX century (Celinski amp Wojterski1978) Large areas of the Babia Gora forests were only slightly used in thelast century For the study area this guarantees that the previous phyto-sociological sampling was at most marginally influenced by anthropogenicchanges of vegetation and highly related to natural variability of vegetation

Study areaThe investigations were carried out in the forests of the Babia Gora Na-tional Park situated in the Polish West Carpathians A large tract of unman-aged forests extends between 900 and 1400 m asl on the north slope ofthe Babia Gora massif (1725 m asl) They have been under strict protec-tion since 1954 Two forest belts were included In the montane belt fiveforest associations were distinguished Two of them Carpathian beech for-est Dentario glandulosae-Fagetum and mixed coniferous forest Ab-iet i-Piceetum cover above 90 of the area The remaining three alder

3The forests of the Babia Gora National Park

swamp forest Caltho-Alnetum fir forest Gal io-Abietetum androwan-maple Sorbo-Aceretum form only small patches In the subalpinebelt one forest association was recorded Carpathian subalpine spruce forestPlagiothecio-Piceetum covering nearly the whole area (Celinski ampWojterski 1961 1978)

The climate is cool within the forest belts with a mean annual temper-ature from 2ETH5 infinC mean annual rainfall of 120ETH150 cm the maximumsnow depth of 1ETH2 m and a snow free period of 7ETH8 months (Obresectbska-Starklowa 1983 Holeksa amp Parusel 1989) Acid brown soils leachedbrown soils and podzolized brown soils prevail in the montane belt Inthe subalpine belt soils are mainly humus-iron podzols iron podzols andpodzolized rankers All soil types developed from the Carpathian flysh ofMagura type consisting of sandstone interbedded with mudstone (Adam-czyk 1989)

Materials and methods

Methods of data collection

Phytosociological investigations were conducted in 1957ETH1960 by Celin-ski amp Wojterski (1978) They intended to distinguish all forest associationsand gave their comprehensive floristic and ecological characteristics Thedescription of six distinguished associations is based on 195 published rele-ves Celinski amp Wojterski (lc) placed 114 of their releves in the mostnatural forest sites on the north slope of Babia Gora Most of them weresituated in strictly protected areas of the National Park Hereafter this setof releves is called ldquoCampW samplerdquo

Comparative investigations were carried out in 1991 i e about 30 yearsafter Celinski amp Wojterski (1978) Five fragments of strictly protectedforests (about 300 ha in total) were chosen at the north slope of Babia GoraFor systematic random sampling in these five fragments a grid of 243 pointsspaced 100 yen 100 m was drawn on a map scaled 110 000 Points were num-bered and 114 of them were chosen using random numbers The chosenpoints were located in the field with a compass and measuring tape Thecriterion of patch homogeneity was taken into consideration for the finallocation of releves If a random point was located close to a border betweentwo different vegetation patches it was moved to the nearest homogenouspatch The size of releves was 270 m2 and it was equal to the mean area of114 releves from the CampW sample All vegetation layers with the exceptionof mosses and liverworts were included The sample collected in 1991 iscalled ldquorandom samplerdquo hereafter

Comparison of two samples

Grouping of 228 releves from the CampW and random samples was con-ducted with cluster-analysis using MULVA (Wildi amp Orloci 1983) A


correlation coefficient was used to calculate the resemblance matrix and thecomplete linkage algorithm was accepted for clustering Releves from therandom sample were rated to syntaxonomic units distinguished by Celin-ski amp Wojterski (1978) on the basis of their co-occurrence with relevesfrom the CampW sample Both samples were subjected to indirect gradientanalysis (DCA) with CANOCO package (Ter Braak amp Smilauer 1998)Standard options were used in CANOCO Both in classification and ordi-nation all species were taken into consideration and Braun-Blanquetrsquos scal-ing of cover was transformed for values proposed by Van der Maarel(1979)

Differences in species frequencies were analysed with 2 test and 005significance level was accepted (no Bonferroni correction) Because of non-random sampling of the CampW sample and spatial autocorrelation in bothsamples the 2 statistics is only of tentative value and significant or nonsig-nificant differences do not indicate changes in species frequency as they canresult from differences in sampling methods In this analysis only specieswith frequency of at least 20 were taken into account

Samples were compared in respect of altitudinal changes in the totalnumber of species and in numbers of species typical for mixed forests ofthe montane belt and for subalpine forests Species that positively distin-guish mixed montane forests or subalpine forests were found through in-spection of tables published by Celinski amp Wojterski (1978)

Elevational ranges of two ferns Athyrium filix-femina growing mainlyin the montane forest belt and A distentifolium ETH a subalpine species werecompared between the CampW and random samples To make the samplescomparable as much as possible some releves were randomly eliminatedfrom each sample to obtain similar distribution of releves according to ele-vation and stand density

CampW and random samples collected in the montane belt were comparedin respect of the presence of species diagnostic for communities of theQuerco-Fagetea and Vaccinio-Piceetea classes Both lists of specieswere composed according to Celinski amp Wojterski (1978) Number andtotal cover of species of both groups were calculated in each releve TheBraun-Blanquetrsquos scale was replaced with percent cover according to pro-posal of Pawłowski (1972) + = 01 1 = 5 2 = 175 3 = 375 4 =625 5 = 875 Then two indexes were calculated for each releve thatshow proportions between both groups of species according to theirnumber (IN) and cover (IC)

IN = NQ-F (NQ-F + NV-P)IC = CQ-F (CQ-F + CV-P)

where NQ-F and CQ-F are number and total cover of species characteristicfor the Querco-Fagetea class and NV-P and CV-P are number and totalcover of species characteristic for the Vaccinio-Piceetea class


