Endangered, expansive and invasive species in pteridoflora of Lower Silesia

213 Endangered,-expansive-and-invasive-species-in-pteridoflora-of-Lower-Silesia 213 Endangered, expansive and invasive species in pteridoflora of Lower Silesia EWA SZCZÊŒNIAK Institute of Plant Biology, Univeristy of Wroc³aw, Kanonia 6/8, PL-50-328 Wroc³aw, Poland; e-mail: ewaszcz@biol.uni.wroc.pl ABSTRACT: Pteridoflora of Lower Silesia consists of 62 species and is one of the most diverse in Poland. The aim of the presented study was to determine pteridophyte reaction to human activity in Lower Silesia. Actualised list of endangered pteridophytes consists of 42 species, among them 31 are categorized as highly threatened: 2 regionally extinct (Botrychium multifidum, Woodsia ilvensis), 13 critically endangered and 16 endangered or vulnerable. Remaining 20 species are not endangered, among them 3 are expansive (Equisetum arvense, Pteridium aquilinum, Athyrium distentifolium) and 1 species is potentially invasive (Azolla filiculoides). ABSTRAKT: Pteridoflora Dolnego Œl¹ska sk³ada siê z 62 gatunków i jest jedn¹ z najbardziej zró nicowanych w Polsce. Celem prezentowanych badañ by³o okreœlenie reakcji paprotników na aktywnoœæ cz³owieka na Dolnym Œl¹sku. Zaktualizowana lista gatunków zagro onych obejmuje 42 gatunki, w tym 31 zaliczono do wysokich kategorii zagro enia: 2 wymar³e w regionie (Botrychium multifidum, Woodsia ilvensis), 13 krytycznie zagro onych, 16 wymieraj¹cych lub nara onych na wymarcie. 20 gatunków nie jest zagro onych, w tym 3 s¹ ekspansywne (Equisetum arvense, Pteridium aquilinum, Athyrium distentifolium) i 1 potencjalnie inwazyjny (Azolla filiculoides). KEY WORDS: ferns, horsetails, club-mosses, endangered species, expansive species, invasive species, Lower Silesia Introduction Geological and morphological diversity of mountain and lowland habitats as well as influence of Atlantic climate make the pteridoflora of Lower Silesia one of the most diverse in Poland. The pteridophyte flora of Poland comprises 75 taxa (Mirek et al. 2002), 62 of them appear in Lower Silesia. 7 species occur mainly or even exclusively in the region, or have there one of scattered SZCZÊŒNIAK E. 2008. Endangered, expansive and invasive species in pteridoflora of Lower Silesia. In: E. Szczêœniak, E. Gola (eds), Club mosses, horsetails and ferns in Poland resources and protection. Institute of Plant Biology, University of Wroc³aw, Wroc³aw, p. 213 223.

