Neophytes in Austria: Habitat preferences and ecological effects

Johannes Walter1), Franz Essl2), Thorsten Englisch3) & Michael Kiehn1)

1) Inst. of , Dept. of Systematic and Evolutionary Botany, Univ. of Vienna, Rennweg 14, 1030 Vienna, Austria; [email protected] 2) Federal Environment Agency, Spittelauer Lände 5, 1090 Vienna, Austria 3) Inst. of Botany, Dept. of , Univ. of Vienna, Rennweg 14, 1030 Vienna, Austria

Summary Recently, the first national inventory of alien in Austria was published, containing annotated lists of , fungi and animals and providing information on their distribution and habitat prefe- rences. The present paper reviews this study, focusing on the habitat preferences and ecological effects of species. Most of the 1110 neophytic vascular plant species recorded for Austria occur in ruderal and sege- tal vegetation. Certain natural and semi-natural vegetation types, however, are also strongly invaded by neophytes. These include riparian areas, floodplain forests and dry vegetation of Pannonic eastern Austria. In contrast, the invasion success of neophytes in alpine meadows and dwarf shrub commu- nities, in bogs, fens and moist meadows, as well as in rocks and screes is very low. The invasion suc- cess of neophytes seems to be associated with a strong anthropogenic and natural disturbance regi- me, excessive supply of nutrients and warm climate. The number of neophytes that pose a threat to biodiversity is low: 17 species are classified as inva- sive and another 18 species as potentially invasive. Although invasive neophytes compose only a small fraction of the complete (0.9%) in Austria, they probably exert a significant influence on natu- ral and semi-natural ecosystems. Ecological effects caused by invasive neophytes in Austria include changes in species composition, succession patterns, nutrient cycles via eutrophication and in evolu- tionary paths via hybridization. Key words: alien species, biological invasion, ecological effects, , naturalization, vascu- lar plants

1. Introduction Human activities such as , Alien species are acknowledged as a major aquaculture, , transportation, threat to the conservation of global biodi- recreation and building activities promote versity (e.g. Sala et al. 2000; McNeely et al. the intentional and accidental spread of 2001; Cronk & Fuller 2001; Sukopp 2002; species across their natural boundaries. Cox 2004). While detailed case studies of Trade and passenger traffic have increa- alien species are necessary to understand sed enormously during the past centuries the invasion processes, inventories of alien and especially during the last decades; this species have proven to be useful, especially has accelerated the introduction of alien for deriving empirical hypotheses that can species (Jäger 1988; Kowarik 2003). be tested by experimental methods and for To face the conservational and econo- describing invasion patterns at various sca- mic problems caused by alien species, les, from global to local (Kühn & Klotz international cooperation is needed. 2003; Pyšek et al. 2003). Therefore, the Convention of Biological

In: Nentwig, W. et al. (Eds.): Biological Invasions – From Ecology to Control. 13 NEOBIOTA 6 (2005): 13-25 J. Walter, F. Essl, T. Englisch & M. Kiehn

Diversity (CBD), ratified by Austria in The questions addressed in this paper are 1994, underlines the urgent need for well- (1) which habitats are colonized and (2) designed studies examining patterns and which ecological effects are provoked by processes associated with species loss at neophytic vascular plant species in all scales around the world. Austria. To help accomplishing this task, the Austrian Ministry of Agriculture and 2. Material and Methods Forestry, Environment and Water 2.1 Definitions and Data Management, in cooperation with the Austrian Federal Environment Agency, Alien plant species have been defined vari- commissioned a national inventory of ously, with substantially different meanings alien species (Essl & Rabitsch 2002; (e.g. Richardson et al. 2000; Schröder 2000; Rabitsch & Essl 2004). The present con- Pyšek et al. 2004). We use the definitions tribution uses the compiled data and case provided in Table 1 to determine which studies to analyse patterns within vascular species to include in our lists. neophytic plants. This taxonomic group is The present paper deals with alien vascu- best suited for such an approach because lar plant species which arrived in Austria it is well studied and rich in neophytes. after 1492 by direct or indirect human sup-

Table 1: Terminology and definitions pertaining to non-indigenous vascular plant species in this paper (after Scholz 1995, Schroeder 1974, 2000). terminology definition reference alien plant taxa in a given area whose presence there is due Pyšek et al. 2004 to intentional or unintentional human involvement, or which have arrived there without the help of people from an area in which they are alien plant taxa introduced intentionally or unintentionally Schroeder 1974, 2000 by humans before 1492 and occurring or having occurred in the wild neophytes plant / fungi / animal taxa introduced intentionally Schroeder 1974, 2000 or unintentionally by humans following 1492 and occurring or having occurred in the wild anecophytes plant taxa having evolved under intentional or Scholz 1995 unintentional human selection from wild-growing non-indigenous ancestors and growing or having grown in the wild naturalized alien taxa that reproduce consistently in the wild Kowarik 2003 (at least two spontaneous generations within at least 25 years) casual alien taxa which do not form self-replacing popula- Kowarik 2003 tions in the wild (less than two generations within 25 years) invasive posing a threat to indigenous biodiversity at the gene- IUCN 2003 tic, species or ecosystem level potentially expected to fulfil above criterion if current spread Essl & Rabitsch 2002 invasive continues

