Ann. Bot. Fennici 49: 305–318 ISSN 0003-3847 (print) ISSN 1797-2442 (online) Helsinki 30 November 2012 © Finnish Zoological and Botanical Publishing Board 2012 Palaeoecological studies on the decline of Cladium mariscus (Cyperaceae) in NE Poland Mariusz Gałka* & Kazimierz Tobolski Adam Mickiewicz University, Department of Biogeography and Palaeoecology, Dzięgielowa 27, PL-61-680 Poznań, Poland (*corresponding author’s e-mail: [email protected]) Received 14 May 2012, final version received 19 June 2012, accepted 21 June 2012 Gałka, M. & Tobolski, K. 2012: Palaeoecological studies on the decline of Cladium mariscus (Cyperaceae) in NE Poland. — Ann. Bot. Fennici 49: 305–318. The history of the occurrence of Cladium mariscus (Cyperaceae) in NE Poland at the north-eastern limit of its distribution in Europe is discussed. The decline of the species may be related to gradual oligotrophication of its habitats, caused by the isolation of calcareous deposits and the decline of calcium carbonate in the substratum. The pres- ence of C. mariscus in Kojle and Perty, lakes in NE Poland, is related to the occurrence of calcareous sediments, which may compensate for the lack of sufficient warmth. The occurrence of calcium carbonate in the substratum allows for the growth of C. maris- cus in areas that are influenced significantly by a continental climate. The abundance of Ca2+ cations in the substratum compensates for that climatic factor. Introduction Buczek (2005), Theocharopoulos et al. (2006), Karcz (2008), and Šumberová et al. (2011). Cladium mariscus (Cyperaceae) is a thermophil- A study of the ecological amplitude of an ous species (Szafer 1954, Berglund 1968, Walter assemblage with C. mariscus in NW Poland & Straka 1970) very useful as an indicator of by Jasnowski (1962) distinguished four vari- palaeoclimate. Because of its habitat requirements ants in the Mariscetum assemblage (= Cladietum and biogeographical significance, it has been the marisci): (1) typical, consisting of dense Cla- subject of many palaeoecological studies carried dium agglomerations (sometimes the extreme out in various parts of Europe (von Post 1925, one-species variant), (2) calciphilous, (3) acido- Conway 1937, Jalas & Okko 1950, Valovirta philous, and (4) halophilous. Jasnowski (1962) 1962, Hafsten 1965, Berglund 1968, Balátová- presented the phytocoenotic relationships of the Tuláčková 1991, Gałka & Tobolski 2006, 2011, four variants in a phytosociological table. Pott Gałka 2007, Pokorný et al. 2010). Phytosocio- (1995) suggested a wide ecological amplitude logical characteristics of assemblages with C. for patches of the Cladietum marisci assem- mariscus and the habitat requirements of such blage. Close relationships with substrates rich assemblages were studied by Fiałkowski (1959), in calcium (calcareous peatlands “Kalkflach- Kępczyński and Ceynowa (1968), Staniewska- moore”, calcareous gyttja, and lacustrine chalk) Zątek (1977), Kłosowski (1986/87), Jasnowska are noticeable in more continental regions, for and Jasnowski (1991, 1991a, 1991b, 1991c), example in the Dolne Łużyce region, where C. Eggers (1994), Pott (1995), Salmina (2003, 2004), mariscus can develop even on submerged peat 306 Gałka & Tobolski • ANN. BOT. FENNICI Vol. 49 deposits. In the Atlantic climate, the species including the Tuchola Forest, the Lublin Region, occurs on sandy deposits poor in calcium, and the Drawieński National Park and the Pszczewski on peaty soils. Pott (1995) emphasised the relic Landscape Park. The study is concerned with the character of the species from the postglacial postglacial history of C. mariscus, its fossil habi- warm (Atlantic) period. In the vicinity of Lake tat preferences, and its peat-forming capacity. Constance, Cladium is a typical component of Our hypothesis is that the decline of C. assemblages of lakes subject to terrestrialisation mariscus in NE Poland has a causal link with (“Verlandungsgesellschaften”; Lang 1990). It the gradual oligotrophication of habitats, which prefers sites within the range of headwaters with is taking place together with the disappearance a high content of calcium and oxygen. However, of habitats rich in calcium carbonate. Such dis- it also grows on substrates poor in calcium, such appearance occurs through the loss of calcium as detritus gyttja and peats. carbonate in the aquatic environment after depo- Currently C. mariscus is rare in Poland (Zając sition in sediments, and the gradual decline of & Zając 2001), and it is subject to strict species habitats through the development of Ca-poor protection in this country (Piękoś-Mirkowa & layers on top of calcareous deposits. The lack of Mirek 2006) and in the European Union (Herbi- access to calcareous deposits probably results in chowa & Wołejko 2004). The current distribution a decrease in the occurrence of C. mariscus. of C. mariscus in NE Poland was analysed by Polakowski (1969) and Kłosowski (1986/1987). Those studies included