214 Ewa-Szczêœniak 214 Polish localities (Asplenium adulterinum, A. adiantum-nigrum, A. cuneifolium, Cryptogramma crispa, Pilularia globulifera, Woodsia ilvensis, W. alpina). Pteridophytes produce prodigious amounts of light spores, e.g., Dryopteris carthusiana produces on average 7.3 million spores per leaf (Moran 2004), which can be carried by the wind for long distances, even thousands of kilometers (Tackenberg et al. 2003). They seem to be potentially expansive plants, however their biology and particular requirements of their gametophytes and young sporophytes make them week competitors and a marginal group in Polish flora; 75 taxa of pteridophyte flora compose less than 3% of the entire flora of the country. Almost all pteridophyte species are sensitive to changes in habitat conditions that are characteristic of anthropogenic environments. The specific conditions prevailing in man-made or disturbed habitats reduce the proportions of germinating spores, properly developed gametophytes and viable sporophytes. About 37% of Polish pteridophyte species are endangered and in that 21% is extinct or very close to extinction (Zarzycki, Szel¹g 2006). The aim of the presented study was to actualize the list of endangered pteridophyte species and their categories of threat, and to compare the results of research with the list prepared in 2003 (K¹cki et al. 2003). Moreover, the author tried to determine pteridophytes reaction to human activity in the habitat types found in Lower Silesia. 1. Material and methods Research was conducted within administrative borders of the Dolnoœl¹skie province, in area of 19 946,77 km 2. To assess a degree of endangerment of club mosses, horsetails and fern species in Lower Silesia, the author used main definitions, criteria and categories of the IUCN (Gärdenfors et al. 2001), with regard to modification for regional red lists (K¹cki et al. 2003, 2006). The following guidelines were regarded as very substantial: frequency of occurrence, distribution in a region (area of occurrence) and its changes over time, also population size and fluctuations and declines in number of individuals. The same guidelines were used to assess a rate of expansion or invasion. An expansive species is a native taxon which increases the number of sites within its native range; this definition accords with the description of ecological expansion given by Jackowiak (1999). The definition of invasive species as a naturalised alien species which is an agent of change, and threatens human health, economy and/or native biological diversity follows Hulme (2007) and partially accords with definition of chorological expansion by Jackowiak (1999).

215 Endangered,-expansive-and-invasive-species-in-pteridoflora-of-Lower-Silesia 215 Nomenclature of plant species follows Mirek et al. (2002), systematic classification accords with Smith et al. (2008), plant communities are classified according to the system proposed by Matuszkiewicz (2008). Distribution of species was mapped on a 1 1 km grid in accordance with the ATPOL system (Zaj¹c 1978). 2. Results Pteridoflora of Lower Silesia consists of 62 club mosses, horsetails and fern species. 42 taxa are endangered, 20 are not endangered and among them 3 are expansive and 1 species is potentially invasive. 2.1. Endangered species The first list of endangered plants, prepared for Lower Silesia, included 39 species of club mosses, horsetails and ferns (K¹cki et al. 2003). Three of them were thought to be regionally extinct (Botrychium multifidum, Pilularia globulifera, Woodsia ilvensis), 11 were included into critically endangered category (CR), 19 were classified as endangered (EN) or vulnerable (VU), and 6 were included into lower categories of threat. The distribution and dynamic tendencies of chosen pteridophytes have been analyzed for last 5 years making it possible to present a new evaluation of the pteridoflora condition and the second list of threatened pteridophyte species. The second list consists of 42 species (68% of all pteridophyte species which occur in Lower Silesia). Only 15 pteridophytes are not endangered in the region. After rediscovery of Pilularia globulifera, the group of extinct species counts 2 taxa (Botrychium multifidum, Woodsia ilvensis). Moreover, 13 are critically endangered, 16 are endangered and vulnerable, and 11 are included into lower