Results

A joint classification of CampW and random samples resulted in completeseparation of syntaxa distinguished by Celinski amp Wojterski (1978) Italso revealed that in the random sample only three common associationswere represented Dentario glandulosae-Fagetum Abiet i-Picee-tum and Plagiothecio-Piceetum From among three subassociations ofCarpathian beech forest only two were found in the random sampleDentario glandulosae-Fagetum typicum and Dg-F festuceto-sum sylvat icae There were no releves from Sorbo-Aceretum Cal-tho-Alnetum Gal io-Abietetum and Dentario glandulosae-Fa-getum al l ietosum ursini in the random sample For further analyses 24releves representing four syntaxa lacking in the random sample were ex-cluded from the CampW sample and that makes both samples more coherent

Distribution of releves in the altitudinal gradient is similar in both sam-ples (2 = 322 df = 4 p gt 005) (Fig 1A) CampW and random samples differsignificantly according to the cover of tree stand (2 = 461 df = 4 p lt0001) Only in a few releves from the CampW sample is the cover below70 while in the random sample such low value is noted in nearly 50 of releves (Fig 1B)

Both samples spread in similar pattern along the first axis of DCA dia-gram that indicates a gradient from Dentario glandulosae-Fagetumtypicum through Dg-F festucetosum and Abiet i-Piceetum toPlagiothecio-Piceetum In the random sample however the separationof syntaxa is less clear than in the CampW sample (Fig 2A) Releves fromboth samples are partly separated along the second axis ETH scores for relevesfrom the CampW sample are usually lower than those from the random sam-ple Such separation is statistically significant between whole samples aswell as in Dentario glandulosae-Fagetum festucetosum Abiet i-Piceetum and Plagiothecio-Piceetum (Kruskal-Wallis test p lt 001 inall cases) In beech and mixed coniferous forests the distribution of randomreleves with tree cover 70 and lt 70 do not differ significantly alongthe II axis (Kruskal-Wallis test p gt 01 in both cases) This suggests thatthe separation of CampW and random releves from these forests is not relatedto lower cover of tree stratum in the random sample On the contrary inPlagiothecio-Piceetum random releves with stand cover lt 70 arescored significantly higher on the second DCA axis then releves with cover 70 (Kruskal-Wallis test p = 002)

DCA ordination of species suggests that differences between CampW andrandom samples are caused mostly by species forming tall-herb communi-ties from the Betulo-Adenostyletea class as well as species of moistforest sites All these species Adenostyles alliariae Adoxa moschatellinaAthyrium distentifolium Cicerbita alpina Rosa pendulina Stellaria nemo-rum Streptopus amplexifolius Thalictrum aquilegiifolium and Veratrum al-bum are situated in the higher part of the DCA diagram From the otherhand acidophile species typical for forests of the Vaccinio-Piceetea classBlechnum spicant Huperzia selago and Lycopodium annotinum are more


30

25

20

15

10

5

0800 900 1000 1100 1200 1300

Altitude above sea level (m)

Freq

uenc

y (

)

35

30

25

20

15

10

5

0

Stand cover ()

Freq

uenc

y (

)

CampW sample Random sample

40

0 10 20 30 40 50 60 70 80 90

A

B

Fig 1 Altitudinal distribution of releves (A) and tree stand cover in releves (B) standcover was assessed to the nearest 10 in both samples

relevant to the CampW sample as they are placed in the lower part in theDCA diagram (Fig 2B)

Pattern revealed by DCA is partly confirmed by differences in speciesfrequency between CampW and random samples (Table 1) Frequencies oftree species Abies alba Acer pseudoplatanus and Picea abies in the treelayer and especially in the shrub layer are lower in the random than in theCampW sample The reverse is for these species in the herb layer Thesedifferences are observed in the montane forest belt where all three treespecies occur together On the contrary the frequency of Fagus sylvaticadoes not differ between samples

Significant differences in frequency between CampW and random samplesare noted for 12 out of 28 species diagnostic for communities of the Querco-Fagetea class Nine of these species occur with higher frequency in the


Fig 2 DCA diagram of releves (A) and species (B) Forest communities Dentarioglandulosae-Fagetum typicum ETH Dentario glandulosae-Fagetum fest-ucetosum ETH Abiet i-Piceetum ETH Plagiothecio-Piceetum ETH CampWsample ETH filled marks random sample ETH empty marks Species characteristic for classesQuerco-Fagetea ETH Vaccinio-Piceetea ETH Betulo-Adenostyletea ETH x andaccompanying species ETH first two axes explained 225 of the variability the totalinertia was 401

Table 1 Frequency of species in forest associations in the CampW and random samplesBold numbers indicate significant differences between samples Probable changes in fre-quency are marked with grey background (see discussion)

Abies alba

Abies alba

Acer pseudoplatanus

Acer pseudoplatanus

Acer pseudoplatanus

Picea abies

Picea abies

Picea abies

Sorbus aucuparia

Anemone nemorosa

Carex sylvatica

Chrysosplenium altern

Dentaria bulbifera

Dentaria glandulosa

Epilobium montanum

Euphorbia amygdaloides

Festuca altissima

Galium odoratum

Impatiens noli-tangere

Lysimachia nemorum

Mercurialis perennis

Mycelis muralis

Paris quadrifolia

Polystichum aculeatum

Pulmonaria obscura

Stellaria nemorum

Veronica montana

Viola reichenbachiana

Blechnum spicant

Hupertia selago

Luzula luzulina

Lycopodium annotinum

Vaccinium myrtillus

Vaccinium vitis-idaea

Adenostyles alliariae

Athyrium distentifolium

Cicerbita alpina

Streptopus amplexifolius

Hieracium murorum

Luzula sylvatica

Maianthemum bifolium

Phagopteris connectilis

Valeriana tripteris

Rubus idaeus

Geranium robertianum

Abies

alba Fagus sylvatica Sorbus aucuparia ndash Carex sylvatica Circaea

alpina Dryopteris filix-mas Galeobdolon luteum Milium effusum Ranunculus lanuginosus Rubus hirtus

Sanicula europaea Symphytum tuberosum ndash Dryopteris dilatata Homogyne

alpina Calamagrostis villosa Petasites albus Rumex arifolius

Athyrium filix-femina Gymnocarpium dryopteris Oxalis acetosella Polygonatum

verticillatum Prenanthes purpurea Senecio nemorensis Soldanella carpatica Sambucus racemosa


