Seed size, shape and persistence in soil: a test on Italian

Seed size, shape and persistence in soil: a test on Italian florafrom Alps to Mediterranean coasts

Bruno Cerabolini1*, Roberta M. Ceriani1, Marco Caccianiga2, Rossella De Andreis1 andBarbara Raimondi11Dipartimento di Biologia Strutturale e Funzionale, Università degli Studi dell’Insubria, via J.H. Dunant 3, 21100Varese, Italy; 2Dipartimento di Biologia, Sez. Botanica Sistematica, Università degli Studi di Milano, via Celoria 26,20133 Milano, Italy

Abstract

Seed size is a good predictor of seed persistence in soilfor British, Argentinean, Iranian and – to some extent –New Zealand species. It has been suggested that seedshape should also be linked to the ease of burial and,thus, to seed persistence, even if some studies failed toshow this. The relationship between seed size andshape and persistence in soil was analysed for 259species of the Italian flora, belonging to a wide range ofhabitats, from alpine pasture to limestone prairies andmeadows of the Prealps, and from woodlands toMediterranean maquis and garigues. Seed size wasrelated to persistence in soil in the same way as in mostother floras examined. Furthermore, seed shape washighly related to persistence in soil among the speciesanalysed, when considered both altogether and dividedamong the different habitats. Our results suggest that notonly seed size, but also seed shape, are key factors indetermining seed fate and seed persistence in soil.

Keywords: dormancy, grassland, Mediterranean scrub,seed bank, seed mass, seed shape, woodland

Introduction

Thompson et al. (1993) proposed a simple method topredict seed persistence in soil. They observed that,among 97 herbaceous species of the British flora,small and rounded seeds tended to persist in soil,while large and elongate or flattened ones weretransient in soil. They suggested that ease of burialand rates of predation could be the mechanisms

underlying the relationship between seed size andshape and persistence in soil. This hypothesis wassupported by earlier theoretical and experimentalwork (e.g. Grime et al., 1988; Venable and Brown,1988; Chambers et al., 1991), and Thompson et al.(1993) considered the possibility that the methodcould be applied to floras outside north-west Europe.The potential of this method is great, as collection oforiginal seed bank data, through either seedextraction or seedling emergence, involves a hugeeffort, both in time and in labour. Furthermore, thereis often a large disparity between the seed bankestimates from the two techniques (e.g. Brown, 1992),and results of a single investigation are frequentlyinconclusive.

The interest and the potential benefits concerningthis new inductive method led to several attempts tovalidate the model on species and/or communitiesother than those analysed by Thompson et al. (1993).Patterns reported for the British flora were confirmedby measurements carried out on 71 herbaceousspecies from temperate mountain grasslands ofArgentina (Funes et al., 1999) and on the flora ofArasbaran Protected Area in north-west Iran(Thompson et al., 2001). However, Leishman andWestoby (1998) and Moles et al. (2000) found that seedsize was not related to persistence in soil in Australiaand in New Zealand, respectively. The importance ofseed shape during the burial process has not beensupported by recent experimental data, except forThompson et al. (1993) and partly data of Peart (1984).All subsequent studies have failed to demonstratethat, for seeds of a given mass, a flattened orelongated shape might slow the rate of burial.

Among the reasons for the lack of relationshipbetween seed size and shape and persistence in soil,the following have been suggested (Thompson et al.,1993, 1998, 2001; Leishman and Westoby, 1998; Funes

Seed Science Research (2003) 13, 75–85 DOI: 10.1079/SSR2002126

*CorrespondenceFax: +39 0332 421554Email: [email protected]

et al., 1999; Moles et al., 2000): (1) differences in theevolutionary history of seed dispersal; (2) differencesin burial mechanisms and the relative importance ofseed predation; (3) differences in vegetation structure,disturbance and fire frequency.

In this study we try to assess whether or not seedsize and shape are related to persistence in soil among259 Italian species from a variety of habitats. Thisflora includes a wide range of biogeographicalregions from the Alps to the Mediterranean area, withquite separate evolutionary histories, so that thisstudy can be considered, at least partially, as anindependent test of the hypothesis proposed byThompson et al. (1993). We also try to analyse therelative influence of seed size and shape on persistentseed bank formation.

Materials and methods

Data on seed mass, dimensions and persistence in soilwere collected for 259 species of the Italian flora (165genera, 46 families). Species were chosen to consider awide range of habitats: alpine pastures, limestoneprairies and meadows of Lombardy Prealps, ground-flora of woodlands of Po Plain, Mediterraneanmaquis and garigues of Elba Island. The species listincluded herbs (forbs, grasses and sedges) andshrubs, belonging to almost all life forms (sensuRaunkiaer). From the biogeographical point of view,species can be divided into four main groups: (1)alpine and northern species (circumboreal and euro-siberian), (2) endemic species of Alps and ofLombardy Prealps, (3) temperate species, and (4)Mediterranean species.

