Catalogue of alien plants of the Czech Republic

101 Pages·2012·0.61 MB·English

Preslia84:155–255,2012 155
Catalogue of alien plants of the Czech Republic (2nd edition):
checklist update, taxonomic diversity and invasion patterns
Nepůvodní flóra České republiky: aktualizace seznamu druhů, taxonomická diverzita a průběh invazí
PetrPyšek1,2, JiříDanihelka1,3, JiříSádlo1, JindřichChrtek Jr.1,4,
MilanChytrý3, VojtěchJarošík2,1, ZdeněkKaplan1, FrantišekKrahulec1,
LenkaMoravcová1, JanPergl1, KateřinaŠtajerová1,2& LubomírTichý3
1InstituteofBotany,AcademyofSciencesoftheCzechRepublic,CZ-25243Průhonice,
Czech Republic, e-mail: [email protected], [email protected], [email protected],
[email protected],[email protected],[email protected],[email protected];
2DepartmentofEcology,FacultyofScience,CharlesUniversityinPrague,Viničná7,CZ-
12844Prague,CzechRepublic,e-mail:[email protected];3DepartmentofBotanyand
Zoology, Masaryk University, Kotlářská 2, CZ-611 37 Brno, Czech Republic, e-mail:
[email protected], [email protected], [email protected]; 4Department of Botany,
FacultyofScience,CharlesUniversityinPrague,Benátská2,CZ-12801Prague,Czech
Republic
Pyšek P., Danihelka J., Sádlo J., Chrtek J. Jr., Chytrý M., Jarošík V., Kaplan Z., Krahulec F.,
MoravcováL.,PerglJ.,ŠtajerováK.&TichýL.(2012):CatalogueofalienplantsoftheCzech
Republic(2ndedition):checklistupdate,taxonomicdiversityandinvasionpatterns.–Preslia84:
155–255.
AcompletelistofallalientaxaeverrecordedinthefloraoftheCzechRepublicispresentedasan
updateoftheoriginalchecklistpublishedin2002.Newdataaccumulatedinthelastdecadeare
incorporatedandthelistingandstatusofsometaxaarereassessedbasedonimprovedknowledge.
AlienfloraoftheCzechRepublicconsistsof1454taxalistedwithinformationontheirtaxonomic
position,lifehistory,geographicorigin(ormodeoforigin,distinguishinganecophyteandhybrid),
invasivestatus(casual;naturalizedbutnotinvasive;invasive),residencetimestatus(archaeophyte
vsneophyte),modeofintroductionintothecountry(accidental,deliberate),anddateofthefirst
record.Additionalinformationonspeciesperformancethatwasnotpartofthepreviouscatalogue,
i.e.onthewidthofspecies’habitatniches,theirdominanceininvadedcommunities,andimpact,is
provided.TheCzechalienfloraconsistsof350(24.1%)archaeophytesand1104(75.9%)neo-
phytes.Theincreaseinthetotalnumberoftaxacomparedtothepreviouscatalogue(1378)isdueto
additionof151taxaandremovalof75(39archaeophytesand36neophytes),importantpartofthe
latterbeingthereclassificationof41taxaasnative,mostlybasedonarchaeobotanicalevidence.The
additionsrepresenttaxanewlyrecordedsince2002andreportedinthenationalliterature;taxa
resulting from investigation of sources omitted while preparing the previous catalogue;
redeterminationofpreviouslyreportedtaxa;reassessmentofsometaxatraditionallyconsidered
nativeforwhichtheevidencesuggeststheopposite;andinclusionofintraspecifictaxapreviously
notrecognizedintheflora.Thereare44taxaonthelistthatarereportedinthepresentstudyforthe
firsttimeasaliensintroducedtotheCzechRepublicorescapedfromcultivation:Abiesconcolor,
A. grandis, A. nordmanniana, Avena sterilis subsp. ludoviciana, A. ×vilis, Berberis julianae,
B.thunbergii,Bidensferulifolius,Buddlejaalternifolia,Buglossoidesincrassatasubsp.splitgerberi,
Buxussempervirens,Corispermumdeclinatum,Cotoneasterdielsianus,C.divaricatus,Euphorbia
myrsinites,Gleditsiatriacanthos,Helleborusorientalis,Hieraciumheldreichii,Koelreuteriapani-
culata,Lonicerapericlymenum,Lotusornithopodioides,Malusbaccata,M.pumila,Miscanthus
sacchariflorus,Morusalba,Muscariarmeniacum,Paeonialactiflora,Pennisetumalopecuroides,
Pinguicula crystallina subsp. hirtiflora, P. grandiflora subsp. rosea, Podophyllumhexandrum,
Pyracanthacoccinea,Rhodotyposscandens,Rumexpatientia×R.tianschanicus‘Uteuša’,Salix
cordata,Sarraceniapurpurea,Sasapalmata‘Nebulosa’,Scolymusmaculatus,Spiraeajaponica,
156 Preslia84:155–255,2012
Tagetestenuifolia,Thujaoccidentalis,Trifoliumbadium,VacciniumcorymbosumandViburnum
