sabor thesis

8/2/2019 Sabor Thesis

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VEGETATION ECOLOGICAL STUDIES ATTHE LOWERCOURSE OF SABORRIVER(TRS-OS-MONTES,NE-PORTUGAL)

University Bremen (FRG)

Diploma ThesisDepartment of Ecology and Evolutionary Biology

Vegetation Ecology and Conservation Biology

ANDR HOELZER

Bremen, January 2003


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ACKNOWLEDGEMENTS

This work would never have been possible without the decisivecooperation of a number of persons. To all them I would like to express my most

sincere gratitude:

Martin Diekmann, for having assumed the scientific orientation and responsibilityof the present work, and above all, for the confidence he gave to me. Lira Bravo,Pedro Couteiro, Ana Macedo, Margarida Ribeiro and Isidro Soares, for providingrefuge whenever and help in whatever necessary. Carlos dAbreu for validinformations. Antnio Ginja for transmitting innumerable information about thelocal situation. Carlos Aguiar for his always prompt availability and patience tointroduce me to the astonishingly rich vegetation of Trs-os-Montes and forgiving valid suggestions for fieldwork. Antonio Cresp and all the crew of theHerbarium of Vila Real, for allowing my participation in all their work done. Bijan

Ardeschirpur, Antnio Soares da Luz, John Kleba and Gabi Siemon, MartaRibeiro, and Hella Schmidt for invaluable help allowing the continuity of this workin a final, difficult stage. Alexandra Krause for help in the revision of this text.

My parents, who never stopped to believe in me.

It is to them, and to the honest peasants of Trs-os-Montes, that I dedicate thiswork.

La botanique est l'art de desscher lesplantes entre des feuilles de papier buvard etde les injurier en grec et en latin.

Alphonse Karr


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SUMMARY

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SUMMARY

A vegetation ecological study was conducted at the lower course of Sabor river, northeasternPortugal. The valley of this river constitutes an agroecosystem with typical Mediterraneantraits and is known for its diversity of habitats with conservational value. The valley suffered

from considerable abandonment of agricultural areas over the past four decades, whereasthe extension of not intervened vegetation increased substantially. However, the wholeextension of the lower course of this river is endangered by the construction of ahydroelectric power plant, and submersal of huge areas will be an immediate impact. In orderto characterize the floristic-structural dynamics and diversity of the vegetation covering thevalley, representative samples of different communities at different altitudes along the rivervalley were taken. In all, 109 relevs with an homogeneous area of 10 x 10 m 2 comprised asection of the river with an extension of 30 km. Samples were classified into distinct types ofcommunities, according to their structure: riparian communities, rupicolous communities,scrublands, woodlands and grove communities. Two basic approaches were applied toexamine the ecology of vegetation. First, the total species numbers within the differentsamples were compared. Riparian communities proved to be the richest in terms of species,

and species numbers were higher than 60/100 m2 in several cases. A strong concentration ofdiversity coincided with the immediate riverside zone, whereas other environmental factorsdid not explain significantly the concentration of species. The communities subjected toagricultural intervention were the second richest community type in terms of speciesnumbers. By far the highest percentage of all registered species pertained to a therophyticlife form.The second approach was based on multivariate statistical analysis of the data setconstituted by the samples. According to a recent methodology that permits description offloristic-structural dynamics, different structural parameters were focussed to build structuralmatrices: specific diversity, abundance, stratification and conjoint data matrices of theseparameters. The introduction of stratification constitutes an extension in relation to theoriginal framework of the methodology and proved to be useful to further describe vegetationstructure. Several tendencies of structural expression were detected that constituted indifferent degrees the apparent community types. The communities were found to exhibit highdegrees of dynamics between each others, but also the intracommunitarian dynamics turnedout to be high. This may be an explanation for a high degree of superimposition detectedbetween the various community types in floristic-structural terms. A basic feature found wasthe structural similarity, regardless considerable differences according to the envisagedparameter, in terms of representation of life forms, but a different specific composition,indicating that to a higher extension functionally homologous species could contribute tomaintain structural dynamics and diversity. Contrasting the obtained results with informationabout the magnitude of agricultural impact in the different sites and site history, a tendency toincrease higher variability of floristic-structural combinations within the communities in the

course of regenerating succession processes was suggested. The singularity of ripariancommunities was corroborated both in terms of structural diversity and the fact that specieswith low frequencies over the whole area reached highest expressions within this communitytype. It is suggested that riverside communities exert a significant influence upon all othercommunity types with more upland characteristics, as indicated by the transmission ofsupposed riparian tendencies into other types, thus having provided potential for theobserved rapid ecosystem restoration. Considering the dependence of this community typeupon the fluvial dynamics in force, it is expected that the impact of the hidroelectric powerplant would not only affect the riverside vegetation, but equally the vegetation out of theimmediate influence zone of the future lagoon.


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CONTENTS

1. Introduction page 1

2. Methodology 5

2.1 Study area 5

2.1.1 General considerations 52.1.2 Topography 52.1.3 Climate 62.1.4 Hydrology 82.1.5 Geology 92.1.6 Soils 92.1.7 Bioclimatic description 102.1.8 Biogeography and Vegetation 112.1.9 Land use 14

2.2 Sampling 18

2.3 Data analysis 21

2.3.1 Species richness 21

2.3.2 Floristic-structural analysis 22

Arrangement of basic structural matrices 23- Diversity BSM 23- Abundance BSM 24- Stratification BSM 25

- Conjoint matrix of diversity and abundance 25- Conjoint matrix of diversity, abundanceand stratification 25

Arrangement of contingency matrices 26- Life form contingency matrix 26- Frequency class contingency matrix 26

Cluster analysis 27

Ordination by Principal Component Analysis 27- Clusters 28- Distribution of clusters over apparentcommunities, land use intensity andgeographic sectors 28

- Distribution of life forms 29- Distribution of frequency classes 29- Maximal Expressive Amplitudes 29

Discriminant Canonical Analysis 29

Assessment of intensity of land use 30


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3. Results 31

3.1 Species richness 31

3.2 Floristic-structural analysis 35

Cluster analysis with BSM 35

Ordination by PCA 37

Correlation Clusters (Tendencies of Behaviour) 38- Diversity 39- Abundance 41- Stratification 43- BSMDA 45- BSMDAS 47

Expressive Amplitudes 49

Life form, frequency classes and expressivityin apparent communities 50

Discriminant analyses 53- Frequency classes by community types 53- Life forms by community types 54- Frequency classes by land use categories 55- Life forms by sectors 56- Frequency classes by sectors 57

Assessment of land use intensity 58

4. Discussion 60

4.1 Species richness 60

4.2 Floristic-structural analysis 62

5. Literature cited 70

Appendices

Appendix 1: Definition of the geographical sectorsAppendix 2: Sample plotsAppendix 3: Species catalogue


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INTRODUCTION

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1. INTRODUCTIONConsiderable effort has been made to valuate the biotic diversity

arising on a spatial and temporal scale within areas subjected to anthropizedcultivations, and the degree of species richness in those areas, as well as thebenefits proceeding from them, are often underestimated (PAOLETTI et al.,1992; PAOLETTI &PIMENTEL, 1992). These ecosystems, commonly referred toas agroecosystems, have been defined as an interactive group of biotic andabiotic components, some of which are under human control, that forms aunified whole (ELLIOT &COLE, 1989 Agroecosytems are also considered asdecisive interfaces between the anthropic and the biotic components withinthe framework of landscape ecology (Fig 1.1). This implies the recognition ofthe dynamic role of man as a forming element by means of land use,reflecting the spatial intervention on ecosystems with the objective of adaptingthem to mans needs; thus quests for more systematic investigations of theecological implications arose (BOLs, 1992; NAVEH &LIEBERMAN, 1990; VILS,1992).

Evidence exists that biotic diversity can increase with the complexity oflandscape structure resulting from traditional agricultural systems (ALTIERI et

al., 1987; GLIESSMAN, 1990). In most cases, however, agroecosystems andtheir parental ecosystems are often substantially different in structure andfunction, as often becomes manifest through reduced species diversity, lowerresilience or greater homogeneity, amongst others, in the derived ecosystems(ALTIERI et al., 1983).A trait that distinguishes these systems from most other natural systems arethe periodic and chronic disturbances intrinsic to agricultural management,leading to changes with different effects, according to their spatial extension;for example, changes at local scale are supposed to affect dominant species,structure and boundaries between different patches of vegetation, whereas ata regional scale alterations in land use or changes in the arrangement of basiclandscape-forming units are expected consequences (ELLIOT & COLE, 1989;LEPART &DEBUSSCHE, 1992; OKEY, 1996).

abiotic subsystem

(geome)

soil interface

biotic subsystem

(ecosystem)

agr

arianinterface

(ag

roecosystem)

socioeconomic

subsystem

ENERGY

Fig. 1.1. Agroecosystems as linkage between the elements that constitutelandscapes. Adapted from BOLS (1992).


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In the functional context of agroecosystems, riparian vegetationcommunities are particularly interesting, because they exhibit a high degree ofstructural and compositional diversity (CRESP et al., 2001b). Riparianvegetation occupies one of the most dynamic areas of landscape, and thedistribution as well as the composition of riparian plant communities reflects

history of both fluvial disturbance regimes (floods) and nonfluvial disturbanceregimes of adjacent upland areas (GREGORY et al., 1991; see Fig. 1.2).Riverine landscapes are constituted by extensive interconnected series ofbiotopes and environmental gradients, and natural disturbance regimesmaintain a multiplicity of interactive pathways across the whole system, sothat these landscapes need to be envisaged in a holistic geomorphicperspective. The action of disturbance and environmental gradients in concertgenerates broad-scale patterns and processes responsible for elevated levelof biodiversity (Ward, 1998).