CampW sample The remaining 3 species are more common in the random sam-ple Stellaria nemorum nearly in all communities Anemone nemorosa andDentaria glandulosa in the typical subassociation of beech forest

As much as 6 out of 8 species characteristic for the Vaccinio-Piceeteaclass reveal significantly different frequencies between samples Five ofthem are rarer in the random than in the CampW sample in one or bothacidophile forest types Instead in beech forest these species are evenslightly more frequent and Vaccinium myrtillus is much more frequent inthe random sample

Four out of 7 species typical for tall-herb communities occur more fre-quently in the random sample These differences are particularly well pro-nounced in forests of the Vaccinio-Piceetea class

Also the frequencies of 7 accompanying species significantly differ in par-ticular communities between both samples Three species occur with higherfrequency in the CampW sample and four of them grow more frequently in therandom sample Only for two species differences are noted in more than onecommunity Geranium robertianum is less frequent and Rubus idaeus is morefrequent in the random sample ETH the first one in both subassociations ofbeech forest and the second one in both acidophile communities

The average number of species per releve is nearly the same in bothsamples ETH 205 in the CampW sample and 211 in the random sample Dif-ferent however is the variability of the number of species along the altitu-dinal gradient The decline in species number with elevation is steeper andparticularly rapid around 1100 m asl in the CampW sample (Fig 3A B)This results mostly from different disappearance of species typical for mon-tane belt with altitude (Fig 3C D) Moreover in the random sample mon-tane species are replaced by quite a numerous group of subalpine tall-herbspecies above 1100 m asl In the CampW sample these species occur in smallnumbers (Fig 3E F)

Different are the altitudinal ranges of two Athyrium species A filix-femina reach higher and A distentifolium descend lower in the randomsample than in the CampW sample As a result the altitudinal belt with bothspecies is threefold wider in the random sample than in the CampW sample(190 m vs 60 m) (Fig 4)

Arrangement of CampW releves from the montane belt in order of decreas-ing IN and IC resulted in separation of releves from beech and mixed conif-erous forests with clear discontinuity between them Only several relevesare of a transitional character between both forest types ETH most of themare from Dentario glandulosae-Fagetum festucetosum and one isfrom Abiet i-Piceetum These few transitional releves represent relativewide ranges of IN (040ETH075) and IC (010ETH075) and they make merelytenth part of the whole set (Fig 5A B)

Arrangement of random releves in order of decreasing IN and IC gavedifferent results (Fig 5C D) Releves belonging to different syntaxa aresomewhat mixed and they are not strictly separated into groups In thissample nearly half of releves are within ranges of IN and IC represented byfew transitional releves from the CampW sample


Altitude (m asl)

D

Num

ber

of s

peci

es

40

30

20

10

0800 900 1000 1100 1200 1300 1400

A B

C

0

1

2

3

4

5

6

7

8

9

40

30

20

10

0

40

30

20

10

0

40

30

20

10

0

800 900 1000 1100 1200 1300 1400

800 900 1000 1100 1200 1300 1400800 900 1000 1100 1200 1300 1400

800 900 1000 1100 1200 1300 1400 800 900 1000 1100 1200 1300 1400

FE

0

1

2

3

4

5

6

7

8

9

Altitude (m asl)

Num

ber

of s

peci

esN

umbe

r of

spe

cies


Fig 3 Altitudinal changes in number of species in the CampW sample (A C E) and in therandom sample (B D F) Changes in the number of all species (A B) species diagnosticfor montane forests (C D) subalpine species (E F)

Discussion

Non-random sampling is a widely accepted method in phytosociology(Orloci 1988 Fischer amp Bemmerlein 1989 Leps amp Hadincova 1992)Phytosociological studies base frequently on large samples consisting ofsome hundreds of releves Fixing so many random points is time-consum-ing and would make impossible a relatively quick survey of vegetation overlarge areas i e it would make useless one of the greatest advantages of thephytosociological method Moreover random location of releves could re-


900 1000 1100 1200 1300 1400

A CampW sample

B random sample5

4

3

2

1

+

800

Bra

un-B

lanq

uetrsquos

sca

le

900 1000 1100 1200 1300 1400800

Altitude (m asl)

5

4

3

2

1

+

Bra

un-B

lanq

uetrsquos

sca

le

Fig 4 Altitudinal distribution of releves with Athyrium filix-femina () and Athyriumdistentifolium () in the CampW sample (A) and in the random sample (B) Grey rectanglesshow the altitudinal range of co-occurrence of both ferns

sult in omission of rare communities as it was detected in our randomsample The lack of strict rules at the stage of field studies in phytosociol-ogy brings about an individualistic and subjective location of releve It hap-pens that releves are placed in these patches that fit in with an earlier visionof a particular community described by phytosociologist (Fischer amp Bem-merlein 1989 Frey 1995) As a result phytosociological samples aremostly unique and difficult (practically impossible) to repeat (Feoli amp La-gonegro 1982 Hatcher et al 1999)

The comparison of contemporary vegetation with results of former phy-tosociological data most often relies on two data sets collected at the samearea Releves in both samples however derive from different vegetationpatches as description of releve location is usually insufficient for accurateresampling We suggest that preferential sampling in both vegetation sur-


Dentario glandulosae-Fagetum typicum Dentario glandulosae-Fagetum festucetosum

Abieti-Piceetum

C

10

08

06

04

02

0

A B

D

IN

IN

IC

IC

10

08

06

04

02

0

10

08

06

04

02

0

10

08

06

04

02

0

Fig 5 Arrangement of releves from montane forests in order of decreasing values ofindexes IN and IC in the CampW sample (A B) and in the random sample (C D) arrowsat (A) and (B) point at the positions of discontinuity between beech and mixed coniferousforests

veys can give sufficient results in case of considerable vegetation changesas it was evidenced by Wildi (1989) in riverine sites in Switzerland or byJakubowska-Gabara (1996) in the Polish xerophilous oak forest For moresubtle temporal changes a better solution seems to be the comparison of anarchival and subjective sample with a contemporary random sample In-stead of two subjective samples biased in different and unknown directionsin this situation we have only one such uncertainty