Seed material was obtained from field collections.To quantify seed size, for each species a set of50–2000 air-dried mature seeds was weighed,excluding clearly non-viable or damaged diaspores.Seed length, width and depth were measured on 10seeds per species. Seed variance was then calculatedas a quantitative expression of seed shape, followingthe methods proposed by Thompson et al. (1993): theaverage length, width and depth were transformedso that length was unity and the variance of the newvalues was calculated. Measurements were almostalways carried out on the dispersule, according toThompson et al. (1993). Thus, grass caryopses weremeasured with the persistent lemmas and awns,while the nut of sedges was measured with itsutricle. The achenes of Asteraceae were measuredwithout the pappus, and in species with fleshy fruits(e.g. Vaccinium myrtillus and Fragaria vesca),measurements were made on isolated seeds.However, in those Fabaceae with indehiscentlomentum (e.g. Coronilla spp. and Hippocrepis comosa),measurements were carried out on the single-seeded

portion of the fruit, which represented the dispersalunit.

Information on seed dormancy and speciespersistence in soil was recorded from the literature(e.g. Kalamees and Zobel, 1997; Thompson et al., 1997;Jensen, 1998; Urbanska and Fattorini, 1998), or fromoriginal data collected through soil seed bankinvestigations and germination tests by the authorssince 1999. Species persistence in soil was definedaccording to a simple scheme in which three classesare distinguished (Bakker, 1989; Thompson et al.,1997): transient species, persisting for less than 1 year;short-term persistent species, persisting for more than 1but less than 5 years; and long-term persistent species,persisting for at least 5 years.

Differences in seed weight and shape betweenlong-term persistent species and transient and short-term persistent ones were tested using a t-test inSYSTAT 10 for Windows (SPSS Inc., Chicago, IL). Seedweights were log transformed before statisticalanalysis.

Results

Seed mass ranged from 0.01 to 105.60 mg, whilevariance ranged from 0.0014 to 0.3298 (data inAppendix 1). This is a wider range of seed variancethan that recorded in all previous studies (Thompsonet al., 1993, 2001; Leishman and Westoby, 1998; Funeset al., 1999; Moles et al., 2000).

In our dataset, 150 species were classified ashaving transient seeds (seed bank type 1), 45 wereclassified as having short-term persistent seeds (seedbank type 2) and 34 were classified as having long-term persistent seeds (seed bank type 3). The seedbank type of 30 species can not be determined atpresent, owing to insufficient or contradictoryinformation.

Almost all the species with long-term persistentseeds were located inside the boundary indicated byThompson et al. (2001) (continuous line, Fig. 1). Onlythe persistent sedge, Carex sylvatica, was far outsidethis boundary, being characterized by a relativelyhigh variance. However, this discrepancy may only beapparent; the utricle of C. sylvatica has a very longbeak (up to 3.5–4.0 mm) that is probably lost beforeburial. Transient species and short-term persistentspecies were widely scattered across the range of seedsizes and variances, and included many species withlight and/or rounded seeds.

Long-term persistent species tended to have smalland spherical seeds, while transient species and short-term persistent species had bigger, more flattenedand/or elongate seeds (one-tailed t-test; Table 1), andthis trend was clearly confirmed when herbaceousspecies and shrubs were considered separately.

76 B. Cerabolini et al.

Seed size, shape and persistence: Italian flora 77

Figure 1. Relationship between seed mass and shape (variance of seed dimensions) in 259 species from the Italian flora. (●)Long-term persistent species (seed bank type 3); (�) short-term persistent species (seed bank type 2); (�) transient species(seed bank type 1); (x) species whose seed bank type could not be determined, owing to insufficient or contradictoryinformation. The line shows the threshold drawn by Thompson et al. (2001).

TRANS (1) ¥ NCTRANS (2)PERS (3)

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0.10

0.010.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

Variance of seed dimensions

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ass

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Table 1. Relation between seed size and shape and persistence for species from the Italian flora

Sample size Probability

Long-term Short-term One-tailed t-testpersistent persistent and

transient

All species Seed mass 34 195 0.0001 ***All species Seed variance 34 195 0.0000 ***Growth form

Shrubs Seed mass 3 30 0.0004 ***Shrubs Seed variance 3 30 0.0000 ***Herbaceous Seed mass 31 165 0.0013 **Herbaceous Seed variance 31 165 0.0000 ***

HabitatsAlpine pastures Seed mass 7 66 0.3050 NSAlpine pastures Seed variance 7 66 0.0000 ***Limestone prairies and meadows Seed mass 15 73 0.0030 **Limestone prairies and meadows Seed variance 15 73 0.0000 ***Ground-flora of temperate woodlands Seed mass 9 43 0.0009 ***Ground-flora of temperate woodlands Seed variance 9 43 0.1120 NSMediterranean maquis and garigues Seed mass 3 13 0.0098 **Mediterranean maquis and garigues Seed variance 3 13 0.0007 ***

BiogeographyEndemic species Seed mass 4 18 0.4187 NSEndemic species Seed variance 4 18 0.0783 NSMediterranean species Seed mass 5 23 0.0269 *Mediterranean species Seed variance 5 23 0.0006 ***Temperate species Seed mass 17 77 0.0001 ***Temperate species Seed variance 17 77 0.0029 **Alpine and northern species Seed mass 8 77 0.1420 NSAlpine and northern species Seed variance 8 77 0.0000 ***

One-tailed t-test. *** P < 0.001; ** P < 0.01; * P < 0.05; ns = not significant.