The particular interest of riparian vegetation resides in the fact that on alarge scale, alluvial landscapes present a continuum from flooding-prone to

particularly flood-protected sites, thus assuring refuges and propagulesources at any given time even under changing situations and limiting speciesloss to at most local levels (SCHNITZLER, 1997). Additionally, higher fertility asa result of periodical flooding in many of those habitats contributes to highspecies richness, productivity and a high potential of coexistence. Becausethe microrelief particularities and local distribution patterns of those sites areexpected to create distinct patches of vegetation units, various stages ofsuccession are supposed to exist, ranging from innovation stages on sitesexposed to high kinetic energy of floods (characterized by patches of pioneerherbaceous, shrub and tree species), over equilibrium and climactic stageswith a highly structured functioning and fragmentation into mosaic units

(caused by different maturity, decay or death of individuals), to eliminationstages. For all the aforementioned reasons, riparian zones exercise potentially

Fig. 1.2. General classification of zones composing the riverinelandscape. Zones 2 and 3 make up together the complete riparian zoneof influence. Key: (1) active channel, (2) riparian zone, (3) zone ofinfluence, (4) upland area. Adapted from NAIMAN et al. (1992)


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important roles within landscapes as corridors for plant dispersal andadditional importance arises during periods of rapid environmental changebecause of frequently ameliorated microclimates along the river valleys(FRANKLIN, 1992; GREGORY et al., 1991).

The subject of the present study is the Mediterranean agroecosystemlocated in the valley of the lower course of Sabor river, northeastern Portugal.This agroecosystem is characterized by a profound adaptation of itslandscape to a large-scale agriculture that had continued duration up to thebeginning of the 1970s (cf. also chapter 2), and is now in a state of apparentrecuperation over great parts of its area. Interestingly, the studied areacomprises a series of habitats and sites the conservational value of which hadbeen stated on various occasions: parts of the river course had beenclassified as CORINE biotope (code C11800100 Rio Sabor), comprising anarea of 6.400 hectares exclusively of wetlands; the river valley of the lowercourse includes also a series of habitats of communitarian interest, in the

sense of the Directive Habitats 92/42/CE, having inclusively being proposedfor integration in the European habitat network NATURA 2000 (FARINHA &TRINDADE, 1994; KOE et al., 1998; MINISTRIO DO AMBIENTE, 1999; ROMO,1992).

However, the project of construction of a hydroelectric power plantlocated at the lower course of this river, dating back to the 1950s (HIDRO-ELCTRICA DO DOURO, 1961), has recently gained renewed interest on part ofenergy suppliers and local power. Although an assessment of environmentalimpact has been elaborated, there exists practically no information of publicaccess concerning the values and potentials of the specific landscape of thisriver valley.

Among the heavy potential impacts ensuing such a profound anthropogenicflow regulation, the following can be mentioned (WARD, 1998):

- disruption of natural disturbance regimes- truncation of environmental gradients- severing of interactive pathways- elimination of upstream-downstream linkages

These are all supposed to interfere with successional trajectories, habitatdiversity and migration pathways, leading ultimately to drastically alteredlandscape functions and reduced biodiversity. Considering the dimensions ofthe before mentioned project, the need for studies at a large spatial scale toelucidate the structure and potentials of vegetation seems sufficiently evident,all the more as the ecosystem in concern is exposed to a climate type thatpromotes erosion, thus being at utmost vulnerability to suffer from irreversibleeffects of large scale impacts.

With this background, the purpose of the present work is to apply ananalytical methodology to describe the floristic-structural behaviour of the

vegetation of this agroecosystem. The methodology has already been appliedto various situations in several ecosystems in northern Portugal (CRESP et al.,


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INTRODUCTION

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2000, 2001a, 2001b, 2001c; FERNANDES, 2001; PIOT-ADV, unpubl.), andconsists in a multivariate statistical analysis of structural matrices based on aset of relevs representing the distinct community types present in the studyregion, in order to enable the characterization of the floristic-structuraldynamics of the vegetation in the considered zone. Structure is in this context

envisaged as a product of population dynamics dependent upon thecompetitive capacities of each species (i.e. according to an individualistic,Gleasonian viewpoint, e.g. ONEILL et al., 1986), so that the structuraldynamics of the communities could be explained by interactions between thedifferent populations within the given context of their metapopulations(HOLYOAK & RAY, 1999; HUSBAND & BARRETT, 1996) on the one hand, andecological factors on the other hand, resulting eventually in chaotic processessubjacent to the structural behaviour of these communities and a multiplicityof stable states (MAY,1976,1977;STONE,1993;STONE &EZRATI,1996;TILMAN& WEDIN, 1991). Consequently, in addition to the dynamics between distinctcommunities, also dynamics at an intracommunitarian level could be

expected, notable through a higher degree of variability of floristic-structuralcombinations within a given type of community, providing, simultaneously, anestimation of resilience by analysing this combinatorial variability (CRESP etal., 2001a, 2001b).

Reference to resilience is especially interesting while considering theeffects of anthropogenic disturbance on the structure of ecosystems, togetherwith resistance, i.e. the ability to withstand shifts induced by perturbations.Resilience constitutes an important property of ecosystems, which isunderlying to a more or less rapid restoration of initial structures and functionsafter disturbance having ceased (ALLEN, 2001; BATABYAL, 1998; OKEY, 1996;WESTMAN, 1986; WHITFORD et al., 1999).Namely in Mediterranean regions, the anthropogenic impact has not alwaysled to drastic decrease in resilience of native vegetation, and a large variety ofpossible landscapes remained, thus maintaining high levels of biodiversity(LEPART &DEBUSSCHE, 1992). Nevertheless, resilience seems to depend, in acomplex way, upon the diversity of landscape, defined as the combination ofnumber of vegetation types and the degree of spatial heterogeneity, withheterogeneity being likely to result in faster recuperation (BASCOMPTE &RODRGUEZ,2001;CUMMING,2002;LAVOREL, 1999). Consequently any kind ofperturbation drastically affecting the diversity of landscape would be expected

to reduce significantly the resilience of an ecosystem. Species and functionaldiversity are also supposed to be important in the context of ecosystemsperformance and resilience to environmental changes, but there is still a greatdemand for elucidation of the relative roles of these parameters (LAVOREL etal., 1998).

These considerations constitute an outline of the purposes of thepresent study, focussing the impacts of agricultural activities on the diversityof floristic-structural combinations in relation to a more pristine vegetationtype, as has been studied in the case of another agroecosystem (CRESP etal., 2001c).


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METHODOLOGY

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2.METHODOLOGY

2.1STUDY AREA

2.1.1 General considerations

The whole area considered in the present study is located in the valleyof the lower course of the Sabor river and pertains to the region ofTrs-os-Montes e Alto Douro (Fig. 2.1). Thisregion corresponds to thenortheastern area of the continental

Portuguese territory, and iscircumscribed by the district ofBragana. It is part of the Portugueseportion of the Douro river drainagebasin, and the Sabor river, traversingthe region in a roughly North to Southorientation, is the first right-banktributary of the former on Portugueseterritory. The total surface of theSabor drainage basin amounts to 3830 km2 (HIDRO-ELCTRICA DO

DOURO, 1961).

2.1.2.Topography

The region is characterized by the persistence of residual primitiveplateaus (peneplains) with average altitudes of 700 800 m, and is rich inerosion surfaces dissected by a drainage network. Water courses areenclosed in deep and narrow valleys that present frequently steep slopes, withthe valley of Sabor river and its main tributaries standing out, i.e. Mas,Angueira and Azibo rivers, as well as the rivers Ribeira de Zacarias andRibeira de Vilaria (CABRAL, 1985).

The eastern parts of the region can be considered as a prolongation of theIberian meseta, interrupted north of the central chain by the tectonic accidentdesignated as Manteigas-Vilaria-Bragana, of late variscian origin, followinga general NNE-SSW orientation, which after neotectonic reactivations duringthe late Cenozoic formed a step between the northern Meseta and the higherplains of Trs-os-Montes (CABRAL, 1995). Thus the surface of northeasternTrs-os-Montes was elevated to altitudes in the range of 600 to 800 metresabove sea level. Unlike the peneplain on the Spanish side, with low relief andTertiary cover, the plateau on the Portuguese side is deeply incised by its

rivers, which have carved canyons of considerable depth into the ancientcrystalline rocks; the dissection of the actual drainage network is supposed to

Fig. 2.1. Localisation of the study area in north-eastern Portugal.


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date back to times as recent as the beginnings of Quaternary only (MEDEIROS,1987; STANISLAVSKI, 1959). To illustrate these erosive forces, the averagealtitude of the Sabor drainage basin area amounts to 660 m (HIDRO-ELCTRICADO DOURO, 1961), whereas, within the considered area (cf. 2.2), the level ofSabors riverbed decreases from 200 m to 140 m.

2.1.3 Climate

Portugal as a whole is a region of transition between Atlantic and

Mediterranean influence (RIBEIRO, 1991). Although the northern parts of thePortuguese territory commonly are thought to be dominated by Atlanticclimate, namely the eastern part of the province, protected by several highmountain chains Gers, Barroso, Maro, Alvo, Montemuro has a markedcontinental character. The profoundly carved valley of Douro river favours theprogression, from east to west, of a continental type of climate (MEDEIROS,1987). Especially in the lower parts of upstream Douro valley, the protectedposition enables the existence of a Mediterranean climate (ALCOFORADO et al.,1993).