Undoubtedly plots permanently marked in the field are the best sourceof data in studies of long-term vegetation dynamics (Bakker et al 1996Falinski 2003) However they are very rare so far and established forspecial purposes Changes detected on such even large plots are of limitedvalue as not representative for extensive areas For studies of vegetationchanges we need rather data collected over large areas on small and numer-ous permanent plots arranged in random or stratified random samples Thisattitude has been used recently in Polish national parks (Loch 1992) andin the next decade the first results should be obtained on these plots

The pattern of differentiation of Babia Gora forests depended on thesampling method In the standard phytosociological data set collected by


Celinski amp Wojterski (1978) forest communities formed discrete unitswith poorly represented transitional patches It is observed both in thegradient containing beech and coniferous forests of the montane belt andin the altitudinal gradient including two forest belts On the contrary thepattern of forest vegetation derived from random sampling does not indi-cate discontinuity in any of the analysed gradients Phytocoenoses recog-nised as transitional between beech and mixed coniferous forests werepoorly represented in the CampW sample In the random sample such phyto-coenoses were even more numerous than those regarded by Celinski ampWojterski (1978) as representative examples of both forest types Thisresult could be expected taking into account the phytosociological method-ology Celinski amp Wojterski (lc) aimed at a distinction of forest vegeta-tion units typical for the Babia Gora massif identifying them through thecomparison with known syntaxa and pointing at differences between themAccording to our results it is highly probable that they chose vegetationpatches with high abundances of characteristic species They preferredpatches with a high number of these species however they left out vegeta-tion patches with balanced contribution of species diagnostic for varioussynataxa

Omission of transitional patches was accepted in phytosociology as astandard and has important implication for the vegetation science Phytoso-ciologists have been aware of this problem for long but the knowledgeabout this problem still is limited (Orloci 1988 Mucina 1997) Our ran-dom sample indicates that about half of the area in the montane belt iscovered with patches of transitional character between beech and mixedconiferous forests There are only few releves from such patches in tablesof Celinski amp Wojterski (1978) A similar problem was revealed in thetransition zone between two forest belts Results of Celinski amp Wojterski(lc) suggest that the border between montane and subalpine forest belts issharp and easy for recognition in the field They underlined the altitudinalseparation of Athyrium filix-femina and A distentifolium and they stressedthat the first one distinguishes the montane forest belt and ldquonever crossesthe border between montane and subalpine forest beltsrdquo (Celinski ampWojterski lc p 31) They placed this border at about 1150 m asl Athigher elevation A distentifolium should be the only species This patternis expressed by a very narrow altitudinal zone with both fern species in theCampW sample Also the whole group of species typical for the montaneforest belt disappeared abruptly above 1150 m asl In the random samplethe disappearance of montane species as well as the transition between for-est belts were gradual in the altitudinal gradient

Uncritical comparison of the CampW sample with our random sample couldlead to a false conclusion that forest communities of Babia Gora changed con-siderably One could even suggest that 30 years of protection caused their de-generation This process according to Falinski (1966 1988) leads to disap-pearance of diagnostic species and loss of peculiarities of communities

Differences in frequency of species between samples particularly speciesof diagnostic value should be treated carefully Commonly the frequencies


of species positively distinguishing syntaxa were lower in the random sam-ple It was observed for species of Querco-Fagetea in Dentar io gland-ulosae-Fagetum and species of Vaccinio-Piceetea in Abieti-Picee-tum and Plagiothecio-Piceetum These results do not necessarily meanthat these species were disappearing during 30 years Their higher fre-quencies in releves collected by Celinski amp Wojterski (1978) probablyresulted as it was mentioned earlier from preferential sampling for phyto-coenoses rich in them Another possibility is that Celinski amp Wojterski(lc) preferentially sampled in patches with dense tree stratum that couldresult in higher frequencies of diagnostic forest species This alternative isprobable for Plagiothecio-Piceetum as the position of releves re-presenting this forest on DCA diagram was related to the stand cover

It could be accepted however that higher frequencies of diagnosticspecies in the latter random sample indicate their spread during the last30 years This situation was noted for Anemone nemorosa and Dentariaglandulosa in Dentario glandulosae-Fagetum typicum and for Stel-laria nemorum in Dentario glandulosae-Fagetum festucetosumBoth A nemorosa and D glandulosa are spring ephemerals and their abun-dance can substantially fluctuate according to weather conditions changingfrom year to year Their frequencies are also highly dependent on the sam-pling time In our comparison the second possibility of higher frequenciesof these species in the random sample is probable as it was collected earlier(mid June) than the CampW sample (mid June to August) Quite a largenumber of species characteristic for Carpathian beech forest showed onlyslightly higher frequency in the random sample and these species are notspring ephemerals Because of preferential sampling for these species in the1950s such a result can be interpreted as their expansion from the 1950s tothe 1990s (comp Table 1)

A few subalpine species typical for tall-herbs and tall-forbs of Betulo-Adenostyletea had higher frequencies in the random sample These dif-ferences were noted particularly in coniferous forests Abiet i-Piceetumin the montane forest belt and in the subalpine Plagiothecio-PiceetumTwo major causes of these differences can be evidenced In the montaneforests patches with the above-mentioned species could be passed by inthe phytosociological survey by Celinski amp Wojterski (1978) to makethem more distinct from subalpine forest This is related to the previouslydiscussed problem of the distribution of two Athyrium species Next treestands in Babia Gora forests have been thinned recently due to very highmortality of old silver firs in the montane forests (Szwagrzyk amp Szewczyk2001) and mortality of Norway spruce in the subalpine forests (Jaworski ampKarczmarski 1995 Holeksa amp Cybulski 2001) Apart from this Holeksa(2003) showed the strong relationship between the distribution of Athyriumdistentifolium and canopy gaps in the subalpine spruce forests Thus thechanges in tree stands during 30 years can also be regarded as a direct cause ofspreading of heliophilous perennials from tall-forbs However it is difficultto define the contribution of preferential sampling and thinning of stands toobserved differences in abundance of subalpine species