rhytidophyllum.Alladdedanddeletedtaxaarecommentedon.Ofthetotalnumberoftaxa,985are
classifiedascasuals,408asnaturalizedbutnotinvasive,and61asinvasive.Thereductioninthe
numberofinvasivetaxacomparedtothepreviouscatalogueisduetoamoreconservativeapproach
adoptedhere;onlytaxathatcurrentlyspreadareconsideredinvasive.Casualtaxaarestronglyover-
representedamongneophytescomparedtoarchaeophytes(76.7%vs39.4%),whilenaturalizedbut
non-invasivetaxafollowthereversedpattern(18.8%vs57.4).However,thesetwogroupsdonot
significantlydifferintheproportionofinvasivetaxa.Ofintroducedneophytes,250taxa(22.6%)are
consideredvanished,i.e.nolongerpresentintheflora,while23.3%becamenaturalized,and4.5%
invasive.Inadditiontothetraditionalclassificationbasedonintroduction–naturalization–invasion
continuum, taxa were classified into 18 population groups based on their long-term trends in
metapopulationdynamicsinthecountry,currentstateoftheirpopulations,andlinktothepropagule
pressurefromcultivation.Mappingthesepopulationgroupsontotheunifiedframeworkforbiologi-
calinvasionsintroducedbyBlackburnetal.in2011madeitpossibletoquantifyinvasionfailures,
andboom-and-busts,intheCzechalienflora.Dependingoninclusioncriteria(whetherornot
extinct/vanishedtaxaandhybridsareconsidered),alientaxaeverrecordedintheCzechRepublic
contribute29.7–33.1%tothetotalcountry’splantdiversity;takingintoaccountonlynaturalized
taxa,apermanentelementofthecountry’sflora,thefigureis14.4–17.5%.Analysisofthedatesof
thefirstrecord,knownfor771neophytes,indicatesthatalientaxaintheflorahavebeenincreasing
atasteadypacewithoutanydistinctdecelerationtrend;byextrapolatingthisdatatoall1104neo-
phytesrecordeditispredictedthattheprojectednumberwouldreach1264in2050.Deliberate
introductionwasinvolvedin747cases(51.4%),theremaining48.6%oftaxaareassumedtohave
arrivedbyunintentionalpathways.Archaeophytesaremoreabundantinlandscapes,occupyon
averageawiderrangeofhabitattypesthanneophytes,butreachalowercoverinplantcommunities.
Thealienfloraisfurtheranalysedwithrespecttorepresentationofgeneraandfamilies,originand
life history.
Keywords:abundance,alienflora,checklist,casual,coverinplantcommunities,CzechRepub-
lic,exoticspecies,geographicorigin,habitatniche,hybridization,impact,introduction–naturaliza-
tion–invasioncontinuum,invasiveplants,lifehistory,naturalized,non-nativespecies,residence
time, taxonomy
Introduction
ThelastdecadewasaperiodofintensiveresearchonbiologicalinvasionsinEurope(see
Pyšek&Hulme2011forreview),animportantpartofwhichrepresentedthecollationof
regional data on alien plant species. With the exception of the UK (Clement & Foster
1994,Ryvesetal.1996,Prestonetal.2002),completechecklistsofalienflorasforEuro-
peancountriesonlystartedtoappearatthebeginningofthe2000s(Essl&Rabitsch2002,
Klotzetal.2002,Reynolds2002).Thefirstcomprehensivechecklistofalienplantsinthe
CzechRepublicwaspublished10yearsagoasapartoftheCatalogueofalienplantsofthe
CzechRepublic(Pyšeketal.2002).Itprovidedinformationon1378alientaxaandstimu-
lateddevelopmentoftheassociateddatabaseCzechFlor,heldattheInstituteofBotanyAS
CRinPrůhonice.Thesedata,togetherwithotherdatasetsresultingfromrecentresearch,
havebeenusedforanumberofanalysesofplantinvasionsinthecountrythataddressed
issuessuchasspeciesinvasiveness(Kubešováetal.2010,Moravcováetal.2010),associ-
ationswithpollinators(Pyšeketal.2011a),habitatinvasibility(Chytrýetal.2005,2008a,
2009b,Sádloetal.2007),ratesofspreadandrangefilling(Williamsonetal.2005,2009,
Pyšeketal.2011c),interactionoftraits,propagulepressureandresidencetimeinaffect-
inginvasionsuccess(Pyšeketal.2009b),pathwayefficiency(Pyšeketal.2011b),andrisk
assessment (Křivánek & Pyšek 2006, Chytrý et al. 2009b). In addition, data on native
Pyšeketal.:CatalogueofalienplantsoftheCzechRepublic 157
speciesthatarealsopartoftheCzechFlordatabaseprovidedbasisforanalysesoftheper-
formance of central-European species as aliens in other parts of the world (Pyšek et al.