Furthermore, the significant relationship betweenseed size and shape and persistence was retainedwhile analysing species from different habitats, exceptwhen considering seed mass in alpine pasture speciesand seed shape in the ground flora of temperatewoodlands.

The same general pattern could be observed whenbiogeographical groups were considered: thedifferences in seed mass and variance were notsignificant only in the small group of endemic speciesof the Alps and of Lombardy Prealps.

To investigate the possibility that the relationshipbetween dormancy and seed size and shape wasconsistent within each family, the dataset wasanalysed according to the method proposed byLeishman and Westoby (1998). Families that werecontrasted for seed persistence were isolated andresults are shown in Fig. 2. Each line leading from anuppercase to a lowercase letter represents anevolutionary divergence from persistent to non-persistent seed banks. The uppercase letter shows themean seed mass and variance for long-term persistentspecies (seed bank type 3), while the lowercase letterindicates the mean seed mass and variance for short-term persistent and transient species (seed bank types1 and 2). A clear trend toward the reduction, both inseed mass and in variance (from transient topersistent species), was observed in only threefamilies (Lamiaceae, Ranunculaceae andScrophulariaceae). A decrease in seed mass only wasfound in Rosaceae, Campanulaceae and Euphorbiaceae. Inthe seven remaining families, a constant reduction ofseed variance was noticed. A spherical dispersule

appears to be the first, and most important, conditionfor persistence in soil, regardless of seed mass, at leastamong the 259 considered species.

Discussion

Our results suggest that the method proposed byThompson et al. (1993) can be used to distinguishlong-term persistent species from short-termpersistent and transient species among 259 species ofthe Italian flora. In this dataset, the limits in seed massand variance pointed out by Thompson et al. (2001)can distinguish long-term persistent species, but theydo not delimit an exclusive area, as transient andshort-term persistent species also can be found. Itappears that the threshold in size and shape drawn byThompson et al. (2001) could be interpreted as a linebelow which a seed can persist for long periods in thesoil, but does not necessarily do so. In fact, in thisstudy there were no species with long-term persistentseeds that had a seed mass >3.66 mg and a variance of>0.15, except for Carex sylvatica (seed variance of 0.19).This pattern confirms the observations for theArgentinean and Iranian floras, and partiallyconfirms that of the New Zealand flora.

Among the Italian species studied here, theprobability of burial, and thus the potential to createpersistent soil seed banks, seems to rely upon bothreduction of seed mass and progressive rounding ofthe dispersule. However, it cannot be assumed thatthis will always be the case, since relatively largediaspores may be readily incorporated into the coarse


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A Polygonaceae

B Caryophyllaceae

C Ranunculaceae

D Rosaceae

E Linaceae

F Primulaceae

G Lamiaceae

H Campanulaceae

I Juncaceae

J Cyperaceae

K Euphorbiaceae

L Scrophulariaceae

M Cistaceae

Figure 2. Seed mass and variances of seed dimensions for 13 phylogenetically independent contrasts. Each contrast is denotedby a letter (from A to M), with the uppercase letter showing the mean seed mass and variance for long-term persistent speciesand the lowercase letter the mean seed mass and variance for short-term persistent and transient species. Each line leadingfrom an uppercase to a lowercase letter represents an evolutionary divergence from persistent to non-persistent seed banks.Dashed line shows the threshold drawn by Thompson et al. (2001).

soils of some alpine ecosystems (Chambers et al.,1991).

Seed size is a key trait in determining seed fate,since small seeds are both less attractive to animalsand more easily buried in soil than large ones,therefore additionally depressing predation rate.Moreover, our results show that for seeds of a givensize, a flattened or elongated shape might be anobstacle to seed incorporation into a persistent seedbank, as Thompson et al. (1993) suggested, even ifsubsequent studies failed to support this hypothesis.When data from all four published studies arecombined (Thompson et al., 1993; Leishman andWestoby, 1998; Funes et al., 1999; Moles et al., 2000),long-term persistent species (n = 178) tend to havespherical seeds, while transient species and short-term persistent species (n = 121) have more flattenedand/or elongate seeds (one-tailed t-test, P < 0.001),thus confirming that seed shape should affect seedpersistence in soil.