Considering various climatic and physiographic characteristics of Trs-

os-Montes, climatically homogeneous zones have been established,concerning the intersection of thermic and precipitation regimes(AGROCONSULTORES & COBA, 1991). Three main sub-zones are considered,by analogy to local designation: Terra Fria (cold land), Terra de Transio(transition land) and Terra Quente (warm land). The cold land, coveringmainly the higher surfaces comprised between 600 and 1300 m, where meanannual rainfall ranges from 600 to 1400 mm, generally tends to have longerwinters and snow may fall from early December to March; frosty days mayoccur even in May (FERREIRA et al., 1996). This zone, however, is notrepresented in the sites considered in this study.

The complete study area is inserted in the Terra Quente zone, whichrepresents areas with altitudes from sea level to around 500 m, thus in

Fig. 2.2. Altitudes (A) and slopes (B) in northeastern Trs-os-Montes. The zone comprisingthe sample sites is outlined. (SNIRH, 2003)


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general incident with the slopes of river valleys. Winters tend to be shorter andmilder and snowfall is rare, and the latest frosts use to occur only in March.According to the precipitation regime, this zone can be subdivided into furthersub-zones; the only situation, however, occurring in the study areacorresponds to annual rainfalls inferior to 600 mm. The transition zone is

located at altitudes ranging from 400-500 to 600-700 m. Temperature andrainfall are similar to that found in the warm land, with the only difference ofcooler summers. Table 2.1 resumes some climatic characteristics.

In global terms, the mountain areas receive higher rainfalls than lower lands,and, on the other hand, the temporal distribution of rainfall is high, so that highdifferences occur between the wettest and the driest months; there are alsosignificant differences in mean air temperature between the coldest andhottest months at all locations in the region. Winter rainfalls represent about70-80% of the total annual precipitations, and a marked hydric deficit is

notable during the months June to September (FERREIRA et al., 1996; see alsoFig. 2.3, and Tables 2.2, 2.3).

ZONEALTITUDE

(m)ANNUAL PRECIPITATION

(mm)MEAN TEMPERATURE

(C)

Terra Fria 600 1300 600 < P < 1400 9 < T < 12.5

Terra de Transio 400/500 600/700 600 < P < 1200 12.5 < T < 14

Terra Quente < 400/500 400 < P < 1200 T > 14

Table 2.1. Some basic characteristics of climatically homogeneous zones of northeastern Portugal.Compiled after AGROCONSULTORES & COBA (1991) and FERREIRA et al. (1996).

Locality alt (m) T (C) P (mm) period source

Mirandela 240 14.6 505 1931-60 SMN (1970)

Bragana 725 11.6 972 1931-60

Torre de Moncorvo 408 15.2 549 1931-60

Ponte do Sabor 110 547 1941-70 INMG (1990)

Mogadouro 750 786 1941-70 Alfndega da F 600 579 1941-70

Cerejais 475 559 1941-70

Tab. 2.2. Rainfall and temperature data of some stations in the study region. In bold letters,stations located within or in proximity to the study area. Alt = altitude; T = mean annualtemperature; P = mean annual rainfall.


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position T (C) Tmax(C)

Tmin(C)

P(mm)

Hrel(%)

I(%)

N of dayswith frost

plateau 12-14 17-19 6-8 500-800 60-70 55 - >60 40 - 70slopes/valleys

14-16 18-22 7-9 400-600 50-60 55-60


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2.1.5 Geology

Although the whole considered area pertains to the so called Galician-Castilian zone of the Iberian mass of the variscian orogeny, which is basicallymade up of granites and orthogneisses, the Douro river and his maintributaries follow a belt of Palaeozoic or pre-Cambrian schists, with someinserted layers of quarzite (LAUTENSACH, 1964). Hence it follows that theresearch area is mainly composed of schists forming the bedrock of thestudied sites (MARTINS, 1985).Nearly the whole extension of the river valley in consideration is constitutedmainly by metamorphic rocks pertaining to the greywacke-schist complex,Ordovician schists and quartzites in the Moncorvo-subregion, metamorphicSilurian schists in the zone where the basin of Ribeira do Zacarias enters, andsome spots of granites in diverse localities. Upstream, the study area islimited by the lithological complex corresponding to the Morais massive, with

predominance of greenschists, mica-schists, gneisses, and amphibolites, andthe Silurian complex, constituted by metamorphic and quartzitic rocks(AGROCONSULTORES & COBA, 1991; DGMSG, 1974; MINISTRIO DA ECONOMIA,2000; see Fig. 2.4).

2.1.6 Soils

The soil types prevailing in the study area are basically leptosols andanthrosols, with small occurrences of fluvisols wherever the extension of therivers floodplain permits. Leptosols are very thin soils presenting generallyonly an A horizon of roughly 0,1 m depth, and are limited in this area by ahard rock layer which is nearly invariably schist; those soils are typical of

Fig. 2.4. Detail from the Geological Map 1 : 200 000 showing the area of lower course ofSabor river (MINISTRIO DA ECONOMIA, 2000).


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sloping lands and drier areas, as the valley considered here(AGROCONSULTORES & COBA, 1991; FERREIRA et al., 1996). Two classes ofleptosols occur in Sabor valley: orthi-dystric leptosols and orthi-eutricleptosols, the former based on schist and the latter, in some areas adjoiningthe upstream limit of the study area, on basic rocks. It is by far the soil unit of

major representation in the region; after deep ploughing, those soils aresuitable for extensive agriculture as for example cereal cropping andpermanent tree crops as olive and almond, supporting equally forests(AGROCONSULTORES & COBA, 1991).Anthrosols are soils that have suffered profound modification of originalcharacteristics provoked by human activities. The only type represented in thestudy area, namely in the section Pices Felgar, are surribi-aric anthrosols,resulting from profound mobilizations and greater movements of material andfrom mixtures of original soils with fragments of the substrate rock; they aremainly used for the same crops as the leptosols (AGROCONSULTORES & COBA,1991).

Fluvisols are composed of sedimentary materials, without any expression ofhorizons, rich in organic matter (FERREIRA et al., 1996); although they arefertile and frequently are irrigated for intensive cropping (as in the nearbyVilaria valley), in Sabor valley they do not have any special use due to theirremoteness and difficult access.

2.1.7 Bioclimatic description

According to a comparative study of some aridity scales in Portugal, the study

area pertains to a pre-Mediterranean domain (ALCOFORADO et al., 1993). TheMediterranean climate is characterized by scarcity of rainfalls during summer,the occurrence of at least two months where the numerical value of meanprecipitation is inferior to twice the value of mean temperature (P < 2T),although there might be excesses of rainfall in winter (COSTA et al., 1998). TheMediterranean character of the vegetation and its correlation with the upperDouro, Sabor and Tua rivers was already stated by ROZEIRA (1944); heoutlined the importance of that rivers for the Mediterranean elements, both interms of distribution of species and in terms of the modification of climatewithin their valleys.

Considering the Thermicity index It, and following the classification ofRIVAS-MARTNEZ (1987,1996) and RIVAS-MARTNEZ et al. (2002), the studiedzone pertains to a mediterranean thermotype, and of the six bioclimatic stagesrecognized for the Mediterranean area, three are represented in the studiedzone, the thermomediterranean, with 350 < It < 450, the mesomediterranean(210 < It < 350) and the supramediterranean ( 80 < I t < 210), and theombroclimate varies from dry (annual precipitation between 350 and 500 mm)to subhumid (500 < P < 900; MINISTRIO DO AMBIENTE,1999).As a generalrule, the Mediterranean character becomes more accentuated the more thelocality is situated in the interior and the lower its altitude is (RIBEIRO, 2000a).


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The greatest part of the valley of the lower course of Sabor riverpertains to a subhumid mesomediterranean1 stage, with expression of athermomediterranean stage with dry ombroclimate at lowest altitudes(riverbed) within the most downstream portions (COSTA et al., 1998; RIVAS-MARTNEZ &LOIDI, 1999; cf. Fig. 2.5).

2.1.8 Biogeography & Vegetation

Biogeography, as a branch of geography, deals with the spatial distribution ofspecies, linking information about the physical environment with the biological,supported by chorological, geological, bioclimatic and phytosociological data,as plants supply the biggest part of terrestrial biomass, and due to their fixedcharacter (COSTA et al., 1998).One of the traditionally used criterions in the recognition and demarcation ofbiogeographical areas is thus the distinction and cartography of taxa orsyntaxa that present a regionally restricted distribution, i.e. endemisms(RIVAS-MARTNEZ, 1987).

1Thermicity index It for Torre de Moncorvo equals 279 (with T=15,2C, M=9.3C and m=3.4C[SMN, 1970]).

Fig. 2.5. Thermoclimatic belts in northeastern Portugal, with the study areaoutlined (RIVAS-MARTINEZ et al., 2002).


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In accordance with RIVAS-MARTNEZ (1987) and COSTA et al. (1998), thebiogeographical classification of the region is as follows (see Fig. 2.6):

Holarctic KingdomMediterranean Region

Western Mediterranean SubregionIbero-Atlantic Mediterranean SuperprovinceCarpetan Iberic Leones Province

Lusitan Duriensean SectorTerra Quente Superdistrict

The whole Lusitan Duriensean Sector is a highly complex unity, due to theterritorys physiography, composed of a substrate of meso- or even nearlythermomediterranean plateaus and valleys and some insertedsupramediterranean elevations.