2009a, Phillips et al. 2010, Stohlgren et al. 2011). Within the DAISIE and ALARM
(Setteleetal.2005)projects,thedatafromthe2002cataloguewerepartofthepan-Euro-
peandatasetthatwasusedtoanalyseinvasionpatternsatthecontinentallevel,including
cross-taxonomic evaluation of the role of macroeconomic and demographic factors in
determiningregionallevelsofinvasion(Pyšeketal.2010b,Essletal.2011),distribution
ofalienspeciesinhabitats(Pyšeketal.2010a),assessmentofecologicalandeconomic
impactsofalienspeciesinEurope(Winteretal.2009,Vilàetal.2010)andrisk-assessment
for plants based on habitat mapping (Chytrý et al. 2008b, 2009a, 2012).
Thesestudiesclearlyindicatethevalueofcompletenationalorregionalchecklistsfor
understandinginvasions.Thisstartedtobefullyrecognizedinthe2000sandresultedin
a call for pan-European inventory of invasive species within the European framework
programmes;untilthentherewassomeinformationonalienflorasavailableforEuropean
countries (Weber 1997), but the quality of data was highly variable (Pyšek 2003). The
DAISIEproject(2004–2008)madeitpossibletoorganizeanddevelopthislineofresearch
based on extensive international cooperation in Europe (DAISIE 2009). The project
assembled available data on alien plants for 48 European countries and regions, which
until then were scattered in a variety of published and unpublished accounts and data-
bases. For some countries DAISIE collected the first comprehensive checklists of alien
speciesbasedonprimarydata(Lambdonetal.2008),andestablishedanonlinedatabase,
theEuropeanInvasiveAlienSpeciesGateway(DAISIE2008).Atthesametimeitstimu-
latedelaborationofcomprehensivealienspecieschecklistsinindividualcountries,apro-
cess that still continues, and yielded new plant data for e.g. Belgium (Verloove 2006),
Estonia(Ööpiketal.2008),Italy(Celesti-Grapowetal.2009),Greece(Arianoutsouetal.
2010), and most recently Slovakia (Medvecká et al. 2012).
TheCzechRepublic,acentral-Europeancountrywithanarea78,864km2,10.3million
inhabitants,andahumanpopulationdensityof131inhabitantsperkm2,ispronetoplant
invasionsduetohistoricalandgeographicalfactors:locationonthecrossroadsofthecon-
tinent,manynaturalorhuman-createdmigrationroutesopeningpossibilitiesforcoloniza-
tion, and long-lasting human influence that further diversified the naturally diverse and
heterogeneous landscape mosaic (see Pyšek et al. 2002 for details). These features,
togetherwithastrongbotanicaltraditionandin-depthknowledgeofplantcommunities
(Chytrý2007,2009,2011)makethecountryasuitablemodelforstudyingregionalpat-
ternsofplantinvasions.Inthelastdecadesincethepublicationofthepreviouscatalogue
awealthofinformationonalienspecieshasbeenaccumulated,whichcreatedaneedfor
a revision of the original checklist.
Theaimof thepresent paper istoupdate and improvetheoriginal checklistof alien
planttaxaintheCzechRepublic(Pyšeketal.2002)byincorporatingnewdataaccumu-
latedinthelastdecade,reassessingthestatusoftaxaresultingfromimprovedtaxonomic
knowledge,andwhereverneeded,correctingerrorswhichcanhardlybeavoidedinsuch
a comprehensive work. We also provide additional information that was not part of the
previous catalogue, including the width of species’ habitat niches, their dominance in
invadedcommunitiesandtheirimpacts.Changesfromthe2002versionaredocumented
so that the reasoning behind them can be followed.