The distribution of Italian species in the ‘seedmass/seed variance’ space reveals another interestingtrend, since the data in the diagram are extendedmainly in the horizontal plane. In comparison withthe Australian and New Zealand graphs (Leishmanand Westoby, 1998; Moles et al., 2000), the left upperarea in our diagram is almost empty, since heavyspherical seeds are quite rare in the examined flora.Seeds of the majority of the considered species show asmall range of masses (approximately between 0.10and 10.00 mg), while their shape varies much more,occupying the entire range from virtually spherical(variance of seed dimensions of 0.001) to completelyflattened or elongated (variance of 0.33). In thehabitats analysed, it seems that the major constraintsact on seed size, while the main adaptive gradientrefers to seed shape. At one end of the gradient, wefound the progressive rounding of the diaspore and,thus, the possibility of long-term persistence in soil,while, at the other, the flattening of the diaspore maybe linked to a higher probability of wind dispersal,and perhaps epizoochory. These dispersal modesmight be associated to some extent with humanactivities and disturbance (agriculture, cattle-breeding, fire), and it is worth noticing that the onlytwo groups of species that do not completely fit theThompson et al. (1993) model in the present study arethose of the more stable habitats (i.e. alpine pasturesand ground flora of temperate woodlands).

Our data shed new light on some of the reasonswhy seed size and shape may (or may not) be relatedto persistence in soil. Neither past (Quaternaryglaciations or periglacialism) nor present climate(Funes et al., 1999) can be the whole story, since therelationship exists both in cold and/or wet regions(Great Britain, Argentina, Alps and northern Italy)and in dry and warm ones, like the Mediterranean

area. The hypothesis that fire could have broken thelink between seed size, shape and soil persistence(Leishman and Westoby, 1998) also seems unlikely; infire-prone Mediterranean-type ecosystems, small,compact, persistent seeds have been successfultogether with the heavy, persistent, hard seeds ofmany Fabaceae. For example, the hard seeds of Cistusspecies, which are considered obligate seeders inthese habitats (Tarrega et al., 2001), are stored withinlong-lived soil seed banks, their germination isstimulated by heat (see, for example, Hanley andFenner, 1998) and they are characterized by a ratherlow weight (three species, this work, had an averagemass of 0.71 mg) and spherical shape (average seedvariance of 0.02). Neither can vegetation structure beconsidered among the main causes of the complete orpartial lack of the relationship in Australia and NewZealand (Moles et al., 2000), as we also examinedspecies from a number of habitats of increasingstructural complexity. Although we are unable to addanything new to the debate about whether thehistorical level of seed predation influences thepersistence of large-seeded species (Moles et al., 2000),it seems clear that predation is one of the mainselective forces on seed size and shape, positivelyselecting small seeds for survival and possibleincorporation into the seed bank (e.g. Hulme, 1994,1998a, b).

Acknowledgements

Thanks to Ken Thompson and Angela Moles forhelpful discussions of the results and comments onthe manuscript. We are grateful to Antonio DiGuardo, who made useful suggestions on an earlierversion of this paper. The research was supported byCentro Flora Autoctona of Lombardy and by theConsorzio Parco Monte Barro (Lecco – Italy), and ispart of the Life Nature 2000 Project ‘Integratedmanagement of Insubric-Prealpine habitats’(LIFE00NAT/IT/7258).

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Appendix 1

Seed mass and shape (variance of seed length, width and depth) for the 259 species analysed in this study, showing persistencecategory, life form, habitat and biogeography. Species nomenclature follows Pignatti (1982)

Family Seed mass Variance Life form Habitat Biogeography(mg)

Transient species (n = 150)Achillea millefolium Asteraceae 0.05 0.214 Herb Lime AlpAchnatherum calamagrostis Poaceae 0.29 0.238 Herb Alp AlpAllium ericetorum Liliaceae 1.57 0.143 Herb Alp AlpAllium insubricum Liliaceae 3.37 0.025 Herb Alp EndAllium sphaerocephalon Liliaceae 1.61 0.092 Herb Lime TempAllium ursinum Liliaceae 6.16 0.046 Herb Wood TempAnemone nemorosa Ranunculaceae 2.53 0.150 Herb Wood AlpAnemone ranunculoides Ranunculaceae 1.50 0.153 Herb Wood TempAntennaria carpathica Asteraceae 0.08 0.141 Herb Alp AlpAnthericum ramosum Liliaceae 2.51 0.065 Herb Lime MedAnthoxanthum odoratum Poaceae 0.73 0.219 Herb Lime TempAnthyllis vulneraria Fabaceae 1.96 0.096 Herb Alp TempArabis turrita Brassicaceae 0.59 0.197 Herb Wood TempArbutus unedo Ericaceae 2.53 0.112 Shrub Med MedAsarum europaeum Aristolochiaceae 3.16 0.077 Herb Wood AlpAsparagus acutifolius Liliaceae 40.08 0.001 Shrub Med MedAster amellus Asteraceae 0.54 0.171 Herb Lime TempAstrantia major Apiaceae 3.19 0.196 Herb Wood AlpBartsia alpina Scrophulariaceae 0.42 0.107 Herb Alp Alp