categories of threat. The proportion of endangered species is different in particular systematic groups. The most threatened group are Lycopodiales (Cl. Lycopodiopsida), Selaginellales (Cl. Selaginellopsida), Isoëtales (Cl. Isoëtopsida), and Ophioglossales (Cl. Psilotopsida), whereas a ratio of threatened species is the lowest in Polypodiales (Cl. Polypodiopsida; Tab. 1). Three species added to the new list are endangered because of the decreasing area of their natural habitats (Equisetum pratense, Thelypteris palustris; both estimated as near threatened species) or the decreasing number of sites (Equisetum ramosissimum classified as DD data deficient; still there is too little known to estimate more precisely its category of threat). The research and analysis of distribution dynamics changed the threat categories of 7 species. New stands were found for Pilularia globulifera (category RE

216 Ewa-Szczêœniak 216 Tab. 1. List of threatened pteridophyte species of Lower Silesia Tab. 1. Lista zagro onych gatunków pteridofitów Dolnego Œl¹ska Class of plant systematics (Klasy w uk³adzie systematycznym) Total No. of species/ No. of threatened species (Ogólna liczba gatunków/ liczba gatunków zagro onych) 2003 2008 Class of plant community; * diagnostic species (Klasy zbiorowisk roœlinnych *gatunki diagnostyczne) Cl. Lycopodiopsida O. Lycopodiales 9/9 Diphasiastrum alpinum (L.) Holub VU VU *Nardo-Callunetea, Juncetea trifidii Diphasiastrum complanatum (L.) Holub VU EN *Vaccinio-Piceetea Diphasiastrum issleri (Rouy) Holub CR DD Diphasiastrum tristachyum (Pursch) Holub CR CR *Nardo-Callunetea Diphasiastrum zeilleri (Rouy) Holub DD CR Huperzia selago (L.) Berh. ex Schrank et Mart. LC LC *Vaccinio-Piceetea, Juncetea trifidii Lycopodiella inundata (L.) Holub EN EN *Scheuchzerio-Caricetea Lycopodium annotinum L. VU VU *Vaccinio-Piceetea Lycopodium clavatum L. VU VU *Nardo-Callunetea Cl. Selaginellopsida O. Selaginellales 1/1 Selaginella selaginoides (L.) P. Beauv. ex Schrank et Mart CR CR *Scheuchzerio-Caricetea Cl. Isoëtopsida O. Isoëtales 1/1 Isoëtes lacustris L. CR CR *Litorelletea uniflorae Cl. Psilotopsida O. Ophioglossales 4/4 Botrychium lunaria (L.) Sw. VU VU Nardo-Callunetea Botrychium matricariifolium (Retz.) A. Braun ex W.D.J. Koch CR CR Nardo-Callunetea,Quercetea roboripetraeae Botrychium multifidum (S.G. Gmel) Rupr. RE RE Nardo-Callunetea, Molinio-Arrhenatheretea Ophioglossum vulgatum L. VU VU *Molinio-Arrhenatheretea Cl. Equisetopsida O. Equisetales 9/5 Equisetum hyemale L. NT NT Querco-Fagetea Equisetum pratense Ehrh. NT Querco-Fagetea Equisetum ramosissimum Desf. DD Equisetum telmateia Ehrh. VU VU Querco-Fagetea, Molinio-Arrhenatheretea Equisetum variegatum Schleich. EN CR *Thlaspietea rotundifolii Cl. Polypodiopsida O. Osmundales 1/1 Osmunda regalis L. EN CR Alnetea glutinosae O. Hymenophyllales 1/1 Trichomanes speciosum Willd. CR CR O. Salviniales 2/2 Pilularia globulifera L. RE CR *Litorelletea uniflorae Salvinia natans (L.) All. VU VU *Lemnetea O. Polypodiales 34/18 Asplenium adiantum-nigrum L. CR CR *Asplenietea rupestria Asplenium adulterinum Milde CR CR *Asplenietea rupestria Asplenium cuneifolium Viv. EN EN *Asplenietea rupestria Asplenium septentrionale (L.) Hoffm. NT NT *Asplenietea rupestria Asplenium viride Huds. VU VU *Asplenietea rupestria Blechnum spicant (L.) Roth. LC LC *Vaccinio-Piceetea Cryptogramma crispa (L.) R.Br. CR CR *Thlaspietea rotundifolii Dryopteris cristata (L.) A. Gray EN EN *Alnetea glutinosae Gymnocarpium robertianum (Hoffm.) Newman LC LC *Thlaspietea rotundifolii Matteucia struthiopteris (L.) Tod. VU VU *Querco-Fagetea Oreopteris limbosperma (Bellardi ex All.) Holub EN EN Querco-Fagetea, Vaccinio-Piceetea Phyllitis scolopendrium (L.) Newman CR EN *Querco-Fagetea, Asplenietea rupestria Polystichum aculeatum (L.) Roth VU VU *Querco-Fagetea Polystichum braunii (Spenn.) Fée EN EN *Querco-Fagetea Polystichum lonchitis (L.) Roth EN EN *Vaccinio-Piceetea Thelypteris palustris Schott NT *Alnetea glutinosae Woodsia alpina (Bolton) Gary CR CR Thlaspietea rotundifolii Woodsia ilvensis (L.) R.Br. RE RE *Asplenietea rupestria