158 Preslia84:155–255,2012
Methods
Data sources
ThebasisforthepresentchecklistwastheCatalogueofalienplantsoftheCzechRepublic
publishedadecadeago(Pyšeketal.2002).Forhistoricaldata,thecompilationofboththe
previousandcurrentchecklistreliedonanoutstandingtraditionofthefloristicresearchin
theCzechRepublicdatingbacktothesecondhalfofthe18thcentury(reviewedindetailin
Pyšeketal.2002).Alreadyinthe19thcentury,aseriesofflorasandspecieslistswerepub-
lished,coveringthepresentterritoryoftheCzechRepublic(seeKrahulec2012forareview
ofthehistoryofbotanicalresearch),andrecognizingplantsbygeographicorigin;thesepro-
videvaluableinformationabouttheoccurrenceofplantsatthosetimesandresidencetimes
of neophytes (Pohl 1809–1814, Presl & Presl 1819, Opiz 1823, 1852, Rohrer & Mayer
1835,Makowsky1863,Oborny1886,Formánek1887–1897).Thewealthofinformationon
alienplantscanbefoundespeciallyintheremarkableworksbyČelakovský(1868–1883,
1882–1894),whorecognizedthealienstatusandoriginofsomeplantspresentintheCzech
floraandcommentedinconsiderabledetailontheirdistribution.Therecognitionofalien
plants continued in floras and specialized studies in the 20th century (e.g. Polívka
1900–1904, Laus 1908, Domin 1917, 1918, 1919, Dostál et al. 1948–1950, 1954, 1958,
1989).Sincethe1960s,systematicattentionstartedtobepaidtoplants,includingaliens,in
specifichuman-madehabitats(ports,railways,oilseedorwoolprocessingfactories,grain
silos, mills, rubbish tips, arable land, etc.) thanks to a specialized research section estab-
lishedattheInstituteofBotany,Průhonice,inthe1960s.Thisworkyieldedseveralfocused
compendia(e.g.Hejnýetal.1973)andprovidedabasisforsystematicrecordingofalien
plants(e.g.Jehlík1986,1998a).
TheFloraoftheCzechRepublic,witheightofnineplannedvolumespublishedupto
now(Hejný&Slavík1988–1992,Slavík1995,1997a,2000,Slavík&Štěpánková2004,
Štěpánková2010)andtheKeytothefloraoftheCzechRepublic(Kubátetal.2002),served
as a fundamental information source for this checklist. Other recent sources included
national floristic literature, namely that published in the journals of the Czech Botanical
Society (see References). During the last decade, new records for the flora of the Czech
Republichavebeensystematicallyreportedinanannuallypublishedseries,Additamentaad
floram Reipublicae Bohemicae, which has thus far yielded 10 summarizing accounts
(Hadinecetal.2002,2003,2004,2005,Hadinec&Lustyk2006,2007,2008,2009,2011,
2012). The series, initiated and edited by J. Hadinec, in cooperation with František
ProcházkaandPavelLustyk,provedavaluablesourcebecauseitnotonlyreportsnewfinds
butalsocriticallyre-evaluatesstatusofparticularspeciesandprovidesadditionaldataon
theirdistribution.
For archaeophytes, a strong tradition of Czech archaeobotanical research provided
asolidbasisforevaluationofspeciesoriginandimmigrationstatus.Mainsourcesinclude
theworks ofE.OpravilandV.Čulíková(seeReferences),theresultsofwhicharenow
availableintheArchaeobotanicaldatabaseoftheCzechRepublic(CZAD;Archaeologi-
cal Institute AS CR 2011).
Other data sources included unpublished information provided by many colleagues
(seeAcknowledgments),herbariumcollectionstoverifysomeliteraturereports(namely
PR,PRC,BRNUandPRA;codesfollowThiers2012)andourownfloristicfieldrecords
from 2002–2012.
Pyšeketal.:CatalogueofalienplantsoftheCzechRepublic 159
Thedatapresentedhereandinthepreviouscatalogue(Pyšeketal.2002)areorganized
in the working database CzechFlor held at the Institute of Botany AS CR, Průhonice.
Classification of taxa: invasion status
Thisworkfocusesonalienspecies(synonyms:adventive,exotic,introduced,non-indige-
nous,non-native)intheCzechRepublicwhichwedefineasspeciespresentintheregion
becausehumanactionsenabledthemtoovercomefundamentalbiogeographicalbarriers
(i.e. human-mediated extra-range dispersal); they occur in the area as a result of inten-
tionaloraccidentalintroductionbyhumans,orofaspontaneousspreadfromotherregions
wheretheywereintroducedbyhumans.Crossesresultingfromhybridizationwithoneor
both alien species involved are considered alien (Pyšek et al. 2004a). We define native
species(synonym:indigenousspecies)asthosethathaveevolvedinagivenareaorthat
arrivedtherebynaturalmeans(throughrangeexpansion)withoutanyintentionaloracci-
dental intervention of humans from an area where they are native (Pyšek et al. 2004a).
Weclassifiedspeciesaccordingtothestagetheyreachedalongtheintroduction–natu-
ralization–invasioncontinuum(INIC)thatdescribeshowspeciesproceedintheinvasion
processbyovercominggeographical,environmentalandbioticbarriers(Richardsonetal.
2000,2011,Richardson&Pyšek2006,Blackburnetal.2011).Basedonthisconceptwe
use the following terms to describe the invasion status:
(i)Casualspeciesarethosealienspeciesthatdonotformself-sustainingpopulations
intheinvadedregion;theymayflourishandreproduceoccasionallyinanareabuttheir
persistence depends on repeated introductionsof propagules.