Biscutella laevigata Brassicaceae 5.60 0.235 Herb Alp AlpBrachypodium rupestre Poaceae 2.57 0.261 Herb Lime TempBrachypodium sylvaticum Poaceae 3.89 0.289 Herb Wood TempBriza media Poaceae 0.41 0.060 Herb Lime AlpBromus erectus Poaceae 3.06 0.283 Herb Lime TempBuphthalmum salicifolium Asteraceae 0.36 0.193 Herb Lime AlpBupleurum ranunculoides Apiaceae 1.55 0.178 Herb Alp AlpCalamagrostis varia Poaceae 0.13 0.252 Herb Lime TempCarex austroalpina Cyperaceae 0.70 0.157 Herb Alp EndCarex digitata Cyperaceae 1.09 0.184 Herb Wood TempCarex firma Cyperaceae 1.11 0.165 Herb Alp AlpCarex montana Cyperaceae 0.99 0.140 Herb Wood TempCarex sempervirens Cyperaceae 0.95 0.206 Herb Alp AlpCarlina acaulis Asteraceae 4.05 0.186 Herb Alp TempCentaurea bracteata Asteraceae 1.72 0.135 Herb Lime TempCentaurea rhaetica Asteraceae 2.06 0.124 Herb Alp EndCentaurea scabiosa Asteraceae 5.86 0.135 Herb Lime TempCentaurea triumfetti Asteraceae 9.82 0.128 Herb Lime TempChrysopogon gryllus Poaceae 2.90 0.309 Herb Lime TempCircaea lutetiana Onagraceae 2.06 0.101 Herb Wood AlpCirsium pannonicum Asteraceae 2.13 0.187 Herb Lime TempConvallaria majalis Liliaceae 29.05 0.038 Herb Wood AlpCoronilla coronata Fabaceae 12.12 0.127 Shrub Lime TempCoronilla emerus Fabaceae 6.09 0.242 Shrub Lime TempCoronilla vaginalis Fabaceae 6.92 0.104 Shrub Alp TempCoronilla varia Fabaceae 6.98 0.167 Herb Lime AlpCrepis froelichiana Asteraceae 0.59 0.261 Herb Alp AlpCruciata glabra Rubiaceae 1.43 0.040 Herb Wood TempDactylis glomerata Poaceae 0.79 0.273 Herb Lime TempDianthus monspessulanus Caryophyllaceae 1.03 0.058 Herb Alp AlpDianthus seguieri Caryophyllaceae 1.69 0.124 Herb Lime TempDianthus sylvestris Caryophyllaceae 0.42 0.146 Herb Lime AlpEchium vulgare Boraginaceae 2.46 0.025 Herb Lime TempErica arborea Ericaceae 0.03 0.070 Shrub Med MedErica carnea Ericaceae 0.08 0.101 Shrub Alp AlpErica scoparia Ericaceae 0.02 0.059 Shrub Med MedFestuca heterophylla Poaceae 1.44 0.278 Herb Wood TempFragaria vesca Rosaceae 0.36 0.061 Herb Wood TempGalium lucidum Rubiaceae 0.84 0.029 Herb Lime MedGalium verum Rubiaceae 0.29 0.149 Herb Lime TempGentiana clusii Gentianaceae 0.44 0.089 Herb Alp AlpGentiana insubrica Gentianaceae 0.16 0.015 Herb Alp EndGentiana utriculosa Gentianaceae 0.06 0.109 Herb Alp AlpGeranium nodosum Geraniaceae 5.49 0.055 Herb Wood AlpGeranium sanguineum Geraniaceae 8.24 0.047 Herb Wood TempGladiolus palustris Iridaceae 1.66 0.156 Herb Lime TempHelleborus niger Ranunculaceae 8.59 0.120 Herb Wood TempHepatica nobilis Ranunculaceae 2.27 0.154 Herb Wood AlpHieracium pilosella Asteraceae 0.27 0.225 Herb Alp TempHieracium porrifolium Asteraceae 0.64 0.211 Herb Lime EndHieracium sylvaticum Asteraceae 0.40 0.231 Herb Wood AlpHippocrepis comosa Fabaceae 2.91 0.161 Herb Lime TempHorminum pyrenaicum Lamiaceae 0.71 0.066 Herb Alp AlpImpatiens parviflora Balsaminaceae 7.20 0.121 Herb Wood TempInula hirta Asteraceae 0.27 0.186 Herb Lime TempKnautia arvensis Dipsacaceae 2.91 0.164 Herb Lime TempKnautia transalpina Dipsacaceae 3.52 0.168 Herb Alp EndKnautia velutina Dipsacaceae 2.53 0.173 Herb Alp EndKoeleria macrantha Poaceae 0.44 0.263 Herb Lime Alp