14 Neophytes in Austria port and which grow or have grown in the Austria 2003). The country is covered to wild (neophytes). Plant species that have 43 % by forests and to 31 % by agricultu- evolved under human selection (“anecophy- ral land. Whereas the lowlands are shaped tes”) are included (Scholz 1995). by agriculture, the sparsely populated A species is defined as “invasive” if it mountains are dominated by forests or poses a threat to indigenous biodiversity at alpine vegetation. In the eastern lowlands, the genetic, species or ecosystem level the intersection of two biogeographic (IUCN 2001). We are aware that the term regions (Pannonic and Central-European “invasive” is also used with different mea- region) promotes a high biodiversity nings (Rejmánek et al. 2002; Pyšek et al. (Adler et al. 1994; Ellmauer 1994). 2004). For the present study, however, its meaning is restricted to conservational 3. Results concerns and delimited by expert judge- 3.1 Habitat preferences ment. Those taxa that threaten indigenous biodiversity in adjacent countries but are Ruderal and segetal vegetation still rare in Austria were classified as In ruderal and segetal vegetation, 792 of “potentially invasive”. Furthermore, the the 1110 neophytes recorded for Austria species were classified according to their were documented. Favorable import rou- status (naturalized or casual). tes and habitat conditions, as given in and nomenclature follow Adler et al. large cities (Pyšek 1998; Sukopp 2002), (1994), recent taxonomic changes were promote a high diversity of neophytes in incorporated. these habitat types. In Austria, railway sta- The national inventory of alien species tions (e.g. Brandes 1993; Zidorn & in Austria provided an annotated list of Dobner 1999; Hohla et al. 1998, 2000), neophytic vascular plants with additional motorways (Oppermann 1998; Gerstber- information on their distribution and habi- ger 2001), large industrial areas (Geissel- tat requirements (Walter et al. 2002). brecht-Taferner & Mucina 1995) and rub- Additionally, case studies of the invasion bish dumps (Walter 1992) serve as focal history of 20 invasive or currently rapidly points for neophytic ruderal species. spreading neophytes were published (Essl Certain species that prefer ruderal and & Walter 2004). Here, we use the compiled segetal habitats have recently spread con- data and case studies for further analyses. spicuously. One of them is the South African Senecio inaequidens, having spread 2.2 Study area mainly along railways over the past 20 Austria is a landlocked country in Central years. The Mediterranean Geranium purpu- Europe covering an area of 83,858 km2. reum was first recorded for Austria in The population comprises slightly more 1990; it has since spread rapidly along rail- than 8 million inhabitants (97 inhabitants ways and is now found in seven of per km2), most of them living in the low- Austria’s nine federal states. Duchesnea indi- lands and in the major valleys of the Alps. ca, native to South- and Southeast Asia, 66 % of the population live in urban was a rare casual in Austria up to the areas, 34 % in rural areas. Two-thirds of 1970s; it spread rapidly in the 1990s and Austria are dominated by mountainous has become widespread in the last years. regions, and 10 % of the total area Several neophytes, e.g. grass species of belongs to the alpine zone (Statistik the families Poaceae and Paniceae, have

15 J. Walter, F. Essl, T. Englisch & M. Kiehn spread prominently in the last decades. tsuga menziesii, Quercus rubra, Spiraea japonica) The North American Panicum capillare was are currently spreading. Some of these spe- first recorded in Austria in 1855 but has cies are planted for timber production spread remarkably since the 1970s. More (especially Pseudotsuga menziesii, Quercus recently, P. dichotomiflorum, P. gattingeri, P. hill- rubra) and are therefore of high economic manii and P. schinzii, recorded since the value. In the Pannonic region of eastern 1950s, 1980s or 1990s, have spread mainly Austria the zonal xerothermic mixed oak in maize cultures (Schröck et al. 2004). forests are strongly affected by invasive Since the mid-1990s, Sorghum halepense has neophytes (Robinia pseudacacia, Ailanthus been increasing in frequency and range in altissima; Fig. 1). The most widespread neo- Austria (Essl in press). phytic tree is Robinia pseudacacia, compri- sing 0.2 % of the standing crop of forest Zonal forests trees (Kirchmeir et al. 2001). In Austrian zonal forests, 138 neophytic Floodplain forests species were recorded, most of them being only locally established or casual. Impatiens In Austria, floodplain forests are strongly parviflora is the only widespread herbaceous invaded by neophytes: a high proportion species. A few others are locally naturalized of the 49 neophytes recorded here are (e.g. pardalianches, Galeobdolon widespread. Of particular conservational argentatum, Scutellaria altissima). Certain rare concern is Acer negundo,which forms a neophytic woody species (Cotoneaster spp., dense understorey in willow forests of Mahonia aquifolium, Prunus serotina, Pseudo- eastern Austria, e.g. in the national park

Fig. 1: Distribution map of Robinia pseudacacia woodlands in Austria (Essl et al. 2002 and sup- plementary unpublished data).