The river valleys in the study area are believed to be an importantlandscape element determining plant migrations and a shelter for thermophilicspecies during cold periods. Hence various climatic disjunctions can be foundthere, from xerophytic paleoclimatic relicts as Juniperus oxycedrus,mesophytic paleoclimatic relicts like Arbutus unedo and Buxus sempervirens,to pre-Wrmian mediterranean climatic disjunctions like Allium roseum,Asparagus albus, Olea europaea var. sylvestris and Rhamnus lycioidessubsp. oleoides (HONRADO et al., 2001).

In the following, a generic characterization of the vegetation is given,

according to CAPELO et al. (1998) and COSTA et al. (1998). The Terra QuenteSuperdistrict is characterized by its climatophilous mixed forests of cork oak

Fig. 2.6. Biogeography of northeastern Portugal to sector level. The studyarea is outlined. Key: Eurosiberian Region 4.4: Juresian Sector.Mediterranean Region 15.6: Salmanticensean Sector 15.8: LusitanDuriensean Sector 15.9: Bercian-Sanabriensean Sector (RIVAS-MARTNEZ etal., 2002).


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and juniper (Rusco aculeati-Quercetum suberis subassociation juniperetosumoxycedri ined.), and its subserial communities, mainly dwarf scrubs ofLavandulo-Cytisetum multiflori and broom-dominated communities of Cytisomultiflori-Retametum sphaerocarpa as forest mantle vegetation and also inprogressive successional processes, or Cytiso scoparii-Retametum

sphaerocarpa in regressive succession. As a first step in the degradation ofcork oak woods, shrubby or woody formations of species with lustrous leavesoccur (Arbutus unedo accompanied by thermophilous species like Phillyreaangustifolia, Pistacia terebinthus and Viburnum tinus, or in even moredegraded stages, Erica arborea). Cork oak is frequently associated with Q.faginea, as already observed by BRAUN-BLANQUET et al. (1956). Oligotrophictherophytic grasslands are frequent, classified as Anthyllido lusitanicae-Tuberarietum guttati. On more acid and exposed soils, communities ofLavandulo sampaioanae-Cistetum populifoliican be identified.

In edapho-xerophilous conditions, mainly occupying steep slopes, holmoak dominated forests, classified as Genisto hystricis-Quercetum rotundifoliaejuniperetosum oxycedri, substitute the cork oak woods. In subserial stages,again broom dominated communities, in that case pertaining to Cytisomultiflori-Retametum sphaerocarpa occur, which might be substituted byextremely poor communities dominated by Cistus ladanifer. Under basiphilousconditions, dwarf scrubs of Lavandulo sampaioanae-Cistetum albidi mayoccur. The underlying intensive anthropozoic dynamics of these scrubbyformations has first been described by BRAUN-BLANQUET et al. (1964).

Bordering the margins of permanent watercourses, with markededapho-hygrophilous conditions, riparian forest ofScrophulario scorodoniae-Alnetum glutinosae are constant, but they are restricted to very narrow stripsof gallery forests, due to the topography of the mainly V-shaped river valley,with Clematis campaniflora and Scrophularia scorodonia as notablecompanion species. Bordering the temporary watercourses, but also the morelotic facies of permanent watercourses with strong currents, willows ofSalicion salviifoliae appear. In the floodplain of Sabor river, rupicolouschamaephytic communities ofDiantho laricifolii-Petrorhagietum saxifragae arefrequent, with notable thermophilous traits, and a peculiar scrub communitydominated by Buxus sempervirens and Erica arborea (cf. also AGUIAR et al.,1999).

In the semiarid ombrotype of meso- and thermomediterranean stages,coinciding with the deepest parts of the valley in the most downstream sectionof Sabor river, there is no expression of the climactic forests at all, but insteadremnants of the typical shrubby formations of Pistacio-Rhamnetalia alaterni(Asparago-Rhamnion oleoidis), with the species Asparagus albus andRhamnus oleioides as bioindicators (RIVAS-MA RTNEZ, 1987), can beobserved. A simplified illustration of the distribution of communities is shownin Fig. 2.7.


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2.1.9 Land use

Land use is ancient in the region, with first human settlements datingback to Holocene, and most ancient agriculture came about in the transitionbetween the 6th to the 5th millennium BC, a fact that was equally confirmed forthe proximities of the study area (SANCHES, 1997); cereal cultivation seems tobe usual at least from the late 6th millennium BC on, and from the thirdmillennium BC on there is evidence of livestock raising. Around the earlysecond millennium, it appears that an intensification and diversification insubsistence activities plus an increased number of permanent settlementstook place.The evolution of the cultural landscape for the studied area is, consequently,essentially comparable with that described for the Mediterranean as a whole(NAVEH & LIEBERMAN, 1990): after the emergence of hunter-gatherereconomies in Upper Pleistocene, a gradual intensification of anthropogenicfactors (including burning), the Neolithic brought more profound agriculturaltransformations, with the creation of a diversified flora of species adapted todrought, fire and grazing. The evolution of denser pastoral-agrarianpopulations implied clearance of arable slopes, often terraced orpatchcultivated. Gradually, the dense woody natural landscape wastransformed into more open cultural landscape.

Fig. 2.7. Distribution of important communities in the valley of Sabor river (HOELZER &AGUIAR,unpubl.)


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In present times, different systems of land use in northeastern Portugal havebeen identified (MOREIRA, 1984), two of which being represented in theconsidered area (AGROCONSULTORES & COBA, 1991). The most important atthe slopes of Sabor valley has been the cereal and olive exploration system ofTerra Quente (Fig. 2.8), where cereal monoculture wheat and some rye is

predominating, mainly based on the traditional biannual rotation of crop andfallow. The cereal crops are nowadays without any importance at Sabor valleyslopes, completely abandoned since the early 1970s (GINJA, A., personalcomm.), but were extremely extended following the Wheat campaign,consisting in a forced augmentation of wheat cultivated areas in the wholecountry as a mean to reduce importations, in the decade of 1930 (MARTINS,1985).

A common pattern of land use organization found in the region resides in a

radial structure of utilization intensity, with the villages constituting the centre,surrounded by horticulture and other intensive crops, then in a greaterdistance the cereal fields, and finally the woodland and scrubland dominatedareas (AGUIAR &RODRIGUES, 2002). Furthermore, it has to be remarked thatthe whole traditional system of agriculture of Trs-os-Montes was built uponan efficient utilization of the disposable resources, with insignificant resort toexternal inputs (VAZ &VAZ, 2000).

Of outstanding importance within the context of local economy are theorchards of olive and almond trees, either as monoculture or mixed. Theseare often the only viable crops where slopes are too steep for any other kind

of cultivation. Besides, some benefit is provided by the cork oak woodlands,both by spontaneous and by cultivated populations. The olive and almond

Fig. 2.8. Traditional land use in the Terra Quente zone (adapted from MOREIRA,1984).


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groves, installed by means of cuttings, are generally treated in an extensiveregime; two ploughings and one raking were common (BALTASAR, 1989).However, as a result of the lack of manpower in present days, the number ofploughings per year may be reduced to one or even less in most orchards.Nowadays, the current treatment consists of two ploughings in the case of

olive groves and generally one ploughing in almond groves (GINJA, A.,personal communication). It is worth to remark that in the Trs-os-Montesregion namely the extension of the cultivation of olive trees becameestablished only since the 18th century (RIBEIRO, 1991), after a previousintroduction during the 16th century in the Sabor valley and other zonesnearby (PEREIRA, 1997). From historical sources it is known that the majordiffusion of olive cultivation started in the beginning of the 19 th century(MENDES, 1994).

Other crops had outstanding importance in past times. Up to the 1970s flaxwas cultivated, but it was around the middle of the 18th century that the related

industry reached its height (OLIVEIRA, 2000). It was cultivated preferably in theproximity of watercourses for fibre extraction. Nowadays, there are practicallyno areas where flax is cultivated. Hemp for fibre production was equally basisof a well-developed industry in this region, until its substitution by silk industryin the middle of the 18th century (CABRAL, 1895). The silk industry, based onimportant groves of mulberry, had a major expression in the whole region untilthe end of the 19th century (CEPEDA, 1999). Another cultivated crop in theregion used in leather industry (tannery) was sumac (Rhus coriaria);nowadays there exist some spontaneous remnant formations dominated bythis shrub in some points of Sabor valley.

Out of the immediate proximity of settlements, at the slopes of the valley,punctually horticulture is practised, in small plots adjacent to some smalltemporary watercourses draining into the Sabor floodplain.

Integral part of the mentioned kind of exploration is the natural pasture bysheep and goats, with the multiple function of meat, milk and wool production,based on spontaneous vegetation and also remainders of pruning as leavesand twigs of the olive and almond trees. This occurs over nearly all the area,with some preference to the floodplain areas during summer, because ofscarcity of water.

Another important observation is the existence of ancient communal lands,the so-called baldios, that is large areas where intensive agriculture has neverbeen possible (OLIVEIRA et al., 1995; RIBEIRO, 1991). As a consequence of thegeneral decline of the region, following the great emigration movementsstarting at the beginning of 20th century and becoming most accentuated inthe 1960s (CEPEDA, 1999), these lands often became transformed intocompletely unused lands. In the 19th century, an estimated three quarters ofthe area of Trs-os-Montes were baldios (RIBEIRO, 1991). Particular decisiveis the fact that mainly since 1938 large scale forest plantations were installedin these communal areas, and given the importance of these areas as an

additional subsistence source (episodic crops, apiculture, pasture), violentconflicts rose up, involving forest fires as weapon in a political conflict


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(BAPTISTA, 1978). Although there is no documentation available for thisspecific region, especially since the second half of the 1960s an increasedtendency for fires in baldio areas becomes evident (DEVY-VARETA, 1993).