Lamiastrum galeobdolon Lamiaceae 1.84 0.106 Herb Wood TempLaserpitium nitidum Apiaceae 3.78 0.094 Herb Alp EndLaserpitium siler Apiaceae 7.19 0.205 Herb Lime AlpLathyrus vernus Fabaceae 18.31 0.003 Herb Wood TempLeontodon helveticus Asteraceae 1.71 0.271 Herb Alp AlpLeontodon hispidus Asteraceae 0.93 0.274 Herb Lime TempLeontodon tenuiflorus Asteraceae 0.86 0.245 Herb Alp EndLilium bulbiferum croceum Liliaceae 7.40 0.262 Herb Lime AlpLilium martagon Liliaceae 7.93 0.231 Herb Wood TempLuzula alpino-pilosa Juncaceae 0.20 0.070 Herb Alp AlpLuzula pilosa Juncaceae 0.40 0.081 Herb Wood AlpMaianthemum bifolium Liliaceae 13.84 0.009 Herb Wood AlpMelampyrum cristatum Scrophulariaceae 3.24 0.144 Herb Lime TempMelampyrum pratense Scrophulariaceae 5.88 0.127 Herb Wood AlpMelica ciliata Poaceae 1.06 0.149 Herb Lime MedMercurialis perennis Euphorbiaceae 7.42 0.004 Herb Wood TempMyosotis alpestris Boraginaceae 0.49 0.032 Herb Alp AlpMyrtus communis Myrtaceae 5.51 0.067 Shrub Med MedOnonis spinosa Fabaceae 2.26 0.029 Shrub Lime MedOxyria digyna Polygonaceae 0.93 0.240 Herb Alp AlpPaeonia officinalis Paeoniaceae 105.60 0.030 Herb Wood TempParis quadrifolia Liliaceae 7.07 0.046 Herb Wood TempParnassia palustris Saxifragaceae 0.05 0.187 Herb Alp AlpPeucedanum cervaria Apiaceae 4.34 0.197 Herb Lime AlpPeucedanum oreoselinum Apiaceae 4.22 0.218 Herb Lime TempPhysoplexis comosa Campanulaceae 0.08 0.137 Herb Alp EndPhyteuma ovatum Campanulaceae 0.18 0.106 Herb Wood AlpPhyteuma scheuchzeri Campanulaceae 0.04 0.111 Herb Alp EndPhyteuma spicatum Campanulaceae 0.20 0.091 Herb Wood TempPistacia lentiscus Anacardiaceae 19.30 0.084 Shrub Med MedPoa nemoralis Poaceae 0.13 0.234 Herb Wood AlpPolygala chamaebuxus Polygalaceae 7.60 0.107 Shrub Alp AlpPolygala nicaeensis Polygalaceae 1.58 0.125 Herb Lime MedPolygonatum multiflorum Liliaceae 23.85 0.020 Herb Wood TempPolygonatum odoratum Liliaceae 36.30 0.013 Herb Lime AlpPulmonaria officinalis Boraginaceae 3.64 0.067 Herb Wood TempPulsatilla alpina Ranunculaceae 6.68 0.313 Herb Alp AlpPulsatilla montana Ranunculaceae 2.36 0.317 Herb Alp TempRhamnus saxatilis Rhamnaceae 10.53 0.069 Shrub Alp TempRhodothamnus chamaecistus Ericaceae 0.06 0.171 Shrub Alp EndSalvia glutinosa Lamiaceae 5.33 0.083 Herb Wood TempSalvia pratensis Lamiaceae 1.76 0.041 Herb Lime MedSanguisorba minor Rosaceae 4.91 0.077 Herb Lime TempSaxifraga aizoides Saxifragaceae 0.05 0.133 Herb Alp AlpSaxifraga oppositifolia Saxifragaceae 0.08 0.103 Herb Alp AlpScabiosa columbaria Dipsacaceae 2.47 0.102 Herb Lime TempScabiosa graminifolia Dipsacaceae 5.77 0.148 Herb Lime AlpScorzonera austriaca Asteraceae 6.75 0.232 Herb Lime TempSenecio fuchsii Asteraceae 1.17 0.194 Herb Wood TempSerratula tinctoria Asteraceae 1.74 0.211 Herb Lime AlpSesleria varia Poaceae 1.50 0.231 Herb Alp AlpSilene acaulis Caryophyllaceae 0.19 0.074 Herb Alp AlpSmilax aspera Liliaceae 38.23 0.014 Shrub Med MedSolidago virgaurea Asteraceae 0.69 0.221 Herb Wood AlpStachys alopecorus Lamiaceae 1.09 0.084 Herb Alp AlpStachys officinalis Lamiaceae 0.98 0.134 Herb Lime TempStachys recta Lamiaceae 1.63 0.057 Herb Lime AlpStipa pennata Poaceae 37.77 0.330 Herb Lime MedSuccisa pratensis Dipsacaceae 1.57 0.197 Herb Lime Alp



Symphytum tuberosum Boraginaceae 6.85 0.047 Herb Wood TempTanacetum corymbosum Asteraceae 0.51 0.204 Herb Wood MedTaraxacum alpinum Asteraceae 0.45 0.197 Herb Alp AlpTelekia speciosissima Asteraceae 0.33 0.198 Herb Alp EndThesium bavarum Santalaceae 3.59 0.117 Herb Lime TempTrifolium badium Fabaceae 0.75 0.103 Herb Alp AlpTrifolium montanum Fabaceae 0.85 0.062 Herb Lime TempTrifolium pallescens Fabaceae 0.62 0.074 Herb Alp AlpTrifolium rubens Fabaceae 2.01 0.032 Herb Lime TempVaccinium myrtillus Ericaceae 0.35 0.081 Shrub Alp AlpViburnum tinus Caprifoliaceae 27.16 0.007 Shrub Med MedVincetoxicum hirundinaria Asclepiadaceae 6.75 0.146 Herb Lime TempViola hirta Violaceae 1.73 0.040 Herb Lime Temp