16 Neophytes in Austria

Donau-Auen (Drescher et al. 2004). neophytes with a restricted distribution Fraxinus pennsylvanica spreads in floodplain are casuals (e.g. Azolla filiculoides). forests of the March and Danube rivers A thermal spring in Carinthia near east of Vienna and outcompetes the rare Villach provides a habitat for some (sub)- native Fraxinus angustifolia (Lazowski 1999; tropical aquatic plants (e.g. Myriophyllum Drescher et al. 2004). Furthermore, per- aquaticum, Sagittaria latifolia, Salvinia natans, ennial tall herbs (Aster lanceolatus, Fallopia rivularis, Vallisneria spiralis, japonica, Helianthus tuberosus, Solidago gigan- Hydrilla verticillata, Lagarosiphon major). This tea) and the annual Impatiens glandulifera is the only site where frost-sensitive aqua- heavily invaded Austrian floodplain tic species are able to survive the harsh forests (e.g. Feráková 1994; Drescher & Austrian winter. Prots 2000; Drescher et al. 2004). Bogs, fens and moist-soil meadows Riparian areas Only five neophytes were recorded in bogs, Riparian areas (banks of rivers, edges of fens and moist-soil meadows. Euthamia gra- lakes and ponds) are strongly affected by minifolia (= Solidago graminifolia) grows in fens neophytes in Austria, containing 88 such and moist meadows of the Rhine Delta in species. Several neophytes (Aster lanceola- Vorarlberg. In raised bogs and transition tus, Solidago canadensis, Fallopia japonica, bogs, only the North American Kalmia angu- Helianthus tuberosus) form dense stands stifolia is naturalized (at one site in Upper mostly by clonal growth. Recently, Bidens Austria), and Erica tetralix was found recent- frondosa, Epilobium ciliatum and Heracleum ly in Salzburg and Upper Austria. mantegazzianum spread rapidly, whereas Echinocystis lobata is invading the riparian Fertilized meadows and pastures vegetation of the March River (Feráková 1994). Several ruderal species frequently In these nutrient-rich grasslands, 32 neo- grow on gravel banks (e.g. Oenothera spp., phytes were recorded, two of them being Conyza canadensis, Erigeron annuus). Some naturalized. Lolium multiflorum is widespread rare naturalized neophytes (e.g. Acorus in lowland regions and also cultivated as a calamus, Mimulus guttatus, Typha laxmannii) valuable forage crop in fodder meadows. mainly occur in reeds of standing water Veronica filiformis occurs in nutrient-rich bodies. Only the riparian vegetation of meadows and lawns. The invasion process the upper reaches of undammed rivers in of this species started in humid areas of the Alps (e.g. Lech in Tyrol) lack neophy- Austria, but the plant has since invaded all tes (Müller & Bürger 1990). lowlands except for the Pannonic region.

Water vegetation Dry, semi-dry grassland and nutrient-poor meadows Aquatic habitats were invaded by 20 neo- phytes in Austria. In nutrient-poor open- These habitats contain 32 neophytes in water ecosystems, hardly any neophytes Austria. Especially in Pannonic eastern were recorded. In nutrient-rich water Austria, however, dry and semi-dry grass- bodies, one invasive neophyte (Elodea land is invaded by Robinia pseudacacia and canadensis) occurs. There is evidence that Ailanthus altissima (Fig. 1). Only one other another species of the (E. nuttallii) species (Phedimus spurius [= Sedum spurium]) is now becoming naturalized. Certain is rather widespread and naturalized.

17 J. Walter, F. Essl, T. Englisch & M. Kiehn

More neophytes regularly invade ruderali- 3.2. Ecological effects zed semi-dry grassland (e.g. Erigeron annu- Of the total 1110 neophytes recorded in us, Solidago canadensis). Austria, 17 taxa are considered to be inva- sive and another 18 species have been Rocks and screes classified as potentially invasive (Table 2). In rocks and screes at high altitudes, neo- These species are causing detrimental phytes are absent in Austria. In sites neigh- ecological effects for the conservation of bouring settlements at lower altitudes, biodiversity. some of the 61 neophytes recorded occur Change in species composition of regularly. A few taxa (e.g. Robinia pseudaca- vegetation types is thought to be the most cia, Cymbalaria muralis) are naturalized at important effect of plant invasions in many sites, whereas a larger number (e.g. Austria. All invasive and potentially inva- Syringa vulgaris, Thuja orientalis, Antirrhinum sive neophytes are reported to fulfil this majus, Erysimum cheiri, Phedimus spurius, criterion. Changes in succession patterns Pseudofumaria lutea [= Corydalis lutea]) are have been recorded for 17 invasive and casuals or locally naturalized. potentially invasive species. These chan- ges include the formation of new vegeta- Alpine grasslands and dwarf shrub tion types and altered succession velocity communities because dense stands of neophytic tall herbs impede the regeneration of trees In the alpine zone of Austria, only one (Kowarik 2003). taxon has been recorded as persisting for Altered nutrient cycles were recorded a while after intentional introduction at for two species. Lupinus polyphyllus (Fig. 2) one site (Sanguisorba dodecandra).

Fig. 2: Distribution map of Lupinus polyphyllus in Austria (unpublished data from “Mapping the Flora of Austria”, database kept at Inst. of Botany, Univ. of Vienna).

18 Neophytes in Austria

Table 2: Habitat preferences and ecological effects of invasive and potentially invasive neophy- tes in Austria. + = main occurrence; (+) = accessory occurrence; data taken from Essl & Rabitsch (2002). Invasiveness: * = invasive, ° = potentially invasive; Family: Ace. = Aceraceae, Api. = Apiaceae, Ast. = , Bal. = Balsaminaceae, Ber. = Berberidaceae, Ela. = Elaeagnaceae, Fab. = Fabaceae, Hyd. = Hydrocharitaceae, Ole. = Oleaceae, Ona. = Onagraceae, Pin. = Pinaceae, Pol. = Polygonaceae, Ros. = Rosaceae, Sal. = Salicaceae, Sim. = Simaroubaceae. Ecological Effects: 1 = changes in species composition, 2) changes in succession pattern, 3) changes of nutrient cycles, 4) hybridization (based on literature and field experience of the authors).