At last, the somehow scattered distribution of cultivated land in the

considered area is equally noteworthy; land tenure is predominantlycharacterized by small sized farms and large number of plots per family(FERREIRA et al., 1996; GONALVES, 1991). The abandonment of a greatnumber of plots as a consequence of the rural exodus has aggravated theaccess to the productive fields. This has contributed to an increase ofuncultivated areas of great dimensions in the entire region, and affectedequally the slopes of Sabor valley.

To sum it up, the whole region of valley of Sabor river was occupied bylarge scale cultivations, leading to a profound modification of landscape whichremained patent up to the 1970s, with a nearly total suppression of

uncultivated areas. The present extensive areas of seemingly naturalvegetation developed in the relative short time span of the last few decades.Fig. 2.9 shows this alteration of landscape documented by aerial photographstaken in 1965 and 1995, respectively.

Fig. 2.9. Aerial photographs taken in 1965 (left; Direcao Geral de Servios Florestais e Agrcolas)and 1995 (right; Centro Nacional de Informao Geogrfica) of the river course at sector Vilar

Seco Salgueiro (Mogadouro). The topmost zone corresponds to the sample sites Quinta doAzinhal/Castro Vicente-Portela of sector Remondes of this study, the area located at the bottomcorresponds to sample sites Salgueiro/Legoinha of sector Parada (cf. Appendix 1). The extension ofareas covered with not cultivated vegetation has significantly increased over the last 40 years.


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2.2 Sampling

Fieldwork was conducted during the months May, June and July 2002.The part of the river valley considered here is limited, upstream, by the bridgeof national road EN 216 which crosses the river between the cities of Macedode Cavaleiros and Mogadouro, also known as Ponte de Remondes, with thecoordinates 648 west of Greenwich / N 4124 (UTM 29TPF835854), and thedistance from Sabor rivers mouth amounts to some 45 km. Downstream, thelimit of the study area is defined by the section Felgar-Pices, with thecoordinates W 659 / N 4115 (UTM 29TPF693680), at a distance ofapproximately 16 km from the river mouth. Thus, the extension of the rivercourse studied here totals approximately 29 km (Fig. 2.10).

The sample plots were arranged in a way to allow for representing thevarious vegetation communities at different height levels, in a roughly

perpendicular orientation in relation to the riverbed, at both sides of the river.A particular difficulty resided in an exact delimitation of entirely homogeneous

Fig. 2.10. Map of the sampled area in the downstream section of Sabor river.Sample sites are indicated with green dots, villages are highlighted in red.


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sample plots, as a result of the complex patchy arrangement of vegetation. Inorder to permit that the sampled vegetation stands were as homogeneous aspossible within each relev, and at the same time could yield a more validrepresentation of the local diversity, the dimension of sample plots wasconstantly fixed at 10 x 10 m2. Localization was proceeded using a compass

and topographical maps at the scale 1 : 25 000 (IGE, 1995, 1996) to enabledetermination of UTM grid coordinates. Altogether, 109 relevs were taken(Appendices 1 and 2).

Each relev was accompanied by a description of basic topographicalparameters (coordinates, altitude, exposition, slope), total cover of each standwas estimated, and all species occurring within the sample plot wererecorded. Of those species that could not be identified immediately in situ,herbarium specimens were collected (whole plants or distinctive parts ofbigger plants), labelled with collection number (date, site code and accessnumber) and stored and carried in plastic bags. The specimens collected

during each day were prepared for pressing and drying in a wooden plantpress, arranged inside sheets of dried newspapers. Moist papers weresubstituted daily for dry until complete dryness was achieved. Thesespecimens2 were used for taxonomical identification, resorting to specificliterature (CASTROVIEJO et al., 1986, 1990, 1993, 1997, 1999, 2000, 2001;FRANCO,1971,1984;FRANCO &AFONSO,1998;GONZLEZ,1994;JAHNS,1982;ROLLN,1981;VALDS ET AL., 1987).

Visual estimates of cover-abundance were assigned to each specieson the five-point Braun-Blanquet scale:

+ rare isolated individuals, very small cover

1 scarce to scattered individuals, cover < 5%

2 abundant, cover between 5 25%

3 , cover between 25 50%



Stratification was recorded by attributing, in each relev, a layer to everypresent species:

(1) herbaceous layer(2) dwarf shrub layer(3) shrub layer(4) tree layer

Note that for a given species only the most representative layer wasconsidered, for example, if within a forest or scrubland community both adult

2Voucher samples of all collected species are deposited in the herbarium ofEscola SuperiorAgrria in Bragana, Portugal (international code: BRESA)


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and juvenile individuals of one species occurred, but the former dominated,only adults were specified.

As one important parameter for the structural analysis, to each speciesthe respective life form, as proposed by RAUNKIAER (e.g. KERSHAW, 1973),

was attributed, resorting to the classification proposed by FRANCO (1971,1984) and FRANCO & AFONSO (1998). Thus the following life forms areconsidered:

(1) therophytes (annual plants completing life history fromseed to seed within one favourable season

(2) hemicryptophytes (perennating buds at ground level)

(3) chamaephytes (perennating buds or shoot apices

borne close to ground, often lignified)(4) nanophanerophytes ( < 2m)

(5) microphanerophytes ( 2 8m)

note: epiphytic phanerophytes were included here

(6) mesophanerophytes ( 8 30m)

(7) macrophanerophytes (> 30m)

(8) geophytes (perennating buds below ground level rhizomes, bulbs or tubers)

(9) hydrophytes (perennating buds under water)

Land use intensity was classified according to an estimated four-point scale:

(1) uncultivated areas (no visible traces of cultivation, or only extensivepasture)

(2) abandoned cultivated areas, but still with marked agrarian traits(3) presently cultivated areas, apparently low-frequent treatments

(ploughings)

(4) presently cultivated areas, frequent treatments (ploughings)

Additionally, to each sampled vegetation stand an a priori community typewas attributed, according to the following typification:

(1) Includes all wood formations with stem height greater than twometres, in the region mainly micro- or mesoforests of micro- ormesophanerophytes, not exceeding 24 m (RIVAS-MARTNEZ et al.,2002; TOMASELLI, 1982). Samples designated as BO (bosque)

(2) Forestations, including all planted wood formations. DesignationFO


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(3) All scrubland communities were included in this category, only

alluding to structure and physiognomy in the sense of a communityof wooden, mostly xerophyllous nanophanerophytes andchamaephytes with an aerial system that cannot be distinguished

clearly into stem and branchage, with size and dimensiondepending on degradation state (Tomaselli, 1982). Thus thiscommunity type subsumes both the communities known asmaquias (high scrubs) and garrigues (dwarf scrubs). Designatedas MA (matagais)

(4) Commercial groves of olive and/or almond trees, but sometimesexhibiting varying degrees of succession, according to treatmentfrequency. Designation PO (pomar)

(5) Riparian communities: all vegetation stands of floodplain directly

affected by flooding events. RI

(6) Rupicolous communities: vegetation stands on bare rockysubstrate, not considering the communities located in floodplain,which are included in 5. Designation RU

2.3 Data analysis

2.3.1 Species richness

A first approach to describe the diversity of the vegetation was to examine ifvariations in total species numbers could be attributed to some kind ofdisturbance or environmental gradient, and to this end the followingparameters were used:

- Community type- Altitude- Distance from riverbed- Slope

- Exposition- Land use intensity

To examine eventual correlations of species numbers with the mentionedfactors, a comparison of means was carried out, applying one-way ANOVAwith the program Minitab for Windows, release 13 (MINITAB, INC., 2002) tocheck for significance.

To check the relation between species numbers and distance, the distance ofeach sample plot relative to the riverbed was determined from the

topographical maps (IGE, 1995, 1996) and the following distance classeswere established:


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CLASS DISTANCE

1 < 20 m2 20 50 m

3 51 150 m4 151 300 m5 > 300 m

The altitude was also determined resorting to the topographical maps, and thefollowing classes were defined:

Exposition and slope were measured in situ with a compass, equipped with atool to determine inclination, to built the following classes:

2.3.2 Floristic-structural analysis

For the structural characterization of the vegetation the methodologicalscheme proposed by CRESP et al. (2000, 2001a, 2001b, 2001c) was applied,which focuses on the floristic and structural combinations within a given set ofplant communities. It consists in a transformation of the information obtainedthrough the sampling of vegetation, into numerical matrices that allow forcomparative multivariate analysis. Objective is the characterization of thestructural behaviour of the vegetation in consideration.These numerical matrices can be distinguished into two categories, in thefollowing designated as basic structural matrices (BSM) and contingencymatrices.