Recent decline of Abies alba in Babia Gora forests seems to be reflectedin its lower frequency in random releves from Dentario glandulosae-Fagetum festucetosum and Abiet i-Piceetum Surprisingly there isno difference in fir frequency between CampW and random samples fromDentario glandulosae-Fagetum typicum One could even suggestfrom such pattern that Abies alba declined mainly in more acidophile mon-tane forests with nearly no changes in beech forest on more fertile soilsAgain we could not exclude the possibility that in acidophile forests Cel-inski amp Wojterski (1978) sampled preferentially for silver fir as its occur-rence in the tree stratum was of diagnostic value Probably they paid lessattention on the presence of seedlings and saplings of trees as their diagnos-tic value was not mentioned Thus the large differences in frequencies ofAbies alba Acer pseudoplatanus and Picea abies in the shrub layer betweenthe CampW and random samples may reflect a dramatic regeneration declineof these species during 30 years Low frequencies of tree saplings in therandom sample are all the more worth noting that this sample containsmany patches with low cover of tree stand Loose stands usually promotedevelopment of young generation of trees Thus the abundance and fre-quency of young trees should be even larger in the random sample than inthe CampW sample and this is really indicated by higher frequency of treeseedlings in the random sample We conclude that the comparison of twosamples fully confirms the strong and widespread pressure of ungulates thathas been exerted on fir and maple regeneration in the Carpathian forests forseveral decades (Jamrozy 1987) It can also be suggested that the pressureof large herbivores on tree regeneration was relatively weak in the 50s and60s of the last century as indicated by the CampW sample The present inten-sity of damages to saplings in old-growth forests seems similar for silverfir maple and Norway spruce as the frequencies of all of them droppeddistinctly This contradicts the option that young spruces are relatively lessdamaged by red deer in Carpathian forests (Jamrozy 1980)

The mean size of releves was similar and nearly identical was the averagenumber of species in both samples Although in the mixed montane forestsCampW releves were richer in species than in the random sample The resultobtained in the lower part of the altitudinal gradient supports the conclu-sion of Chytry (2001) who revealed that releves are often situated inpatches richer in species A greater total number of species is usually relatedto a higher number of diagnostic species and makes easier the identificationof a patch In the subalpine forest the situation was different In this forestCampW releves were poorer in species than random releves Thus the overes-timation of species richness in phytosociological investigation is not a gene-ral rule and it depends on the type of vegetation Probably as it can beconcluded from our results such bias is more probable in communitieswith numerous diagnostic species that are relatively sparse In these com-munities the higher is the number of all species the higher is the number ofspecies possessing a diagnostic value This is the case for most forest typesfrom the Querco-Fagetea class In the opposite most species diagnosticfor forests from the Vaccinio-Piceetea class at least in the subalpine


spruce forests are common elements of phytocoenoses Searching forpatches rich in species in this forest not necessarily results in a longer listof characteristic taxa but can lengthen the set of accompanying species

The subjective phytosociological method gave much better representa-tion of rare plant communities than the systematic random method of datacollection However in the subjective sample a considerable part of vegeta-tion variability was also omitted to emphasize differences between associa-tions Phytosociological description of plant communities resulted in dis-tinct vegetation units with transitional patches poorly represented This wasobserved both in the gradient between beech and coniferous forests in themontane belt and in the altitudinal gradient including two forest belts Onthe contrary the random sample did not indicate discontinuity in any ofthese gradients Our study revealed also that patches with a high number ofcharacteristic species were preferentially sampled during phytosociologicalstudies In general the comparison between phytosociological and randomsamples collected at different times has a limited value for studies on vegeta-tion dynamics but probably this value is still higher than that of a compari-son between two subjective samples

Acknowledgements We are grateful for Zbigniew Dzwonko Janusz Falinski ElzbietaPancer-Koteja Wojciech Rozanski and Jerzy Szwagrzyk for their discussion and help-ful comments on the text We also thank two anonymous reviewers for their detailedcomments that improved the manuscript

References

Adamczyk B (1983) Soils of the Babia Gora National Park ETH In Zabierowksi K (ed)The Babia Gora National Park Nature and man ETH Studia Naturae Ser B 95ETH120(in Polish)

Bakker J P Olff H Willems J H amp Zobel M (1996) Why do we need permanentplots in the study of long-term vegetation dynamics ETH J Vegetation Sci 7 147ETH155

Celinski F amp Wojterski T (1961) La carte des groupements vegetaux du parc national deBabia Gora (Hautes Beskides) ETH Poznanskie Towarzystwo Przyjacioł Nauk WydziałMatematyczno-Przyrodniczy (in Polish and French)

ETH ETH (1978) Forest associations of the Babia Gora massif ETH Poznanskie TowarzystwoPrzyjacioł Nauk Prace Komisji Biologicznej 48 1ETH62 (in Polish with English sum-mary)

Chytry M (2001) Phytosociological data give biased estimates of species richness ETH JVegetation Sci 12 439ETH444

Duckworth J C Bunce R G H amp Malloch A J C (2000) Vegetation gradients inAtlantic Europe the use of existing phytosociological data in preliminary investiga-tions on the potential effects of climate change on British vegetation ETH Global Ecol-ogy and Biogeography 9 187ETH199

Falinski J B (1966) Une definition de la deformation de phytocenose Un systeme desphases de degeneration des groupements vegetaux Discussion phytosociologique(3) ETH Ekologia Polska Ser B 12 31ETH42 (in Polish with French summary)

ETH (1988) Succession regeneration and fluctuation in the Białowieza Forest (NE Po-land) ETH Vegetatio 77 115ETH128


ETH (2003) Long-term studies on vegetation dynamics some notes on concepts funda-mentals and conditions ETH Community Ecol 4 107ETH113