Short-term persistent species (n = 45)Arabis hirsuta Brassicaceae 0.03 0.171 Herb Lime TempArtemisia genipi Asteraceae 0.22 0.099 Herb Alp EndAsperula aristata Rubiaceae 0.74 0.073 Herb Lime AlpAsperula purpurea Rubiaceae 0.66 0.052 Herb Lime AlpAster linosyris Asteraceae 1.33 0.192 Herb Lime MedCalicotome spinosa Fabaceae 7.47 0.055 Shrub Med MedCalicotome villosa Fabaceae 6.00 0.082 Shrub Med MedCampanula glomerata Campanulaceae 0.17 0.154 Herb Lime TempCardamine heptaphylla Brassicaceae 6.02 0.053 Herb Wood TempCentaurium erythraea Gentianaceae 0.01 0.105 Herb Lime TempCerastium latifolium Caryophyllaceae 0.35 0.189 Herb Alp AlpChamaecytisus hirsutus Fabaceae 6.87 0.118 Shrub Lime AlpChamaecytisus purpureus Fabaceae 6.69 0.098 Shrub Lime AlpClematis alpina Ranunculaceae 3.42 0.282 Shrub Alp AlpClematis recta Ranunculaceae 10.20 0.139 Herb Lime TempCytisus emeriflorus Fabaceae 5.15 0.114 Shrub Alp EndCytisus scoparius Fabaceae 7.09 0.054 Shrub Med TempCytisus sessilifolius Fabaceae 13.63 0.120 Shrub Lime MedCytisus villosus Fabaceae 6.86 0.050 Shrub Med MedErigeron uniflorus Asteraceae 0.18 0.200 Herb Alp AlpHelianthemum nummularium Cistaceae 0.57 0.070 Shrub Lime TempHelianthemum oelandicum Cistaceae 0.51 0.056 Shrub Alp TempHolcus lanatus Poaceae 0.29 0.164 Herb Lime AlpLembotropis nigricans Fabaceae 3.33 0.055 Shrub Lime TempLeucanthemum heterophyllum Asteraceae 0.50 0.166 Herb Lime AlpLinum catharticum Linaceae 0.14 0.152 Herb Alp MedLotus corniculatus Fabaceae 1.03 0.062 Herb Lime TempLuzula sylvatica Juncaceae 0.94 0.067 Herb Wood AlpMelittis melissophyllum Lamiaceae 5.39 0.042 Herb Wood TempMolinia coerulea Poaceae 1.00 0.204 Herb Lime AlpPapaver rhaeticum Papaveraceae 0.18 0.118 Herb Alp AlpPedicularis gyroflexa Scrophulariaceae 0.99 0.107 Herb Alp EndPlantago alpina Plantaginaceae 0.35 0.092 Herb Alp AlpPotentilla erecta Rosaceae 0.20 0.061 Herb Alp TempPrimula auricula Primulaceae 0.29 0.060 Herb Alp AlpPrimula glaucescens Primulaceae 0.25 0.122 Herb Alp EndPrunella grandiflora Lamiaceae 1.01 0.079 Herb Lime AlpRanunculus thora Ranunculaceae 2.46 0.068 Herb Alp AlpRhinanthus alectorolophus Scrophulariaceae 2.38 0.139 Herb Alp TempSenecio doronicum Asteraceae 0.28 0.199 Herb Alp AlpSenecio incanus incanus Asteraceae 1.55 0.200 Herb Alp AlpSilene nutans Caryophyllaceae 0.64 0.037 Herb Lime TempSpartium junceum Fabaceae 10.76 0.088 Shrub Med MedStachys sylvatica Lamiaceae 1.23 0.043 Herb Wood AlpThlaspi rotundifolium Brassicaceae 1.65 0.072 Herb Alp End