(ii)Naturalizedspecies(synonym:establishedspecies)formself-sustainingpopula-
tionsforseverallifecycleswithoutdirectinterventionbypeople,ordespitehumaninter-
vention;theyoftenrecruitoffspringfreely,usuallyclosetoadultplantsandtheirpersist-
ence does not depend on ongoing input of propagules.
(iii)Invasivespeciesareasubsetofnaturalizedspecies;theyformself-replacingpopu-
lationsovermanylifecycles,producereproductiveoffspring,ofteninverylargenumbers
atconsiderabledistancesfromtheparentand/orsiteofintroduction,andhavethepotential
to spread over long distances. In addition to this definition, we introduce the
metapopulationcriteriontoseparateinvasivespeciesfromnaturalized,toaccountforthe
historical population dynamics of the treated taxa (see the next section).
We included in the list all taxa that were reported to occur at least once in the wild,
whilethosekeptexclusivelyincultivationarenotconsidered.Forescapeesfromcultiva-
tion,aplantwasincludedinthelistifitreproducedonitsownoutsidethespacewhereit
wassownorplanted(Pyšeketal.2002).Inplantsreproducingbyseed,germinationout-
side such space was considered as an escape from cultivation. A plant reproducing
clonallywasconsideredasanescapefromcultivationonlyifitsurvivedwinterandper-
sisted in a given site until the following growing season.
Comparedtothepreviouscatalogue(Pyšeketal.2002),weadoptedamoreconserva-
tiveapproach;ifthereweredoubtsaboutaspecies’originstatusandnostrongevidenceto
consider it alien, it was not included in the list; this conservative approach resulted in
removing some species that were listed in the previous catalogue (see Appendix 1).
Theclassificationofcasualvsnaturalizedstatusisespeciallydifficultforwoodyplants
reproducing intheparks orgardens where theyareplanted;insomecasesthishappens
160 Preslia84:155–255,2012
overalargeareaandfordecades(e.g.manytreesandshrubsinthePrůhoniceParknear
Praguewherethereisalong-termsystematicrecordingofregeneration).Hereweaimedat
adopting thecriterionof reproduction overseveralgenerations (Richardson etal.2000)
which puts thetimecriterioninadifferentperspectivethanthatappliedfor non-woody
taxa.Suchtaxaarethereforemostlyclassifiedascasual.Also,themajorityofhybridsare
consideredcasual,withtheexceptionofstabilizedhybridsthatincludesomenaturalized
(e.g. Medicago ×varia, Helianthus ×laetiflorus, Mentha ×rotundifolia and Oenothera
spp.) or invasive taxa (e.g. Reynoutria ×bohemica, Populus ×canadensis and Symphyo-
trichum×versicolor).
Unlikethepreviouscatalogue(seePyšeketal.2002andtheirAppendix1),wedonot
explicitlylabeltaxaaslocallynaturalized.Inthepresentpaperthiscanbeinferredfrom
thecombinationofinvasionstatusandregionalabundancecategoryinAppendix2.Inthe
samevein,taxaarenotlabelledaspost-invasivesincethisstatusisincludedintheclassifi-
cation using the population groups (see below).
Classificationoftaxaintocategoriesbasedonlong-termpopulationdynamicsandhistor-
ical link with cultivation: incorporating the unified framework for biological invasions
Inadditiontotraditionalclassificationschemedividingspeciesintothreebasiccategories
alongtheINIC(Richardsonetal.2000,Richardson&Pyšek2006,Pyšek&Richardson
2010)hereweattemptforanevenfinerclassificationbasedonthepopulationapproach
emphasizedbyBlackburnetal.(2011).Thebasisforthisclassificationarethecriteriaof
reproduction and survival applied against the background of the metapopulation
approach.Thismakesitpossibletoseparatespeciesthatsurviveinasingleorfewpopula-
tionsinaspatiallyrestrictedareafromthosethatspreadandformmetapopulationsover
large areas.
Anotherimportantpointtoemphasizeisthatwerefertothepopulationhistoryviewed
from the current perspective, i.e. the statein which the populations of a given species
existatpresent.Therefore,invasionsthatprovedunsuccessfulinproceedingalongthevar-
iousstagesoftheINIC(seeBlackburnetal.2011andtheirFig.1)arereflectedinthecur-
rentclassification,andinchangesofinvasionstatuscomparedtotheprevioustreatment
(Pyšeketal.2002).Fromthisitfollowsthatsometaxathatwerepreviouslyclassifiedas
naturalizedaremovedtothecasualcategory(reflecting‘invasionfailure’),andsometaxa
previously considered invasive are now classified as naturalized (reflecting ‘boom and
bustphenomenon’;sensuBlackburnetal.2011).TheseshiftsamongtheINICcategories
reflectnotonlychangesinspecies’behaviourinthepastdecadebutalsothemoreconser-
vativeapproachadoptedforthecurrentclassification.Anotherprinciplewefollowisthat
ofthehigheststageachievedatthepopulationlevel;individualpopulationsofanalien
speciesmayoccurinaregionindifferentstagesoftheINIC;earlyintheprocess,somecan
benaturalizedwhileothersarestillcasual(e.g.Essletal.2009),whereaslateron,some
can be invasivewhileothers not (e.g. Meyerson etal.2010a, b, Saltonstalletal.2010).