Feoli E amp Lagonegro M (1982) Syntaxonomical analysis of beech woods in the Apen-nines (Italy) using the program package IAHOPA ETH Vegetatio 50 129ETH173

Fischer H S amp Bemmerlein F A (1989) An outline for data analysis in phytosociologypast and present ETH Vegetatio 81 17ETH28

Frey H-U (1995) Waldgesellschaften und Waldstandorte im St Galler Berggebiet ETHVeroumlff Geobot Inst ETH Stift Ruumlbel Zuumlrich 126 1ETH280

Hatcher D Eaton J Gibson M amp Leah R (1999) Methodologies for surveying plantcommunities in artificial channels ETH Hydrobiologia 415 87ETH91

Holeksa J (2003) Relationship between field-layer vegetation and canopy openings in aCarpathian subalpine spruce forest ETH Plant Ecol 168 57ETH67

Holeksa J amp Cybulski M (2001) Canopy gaps in a Carpathian subalpine spruce for-est ETH Forstwissenschaftl Centralblatt 120 331ETH348

Holeksa J amp Parusel J B (1989) Snow cover in the forest zones of the Babia Goramassif (West Carpathians) ETH Biologica Montana 9 341ETH352

Jakubowska-Gabara J (1996) Decline of Potentillo albae-Quercetum Libb 1933 phyto-coenoses in Poland ETH Vegetatio 124 45ETH59

Jamrozy G (1980) Winter food resources and food preferences of red deer in Carpathianforests ETH Acta Theriologica 25 221ETH238

ETH (1987) Damage of trees by game and their dying in mountain stand ETH Sylwan 1313 43ETH48 (in Polish with English summary)

Jaworski A amp Karczmarski J (1995) Structure dynamics and production potential ofspruce stands in the upper mountain forest zone of Babia Gora National Park ETH ActaAgraria et Silvestria Ser Silvestris 33 75ETH113 (in Polish with English summary)

Leps J amp Hadincova V (1992) How reliable are our vegetation analyses ETH J VegetationSci 3 119ETH124

Loch J (1992) Permanent research surfaces in the Gorce National Park ETH Parki Naro-dowe i Rezerwaty Przyrody 11 87ETH97 (in Polish with English summary)

Matuszkiewicz J M (2001) Zespoły lesne Polski [Forest associations of Poland] ETHPWN Warszawa 358 pp (in Polish)

Mucina L (1997) Classification of vegetation Past present and future ETH J VegetationSci 8 751ETH760

Obresectbska-Starklowa B (1983) Climatic relationships in the Babia Gora Region ETH InThe Babia Gora National Park Nature and man ETH Studia Naturae Ser B 41ETH62 (inPolish)

Orloci L (1988) Community organization recent advances in numerical methods ETHCanad J Bot 66 2626ETH2633

Pawłowski B (1972) Skład i budowa zbiorowisk roslinnych oraz metody ich badania[Composition and structure of plant communities and methods of their investiga-tion] ETH In Szafer W amp Zarzycki K (eds) Szata roslinna Polski [Plant cover ofPoland] V I 237ETH269 ETH PWN Warszawa

Rodwell J S (1995) The European Vegetation Survey questionnaire an overview ofphytosociological data vegetation survey programmes and databases in Europe ETHAnn Bot (Roma) 53 87ETH98

Schaminee J H J van Kley J E amp Ozinga W A (2002) The analysis of long-termchanges in plant communities case studies from the Netherlands ETH Phytocoenologia32 317ETH335

Swierkosz K (2003) Changes in the flora of the forest communities of the ldquoUroczyskoObiszowrdquo reserve (Wzgorza Dalkowskie Lower Silesia) in 1973ETH1998 ETH FragmentaFloristica et Geobotanica Polonica 10 119ETH130 (in Polish with English summary)


Szwagrzyk J amp Szewczyk J (2001) Tree mortality and effects of release from competi-tion in an old-growth Fagus-Abies-Picea stand ETH J Vegetation Sci 12 621ETH626

Ter Braak C J F amp Smilauer P (1998) CANOCO 4 CANOCO reference manual anduserrsquos guide to Canoco for Windows ETH Wageningen 351 pp

Van der Maarel E (1979) Transformation of cover-abundance values in phytosociologyand its effects on community similarity ETH Vegetatio 39 97ETH114

Wildi O (1989) Analysis of the disintegrating group and gradient structure in Swissriparian forests ETH Vegetatio 83 179ETH186

Wildi O amp Orloci L (1983) Management and multivariate analysis of vegetation data ETHSwiss Federal Institute of Forestry Research Rapport Nr 215

Addresses of the authorsDr Jan Holeksa W Szafer Institute of Botany Polish Academy of Sciences ul Lubicz46 31-512 Krakow Poland E-mail holeksaib-pankrakowplDr Gabriela Wozniak Department of Geobotany and Nature Conservation SilesianUniversity ul Jagiellonska 28 40-032 Katowice Poland


ential sampling most likely causes underestimation of the true vegetationvariability and emphasizes differences between communities Neverthelessthe knowledge of this aspect of phytosociology is still insufficient andneeds further investigations (Orloci 1988 Mucina 1997)

The non-random distribution of releves can even be accepted as virtueof the method from the classification point of view It makes easier thedistinction between syntaxa and eliminates a large area of doubts relatedto the occurrence of transitional vegetation patches that are difficult forunambiguous classification The results of phytosociological investigationshowever are not only used for vegetation classification During the lastcentury in European countries a huge number of releves has been collectedThere are more than 12000 releves from Polish forests (Matuszkiewicz2001) Czech National Phytosociological Data Basis contained in 1997about 40000 releves (Chytry 2001) It has been estimated that over 1 mil-lion releves were collected in Europe (Rodwell 1995) It is no wonder thatbotanists look at them as a useful point of reference for analyses of tempo-ral changes in vegetation (Wildi 1989 Duckworth et al 2000 Schamineeet al 2002 Swierkosz 2003) The comparison of archival and contemporarydata sets however should take into consideration the peculiarity of sam-pling method in phytosociology Otherwise the obtained results can beeasily misinterpreted

