Communitiy level impacts of alien invasive plants and the role of native range habitats in plant invasions

Abstract

Zfuěr Iilrllěleltí ttn'a:ttíchdt.ullupodle 'le1ichl.lil'u ttctttttadotaltá 'společensn.u Í,řcdk|ádanástudieb1la zanrěřcnana neo{n. tj'nepLil.odnidruh1 introdr'rkor'anépo roce l5()(]'protoŽe.iejichv|il .jesilně.|Šía ríce patrnr.neŽ.jaktonruje u archaeoh'tLr.tj druhu ilrlrodL|kLr\aníchpřcd r' l500. Přičinou.ic.ieiichrelatirněnedálná doba zar,lečcnia p()Zortlh()dnád)nanrikaln\'aze(P\šeketa|.2()02)'ZkoumanéneoÍit}Seod sebeIišive srrc|t rIircch na inradoranáspoleČensn,a'l. glanduIt/eral'lkázala lrrininiálnir'lir na dir'ersitut druhoré sloŽeni společenstera to .1ak běhent terénriiliopokusu (kapitoIa I) tak l t kontparatir.nístudii 1kapitolalt a lll)' N{al1vIir.tohoto druh je zře.jnrěspo.jensniZši kottkurettČní5ilou tohotojednoletehodruhu-ktcn má drobn! kořenorr s!s(éllla.iehoŽ port]Sl\ ne.jsour ptlkryrnosti l' glanduli/ěrtt zccla proslororě hontogenni' Abundance a poknrnost I' glutttlulifera.ieběhem sczónl sniŽor'árra..|ak Iiáno\itédrLrh1břehorrc|r společcnSte\\(-tth'sÍegicrseptum.(-ttsculaeurop(led)ZatěŽu.iilod}hi a ZpusobuiínlortaIitu rost|in(Beer|ing& Perrins l99]), C'haraktcrinradoran(ch spoIečenstc\-kde donlintt1t donráci rritrollIrlidonlillant\ 1{,t'Itt:utltoica' (-ttt.tluusCt'!spus.('hde|.oph't'llttnhulbclsutttI naric neposkr1ujeprostorkonkurenČnčslab1nldrrrhrtnlbezohIcduna inrazi l' gluntluttfertt' l 1...

Conclusions Categorization of the species studied according to their impact on invaded communities This study focused on neophytes, species introduced after 1500 A.D., because their impact on native vegetation is higher and more obvious than that of archaeophytes, introduced before that date, due to considerable invasion dynamics and relatively short residence time (Pyšek et al. 2002). The target neophytes, included in the study, differ strongly in their community level impacts. Impatiens glandulifera had a miniscule impact on species diversity and composition, both in the removal experiment and comparative study (Chapter I). This small impact is likely to be associated with this annual species' lower competitive strength, which has a modest root system and forms stands that are not homogeneous in terms of cover. The density of I. glandulifera populations is known to decrease during the vegetation season, as plants fall due the weight of climbers, which are common in invaded riparian communities (Calystegia sepium, Cuscuta europaea - see Beerling & Perrins 1993). Moreover, the character of communities in which I. glandulifera invades, mostly riparian nitrophilous vegetation, does not provide opportunities for competitively weak species even if they are not invaded. This vegetation is dominated by tall,...