Therefore, if some of the populations of a species reached the naturalized or invasion
stage, the species is classified as such in Appendix 2.
Therefore, the rationale of classification of alien species into finer groups (termed
‘population groups’) is based on the following criteria (Table 1):
Pyšeketal.:CatalogueofalienplantsoftheCzechRepublic 161
(A) Sustainability of populations of the species in the target region of the Czech
Republic;herewedistinguishbetween(i)speciesexistingasnon-self-sustainingpopula-
tionsoroccasionallyrecordedindividuals,correspondingtoBlackburnetal.’s(2011)cat-
egoriesB3+C2,andthecasualstageofRichardsonetal.’s(2000)framework;thereason
forlumpingthecategoriesB3(definedasindividualstransportedbeyondlimitsofnative
range,anddirectlyreleasedintonovelenvironment)andC2(individualssurvivinginthe
wild in location where introduced, reproduction occurring, but population not self-sus-
taining)isthatfromrecordsinfloristicliteratureitisimpossibletoinferwhetherthepres-
enceoftheplantisduetoadirectintroductionofapropaguleintotheregionoraresultof
atemporaryreproductiveeventwithintheregion;(ii)speciesoccurringinself-sustaining
populations; these populations can be numerous and widespread but remain isolated
(C3+D1+D2,naturalizedspecies–lumpingduetoinsufficientknowledgeaboutwhether
thepopulationsrecruitfromtheoriginalpointofintroductionandwhetherthosespreadfar
from itreproduce in new locations); and (iii) species that currently form numerous and
persistentmetapopulationswidespreadoverlargeareas(Blackburnetal.’s2011categoryE).
(B)Historicalpopulationdynamicsisusedtoclassifyspeciesaccordingtothehigh-
eststagetheyreachedintheinvasionprocesscombinedwiththecurrentstate.Wedistin-
guishwhetherornotthemostsuccessfulpopulationsofunsuccessfulspecieshaveestab-
lishedandweresurvivingintheregionbeforedeclinetothecurrentlevelsofoccurrence;
successfulspeciesareclassifiedbasedonthetendencyforspread,withrespecttowhether
thistrendoccurredinthepastorisstillvalid(Table1).Employingthiscriterion,i.e.focus
on the current status of species’ populations and processes that resulted in the present
state,isthereasonwhythecorrespondencewiththecategoriesofBlackburnetal.(2011)
is, however, not automatically translated into those of the introduction–naturaliza-
tion–invasioncontinuum.ThisconcernsthosespeciesclassifiedasD1,D2andconsidered
invasiveinBlackburnetal.’s(2011)scheme(self-sustainingpopulationinthewild,with
individualssurviving,oralsoreproducing,asignificantdistancefromtheoriginalpointof
introduction), populations of which no longer exhibit dynamic spread and are currently
stabilized(Groups7,9,11inTable1),orevendeclineintheCzechRepublic(Group6).
Wealsodonotconsiderasinvasivethosespeciesthatonlystarttoexhibitsymptomsofthe
beginningspread(Groups8,10,12).Adheringtoaconservativeapproach,thesespecies
arestillconsideredasnaturalized.Nevertheless,theymeritparticularattentionintermsof
monitoringastheyarelikelytobecomeinvasiveinthenearfuture.Onlythosespeciesthat
are currently spreading are classified as invasive (Groups 14, 16, 18; Table 1).
(C)Linktopopulationsincultivation.Theabovecriteriaareemployedagainstthe
backgroundofspecies’plantinghistoriesintheregion.Hereweseparatespeciesinto(i)
thosethathaveneverbeencultivated(correspondingtocontaminantandstowawaypath-
waysofintroductionaccordingtoHulmeetal.2008;Appendix2),henceunsupportedby
thepropagulepressurefromplantedpopulations;(ii)thoseinwhichthepeakofplanting
intensitywasinthepastandatpresenttheplantingceasedorisonlyofmarginalimpor-
tance;and(iii)thosethatarestillcommonlykeptincultivation,beitforhorticulturalor
agriculturalpurposes.Forthecultivatedspeciesthiscriterionreferstothedegreeofconti-
nuityofpropagulepressure.Thetimeframeoverwhichthiscriterionappliesisthelastca
200 years for which period the information on the frequency of planting can be inferred.