Species Family effects Ecological Zonal formation habitats Open water Flood-plain formation Riparian areas Bogs, fens, moist meadows grasslandFertilized Dry, grassland nutrient-poor Invasiveness Segetal, ruderal vegetation Rocks, screes Alpine meadows, dwarf shrub vegetation

Acer negundo * Ace. 1, 2 (+) + (+) Ailanthus altissima *Sim.1 + + + Ambrosia artemisiifolia °Ast.1 + Amorpha fruticosa °Fab.1,2+ + Asclepias syriaca °Asc.1 + + Aster lanceolatus *Ast.1,2(+) + + (+) Aster novi-belgii *Ast.1,2(+) + + Bidens frondosa *Ast.1 + Buddleja davidii °Bud.1 + + (+) Duchesnea indica ° Ros. 1 (+) + (+) Elaeagnus angustifolia °Ela.1(+) + Elodea canadensis *Hyd.1,2 + Elodea nuttallii °Hyd.1,2 + Epilobium ciliatum * Ona. 1, 4 (+) + (+) Fallopia japonica *Pol.1,2(+) + + (+) Fallopia x bohemica ° Pol. 1, 2 (+) + (+) Fallopia sachalinensis ° Pol. 1, 2 (+) + (+) Fraxinus pennsylvanica *Ole.1 + Glyceria striata °Poa.1 + (+) Helianthus tuberosus *Ast.1,2(+) + + Heracleum mantegazzianum ° Api. 1 (+) (+) + (+) Impatiens glandulifera *Bal.1(+) + + (+) Impatiens parviflora *Bal.1(+)+ Lupinus polyphyllus °Fab.1,3(+) + Mahonia aquifolium °Ber.1 + Pinus strobus °Pin.1 + (+) Populus x canadensis * Sal. 1,2,4 (+) + + Prunus serotina °Ros.1 + Pseudotsuga menziesii °Pin.1,2 + Robinia pseudacacia * Fab. 1,2,3 + + (+) Rudbeckia laciniata *Ast.1,2(+) + + Senecio inaequidens °Ast.1 + (+) Solidago canadensis *Ast.1,2+ (+)+ Solidago gigantea *Ast.1,2(+) + + Syringa vulgaris °Ole.1,2 + +

19 J. Walter, F. Essl, T. Englisch & M. Kiehn and Robinia pseudacacia live in symbiosis rope. Most neophytes in Germany (Kühn with nodule bacteria. Both species there- & Klotz 2003) and the Czech Republic fore severely alter nutrient cycles and (Pyšek et al. 2002b, 2003) also occur in increase the productivity of the nutrient- ruderal and segetal vegetation. High levels poor habitats they primarily invade of anthropogenic disturbance seem to (Kowarik 1995; Neuhauser 2001). promote the spread of neophytes in these Hybridization events involve two inva- habitats (Kowarik 1999, 2003). Human sive or potentially invasive neophytes. In settlements serve as focal points for plant Austria, crosses of the naturalized North invasions, and there is a clear positive cor- American Epilobium ciliatum with six rela- relation between size and age of towns ted native species have been recorded and the number of neophytes (Sukopp until now. Populus x canadensis includes 1976; Pyšek & Pyšek 1991; Pyšek 1998). various hybrids of a North American (P. Floodplain forests are characterized by deltoides) and a European (P. nigra) poplar natural disturbances, regularly creating species, cultivated for their fast growth open gravel and sand banks. Moreover, (Heinze 1998a, 1998b). Molecular studies most large rivers in Austria were strongly show that up to 10 % of poplar regenera- altered by human disturbance (e.g. eutro- tion in Austria consists of back crosses phication, damming, water management). between P. x canadensis and P. nigra (Heinze River valleys therefore generally serve as 1998b), threatening the native poplar spe- important corridors for neophytes cies (Niklfeld 1999). (Sukopp 1976; Kowarik 1992, 1999; Mül- ler 1995, 1997) and are also strongly affec- 4. Discussion ted by neophytes in Austria. In Central Europe, riparian areas show 4.1 Habitat preferences the highest number of neophytes of all In general, invasion success in Central natural and semi-natural vegetation types Europe seems to be associated with (Lohmeyer & Sukopp 1992, 2001; Pyšek strong anthropogenic or natural distur- et al. 2002b). This finding also holds true bance regimes along with an abundant for Austria: floodplain forests and ripari- supply of nutrients and a warm climate an areas are the natural vegetation types (Lohmeyer & Sukopp 1992; Pyšek 1998; most prone to invasions. Kowarik 1999; Pyšek et al. 2002a). Our Although aquatic habitats in warmer data seem to confirm this hypothesis for climates are heavily invaded by neophytes Austria. Accordingly, neophytes are distri- (e.g. Bossard et al. 2000; Cronk & Fuller buted unevenly in Austria. Lowland 2001), only few neophytes have invaded regions and habitats centered in lowlands these habitats in Austria. This finding is (riparian vegetation, floodplain forests, true for other temperate Central Euro- ruderal and segetal vegetation) are stron- pean countries as well (Pysek et al. 2002b; gly affected by invading neophytes, Kühn & Klotz 2003). This may indicate whereas the vegetation of the montane that climate strongly influences invasive- and alpine zone of the Alps (e.g. rocks ness in aquatic habitats. and screes, alpine grasslands) harbours In Central European dry and semi-dry low numbers of neophytes. grassland and nutrient-poor meadows, The habitat preferences of neophytes few neophytes were recorded (Lohmeyer in Austria show the same pattern as in & Sukopp 1992; Kowarik 2003). neighbouring countries of Central Eu- Although the number of neophytes in dry