Long-term persistent species (n = 34)Campanula spicata Campanulaceae 0.06 0.152 Herb Lime EndCampanula trachelium Campanulaceae 0.16 0.150 Herb Wood TempCarex flacca Cyperaceae 1.31 0.120 Herb Lime TempCarex humilis Cyperaceae 1.14 0.105 Herb Lime TempCarex sylvatica Cyperaceae 1.67 0.194 Herb Wood TempCistus incanus Cistaceae 0.55 0.020 Shrub Med MedCistus monspeliensis Cistaceae 0.84 0.022 Shrub Med MedCistus salvifolius Cistaceae 0.74 0.016 Shrub Med MedClinopodium vulgare Lamiaceae 0.43 0.038 Herb Wood AlpEuphorbia cyparissias Euphorbiaceae 1.91 0.046 Herb Lime TempEuphorbia flavicoma Euphorbiaceae 1.18 0.050 Herb Lime TempEuphorbia variabilis Euphorbiaceae 3.66 0.054 Herb Alp EndHypericum montanum Hypericaceae 0.06 0.116 Herb Wood TempHypericum perforatum Hypericaceae 0.08 0.139 Herb Lime TempLinum tenuifolium Linaceae 2.47 0.058 Herb Lime MedLuzula pilosa Juncaceae 1.62 0.057 Herb Wood AlpPotentilla alba Rosaceae 0.60 0.065 Herb Wood TempPotentilla caulescens Rosaceae 0.13 0.112 Herb Alp AlpPotentilla tabernaemontani Rosaceae 0.34 0.087 Herb Lime TempPrimula vulgaris Primulaceae 0.99 0.059 Herb Wood TempRumex scutatus Polygonaceae 2.04 0.038 Herb Alp AlpSaponaria ocymoides Caryophyllaceae 2.06 0.052 Herb Alp AlpSchoenus nigricans Cyperaceae 0.55 0.060 Herb Lime TempScrophularia nodosa Scrophulariaceae 0.14 0.049 Herb Wood AlpSilene elisabethae Caryophyllaceae 0.54 0.085 Herb Alp EndSilene otites Caryophyllaceae 0.41 0.054 Herb Lime TempSilene saxifraga Caryophyllaceae 0.33 0.081 Herb Alp AlpTeucrium chamaedrys Lamiaceae 1.17 0.024 Herb Lime MedTeucrium montanum Lamiaceae 0.50 0.069 Herb Lime AlpTeucrium scorodonia Lamiaceae 0.92 0.015 Herb Wood TempThalictrum minus Ranunculaceae 2.07 0.124 Herb Lime TempThymus froelichianus Lamiaceae 0.06 0.075 Herb Lime TempThymus oenipontanus Lamiaceae 0.13 0.072 Herb Lime TempViola comollia Violaceae 0.72 0.037 Herb Alp End

Non-classified species (n = 30)Aposeris foetida Asteraceae 2.17 0.174 Herb Wood AlpAquilegia atrata Ranunculaceae 1.25 0.076 Herb Wood AlpAquilegia einseleana Ranunculaceae 0.94 0.186 Herb Alp EndAruncus dioicus Rosaceae 0.10 0.220 Herb Wood AlpBuglossoides purpurocaerulea Boraginaceae 10.15 0.020 Herb Wood TempCarex alba Cyperaceae 0.75 0.142 Herb Wood AlpCarex baldensis Cyperaceae 1.61 0.133 Herb Alp EndCarex brizoides Cyperaceae 0.28 0.211 Herb Wood TempCarex curvula Cyperaceae 2.12 0.186 Herb Alp EndCarex mucronata Cyperaceae 0.83 0.199 Herb Alp EndDictamnus albus Rutaceae 15.89 0.026 Herb Lime TempDorycnium pentaphyllum Fabaceae 1.87 0.028 Herb Lime TempErytronium dens-canis Liliaceae 3.77 0.156 Herb Wood TempFumana procumbens Cistaceae 2.06 0.045 Shrub Lime MedGalium sylvaticum Rubiaceae 1.30 0.025 Herb Wood TempGlobularia cordifolia Globulariaceae 0.59 0.033 Shrub Alp EndGlobularia nudicaulis Globulariaceae 0.72 0.178 Herb Alp EndGlobularia punctata Globulariaceae 0.66 0.036 Herb Lime TempHedysarum hedysaroides Fabaceae 5.46 0.163 Herb Alp AlpIris graminea Iridaceae 12.79 0.046 Herb Lime TempKernera saxatilis Brassicaceae 0.14 0.127 Herb Alp TempLeucojum vernum Amaryllidaceae 11.91 0.099 Herb Wood Temp



Prenanthes purpurea Asteraceae 0.28 0.204 Herb Wood TempRosmarinus officinalis Lamiaceae 1.30 0.104 Shrub Med MedRuta graveolens Rutaceae 1.97 0.072 Herb Lime MedScilla bifolia Liliaceae 9.55 0.040 Herb Wood TempTrinia glauca Apiaceae 1.24 0.101 Herb Lime TempVeratrum album Liliaceae 3.67 0.172 Herb Alp TempVeronica urticifolia Scrophulariaceae 0.11 0.200 Herb Wood TempVinca minor Apocynaceae 6.13 0.128 Herb Wood Temp

Life form classes: Herb = forbs, grasses or sedges; Shrub = shrubs or lianas. Habitat classes: Alp = alpine pastures; Lime =limestone prairies and meadows; Med = Mediterranean maquis and garigues; Wood = temperate woodlands. Biogeographicalclasses: Alp = alpine and northern species; Cosm = cosmopolitan species; End = endemic species; Med = Mediterraneanspecies; Temp = temperate species.

Received 3 May 2002accepted after revision 9 October 2002

© CAB International 2003


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