descriptions of the habi- Material and methods tats and floristic composition, and an analysis of the surface layer of the deposits on which Study site Cladium grows. However, no palaeobotanical studies focusing on the postglacial history of this The study site is located in NE Poland, within species have been undertaken in NE Poland. the Suwalski Landscape Park (Fig. 1). Kojle and We carried out studies on the current distri- Perty, on the shores of which C. mariscus grows, bution and history of C. mariscus in NE Poland. are lakes located in the northern part of the park. We believe that this area is important because The lakes, together with the surrounding peat- of its location at the boundary of the species’ lands, fill an extensive depression in the young- range in northern Europe (Meusel et al. 1965), moraine landscape that developed during the and because of the need for protection within the retreat of the Scandinavian icesheet at the end of Natura 2000 protected area. the last glaciation (Ber 1987, Krzywicki 2002). The primary objectives of the study were The soil in the area consists of ground moraine to determine the duration of the occurrence of and has numerous kame hills. Variation in the Cladium mariscus at Kojle and Perty (lakes in land elevation in the vicinity of the lakes is about northeastern Poland), and to determine its past 50 m. In the past, Kojle and Perty constituted habitat requirements. We attempted to establish one lake, but now they are separated by a peat- whether the species has grown at these lakes for land. Their areas, according to the measurements thousands of years, or if it has appeared there in 2010, are 17.127 ha and 19.688 ha for Kojle recently. The stability of the occurrence of C. and Perty, respectively. The surrounding area is mariscus was examined in terms of its presence occupied mainly by pastures to the north, and at the lakes in general, and also at one specific by mixed forests dominated by Pinus sylvestris site at which it is currently most abundant. and Betula pubescens to the south. The slopes Another objective was to reconstruct the vegeta- of the hills include numerous springs with Alnus tion type in which C. mariscus occurred, particu- glutinosa stands. Along the lake borders C. mar- larly during the lake–peatland transition. iscus is accompanied by Schoenoplectus lacus- The palaeobotanical analyses within the area tris, Phragmites australis, Carex paniculata and of the current occurrence of C. mariscus in the Thelypteris palustris. Suwalski Landscape Park form a part of a wider For the study of the current distribution of study, conducted in various parts of Poland, C. mariscus in the Suwalski Landscape Park, ANN. BOT. FENNICI Vol. 49 • Palaeoecological studies on the decline of Cladium mariscus in Poland 307 Lake Lake Linówek Purwin Lake Kojle Lake Perty 0 200 Core sampling sites Single individuals of Cladium mariscus Rush zone with Cladium mariscus Fig. 1. Setting of the study Peatlands Road area. we examined the coastal zones of all twenty- I 54°16´26.08´´N, 22°53´43.04´´E, seven lakes in the park. We cored material for II 54°16´21.36´´N, 22°53´21.80´´E, the laboratory analyses. Peat deposits and gyttja III 54°16´15.45´´N, 22°53´17.77´´E, were sampled using an Instorf manual corer. For IV 54°16´23.01´´N, 22°53´24.03´´E, the field research, we used a Russian corer with V 54°16´49.60´´N, 22°53´24.29´´E, a length of 100 cm and a diameter of 7 cm. The VI 54°13´24.30´´N, 22°50´29.99´´E. sediment samples were inserted into PVC tubes and wrapped in plastic foil. We sampled the We also sampled the deposits, including the organic sediments from various parts of the peat- uppermost part of the lacustrine sediments and lands surrounding Kojle and Perty, from Lake the overlying peat (200 cm in total), from the Purwin (Fig. 1), and from a peatland located at southern shore of Kojle, at a distance of 3 m the eastern shore of Lake Linówek, in the south- from the C. mariscus zone (Fig. 1, site IV). ern part of the park. The geographic co-ordinates The purpose of that sampling was to determine of the coring sites were as follows: whether C. mariscus grew in this location in the 308 Gałka & Tobolski • ANN. BOT. FENNICI Vol. 49 rush zone of Kojle in the past, and whether the tional radiocarbon dates were calibrated with the site of the occurrence has changed along with OxCal 4.1 software (Bronk-Ramsey 2009). terrestrialisation during the succession process. Results Laboratory studies Lithostratigraphy The sampled sediments were analysed for micro- and macrofossils. We conducted a palynological Stratigraphical data of the analysed cores were analysis, allowing us to estimate the duration collected during the fieldwork and in the labo- and characteristics of the transformations in the ratory. We sampled the lowermost sediments, plant assemblages, with variable sample dis- using variable core lengths, including peats and tances but not exceeding 10 cm.