20 Neophytes in Austria habitats in Austria is low as well, dry mea- Several case studies demonstrate that dows and forests in Eastern Austria are invasive vascular plant species can change heavily invaded by Robinia pseudacacia native ecosystems in different ways: (Wendelberger 1955). This is similar to Competitive tall herbs (e.g. Fallopia japoni- the situation in adjacent Hungary, where ca, Helianthus tuberosus) in nutrient-rich, this species is one of the most problema- well-watered sites form dense stands, out- tic neophytes for nature conservation compete native taxa (Walser 1995; (Török et al. 2003). Kowarik 1999), change succession pat- Rocks and screes of the montane and terns, and form new vegetation types alpine zone, alpine grasslands and dwarf (Sukopp & Sukopp 1994; Hartmann & shrub communities are not colonized by Konold 1995; Walser 1995, Wadsworth et neophytes. al. 2000; Bimova et al. 2004). Most of Climate change – e.g. annual mean tem- these species show vegetative growth and perature in Austria increased by 0.5 °C are able to store nutrients in tubers or rhi- since 1980 (Lexer et al. 2002), leading to zomes in winter, allowing fast growth in prolonged growing seasons and less severe the subsequent vegetation period. Inva- winters (Walther 2002) – may be decisive sion of the neophytic Acer negundo in for the rapid spread of several late-flowe- stands of Salix alba changes succession ring species, which are probably limited patterns and species composition in by climatic factors in Austria: Ambrosia floodplain forests of the lowlands of artemisiifolia, native in North America, was eastern Austria (Drescher et al. 2004). a rare casual in the early decades of the This impedes the regeneration of native 20th century but became naturalized main- willow species by creating a second tree- ly in the lowlands of the Pannonic region layer (Kunstler 1999). in the second half of the 20th century. Invasion of Robinia pseudacacia changes Several American Amaranthus taxa (e.g. dry grasslands in multiple ways: Species Amaranthus hybridus, Amaranthus blitum ssp. numbers decrease, and the spatial structu- emarginatus) are currently becoming natu- re and microclimatic situation are chan- ralized in the climatically most favourable ged by the formation of a tree-layer (Bö- southern and eastern regions of Austria cker et al. 1995; Kowarik 1995, 2003; (Walter & Dobeš 2004). Neuhauser 2001). Robinia pseudacacia also severely alters nutrient cycles and increa- 4.2 Ecological effects of neophytes ses productivity (Kowarik 1995). Dense stands of Robinia pseudacacia are currently Taking country size and varying defini- widespread in eastern Austria (Fig. 1). The tions of the term “invasive” into account, species also invades areas of high conser- our results correspond well with data vation value, e.g. the National parks from other European countries: Ger- Thayatal and Donau-Auen (Essl & Hau- many: 35 invasive neophytes (Kowarik ser 2003; Drescher et al. 2004). 2002); Hungary: approx. 35 invasive neo- Hybridization between native and alien phytes (Török et al. 2003). In Switzerland, species is one of the most important 11 species are classified as invasive and 16 aspects of biotic homogenisation world- as potentially invasive (SKEW 2002). On wide (Vila et al. 2000, Daehler & Carino the British Isles, 39 species are considered 2001). Of special concern for nature con- “pests”, 11 of which have severe ecologi- servation are crosses involving neophytes cal impacts (Williamson 2002). and native parental taxa, especially if the

21 J. Walter, F. Essl, T. Englisch & M. Kiehn offspring is viable and hybridization Schmidt-Fischer, S. (Eds.) (1995): Ge- events are frequent (Daehler & Carino bietsfremde Pflanzenarten. Auswirkungen 2001). In Austria, few taxa (Populus x cana- auf einheimische Arten, Lebensgemein- schaften und Biotope. – Ecomed, Lands- densis, probably crosses of Epilobium cilia- berg, 215 pp. tum with native taxa) fulfil these criteria, Bossard, C.C., Randall, J.M. & Hoshovsky, which may have serious consequences for M.C. (2000): Invasive plants of Califor- the native taxa involved (e.g. Ellstrand et nia’s Wildlands. – University of California Press, Berkeley, 359 pp. al. 1996; Heinze 1998a; Vila et al. 2000). Brandes, D. (1993): Eisenbahnanlagen als In the neighbouring Czech Republic, Untersuchungsgegenstand der Geobota- crosses between Epilobium ciliatum and nik. – Tuexenia 13: 415-444. native taxa of different sections were Cox, G.W. (2004): Alien species and evolution. documented (Krahulec 1999). – Island Press, Washington DC, 400 pp. Cronk, Q.C. & Fuller, J.L. (2001): Plant inva- ders – the threat to natural ecosystems. – Acknowledgements Earthscan, London, 230 pp. The underlying study for this paper benefited Daehler, C.C. & Carino, D.A. (2001): Hybri- from contributions by more than 50 experts. dization between native and alien plants As we can not cite all their (and other collea- and its consequences. – In: Lockwood, J. gues) papers due to limited space, the reader is & McKinney, M. (Eds.): Biotic Homogeni- referred to Essl & Rabitsch (2002) and Essl & zation. Kluwer Academic/Plenum Pub- Walter (2004), where all original references lishers, New York, 81-103. can be found. We wish to thank P. Schöns- Drescher, A. & Prots, B. (2000): Warum breit- wetter, A. Tribsch (both Institute of Botany, et sich das Drüsen-Springkraut (Impatiens University of Vienna), W. Rabitsch, M. Sta- glandulifera Royle) in den Alpen aus? – chowitsch (both Institute of Zoology, Univer- Wulfenia 7: 5-26. sity of Vienna) and R. Kribala for valuable Drescher, A., Magnes, M. & Fraissl, C. (2004): comments on earlier drafts of the manuscript Neophyten im Nationalpark Donau-Auen. and for linguistic revision of the paper. We are – In: BMLFUW (Ed.): Grüne Reihe des also obliged to T. Kucher for producing the BMLFUW, Böhlau, Wien, in press. distribution map of Robinia pseudacacia wood- Ellmauer, T. (1994): Biodiversity hot spots in lands, and to H. Niklfeld and L. Schratt- Österreich – eine erste Annäherung. – Z. Ehrendorfer for the consent to use the distri- Ökologie u. Naturschutz 3: 271-279. bution data for Lupinus polyphyllus created by Ellstrand, N.C., Whitkus, R. & Riesberg, L.H. numerous contributors to the project “Map- (1996): Distribution of spontaneous plant ping the Flora of Austria”. hybrids. – Proceedings of the National Academy of Sciences 93: 5090-5093. We thank the Austrian Federal Ministry of Essl, F. (in press): Invasionsgeschichte und Agriculture, Forestry, Environment and Water pflanzensoziologischer Anschluss der Alep- Management and the Austrian Federal pohirse (Sorghum halepense) am Beispiel des Environment Agency for initiating and com- östlichen Oberösterreich. – Tuexenia 25. missioning this study. Essl, F., Egger, G., Ellmauer, T. & Aigner, S. (2002): Rote Liste gefährdeter Biotopty- References pen Österreichs: Wälder, Forste, Vorwäl- der. – Umweltbundesamt Wien, Monogra- Adler, W., Oswald, K. & Fischer, R. (1994): phien 156, 104 pp. Exkursionsflora von Österreich. – Ulmer, Essl, F. & Rabitsch, W. (2002): Neobiota in Stuttgart-Wien, 1180 pp. Österreich. – Umweltbundesamt, Wien, Bimova, K., Mandak, B. & Kašparova, I. 432 pp. (2004): How does Reynoutria invasion fit Essl, F. & Hauser, E. (2003): Verbreitung, the various theories of invasibility? – Lebensraumbindung und Management- Journal of Vegetation Science 15: 495- konzept ausgewählter invasiver Neophy- 504. ten im Nationalpark Thayatal und Umge- Böcker, R., Gebhardt, H., Konold, W. & bung (Österreich). – Linzer biol. Beitr.