CLASS ALTITUDE

1 < 150 m2 150 199 m

3 200 249 m4 250 299 m5 300 349 m6 > 350 m

CLASS EXPOSITION

1 northern(315 - 45)2 eastern

(45 135)3 southern

(135 225)4 western

(225 315)

CLASS SLOPE

1 < 102 11 203 21 304 31 405 > 40


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Arrangement of basic structural matrices (BSM)

The first step of the mentioned structural analysis is based on the creation ofmatrices, which contain the basic information relating to the structure of

vegetation. Structure of a given plant assemblage is considered, in thepresent context, to have the following main qualities (e.g. KERSHAW, 1973):

- the horizontal arrangement, i.e. the spatial distribution of species withinan area

- the vertical arrangement of species or stratification

The spatial distribution can be focussed by two aspects, taking into accountonly the presence/absence of species, or the frequency of individualsbelonging to these species, hereby expressed as the abundance of each

species in a given stand. As far as the vertical arrangement is concerned, thefloristic-structural behaviour of communities is examined with an emphasis onthe life forms constituting the respective plant assemblages, as an indicationof the inherent potential to develop different layers, expressing at once theadaptation of communities to the ecological conditions in force (CRESP et al.,2000). The characterization of the actual, and not only the potential, layer foreach species constitutes an extension in relation to the originalmethodological framework, whose applicability and eventual advantages shallbe tested in the course of the present work.

- Diversity BSM

The matrix containing the diversity data, as all the other matrices, is organizedin a way that rows correspond to the species (382), and columns representthe sample plots (109). The diversity BSM is based on the presence(numerical value 1) and absence (0) of species within each sample. As thiskind of nonmetrical data is unsuitable for correlation or distance calculations(e.g. HAIR et al., 1995), this matrix must be prepared in a way to allow fordisposal of metrical values. The method used for this adaptation consists inusing an importance scale, based on the importance of each species within inthe whole set of samples. To this end, the presence value of each species is

replaced by the respective mean value over the totality of samples, followingthe method proposed by CRESP et al. (2000, 2001a, 2001b, 2001c). Tab. 2.4shows an example of data treatment. This matrix, as all the following ones,was standardized, by converting each variable to standard scores (Z scores),to permit comparison of the different variables measured on different scales(HAIR et al., 1995) and the construction of conjoint matrices.


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- Abundance BSM

As in the present case the Braun-Blanquet scale was applied (cf. 2.2), usingthe index + for extremely scarce species, all indices were substitutedaccording to the following scheme:

+ 1 1 2 2 3 3 4 4 5 5 6

To the absent species the value 0 was attributed. This BSM was alsostandardized.

plot

species 1 2 3 4

mean

value

1 0 1 1 1 0,75

2 1 0 1 0 0,50

3 0 1 1 0 0,50

4 0 1 0 0 0,25

5 0 0 0 1 0,25

plot

species 1 2 3 4

1 0,00 0,75 0,75 0,75

2 0,50 0,00 0,50 0,00

3 0,00 0,50 0,50 0,00

4 0,00 0,25 0,00 0,00

5 0,00 0,00 0,00 0,25

Tab. 2.4. Transformation of presence/absence of

species into importance scale in diversity BSM. Forfurther use, this matrix is standardized to Z scores.

plot

species 1 2 3 4

1 3 + 4

2 1 2

3 3 5

4 2

5 +

plot

species 1 2 3 4

1 0,00 4,00 1,00 5,00

2 2,00 0,00 3,00 0,00

3 0,00 4,00 6,00 0,00

4 0,00 3,00 0,00 0,00

5 0,00 0,00 0,00 1,00

Tab. 2.5. Transformation of abundance of species expressedin Braun-Blanquet scale in metrical scale. After trans-formation, this matrix is standardized to Z scores


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- Stratification BSM

The index attributed to the stratum of each species in each sample plot (2.2)was used directly to construct the BSM, and again the value 0 was attributed

to absent species. The matrix was standardized as described above (Zscores).

- Conjoint matrix of diversity and abundance (BSMDA)

For each sample, a mean value for every species entry was calculated fromthe corresponding entries of the standardized BSM of diversity andabundance. The result was again a matrix composed of 109 columns and 382rows. Table 2.6 illustrates a part of the original calculations.

- Conjoint matrix of diversity, abundance and stratification(BSMDAS)

To compute the entries of the conjugate matrix of all three structuralparameters, the same procedure as before was applied, only that all threecorresponding entries were used. This matrix condenses all three parametersin a single matrix.

Plot: BO1 BO10 BO11species Abun-

dance

Diver-

sity

New

mean

Abun-

dance

Diver-

sity

New

mean

Abun-

dance

Diver-

sity

New

mean

1 -0,232 -0,220 -0,226 -0,277 -0,265 -0,271 -0,337 -0,308 -0,323

2 -0,232 -0,220 -0,226 -0,277 -0,265 -0,271 -0,337 -0,308 -0,323

3 -0,232 -0,220 -0,226 -0,277 -0,265 -0,271 -0,337 -0,308 -0,323

4 -0,232 -0,220 -0,226 -0,277 -0,265 -0,271 -0,337 -0,308 -0,323

5 -0,232 -0,220 -0,226 -0,277 -0,265 -0,271 -0,337 -0,308 -0,323

species BO1 BO10 BO11

1 -0,226 -0,271 -0,323

2 -0,226 -0,271 -0,323

3 -0,226 -0,271 -0,323

4 -0,226 -0,271 -0,323

5 -0,226 -0,271 -0,323

Tab. 2.6. Extract from the calculations for the BSMDA. The mean value for each entry of the twomatrices was calculated, giving origin to a matrix with equal number of columns (plots) and rows(species)


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Arrangement of contingency matrices

The contingency matrices are created by a crosstabulation of the numericalinformation contained in the BSM with another variable. In the present case,two entries were used: life forms and frequency classes.

- Life form contingency matrix

The species entries of the various BSM were sorted by life forms, and themean value for each life form was calculated for each sample plot. In thiscase, a matrix composed of 109 columns and nine rows was obtained. SeeTable 2.7 as an example of computation.

- Frequency class contingency matrix

To determine the frequency of species in the whole data set, the number ofoccurrences of each species in the 109 sample plots was counted and thepercentage was calculated; for example, a species that occurred in only twoplots within the whole data set, had a frequency of 1,8 %, a species that hadbeen registered in 59 plots had a frequency of 54,1 %. To establish classes offrequency in five percent-intervals, the whole matrices where sorted by thespecies frequency, and the mean value of all species entries that whereenclosed in one of the established classes (0 5 %, 5 10 %, 10 15%, ,45 50 %, > 50 %) was calculated, in the same way that was applied for thelife form contingency matrix, i.e. for every single sample plot. After calculation

of the different class values for all relevs, the new contingency matrix wasmade up of 109 columns (plots) by 11 classes.

plotlife

form species BO1 BO10 BO11

6 276 -0,231 -0,267 -0,322

6 277 7,130 6,549 5,768

6 278 -0,231 -0,267 -0,322

mean 2,223 2,005 1,708

7 137 -0,231 -0,267 -0,322

7 182 6,058 4,709 3,634

7 252 -0,231 -0,267 -0,322

mean 1,866 1,392 0,997

8 5 -0,231 -0,267 -0,322

8 6 -0,231 -0,267 -0,322

8 7 -0,231 -0,267 1,389

Tab. 2.7. Extract from the BSMDAS, sorted by life forms,showing the mean values for macrophanerophytes (7) forthe first three sample plots.


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Analysis of matrices

The information contained in the before mentioned matrices was subjected to

a multivariate analytical scheme based on similarity analysis (clusteranalysis), ordination (principal component analysis, PCA) and discrimination(discriminant canonical analysis). The cluster and principal componentanalyses were conducted with the program MultiVariate Statistical PackageMVSP 3.1 for Windows (KOVACH COMPUTING SERVICES, 2002), anddiscriminant analysis was conducted with the Statistical Package for SocialSciences for Windows 11.0.1 (SPSS, INC., 2001).In addition to these statistical analyses, a descriptive analytic approach basedon life form, frequency classes and determination of maximal expressiveamplitudes was carried out, both focussing the apparent communities,established a priori (cf. 2.2), and the clusters derived from the PCAordinations.

- Cluster Analysis

Purpose of this analysis is the determination of similarity within the given setof samples, based on a set of numerical techniques that lead to a division ofsamples into discrete groups (clusters). The method used here was based oncalculation of simple Euclidean distance and similarity measures. This methodis essentially exploratory and is useful to develop hypotheses concerning thenature of data (HAIR et al., 1995). Cluster analysis has been applied to each

basic structural matrix, and subsequently a similarity analysis of a matrixbased on the mean values for each species entry, of all plots that were part ofthe same community type, has been conducted for all BSM.

- Ordination by Principal Component Analysis (PCA)

Ordination was used to define aneventual underlying structure inthe data matrices. The PCA of thedata matrices consisted in ananalysis of eigenvalues based on

a Pearson correlation matrixcalculated from the originalprepared data matrices, thussimplifying the set of initialvariables through determination ofa reduced set of variables, alsocalled factors (HAIR et al., 1995).In the present case, the PCAconsidered the first threecorrelation factors.The spatial distribution of samples

within this three-dimensionalfactor room can show a

Fig. 2.11. Definition of the eight portions of athree-factorial space as determined by the value

0 of each factor (CRESP

, 1999).


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continuous distribution or divergent groups of samples. The spatial distributionof this expressive cloudallows for a determination of correlation groups, asproposed by CRESP (1999) for a two-factorial situation, and CRESP et al.(2001b) for three factors, in a way that a distinction of samples can be madeaccording to their arrangement within a space (as expressed by the three

factors) divided into eight portions that are separated by the value 0 of eachfactor (Fig. 2.11). The determination of the location of a sample relative to thisspace is simply based on the sign of the factors for each sample, so that foreach sample the attribution of one out of at most eight correlation groups ispossible (Tab. 2.8).