217 Endangered,-expansive-and-invasive-species-in-pteridoflora-of-Lower-Silesia 217 changed to CR), Phyllitis scolopendrium (CR to EN) and Diphasiastrum zeilleri (DD to CR). Diphasiastrum complanatum, Equisetum variegatum and Osmunda regalis are now estimated as critically endangered, while in 2003 they were endangered. The verification of stands and herbarium specimens of Diphasiastrum issleri revealed, that the species required more detailed research. It is temporary included into category DD. A degree of threat is connected with a habitat type of the species. The majority of endangered species occur in open plant communities such as dry and wet meadows, xerothermic grasslands, heatlands, natural or anthropogenic outcrops, peat bogs and natural or anthropogenic water reservoirs (Tab. 1). Almost all these habitats are semi-natural or have been changed by human and need active protection to be maintained. 2.2. Expansive species Expansive species, defined as native species increasing their range, are very rare among Polish pteridophytes. Only 3 species were assessed to be expansive in Lower Silesia, however the area and habitats of their expansions were incomparable. The most common species is a ubiquitous horsetail, Equisetum arvense. This apophyte occurs in natural, semi-natural and anthropogenic plant communities in the whole region. This species is able to survive in alpine belt in the Karkonosze Mts. (Szczêœniak, Malicki 2007), in urban and industrial areas (Szczêœniak 2008), and is the only pteridophyte that tolerates regular agricultural activity in cultivated fields. It is a geophyte, which propagates by means of long rhizomes that fragment to produce abundant daughter plants. Rhizome fragmentation is one of its expansion strategies. It can form dense, difficult to remove populations in fields and gardens, and is the most common pteridophyte species in Lower Silesia. The second species, Pteridium aquilinum (bracken fern), primarily was a natural component of dry, acidic woodlands of all types, but parallel to removal of the forest cover or disturbing of its structure, it begun forming dense, extensive colonies. It is a plant of high competitive abilities that invades disturbed forests, clearings, forest nurseries and young forest plantations, cultivated fields and all disturbed areas in neighbourhood of forests. Its rhizomes grow under the roots of herbs, tree and shrub seedlings, and can not be removed. When the fronds emerge, they shade the smaller plants. Production and release of allelopathic chemicals is an important factor of its ability to dominate other vegetation (Gliessman 1976). In Poland it disperses in the vegetative way. The extermination of the species is difficult and not much effective. The best method of bracken fern reduction is a mechanical control;

218 Ewa-Szczêœniak 218 the most effective is summer mowing, just when the new fronds are fully expanded and starch reserves in the rhizome are at the lowest level ( Martin 1976; Lowday et al. 1983). The expansion of Athyrium distentifolium is limited to the subalpine forest zone. Openings in the forest canopy of up to one hundred square meters are typical structural elements of the subalpine spruce forest. Athyrium distentifolium is a natural element of a herb layer in this forest, and the percentage of the area covered by this fern in gaps of the Carpathian forests is nearly twice as much as outside of that habitat (Holeksa 2003). Similar structures developed in the Karkonosze Mts. The area of gaps increased in the highest part of the subalpine forest zone. The upper forest boundary is characterised by widely scattered dwarf spruces. This boundary in the Karkonosze Mts. is lower than it should naturally be as a result of spruce extinction induced by high air pollution in the 1970s and later pest gradation in weakened forests. The expansion of Athyrium distentifolium in the process of a secondary succession in opened deforested areas protects a thin soil surface and prevents erosion (Fig. 1). 