162 Preslia84:155–255,2012
Table1.–ClassificationofthealienfloraoftheCzechRepublicintopopulationgroups(PG)basedonthecurrentpopulationstateandtheirconnectivity,trendsintheirlong-termdynamics,andlinktocultivatedpopulationsasasourceofpropagulepressureinthepastandpresent.Seetextfordetails.Thepopulationgroupsarereferredbynumberspre-sentedinAppendix2,withtheINIC(introduction–naturalization–invasioncontinuum)statusindicatedandnumberofspeciesshowninparentheses.Thelinktotheunifiedinva-sionframework(Blackburnetal.2011)isindicatedbytheircategoriesthatarerelevanttothegivenpopulationstateshowninparentheses;notethatsomeoftheircategoriesreferringtotheinvasionstagesuchasD1,D2,E(Blackburnetal.2011;theirFig.1)areclassifiedasnaturalizedbecausethefocushereisonthepresentstateandapproachadoptedisconservative.Taxainthesecategoriesmayhavereachedtheinvasionstageinthepastbuttheirpopulationsarestabilizedandnolongerspread.Linktostandardclassi-ficationoftheINICcategories(Richardsonetal.2000)isindicatedbycolouredshading.Theschemealsoseparatesgroupsoftaxaintroducedbyunintentionalpathways(con-taminant,stowaway),marked“none”intheCultivationcolumn,fromthoseintroduceddeliberately(release,escape;Hulmeetal.2008,Pyšeketal.2011b). PopulationsCultivationIntroduction&FailureEstablishment&Establishment&NoStartingspreadOngoingspreadFailuretrend (a)Notself-sustaining(a1)NonePG1:PG2:(B3,C2)casual(395)casual(45) (a2)PastPG3:casual(17) (a3)OngoingPG4&5:casual(501&28) (b)Self-sustaining(b1)NonePG6:PG7:PG8:(C3,D1,D2)naturalized(54)naturalized(40)naturalized(43) (b2)PastPG9:PG10:naturalized(36)naturalized(11) (b3)OngoingPG11:PG12:naturalized(65)naturalized(31) (c)Metapopulations(c1)NonePG13:PG14:(E)naturalized(100)invasive(28) (c2)PastPG15:PG16:naturalized(8)Invasive(9) (c3)OngoingGroup17:PG18:naturalized(19)invasive(24) 9241162688561Totaltaxa
Pyšeketal.:CatalogueofalienplantsoftheCzechRepublic 163
Residence time status
Basedontheresidencetime,i.e.thetimesincethearrivalofaspeciestotheterritoryofthe
presentCzechRepublic,wedistinguisharchaeophytes(taxaintroducedbeforethediscov-
eryofAmerica,approx.1500A.D.)andneophytes(taxaintroducedafterthatdate),fol-
lowingtheconcepttraditionallyusedinEuropeanstudiesonplantinvasions(e.g.Holub&
Jirásek1967,Pyšeketal.2002,2004a).Whenevaluatingresidencetimestatusofhybrids,
wefollowedthatofthealienparent;therefore,crossesofarchaeophyteswithnativeare
considered archaeophytes, and hybridization with neophytes involved are classified as
neophytes regardless of the status of the second parent.
Forneophytes,wedeterminedtheyearofthefirstrecordintheCzechRepublicthatis
usedtoinfertheminimumresidencetime,i.e.thetimeforwhichthespeciesisknowntobe
present(Rejmánek2000,Pyšek&Jarošík2005,Richardson&Pyšek2006);thischaracter-
isticisimportantinevaluationofinvasionstatussinceitindicateshowmuchtimethespecies
hadtocolonizesuitablehabitats(Williamsonetal.2009,Gassóetal.2010),gothroughalag
phase (Kowarik 1995, Crooks 2005) or build relationship with native biota (Pyšek et al.
2011a).Aspointedoutabove,thereliabilityoftheyearsoffirstrecordscruciallydependson
theintensityoffloristicresearchinthepast(seePyšeketal.2002fordiscussion).
Species traits: taxonomic affiliation and life history
TaxonomicaffiliationoftaxatofamiliesfollowstheapproachoftheAngiospermPhylogeny
Group Classification: APG III (Stevens 2001 onwards, Angiosperm Phylogeny Group
2009),andSmithetal.(2006)forferns.Thisclassificationsystemincorporatesdatafrom
molecular, chemical and morphological phylogenies in an attempt to represent the latest
thinking on angiosperm evolution, and in a few lineages (e.g. Scrophulariales) it differs
markedlyfromthetraditionalsystem.