- Clusters

To determine the distance between the various correlation groups that have

been determined by means of ordination of the different BSM, the sampleswere arranged according to their correlation group, and the mean value ofentries was calculated for each species, and for all groups. This new matrixwas used to determine Euclidean distance between the correlation groups,using cluster analysis. Based on their linkage as visualized by the respectivedendrogram, correlation groups could be combined to form apparent clustersin relation to their floristic-structural behaviour. These clusters correspond tothe concept of tendencies of behaviour in the methods original terminology(CRESP et al., 2001a, 2001b; FERNANDES, 2001), and facilitate thedetermination of correlative behaviour between the examined communitiesaccording to the descriptive scheme exposed in the following.

- Distribution of cluster over apparent communities, land useintensity and geographic sectors

The contribution of the different apparent community types to each consideredcluster (behavioural tendency) was expressed as the percentage of samplescomprised by each community type within all the samples forming one cluster.The results are shown as stacked column charts. Similarly, the percentage ofsamples related to a certain class of land use intensity within each cluster wascalculated. Finally, the sample plots were sorted, according to theirgeographical position, into three groups, or geographical sectors (see

Appendix 1), and the percentage of samples belonging to the different sectors

Factor 1 Factor 2 Factor 3 Correlationgroup

- + + 1+ + + 2+ - + 3- - + 4

- + - 5+ + - 6+ - - 7- - - 8

Tab. 2.8. Attribution of correlation group of samples according to thesign of the first three factors (adapted from CRESP, 1999).


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within each cluster was computed in the same way; results are shown in thesame form.

- Distribution of life forms

The proceeding was the same for all structural parameters considered: first,the sample plots of every BSM were sorted by clusters, that is the samplesbelonging to the same cluster of behavioural tendency were joined. Next themean value of all entries belonging to one cluster was computed for each lifeform category, and this was done for all respective clusters. The same type ofcalculation was carried out based on the apparent communities, where thesamples were grouped according to their attributed community, andsubsequently the mean value was calculated for each life form and all

communities. The results are shown as three-dimensional line charts, with therespective mean values as ordinate and the life form category as abscissa.

- Distribution of frequency classes

Again, the mean value of each frequency class, within each sample group,was calculated; graphic representation is as above.

- Maximal Expressive Amplitudes

The maximal expressive amplitude is a concept borrowed from taxonomicalanalysis, with the purpose to determine the maximal morphologicalamplitudes, i.e. the highest capacity of variability in relation to themorphological expression (CRESP, 1999). In its adaptation to describe (plant)communities, the amplitude is expressed as the interval of greatest variabilityin relation to the structural parameters of the considered vegetation (CRESP etal., 2001a).Maximal expressive amplitudes were calculated for each group (tendencycluster or community), determining first the difference between the highestand lowest value in the considered BSM over all species within each sampleplot, and then calculating the difference between the lowest and highest of the

resulting values within each group of samples. This indicator is represented inclustered column charts.

- Discriminant Canonical Analysis

The discriminant analysis aims to estimate the relationship existing between asingle categorical dependent variable and a set of independent metricalvariables (HAIR et al., 1995); to each sample plot a categorical group wasattributed (community type, land use intensity, geographical sector in thepresent case), and the objective is to explain the group membership of eachsample by means of discriminant functions resorting to the set of independent

variables. For the discriminant analyses, only the conjoint matrix of diversity,abundance and stratification (BSMDAS) was used, and the independent


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variables were either the mean structural value for life forms or for frequencyclasses. The method applied was forward stepwise, and to assess the level ofsignificance, the discriminant measure Wilks was used as selectioncriterion.Additionally, to allow for a better discrimination, the occurrence of species

within each life form, or within each frequency class respectively, wasdetermined by counting the present species in the original diversity BSMwithin one life form or class and each sample, and this data matrix wasstandardized to Z scores. An example for this is shown in Table 2.9 for thefrequency classes. This matrix was joined to the original frequency classmatrix (or to the original contingency matrix for life forms, in the case of lifeform count) and the new contingency matrix with twice as much the number ofcolumns was used for discriminant analysis.

- Assessment of intensity of land use

To further analyse the impact of agricultural intervention on the plantcommunities, the incidence of the different types of intervention as definedabove was expressed, in a very rough approximation, as the correspondingpercentage of sites of one intervention type within each sector (see Appendix1).

number of species present of frequency class:

plot 0-5% 5-10% 10-15% 15-20% 45-50% >50%

BO1 4 3 3 5 2 1

BO10 2 2 3 5 3 5

BO11 4 8 2 8 4 5

BO12 1 2 3 2 2 2

BO13 1 3 6 7 3 4

plot 0-5% 5-10% 10-15% 15-20% 45-50% >50%

BO1 -0,042 -0,323 -0,178 0,198 0,099 -1,472

BO10 -0,428 -0,568 -0,178 0,198 1,082 1,202

BO11 -0,042 0,901 -0,582 1,336 2,064 1,202

BO12 -0,621 -0,568 -0,178 -0,939 0,099 -0,804

BO13 -0,621 -0,323 1,035 0,957 1,082 0,534

Tab. 2.9. Arrangement of the matrix containing the number of species presentwithin the different frequency classes, used for discriminant canonical analysis.


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3. RESULTS

3.1 Species richnessThe floristic catalogue of the studied area, which is shown in appendix 3, iscomposed of 382 taxa, distributed among 64 families. Tab. 3.1 and Fig. 3.1show the distribution of species among families. The most representativefamilies are Compositae, Gramineae, Leguminosae, Umbelliferae andCaryophyllaceae.

With regard to life forms, the biggest part of species pertains to therophytes(45%) and hemicryptophytes (30%), followed by phanerophytes (13%),chamaephytes (6%) and geophytes (6%). Only one species pertained to thehydrophytes, occurring in a sample plot recently dried, as a remnant ofaquatic vegetation. Fig. 3.2 shows the distribution of life forms over the totalityof sample plots, and the distribution of life forms according to the differentcommunity types.

Families % per family species nr. perfamily

total speciesno.

Compositae 12,6 48 48

Gramineae 12,3 47 47

Leguminosae 11,5 44 44

Umbelliferae 5,8 22 22

Caryophyllaceae 5,2 20 20

Cruciferae 4,2 16 16

Labiatae, Liliaceae 3,9 15 30

Scrophulariaceae 2,9 11 11

Ranunculaceae 2,6 10 10

Polygonaceae, Rosaceae, Rubiaceae 2,4 9 27

Geraniaceae 1,8 7 7

Cistaceae, Oleaceae 1,6 6 12

Crassulaceae, Cyperaceae, Plantaginaceae 1,3 5 15

Boraginaceae, Papaveraceae 1,0 4 8

Campanulaceae, Euphorbiaceae, Fagaceae,Juncaceae, Polypodiaceae 0,8 3 15

Amaranthaceae, Anacardiaceae,Caprifoliaceae, Convolvulaceae, Dipsacaceae,Ericaceae, Lythraceae, Primulaceae,Resedaceae, Rutaceae, Salicaceae,Solanaceae 0,5 2 24

others 0,3 1 26

Tab. 3.1. Distribution of species among families.


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mean species numbers per comm unity

0

10

20

30

40

50

60

70

BO MA PO RI RU

co m mu n i ty t yp e

Fig. 3.3. Mean species numbers in the differentcommunities.

0%

5%

10%

15%

20%

25%

30%

Compositae

Gramineae

Leguminosae

Umbelliferae

Caryophyllaceae

Cruciferae

Labiatae

Liliaceae

Scrophulariaceae

Ranunculaceae

Polygonaceae

Rosaceae

Rubiaceae

others

family

percentage

Fig. 3.1. Distribution of species among families

Distribution of species over life forms

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

therophytes

hemicryptophytes

chamaephytes

phanerophytes

geophytes

hydrophytes

life form

life form percentage in communities

0%

10%

20%

30%

40%

50%

60%

70%

bo fo ma po ri ru

community type

therophytes

hemicryptophytes

chamaephytes

phanerophytes

geophytes

hydrophytes

Fig. 3.2 A) Percentage of species pertaining to the different life forms over the totality of sampleplots. B) Distribution of life forms within the different community types.

Therophytes provide themost frequent species in thescrublands, groves, ripariancommunities and also inforestation and rupicolous areas,

whereas in woodlands, thephanerophytes are the mostfrequent species.Hemicryptophytes show a morehomogeneous distribution over allcommunities. Geophytes are lessfrequent in riparian communities.

Considering the speciesnumbers in the differentcommunity types1, significantdifferences were found (F =

17,66; p < 0,01; df = 104; seeFig. 3.3), and ripariancommunities had the highestspecies numbers, followed bythe grove communities,woodlands, scrublands andrupicolous communities. Inrelation to the difference ofnumber of species pertainingto the various life forms, there

1 Here and in the following analyses of this chapter, community type FO, which was

only represented by one sample, was included in the woodland type (BO).


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was significance in the case of therophytes (F = 23,39; p < 0,01; df = 104),with highest means in riparian communities, followed by groves, scrublands,rupicolous communities and woodlands. Hemicryptophytes showed a similarbehaviour (F = 15,69; p < 0,01; df = 104), whereas the phanerophytes weremost frequent in the woodlands (with F = 8,83; p < 0,01; df = 104), followed by

rupicolous, riparian, scrubland and finally orchard communities.