2.3. Invasive species The only potentially invasive species, i.e. an alien species increasing its range in the region, is Azolla filiculoides. It is native to warm temperate and subtropical America, and occurs also in Western North America, where reaches Alaska (Lumpkin 1993). As an effect of a human activity it is at present a cosmopolitan plant, with occurrences in South Africa, Asia, Australia, South-, Central- and North America, South-, West-, Central- and North Europe, and Scandinavia (Hussner 2006, Weber 2005). The species was introduced to Europe at the end of the 19 th century and became invasive in western and southern Europe. In the vicinity of Poland it was found in Germany, where it was rather common (Weber 2005), in the Czech Republic (Kubát 2002) and Slovakia (Eliaš 1981). In Poland it was included into ephemerophytes (Rostañski, Sowa 1986 1987; Wo³kowycki 1999). This small free-floating heterosporous fern can spread by spores, but the most effective dispersal is by small fragments of fragile sporophytes (Fig. 2). It is the most frost-tolerant of the Azolla species and can successfully overwinter in -10 to -15 o C. The mutualistic symbiosis with Anabaena azollae enables the fern to benefit from atmospheric nitrogen fixation and causes the extremely fast growth. Azolla can double its biomass in 3 5 days, under laboratory conditions even in 2 3 days (Kitoh et al. 1993); that makes this fern a very popular green manure and thus the only fern with high economic importance. On the other hand, the same attributes make it one of the most invasive plants of open water ecosystems in warm climate.

219 Endangered,-expansive-and-invasive-species-in-pteridoflora-of-Lower-Silesia 219 Fig. 1. Expansion of Athyrium distentifolium at the upper border of spruce forest range, Karkonosze National Park (phot. E. Szczê niak) Ryc. 1. Ekspansja Athyrium distentifolium na górnej granicy zasiêgu boru wierkowego (Karkonoski Kark Narodowy fot. E. Szczê niak) Fig. 2. A mat of Azolla filiculoides on a pond surface in the Wojszyce village (phot. E. Szczê niak) Ryc. 2. Warstwa Azolla filiculoides na powierzchni stawu w Wojszycach (fot. E. Szczê niak)

220 Ewa-Szczêœniak 220 The species was noted in Lower Silesia before the II World War in Wawrzyszewo, where it survived some winters (Schube 1928). A date of extinction of the species at this site is not known. Next 2 stands were noticed in the 1990s in Wroc³aw, and both were destroyed by humans in result of pond liquidation or long-term renovation. Three actual stands of Azolla have been observed since 2007. The species occurs in Wroc³aw, in a Wojszyce village near Wroc³aw, and in the oxbow lake of the Nysa u ycka river near Zgorzelec. For not-botanists it is another kind of duckweed and its common Polish name is czerwona rzêsa red duckweed. It is possible that the species is more common in Lower Silesia. The process of global warming enables azolla to spread in Eastern Europe and to establish new localities. 3. Discussion The majority of pteridophyte species do not tolerate habitat changes. Nowadays, in time of huge human pressure and transformation of biotopes, all groups of pteridophytes become more or less endangered. The lowest percentage of threatened species was observed in Equisetales and Polypodiales, but even there, the red list species make more than 50% of all noted species. Passive protection is not sufficient to stop the extinction of ferns, horsetails and club mosses. Thirty three species of Lower Silesia pteridoflora are protected by law and in spite of that all of them are included into the regional red list with high categories of threat. Locations of three serpentine fern species should be protected by 30 m wide protection zone, guaranteed by Polish low, but no protection zone was established as far. Very valuable species Trichomanes speciosum has guaranteed 100 m wide protection zone and furthermore its stands have the warranty of protection as a Nature 2000 area, but at present only one of two locations is protected as area of Natura 2000 and no protected zones has been established. Only one nature reserve Góra Radunia was created to protect pteridophytes, precisely the serpentine ferns, but the establishment of a nature reserve did not stop the extinction of the species. Curiously, it made it even quicker, because the unique fern species became the focus of interest. National parks are the most protected areas in Poland. Detailed research on pteridoflora was made in the National Park of Góry Sto³owe Mts. and the list of endangered species contained there more than 70% of all noted pteridophytes (Szczêœniak, Œwierkosz 2008). The examination of pteridoflora of the Karkonoski National Park has not been finished yet, but results seem to be similar. The active protection of survived stands and a program of cultivation and recovery of critically endangered species is crucial for keeping present state of endangered populations or its improvement.