22 Neophytes in Austria

35/1: 75-101. Kowarik, I. (1992): Einführung und Ausbrei- Essl, F. & Walter, J. (2004): Ausgewählte neo- tung nichteinheimischer Gehölzarten in phytische Gefäßpflanzenarten Österreichs. Berlin und Brandenburg und ihre Folgen – In: BMLFUW (Ed.): Grüne Reihe des für Flora und Vegetation. – Verhandlun- BMLFUW, Böhlau, Wien, in press. gen des botanischen Vereins Berlin und Feráková, V. (1994): Floristic remarks to the Brandenburg, Beiheft 3, 188 pp. lowest part of Morava river floodplain Kowarik, I. (1995): Ausbreitung nichteinhei- area with special attention to naturaliza- mischer Gehölzarten als Problem des tion of neophytes. – Ekológia, Bratislava, Naturschutzes? – In: Böcker, R., Geb- Supplement 1/1994: 29-35. hardt, H., Konold, W. & Schmidt-Fischer, Geisselbrecht-Taferner, L. & Mucina, L. (1995): S. (Eds.): Gebietsfremde Pflanzenarten. Die Vegetation der Brachen am Beispiel der Auswirkungen auf einheimische Arten, Stadt Linz. – Stapfia 38, 154 pp. Lebensgemeinschaften und Biotope, Eco- Gerstberger, P. (2001): Plantago coronopus med, Landsberg, 32-56. subsp. commutatus als Straßenrandhalophyt Kowarik, I. (1999): Neophytes in Germany: eingebürgert in Mitteleuropa. – Tuexenia Quantitative Overview, Introduction and 21: 249-256. Dispersal Pathways, Ecological Conse- Hartmann, E. & Konold, W.(1995): Späte und quences and Open Questions. – Texte des Kanadische Goldrute (Solidago gigantea et Umweltbundesamtes Berlin 18/99: 12-36. canadensis). Ursachen und Problematik Kowarik I. (2002): Biologische Invasionen in ihrer Ausbreitung sowie Möglichkeiten Deutschland: zur Rolle nichteinheimischer ihrer Zurückdrängung. – In: Böcker, R., Pflanzen. – In: Kowarik I. & Starfinger U. Gebhardt, H., Konold, W. & Schmidt- (Eds.): Biologische Invasionen: Herausforde- Fischer, S. (Eds.): Gebietsfremde Pflan- rung zum Handeln? NEOBIOTA 1: 5-24. zenarten. Auswirkungen auf einheimische Kowarik, I. (2003): Biologische Invasionen: Arten, Lebensgemeinschaften und Bio- Neophyten und Neozoen in Mitteleuropa. tope, Ecomed, Landsberg, 92-104. – Ulmer, Stuttgart, 380 pp. Heinze, B. (1998a): Erhaltung der Schwarz- Krahulec, F. (1999): Two new hybrids of Epi- pappel in Österreich – forstwirtschaft- lobium ciliatum (Onagraceae). – Preslia 71: liche, genetische und ökologische Aspekte. 241-248. – FBVA-Berichte 105, 33 pp. Kühn, I. & Klotz, S. (2003): The alien flora of Heinze, B. (1998b): Molekulargenetische Un- Germany – basics from a new German tersuchungen und Identifizierung von database. – In: Child, L.E., Brock, J.H., Schwarzpappeln und Hybridpappelklo- Brundu,G.,Prach,K.,Pyšek,P.,Wade, nen. – FBVA-Berichte 106, 44 pp. P.M. & Williamson, M. (Eds.): Plant Inva- Hohla, M., Kleesadl, G. & Melzer, H. (1998): sions: Ecological Threats and Manage- Floristisches von den Bahnanlagen Ober- ment Solutions, Backhuys Publishers, österreichs. – Beitr. Naturk. Oberöster- Leiden, The Netherlands, 89-100. reichs 6: 139-301. Kunstler P. (1999): The role of Acer negundo L. Hohla, M., Kleesadl, G. & Melzer, H. (2000): in the structure of floodplain forests in Neues zur Flora der oberösterreichischen the middle course of the Vistula River. – Bahnanlagen – mit Einbeziehung einiger In:Brundu,G.,Brock,J.,Camarda,I., grenznaher Bahnhöfe Bayerns. – Beitr. Child,L.E.& Wade,M.(Eds.):Plant Inva- Naturk. Oberösterreichs 9: 191-250. sions: species ecology and ecosystem IUCN (2001): Guidelines for the Prevention management. Proceedings 5th Interna- of Biodiversity Loss caused by Alien tional Conference on the Ecology of Invasive Species. – (http//www.iucn. Invasive Species, La Maddalena, Sardinia, org/themes/ssc/pubs/policy/invasivesE Italy, Backhuys Publishers, Leiden, The ng.htm) (December 2002). Netherlands, p. 76. Kirchmeir, H., Jungmeier, M., Herzog, E. & Lazowski, W. (1999): Auwald. - In: Umwelt- Grabherr, G. (2001): Der Wald im Klima- bundesamt (Ed.): Fließende Grenzen. wandel am Beispiel des sommerwarmen Lebensraum March-Thaya-Auen, Weitzer Osten Österreichs. – Hauptverband der & Partner, Graz, 129-155. Land- und Forstwirtschaftsbetriebe Öster- Lexer, M.J., Hönninger, K., Schleifinger, H., reichs, Wien, 256 pp. Matulla, C., Groll, N., Kromp-Kolb, H.,