Our investigation attempted to reveal changes in unmanaged forests dur-ing more than 30 years They were also aimed at identifying the limitationsfor analyses of vegetation dynamics that arise from the non-random phyto-sociological sampling In particular we asked the following questions (1)Is the phytosociological sampling oriented on diagnostic species (2) Aretransitional patches underrepresented in phytosociological collectionsFurther we attempted to assess the amount of these biases

The investigations were carried out in forests of the Babia Gora NationalPark in the Polish West Carpathians This choice was made according tothe presence of a detailed phytosociological study based on data collectedat the turn of the 50s and 60s of the XX century (Celinski amp Wojterski1978) Large areas of the Babia Gora forests were only slightly used in thelast century For the study area this guarantees that the previous phyto-sociological sampling was at most marginally influenced by anthropogenicchanges of vegetation and highly related to natural variability of vegetation

Study areaThe investigations were carried out in the forests of the Babia Gora Na-tional Park situated in the Polish West Carpathians A large tract of unman-aged forests extends between 900 and 1400 m asl on the north slope ofthe Babia Gora massif (1725 m asl) They have been under strict protec-tion since 1954 Two forest belts were included In the montane belt fiveforest associations were distinguished Two of them Carpathian beech for-est Dentario glandulosae-Fagetum and mixed coniferous forest Ab-iet i-Piceetum cover above 90 of the area The remaining three alder



















Results






30

25

20

15

10

5

0800 900 1000 1100 1200 1300


Freq

uenc

y (

)

35

30

25

20

15

10

5

0

Stand cover ()

Freq

uenc

y (

)


40

0 10 20 30 40 50 60 70 80 90

A

B








Abies alba

Abies alba

Acer pseudoplatanus

Acer pseudoplatanus

Acer pseudoplatanus

Picea abies

Picea abies

Picea abies

Sorbus aucuparia

Anemone nemorosa

Carex sylvatica


Dentaria bulbifera

Dentaria glandulosa

Epilobium montanum


Festuca altissima

Galium odoratum


Lysimachia nemorum


Mycelis muralis

Paris quadrifolia


Pulmonaria obscura

Stellaria nemorum

Veronica montana


Blechnum spicant

Hupertia selago

Luzula luzulina


Vaccinium myrtillus




Cicerbita alpina


Hieracium murorum

Luzula sylvatica



Valeriana tripteris

Rubus idaeus


Abies

















Altitude (m asl)

D

Num

ber

of s

peci

es

40

30

20

10

0800 900 1000 1100 1200 1300 1400

A B

C

0

1

2

3

4

5

6

7

8

9

40

30

20

10

0

40

30

20

10

0

40

30

20

10

0

800 900 1000 1100 1200 1300 1400

800 900 1000 1100 1200 1300 1400800 900 1000 1100 1200 1300 1400

800 900 1000 1100 1200 1300 1400 800 900 1000 1100 1200 1300 1400

FE

0

1

2

3

4

5

6

7

8

9

Altitude (m asl)

Num

ber

of s

peci

esN

umbe

r of

spe

cies



Discussion



900 1000 1100 1200 1300 1400

A CampW sample

B random sample5

4

3

2

1

+

800

Bra

un-B

lanq

uetrsquos

sca

le

900 1000 1100 1200 1300 1400800

Altitude (m asl)

5

4

3

2

1

+

Bra

un-B

lanq

uetrsquos

sca

le






Abieti-Piceetum

C

10

08

06

04

02

0

A B

D

IN

IN

IC

IC

10

08

06

04

02

0

10

08

06

04

02

0

10

08

06

04

02

0





















References

























































Results






30

25

20

15

10

5

0800 900 1000 1100 1200 1300


Freq

uenc

y (

)

35

30

25

20

15

10

5

0

Stand cover ()

Freq

uenc

y (

)


40

0 10 20 30 40 50 60 70 80 90

A

B








Abies alba

Abies alba

Acer pseudoplatanus

Acer pseudoplatanus

Acer pseudoplatanus

Picea abies

Picea abies

Picea abies

Sorbus aucuparia

Anemone nemorosa

Carex sylvatica


Dentaria bulbifera

Dentaria glandulosa

Epilobium montanum


Festuca altissima

Galium odoratum


Lysimachia nemorum


Mycelis muralis

Paris quadrifolia


Pulmonaria obscura

Stellaria nemorum

Veronica montana


Blechnum spicant

Hupertia selago

Luzula luzulina


Vaccinium myrtillus




Cicerbita alpina


Hieracium murorum

Luzula sylvatica



Valeriana tripteris

Rubus idaeus


Abies

















Altitude (m asl)

D

Num

ber

of s

peci

es

40

30

20

10

0800 900 1000 1100 1200 1300 1400

A B

C

0

1

2

3

4

5

6

7

8

9

40

30

20

10

0

40

30

20

10

0

40

30

20

10

0

800 900 1000 1100 1200 1300 1400

800 900 1000 1100 1200 1300 1400800 900 1000 1100 1200 1300 1400

800 900 1000 1100 1200 1300 1400 800 900 1000 1100 1200 1300 1400

FE

0

1

2

3

4

5

6

7

8

9

Altitude (m asl)

Num

ber

of s

peci

esN

umbe

r of

spe

cies



Discussion



900 1000 1100 1200 1300 1400

A CampW sample

B random sample5

4

3

2

1

+

800

Bra

un-B

lanq

uetrsquos

sca

le

900 1000 1100 1200 1300 1400800

Altitude (m asl)

5

4

3

2

1

+

Bra

un-B

lanq

uetrsquos

sca

le






Abieti-Piceetum

C

10

08

06

04

02

0

A B

D

IN

IN

IC

IC

10

08

06

04

02

0

10

08

06

04

02

0

10

08

06

04

02

0





















References








































30

25

20

15

10

5

0800 900 1000 1100 1200 1300


Freq

uenc

y (

)

35

30

25

20

15

10

5

0

Stand cover ()