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223 Endangered,-expansive-and-invasive-species-in-pteridoflora-of-Lower-Silesia 223 Zagro one, ekspansywne i inwazyjne gatunki w pteridoflorze Dolnego Œl¹ska Geologiczne i morfologiczne zró nicowanie Dolnego Œl¹ska oraz wp³yw klimatu atlantyckiego powoduj¹, e region ma jedn¹ z najciekawszych pteridoflor w Polsce. Pteridoflora Polski obejmuje 75 gatunków (Mirek et al. 2002), 62 z nich wystêpuj¹ na Dolnym Œl¹sku. W wyniku przeprowadzonych badañ wykonano aktualizacjê listy gatunków zagro onych dla wid³aków i paproci. Obecnie obejmuje ona 42 gatunki (68% pteridoflory). Po odnalezieniu stanowisk Pilularia globulifera grupa gatunków wymar³ych w regionie liczy 2 taksony (Botrychium multifidum, Woodsia ilvensis), ponadto 13 jest krytycznie zagro onych wymarciem, a 16 to gatunki wymieraj¹ce lub nara one na wymarcie, pozosta³e zaliczono do ni szych kategorii zagro eñ. Najbardziej zagro eni s¹ przedstawiciele Lycopodiales (Cl. Lycopodiopsida), Selaginellales (Cl. Selaginellopsida), Isoëtales (Cl. Isoëtopsida) i Ophioglossales (Cl. Psilotopsida); udzia³ gatunków zagro onych jest najni szy w Polypodiales (Cl. Polypodiopsida; tab. 1). Stopieñ zagro enia zale y od typu siedliska. Najbardziej zagro one s¹ taksony zwi¹zane z siedliskami otwartymi: wilgotnymi i mokrymi ³¹kami, murawami ciep³olubnymi, wrzosowiskami, wychodniami skalnymi, torfowiskami i siedliskami wodnymi. Niemal wszystkie spoœród nich to siedliska pó³naturalne lub silnie zaburzone i wymagaj¹ce obecnie ochrony czynnej. Jako gatunki ekspansywne zakwalifikowano 3 taksony, lecz skala ich ekspansji jest nieporównywalna. Najpospolitszy jest wszêdobylski gatunek Equisetum arvense, pojawiaj¹cy siê od ni u po piêtro alpejskie Karkonoszy. Drugi takson Pteridium aquilinum pierwotnie by³ gatunkiem leœnym, a obecnie wystêpuje na zaburzonych siedliskach leœnych i odlesionych, staj¹c siê uci¹ liwym chwastem w szkó³kach leœnych oraz na terenach po³o onych w s¹siedztwie lasów. Ekspansja Athyrium distentifolium ograniczona jest do strefy regla górnego i subalpejskiej, gdzie zajmuje siedliska powsta³e po zamarciu œwierczyn górnoreglowych (ryc. 1). Jedynym potencjalnie inwazyjnym gatunkiem paproci na Dolnym Œl¹sku jest Azolla filiculoides, do niedawna bêd¹ca efemerofitem flory Polski, a od kilku lat pojawiaj¹ca siê na Dolnym Œl¹sku i obecnie zimuj¹ca na 3 stanowiskach. Nie mo na wykluczyæ, e stanowisk tego gatunku jest wiêcej (ryc. 2).