23 J. Walter, F. Essl, T. Englisch & M. Kiehn

Schadauer, K., Starlinger, F. & Englisch, phy 25: 155-163. M. (2002): The sensitivity of Austrian for- Pyšek, P. & Pyšek, A. (1991): Vergleich der est to scenarios of climatic change: a dörflichen und städtischen Ruderalflora, large-scale risk assessment based on a mo- dargestellt am Beispiel Westböhmens. – dified gap model and forest inventory Tuexenia 11: 121-134. data. – Forest Ecology and Management Pyšek, P., Jarosik, V. & Kucera, T. (2002a): 162: 53-172. Patterns of invasion in temperate nature Lohmeyer, W. & Sukopp, H. (1992): Agrio- reserves. – Biological Conservation 104: phyten in der Vegetation Mitteleuropas. – 13-24. Schriftenr. Vegetat.kd. 19, 185 pp. Pyšek, P., Sádlo, J. & Mandák, B. (2002b): Lohmeyer, W. & Sukopp, H. (2001): Agrio- Catalogue of alien plants of the Czech phyten in der Vegetation Mitteleuropas. 1. Republic. – Preslia 74: 97-186. Nachtrag. – In: Brandes, D. (Ed.): Adven- Pyšek, P., Sádlo, J. & Mandák, B. (2003): Alien tivpflanzen. Beiträge zu Biologie, Vor- flora of the Czech Republic, its composi- kommen und Ausbreitungsdynamik von tion, structure and history. – In: Child, Archäophyten und Neophyten in Mittel- L.E., Brock, J.H., Brundu, G., Prach, K., europa. Braunschweiger Geobot. Arb. 8: Pyšek, P., Wade, P.M. & Williamson, M. 179-220. (Eds.): Plant Invasions: Ecological Threats McNeely, J.A., Mooney, H.A., Neville, L.E., and Management Solutions, Backhuys Schei, P.J. & Waage, J.K. (2001): Global Publishers, Leiden, The Netherlands, 113- Strategy on Invasive Alien Species. – 130. Gland, IUCN, 50 pp. Pyšek, P., Richardson, D.M., Rejmánek, M., Müller, N. (1995): Zum Einfluß des Menschen Webster, G.L., Williamson, M. & Kirsch- auf Flora und Vegetation von Flußauen. – ner, J. (2004): Alien plants in checklists and Schriftenr. Vegetat.kd. 27: 289-298. : towards better communication Müller, N. (1997): Alien plants in riparian between taxonomists and ecologists. – landscapes – a danger for native flora. – Taxon 53: 131-143. Water Report 1997, 50-58. Rabitsch, W. & Essl, F. (2004): Non-indige- Müller, N. & Bürger, A. (1990): Flußbettmor- nous species in Austria: results of a natio- phologie und Auenvegetation des Lech im nal inventory. – In: Kühn, I. & Klotz, S. Bereich der Forchacher Wildflußland- (Eds.): Biological Invasions: Challenges schaft (Oberes Lechtal, Tirol). – Jahrbuch for Science. Neobiota 3: 77-82. des Vereins zum Schutz der Bergwelt 55: Rejmánek, M., Richardson, D.M., Barbour, 123-154. M.G., Crawley, M.J., Hrusa, G.F., Moyle, Neuhauser, G. (2001): Einfluss der Robinie P.B., Randall, J.M., Simberloff, D. & Wil- auf die Flora und die Vegetation der Wäl- liamson, M. (2002): Biological invasions: der und (Halb)trockenrasen des östlichen politics and the discontinuity of ecological Weinviertels. – Master Thesis, Universität terminology. – Bulletin of the Ecological Wien, 146 pp. Society of America 83: 131-133. Niklfeld, H. (1978): Grundfeldschlüssel für Richardson, D.M., Pyšek, P., Rejmánek, M., die Kartierung der Flora Mitteleuropas, Barbour,M.G.,Panetta,F.D.& West,C.J. südlicher Teil. – Zentralstelle für Floren- (2000): Naturalization and invasion of kartierung, Institut für Botanik, Univer- alien plants concepts and definitions. – sität Wien, 8 pp. Diversity and Distribution 6: 93-107. Niklfeld, H. (1999): Rote Listen gefährdeter Sala, O.E., Chapin, F.S.III, Armesto, J.J., Ber- Pflanzen Österreichs. – Grüne Reihe des low, E., Bloomfield, J., Dirzo, R. & Huber- Bundesministeriums für Umwelt, Jugend Sannwald, E. (2000): Global biodiversity und Familie, Wien, 292 pp. scenarios for the year 2100. – Science 287: Oppermann, F.W. (1998): Die Bedeutung von 1770-1774. linearen Strukturen und Landschaftskor- Scholz, H. (1995): Das Archäophytenproblem ridoren für Flora und Vegetation der Agrar- in neuer Sicht. – Schriftenr. Veg.kd. 27: landschaft. – Dissert. Bot. 298, 214 pp. 431-439. Pyšek P. (1998): Alien and native species in Schröck,C.,Stöhr,O.,Gewolf,S.,Eichberger, Central European urban floras: a quantita- C., Nowotny, G., Mayr, A. & Pilsl, P. tive comparison. – Journal of Biogeogra- (2004): Beiträge zur Adventivflora von