Thefollowinglifehistorieswereassignedtothespecies:annual,biennial,perennial,
semishrub, shrub, tree, fern, aquatic and parasitic (see Appendix 2).
Geographic origin
Taxawereclassifiedaccordingtotheirgeographicorigin(nativerange)atthelevelofcon-
tinents (parts of Europe other than the Czech Republic, Africa, Asia, North America
includingMexico,CentralAmerica,SouthAmerica,andAustralia).Unliketheprevious
catalogue (Pyšek et al. 2002), we distinguished the Mediterranean region as a separate
regionoforigin,coveringrespectivepartsofsouthernEurope,northernAfricaandwest-
ernAsiafromTurkeyandIsraeltoAfghanistan.ThisbroaddefinitionoftheMediterra-
nean region corresponds to the Mediterranean, Submediterranean and Oriental Floristic
SubregionsaccordingtoMeuseletal.(1965).Theregiondelimitedinthiswayisverycon-
venientforplantinvasionstudiesasitincludestheareasoforiginofNeolithicagriculture.
Indications of Europe, Asiaand Africa inAppendix 2 refer totheirpartsother thanthe
Mediterranean region in this delimitation.
Hybridsandspeciesthatoriginatedthroughrecenthybridizationarelistedasaspecial
origincategoryandweemployedclassificationbasedonhowspeciesoriginatedinterms
oftheirevolutionaryhistory.Thisapproachacknowledgesthatsomedidnotevolvenatu-
rally,butunderhumaninfluence,donothaveanaturalhomerange,andtheiroriginalhab-
164 Preslia84:155–255,2012
itatisunknown(Kühn&Klotz2003).Especiallyformanyarchaeophytes,nativeranges
are not known or are highly uncertain, and some archaeophytes are regarded as alien
throughouttheirknownglobalrange.Thesetaxa,termedanecophytes(homelessplants;
Zohary1962)couldbecultivatedplantsthatescapedtothewildorplantsthatco-evolved
withhumanlandusessuchasagriculture(Kühn&Klotz2002,2003,Kühnetal.2004).In
ourtreatment,wefollowthemoreconservativeapproachandlabelasanecophytesmostly
those species that evolved in cultivation, or species occurring in the wild but with their
region of origin being unknown.
Regional abundance
Typeofregionalabundanceinthelandscapewasestimatedforeachtaxonusingthefol-
lowing scale: single locality, rare, scattered, locally abundant, and common across the
wholeCzechRepublic.Aspecialcategorytermed‘vanished’relatestothetaxaforwhich
norecordshavebeenknownforalongperiod,andwhereitishighlyimprobablethatthey
would appear again (Pyšek et al. 2002).
Occurrence in habitats
Thepreviouscatalogueprovidedinformationontheoccurrenceofalienspeciesinphyto-
sociologicalalliances,differenttypesoflandscapesandwithrespecttolanduse(Pyšeket
al.2002).Hereweuseextensivelyreviseddatafromthedatabaseofspeciesoccurrencesin
88majorhabitattypesoftheCzechRepublicasdefinedbySádloetal.(2007),whichcor-
respond to phytosociological alliances or groups of alliances. All four levels of species
affinitytothehabitatsasdefinedbySádloetal.(2007: 305) aretakenintoaccount,i.e.
aspeciesisconsideredasoccurringinahabitatevenifthehabitatisoutsideitsecological
optimum, but the species is occasionally found there.
Cover in plant communities
Toobtainthedataonthecoverofalienspeciesinplantcommunities,weusedvegetation
plot observations (phytosociological relevés) stored in the Czech National Phytosocio-
logical Database held at the Department of Botany and Zoology, Masaryk University,
Brno(Chytrý&Rafajová2003,EU-CZ-001accordingtoDengleretal.2011).Atthetime
ofdataextraction(April2012)thedatabasecontained88,215relevésfromplotssmaller
than 1000 m2 with an indication of plot size and geographical coordinates. Of these,
41,582relevéscontainedatleastonealienspecies.Toreduceoversamplingofsomeareas
orsomevegetationtypes,weselectedonlyonerelevéfromagrouporrelevésassignedto
thesamephytosociologicalalliancewithinthesamegridcellof1.25longitudinal×0.75
latitudinal minutes, i.e. approximately 1.5 × 1.4 km. This stratified resampling yielded
16,033 relevéscontaining437alienspecies,whichwereusedtoquantifyspeciescover.
Onlyspeciesoccurringinatleast25relevéswereevaluatedtoavoidinaccuraciesresulting
from small sample size. For these species, mean percentage cover across all relevés in
which the species was present was calculated.
Impact
ToprovidethefirstinsightsintotheimpactsofalienplantspeciesintheCzechRepublic,
we used the data gathered by the DAISIE project (DAISIE 2008, 2009) and indicated