Freq

uenc

y (

)


40

0 10 20 30 40 50 60 70 80 90

A

B








Abies alba

Abies alba

Acer pseudoplatanus

Acer pseudoplatanus

Acer pseudoplatanus

Picea abies

Picea abies

Picea abies

Sorbus aucuparia

Anemone nemorosa

Carex sylvatica


Dentaria bulbifera

Dentaria glandulosa

Epilobium montanum


Festuca altissima

Galium odoratum


Lysimachia nemorum


Mycelis muralis

Paris quadrifolia


Pulmonaria obscura

Stellaria nemorum

Veronica montana


Blechnum spicant

Hupertia selago

Luzula luzulina


Vaccinium myrtillus




Cicerbita alpina


Hieracium murorum

Luzula sylvatica



Valeriana tripteris

Rubus idaeus


Abies

















Altitude (m asl)

D

Num

ber

of s

peci

es

40

30

20

10

0800 900 1000 1100 1200 1300 1400

A B

C

0

1

2

3

4

5

6

7

8

9

40

30

20

10

0

40

30

20

10

0

40

30

20

10

0

800 900 1000 1100 1200 1300 1400

800 900 1000 1100 1200 1300 1400800 900 1000 1100 1200 1300 1400

800 900 1000 1100 1200 1300 1400 800 900 1000 1100 1200 1300 1400

FE

0

1

2

3

4

5

6

7

8

9

Altitude (m asl)

Num

ber

of s

peci

esN

umbe

r of

spe

cies



Discussion



900 1000 1100 1200 1300 1400

A CampW sample

B random sample5

4

3

2

1

+

800

Bra

un-B

lanq

uetrsquos

sca

le

900 1000 1100 1200 1300 1400800

Altitude (m asl)

5

4

3

2

1

+

Bra

un-B

lanq

uetrsquos

sca

le






Abieti-Piceetum

C

10

08

06

04

02

0

A B

D

IN

IN

IC

IC

10

08

06

04

02

0

10

08

06

04

02

0

10

08

06

04

02

0





















References










































Abies alba

Abies alba

Acer pseudoplatanus

Acer pseudoplatanus

Acer pseudoplatanus

Picea abies

Picea abies

Picea abies

Sorbus aucuparia

Anemone nemorosa

Carex sylvatica


Dentaria bulbifera

Dentaria glandulosa

Epilobium montanum


Festuca altissima

Galium odoratum


Lysimachia nemorum


Mycelis muralis

Paris quadrifolia


Pulmonaria obscura

Stellaria nemorum

Veronica montana


Blechnum spicant

Hupertia selago

Luzula luzulina


Vaccinium myrtillus




Cicerbita alpina


Hieracium murorum

Luzula sylvatica



Valeriana tripteris

Rubus idaeus


Abies

















Altitude (m asl)

D

Num

ber

of s

peci

es

40

30

20

10

0800 900 1000 1100 1200 1300 1400

A B

C

0

1

2

3

4

5

6

7

8

9

40

30

20

10

0

40

30

20

10

0

40

30

20

10

0

800 900 1000 1100 1200 1300 1400

800 900 1000 1100 1200 1300 1400800 900 1000 1100 1200 1300 1400

800 900 1000 1100 1200 1300 1400 800 900 1000 1100 1200 1300 1400

FE

0

1

2

3

4

5

6

7

8

9

Altitude (m asl)

Num

ber

of s

peci

esN

umbe

r of

spe

cies



Discussion



900 1000 1100 1200 1300 1400

A CampW sample

B random sample5

4

3

2

1

+

800

Bra

un-B

lanq

uetrsquos

sca

le

900 1000 1100 1200 1300 1400800

Altitude (m asl)

5

4

3

2

1

+

Bra

un-B

lanq

uetrsquos

sca

le






Abieti-Piceetum

C

10

08

06

04

02

0

A B

D

IN

IN

IC

IC

10

08

06

04

02

0

10

08

06

04

02

0

10

08

06

04

02

0





















References

















































Altitude (m asl)

D

Num

ber

of s

peci

es

40

30

20

10

0800 900 1000 1100 1200 1300 1400

A B

C

0

1

2

3

4

5

6

7

8

9

40

30

20

10

0

40

30

20

10

0

40

30

20

10

0

800 900 1000 1100 1200 1300 1400

800 900 1000 1100 1200 1300 1400800 900 1000 1100 1200 1300 1400

800 900 1000 1100 1200 1300 1400 800 900 1000 1100 1200 1300 1400

FE

0

1

2

3

4

5

6

7

8

9

Altitude (m asl)

Num

ber

of s

peci

esN

umbe

r of

spe

cies



Discussion



900 1000 1100 1200 1300 1400

A CampW sample

B random sample5

4

3

2

1

+

800

Bra

un-B

lanq

uetrsquos

sca

le

900 1000 1100 1200 1300 1400800

Altitude (m asl)

5

4

3

2

1

+

Bra

un-B

lanq

uetrsquos

sca

le






Abieti-Piceetum

C

10

08

06

04

02

0

A B

D

IN

IN

IC

IC

10

08

06

04

02

0

10

08

06

04

02

0

10

08

06

04

02

0





















References








































900 1000 1100 1200 1300 1400

A CampW sample

B random sample5

4

3

2

1

+

800

Bra

un-B

lanq

uetrsquos

sca

le

900 1000 1100 1200 1300 1400800

Altitude (m asl)

5

4

3

2

1

+

Bra

un-B

lanq

uetrsquos

sca

le






Abieti-Piceetum

C

10

08

06

04

02

0

A B

D

IN

IN

IC

IC

10

08

06

04

02

0

10

08

06

04

02

0

10

08

06

04

02

0





















References









































Abieti-Piceetum

C

10

08

06

04

02

0

A B

D

IN

IN

IC

IC

10

08

06

04

02

0

10

08

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04

02

0

10

08

06

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0





















References























































References







































Biased vegetation patterns and detection of vegetation changes using phytosociological databases. A...

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