View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Jagiellonian Univeristy Repository Acta Palaeobotanica 52(1): 105–125, 2012 Local Holocene vegetation changes and settlement history based on pollen analysis of Lake Kwiecko sediments, West-Pomeranian Lake District, NW Poland JACEK MADEJA Department of Palaeobotany, Institute of Botany, Jagiellonian University, Lubicz 46, 31-512 Kraków, Poland; e-mail: [email protected] Received 13 March 2012; accepted for publication 31 May 2012 ABSTRACT: The sediments of Lake Kwiecko, located in the eastern part of the Bytowskie Lake District (part of the West-Pomeranian Lake District, Poland), were studied by pollen analysis. Holocene vegetation history was reconstructed from the beginning of the Preboreal to the Late Middle Ages. On the basis of the curves of selected taxa and the occurrence of plant indicators of the presence of man 6 settlement phases were distinguished and correlated with archaeological data. The investigations have shown that the fi rst week palynological indications of human presence around the lake were connected with the Atlantic chronozone, while the strongest impact of man on vegetation was recorded in the Middle Ages and modern times. KEYWORDS: Holocene palynology, vegetation changes, settlement history, West-Pomeranian Lake District, Lake Kwiecko INTRODUCTION In spite of investigations carried out by many terrains (Tuchola Forest, South-Pomeranian palaeobotanists in north-western Poland, vege- Lake District) for instance by Berglund et al. tation history of the West-Pomeranian Lake Dis- (1993), Milecka (2005), Milecka & Szeroczyńska trict and particularly of the Bytowskie Lake Dis- (2005), and Lamentowicz et al. (2008). trict is not satisfactorily known. In the synthesis The studies of the genesis, age, and evo- of the international IGCP 158B program (Ral- lution of the Lake Kwiecko were initiated by ska-Jasiewiczowa 1987, Ralska-Jasiewiczo wa Więckowski in 1969 (Więckowski 2009), and & Latałowa 1996) only two sites, Lake Wiel- a pilot pollen analysis of four bottom sam- kie Gacno (Hjelmroos-Ericsson 1981) and Lake ples from one of the cores was carried out by Suszek Mały (Miotk-Szpiganowicz 1989, 1992) Wasylikowa (unpubl.). The present paper sup- situated in the South-Pomeranian Lake Dis- plements the hitherto available knowledge of trict, are considered fully representative also for natural and anthropogenic vegetation changes the eastern part of the West-Pomeranian Lake since the decline of the last glaciation to the District. The list of localities, which were used late Subatlantic chronozone in the West- for drawing isopollen maps for Poland shows Pomeranian Lake District. that in the 50 km radius of Lake Kwiecko there were no sites with chronologically justifi ed pol- len records (Ralska-Jasiewiczowa et al. 2004). DESCRIPTION OF THE SITE In the last years palynological investigations in the West-Pomeranian Lake District were carried Lake Kwiecko (54°01′30″N, 16°42′00″E) is out by Malkiewicz & Tomaszewska (2009) and situated in north-western Poland (Fig. 1), in Święta & Latałowa (2003), and in the adjoining the Bytowskie Lake District, which stretches 106 for about 100 km in west-east direction and known as Lake Żydowskie or Dolne. While the belongs to the West-Pomeranian Lake District plant is at work, the 80 metres natural differ- (Kondracki 2002). This is a glacial fl ow-through ence between the elevations of Lakes Kami- lake situated at an elevation of 80 m a.s.l., in enno (upper reservoir) and Kwiecko makes a natural valley surrounded by moraine hills. the water fl ow by the system of canals from The largest lake tributary is river Dobczyca Lake Kamienno to Kwiecko and drive the elec- falling at its southern end, outfl ow constitutes tric turbine. Then, the water is pumped back river Radew rising in the north-west end of the to the upper reservoir by a system of pipes. lake (Fig. 2). Lake Kwiecko is a shallow, up to During the work of the plant the great twenty- 3 m depth lake with the basin of irregularly four hours’ water level oscillations, coming up triangular shape stretches about 900 m in to 3 m, are recorded. When the lake is fi lled west-east and 1400 m in north-south direc- to a maximum its total water surface covers tion. In the southern part of the lake the island 127 ha (Korzeniewski & Śpiewakowski 1977). (5 ha) is located. Lake Kwiecko constitutes the The lake bottom is covered by lake sediments lower reservoir for the pumped-storage power overlain by sands or more often by a thick station functioning since 1970 in the nearby mud layer. The examination of four cores from Żydowo. For this reason Lake Kwiecko is also Lake Kwiecko by Więckowski revealed the Fig. 1. Map of Poland and location of Lake Kwiecko. 