The total species number in all community types was significantly different forthe various altitude classes (F = 4,98; p < 0,01; df = 103). The highest speciesnumbers are registered in the lowest altitudes, and the mean species numberdiminished with increasing altitude (Fig. 3.4). But after excluding the ripariancommunities from the data set, there was no significance detected. Analysingthe variation of the different life forms, again with all communities, only thetherophytes showed the same correlation (F = 6,35; p < 0,01; df = 103).

In relation to thedistance of sample plotsfrom the riverbed, there waslikewise significantdecrease of speciesnumber with increasingdistance (F = 18,33; p 50

-0.500

0.500

1.500

2.500

3.500

4.500

meandiversity(stand.)

% class

Tendency clusters (diversity BSM)

T 1

T 2

Fig. 3.13. Contribution to diversity of the differentfrequency classes, in tendency clusters derived

from PCA of diversity BSM.

tendency clusters (diversity BSM)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

1 2 3 4

land use intensity

T 1

T 2

diversity tendencies in geographical sectors

0%

10%

20%

30%

40%

50%

Remondes Parada Felgar

sector

T 1

T 2

Fig. 3.14. A) Representation of diversity tendencies in the different land use categories. B)Distribution of diversity tendencies among the geographical sectors.


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thero

hemicrypto

chamae

nanophan

microphan

mesophan

macrophan

geo

hydro

-0.400

-0.200

0.000

0.200

0.400

0.600

0.800

1.000

meanabundance(stand.)

life form

T 1

T 2

T 3

T 4

Fig. 3.15. A) Mean abundance values over thedifferent life forms as derived by PCA-ordination ofthe abundance BSM.

0-5 5-

10

10-

15 15-2020-25

25-

3030-

3535-

4040-

4545-

50>

50

-0.500

0.000

0.500

1.000

1.500

2.000

2.500

meanabundance(stand.)

frequency class

T 1

T 2

T 3

T 4

B) Mean abundance values over the differentfrequency classes.

Abundance

The four clusters derived from the abundance BSM showed a more complexbehaviour (Fig. 3.15A):

- cluster T1 shows highestabundances for therophytesand hemicryptophytes,compared with the othertendencies, and the lowest forchamae- andnanophanerophytes; themicro- and mesophanerophyticlife forms are the mostabundant categories within thistendency

- T2 is marked by highabundance of chamaephytesand nanophanerophytes,highest values for both meso-and macrophanerophytes, butreduced abundance ofmicrophanerophytes

- T3 and T4 have reducedamplitudes in relation to theabundance values of differentlife forms, but they exhibithigher abundance fortherophytes than the other twotendencies, the lowest levelsfor all phanerophytic life forms, but a relative peak fornanophanerophytes in T3 and for micro- and mesophanerophytes in T4

The corresponding contribution of the different frequency classes toabundance is shown in Fig. 3.15B:

- T1 shows highest abundance in the classes comprising species withfrequencies ranging from 5 to 15 % and in the class 40 45 %

- T2 exhibits a markedly high abundance in the class of species with 30 35% frequency and in all classes greater than 40 %

- The tendencies T3 and T4 have a homogeneous behaviour, withincreasing abundance of species of increasing frequencies, with theonly difference of T4 showing slightly reduced abundances in theclasses > 45%


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The representation among the apparent communities showed a markedsplitting of tendencies (Fig. 3.16):

- T1 occurs exclusively in riparian communities

- T2 is the prevalent tendency of woodlands, being also represented inthe scrubland and grove communities, and to some degree withinrupicolous communities

- T3 is almost limited to the scrubland and the grove communities

- T4 is a mainly riparian tendency, with weak representation in grovesand rupicolous communities

In relation to land use (Fig. 3.17), all tendencies are perfectly represented inthe uncultivated areas, T2 is still represented in abandoned cultivations, andT3 is the major tendency represented in both types of cultivated areas, as isT4 in a minor degree. The geographical distribution (Fig. 3.18) reveals theabsence of T1 from the sector Parada and its highest proportion in Felgar, thehighest representation of T2 and T4 is in the sector Parada, and T4 is morefrequent in sector Felgar.

0%

20%

40%

60%

80%

100%

bo fo ma po ri ru

community type

T 1

T 2T 3

T 4

Fig. 3.16 Representation of abundance tendencies

in the different communities

0%

20%

40%

60%

80%

100%

1 2 3 4

land use intensity

T 1

T 2

T 3

T 4

Fig. 3.17. Representation of abundancetendencies in different land use categories

0%

10%

20%

30%

40%

50%

60%

70%


sector

T 1

T 2

T 3

T 4

Fig. 3.18. Representation of

abundance tendencies in thegeographical sectors.


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Stratification

The tendency clusters derived from the stratification data showed also adistinct pattern (Fig. 3.19):

- in T1, greater stratification values can be attributed to chamaephytes,nanophanerophytes, whereas micro-, meso- and macrophanerophyteshave comparably smaller values; this is also the tendency with highestvalues of geophytes

- T2 exhibits reduced values for chamaephytes andmacrophanerophytes, and a maximum for micro- andmesophanerophytes

- in T3 the extremely reduced contribution of chamaephytic,

nanophanerophytic and macrophanerophytic layers is notable, as wellas a maximum of stratification values originating from micro- andmesophanerophytes; hemicryptophytic life forms reach highest valuesin this tendency

With respect to the frequency of species (Fig. 3.20), the following can beobserved:

- T1 shows a roughly linear increase of stratification with frequencyclasses

- T2 shows increasingly higher stratification as frequency increases, anda relatively maximum is reached in the class comprising 40 45% offrequency, after which a drastic decrease of stratification of higherfrequent species is observed

thero

hemicrypto

chamae

nanophan

microphan

mesophan

macrophan

geo

hydro

-0.40

-0.20

0.00

0.200.40

0.60

0.80

1.00

1.20

meanstratum(

stand.)

life form

T 1

T 2

T 3

Fig. 3.19. Mean values (expression) of stratification among life forms.


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- T3 has relatively higher stratification values in the class 40 45%, withmore or less equal values for the resting classes

The distribution among community types (Fig. 3.21) reveals the clusters 2 andT3 as tendencies basically related with riparian communities, and T1 asincident with the terrestrial woodland, scrubland and grove communities.Considering the land use, again all three clusters are best represented in theuncultivated areas (T2 and T3 exclusively), the only tendency clusterrepresented in the agrarian areas is T1, and in relation to the geographical

distribution, T1 and T2 are common to all three sectors, whereas T3 iscompletely absent from the sector Parada and has its highest proportionwithin sector Felgar (Fig. 3.22 and 3.23).

0-5

5-10

10-15

15-20

20-25

25-30

30-35

35-40

40-45

45-50

>50 T 1

T 2T 3

-0.500

0.000

0.500

1.000

1.500

2.000

2.500

meanlayer(stand.)

frequency class (%)

T 1

T 2

T 3

Fig. 3.20. Mean values (expression) of stratification among the differentfrequency classes.

Stratification

0%

20%

40%

60%

80%

100%

bo fo ma po ri ru

community type

T 1

T 2

T 3

Fig. 3.21. Representation of stratificationtendencies in different communities.

0%

20%

40%

60%

80%

100%

1 2 3 4

land use intensity

T 1

T 2

T 3

Fig. 3.22. Representation of stratificationtendencies in different land use categories.

0%

20%

40%

60%

80%


sector

T 1

T 2

T 3

Fig. 3.23. Representation ofstratification tendencies in thegeographical sectors.


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BSMDA

In the conjoint data matrix of diversity and abundance, three tendencies werederived, and these had the following properties (Fig 3.24):

- T1 shows a clear prevalence of nanophanerophytic, meso- andmacrophanerophytic life forms, the chamaephytic level and geophyticlife forms show also relatively high values. Compared to the othertendencies, therophytes are least represented within T1

- High expression for therophytes, chamaephytes andnanophanerophytes, and also for geophytes are detected in T2

- T3 shares with T2 the high values for therophytes, but all other lifeforms appear reduced, with the notable exception ofmesophanerophytes, and, to some extent, microphanerophytes

The behaviour of frequency classes is analogous to that exposed in theBSMDAS case below. With respect to the proportions of these clustersrepresented within the apparent communities (Fig. 3.25), a certain restrictionof T3 to riparian communities becomes patent, as becomes the fact that thewoodland communities pertain nearly all to the cluster T1, which is alsorepresented within the scrubland, grove and rupicolous samples. The majortendency in scrublands and groves is, however, corresponds to cluster T2.The distribution of these clusters among the land use categories bears that T2is the most robust tendency, as it has equal distribution in all cases, whereas

T1 and T3 are more restricted to uncultivated areas (Fig. 3.26). In terms ofgeographical distribution, T1 is most frequent in the Parada sector, with

thero

hemicrypto

chamae

nanophan

microphan

mesophan

macrophan

geo

hydro

-0.400

-0.200

0.000

0.200

0.400

0.600

0.800

meanvalue(stand.)

life form

T 1

T 2

T 3

Fig. 3.24. Representation of expression of life forms within the conjoint matrix BSMDA.


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reduced representation namely in the Felgar sector, T2 has its highestrepresentation in the Felgar sector, and T3 is more homogeneouslydistributed among the three sectors (Fig. 3.27).

0%

20%

40%

60%

80%

100%

bo fo ma po ri ru

community type

T 1

T 2

T 3

Fig. 3.25. Representation of tendency clusters BSMDA withinthe different communitiy types.

0%

20%

40%

60%

80%

100%

1 2 3 4

land use intensity

T 1

T 2

T 3

Fig. 3.26. Representation of tendency clusters BSMDAwithin the different land use categories

0%

20%

40%

sabor thesis

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