24 Neophytes in Austria

Salzburg I. – Sauteria 13: 221-337. Wadsworth, R.A., Collingham, Y.C., Willis S.G., Schroeder, F.G. (1974): Zu den Statusangaben Huntley, B. & Hulme, P.E. (2000): Simu- bei der floristischen Kartierung Mitteleu- lating the spread and management of alien ropas. – Göttinger Flor. Rundbr. 8: 71-79. riparian weeds: are they out of control? – Schroeder, F.G. (2000): Die Anökophyten und Journal of Applied Ecology 37: 28-38. das Systen der floristischen Statuskatego- Walser, B. (1995): Praktische Umsetzung der rien. – Botanische Jahrbücher für Syste- Knöterichbekämpfung. – In: Böcker, R., matik, Pflanzengeschichte und Pflanzen- Gebhardt, H., Konold, W. & Schmidt- geographie 122: 431-437. Fischer, S. (Eds.): Gebietsfremde Pflan- SKEW (2002): Schwarze Liste und Graue zenarten. Auswirkungen auf einheimische Liste und "Watch List" der Schweizeri- Arten, Lebensgemeinschaften und Bio- schen Kommission für die Erhaltung von tope, Ecomed, Landsberg, 161-172. Wildpflanzen. – (http://www.cps- Walter, J. (1992): Flora und Sukzessionsver- skew.ch/deutsch/schwarze_liste.htm) hältnisse auf Mülldeponien in verschiede- (May 2002). nen Gebieten Österreichs. – Master Statistik Austria (2003): Räumliche und demo- Thesis, University of Vienna, 241 pp. graphische Angaben über Österreich. Walter, J., Essl, F., Niklfeld,H. & Fischer, M.A. (http://www.statistik.at/fachbereich_top (2002): Gefäßpflanzen. – In: Essl, F. & ograph/tab1.shtml, http://www.statistik. Rabitsch, W. (Eds.): Neobiota in Österre- at/fachbereich_topograph/tab4.shtml) ich, Umweltbundesamt, Wien, 47-173. (März 2003). Walter, J. & Dobeš, C. (2004): Morphological Sukopp, H. (1976): Dynamik und Konstanz in characters, geographic distribution and der Flora der Bundesrepublik Deutsch- ecology of neophytic Amaranthus blitum L. land. – Schriftenr. Vegetat.kd. 10: 9-26. subsp. emarginatus in Austria. – Annal. Sukopp, H. (2002): Neophyten. – Bauhinia 15: naturhist. Mus. Wien 105: 645-672. 19-37. Walther, G.R. (2002): Weakening of climatic Sukopp, U. & Sukopp, H. (1994): Ökologische constraints with global warming and its Lang-Zeiteffekte der Verwilderung von consequences for evergreen broad-leaved Kulturpflanzen. – Abt. Normbildung und species. – Folia Geobotanica 37: 129-139. Umwelt des Forschungsschwerpunkts Wendelberger, G. (1955): Die Restwälder der Technik, Arbeit, Umwelt des Wissen- Parndorfer Platte im Nordburgenland. – schaftszentrums Berlin für Sozialfor- Burgenländische Forschungen 29: 157-166. schung, 91 pp. Williamson, M. (2002): Alien plants in the Török, K., Botta-Dukat, Z., Dancza, I., Ne- British Isles. – In: Pimentel, D. (Ed.): meth,I.,Kiss,J.,Mihaly,B.& Magyar,D. Biological invasions: economic and envi- (2003): Invasion Gateways and Corridors ronmental costs of alien plant, animal and in the Carpathian Basin: biological inva- microbe species, CRC Press, Boca Raton, sions in Hungary. – Biol. Invas. 5/4: 1-8. 91-112. Vila, M., Weber, E. & D´Antonio, C.M. Zidorn, C. & Dobner, M.J. (1999): Beitrag zur (2000): Conservation implications of inva- Ruderalflora der Bahnhöfe von Nordtirol. sion by plant hybridization. – Biol. Invas. – Ber. naturwiss.-medizin. Ver. Innsbruck 2: 192-193. 86: 89-93.

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