1 – lakes, 2 – rivers, 3 – elevation a.s.l. 107 Fig. 2. Location of archaeological sites in the nearest vicinity of Lake Kwiecko. A –stronghold, B – settlement, C – cemetery, D – settlement point , E – settlement trace, F –camp site, G – Bronze Age ornaments treasure, 1 – Mesolithic, 2 – Mesolithic/ Neolithic, 3 – Neolithic, 4 – Funnel Beaker culture, 5 – Bronze Age , 6 – Lusatian culture, 7 – Pomeranian culture, 8 – Wiel- barska culture, 9 – Middle Ages occurrence of distinct laminae at the depth of glacier stages were its southward transgres- 19–21 m, which accumulated in 8–13 years’ sions, the effect of which are the now exist- cycles connected with changes of solar activ- ing deposits and land forms, attributed to the ity. An unusual feature of the sediments of main marginal phase of the Pomeranian stage this lake is the presence of exoskeletons of and Kashubian-Warmia and Koszalin phases Chara fragilis stems with numerous oospores (Karczewski 1994). (Więckowski 2009). The coring took place in The thickness of the Pleistocene deposits the deepest place (3 m) of the northern part usually exceeds 100 m and most often they of the lake. were formed by the glacial and fl uvioglacial accumulation, for instance glacial tills, sands, GEOLOGY AND GEOMORPHOLOGY gravels, loams, and clays. The relief of the landscape developed under the infl uence of the In the light of the existing divisions of Poland systems of subglacial channels, river valleys, into tectonic units the Bytowskie Lake District kettle holes, hills of front moraines, and eolian is situated within the range of a marginal syn- forms. The highest elevation of 256 m a.s.l. is cline and Pomeranian-Kujavic embankment located on the top of a front moraine (Siemier- (Pożaryski 1969). zycka Góra near Bytów). On the territory of the The evidence of four Quaternary glaciations Bytowskie Lake District there occur numerous can be traced in the Bytowskie Lake District. small water basins and lakes (e.g. the largest The oldest San I glaciation left behind the Bobięcińskie Wielkie Lake is 48 m deep and boulder clay covers preserved only in some covers 524.6 ha). depressions. During the San II glaciation the thickness of the ice-sheet was 1500–2000 m at SOILS least. The Oder glaciation had similar charac- ter (Mojski 1993). For the last time the gla- The dominating surface formations on the cier cover spread over the whole area of the territory of the Bytowskie Lake District are Bytowskie Lake District during the Vistula the deposits of the last glaciation, among glaciation (Borówka 2002). The important which boulder clays are the most signifi cant, 108 while sands, gravels, erratic blocks, and in the Bytowskie Lake District) should be mentioned central part also fl uvioglacial deposits are less for instance Czubiński (1950, 1960), Żukowski important. Holocene lake-and-mire sediments (1962), Jasnowska & Jasnowski (1983), and (gyttja, mud, peat) are also present. Swampy Śpiewakowski & Korczyński (1993). soils usually follow gullies, melts, and river A large area of the West-Pomeranian Lake valleys and are represented by the sludge-bog, District is covered by beech forests, with the peat, and decay soils. dominance of Melico-Fagetum association, Holocene deposits include also various soil while on drier and more acidic soils the acido- types, which were formed in the course of philous beech forest Luzulo-Fagetum predomi- complicated pedogenesis processes, with the nates. Planted Pinus sylvestris often occurs in predominance of those developed on glacial forest stands. Mixed beech-oak forests from deposits and peats. The distribution of soils the class Quercetea robori-petraeae grow on reveals some sort of zonation: brown soils occur lessivé and rusty soils of steep moraine slopes. mainly on ground moraine, while podsols and The frequent forest type is represented by pseudo-podsols on outwash plains (Bednarek mixed pine-oak woods (Querco-Pinetum). The & Prusinkiewicz 1999), which cover 75% of the sub-oceanic middle-European pine forests Bytowskie Lake District. The area of the ter- Leucobryo-Pinetum, with small shrubs of Vac- minal moraines is covered by a mosaic of soils cinium myrtillus, V. vitis-idaea, and Calluna mentioned above. The arable land is dominated vulgaris in the herb layer, play a great role by brown soils developed on clays and podsols in the whole of the West Pomerania. Horn- formed on sands. beam forests (Stellario holosteae-Carpinetum) The soils of the Bytowskie Lake District, cover small areas on fertile, humic habitats, irrespective of the bedrock from which they on brown and lessivé soils. In the Bytowskie were formed, are acidifi ed to a high degree, Lake District, as in the whole Western Lake poor in humus, and relatively poor in assimila- District, fragments of carrs can be found along ble elements like phosphorus, potassium, and some rivers and streams, alder-ash carr Cir- magnesium (Kordiasz & Kozłow 1998). caeo-Alnetum being the most frequent among them. Swamp scrub and wet alderwoods from CLIMATE the class Alnetea are common on boggy habi- tats and near springs.