Late Glacial and Holocene history of Plešné Lake and its surrounding landscape based on pollen and palaeoalgological analyses

Abstract

Pollen analysis has been carried out on a 549 cm thick sediment profile from lake Plešné jezero (Plešné Lake) in the Bohemian Forest (Šumava, Czech Republic; 1090 m a.s.l.; 48• 47 N; 13• 52 E). Analyses of 67 samples characterise the development of the lake biotope and the surrounding landscape during the last ca. 14,000 years. The pollen diagram shows a very distinct transition between the Late Glacial and the Holocene biostratigraphic units at a depth of ca. 312 cm. In the surroundings of Plešné Lake the vegetation was treeless during the entire Late Glacial. The alpine tree limit, formed by Betula and Pinus with undergrowth of shrubs, might have been at ca. 500 m a.s.l. Pollen transported from long distances was significant due to the openness of the landscape, coming from southern Europe and even Africa, and including high numbers of Artemisia, Poaceae, Chenopodiaceae, and some other herbs and shrubs from steppe and forest-steppe areas in southern Europe or Africa (likely Ephedra, certainly Lygeum spartum). The expansion of shrubs, particularly Juniperus, preceded the expansion of trees near the end of the Late Glacial. Afforestation of the region by thin stands of Betula and Pinus occurred during the Preboreal. Significant warming in the Boreal resulted in the expansion of Corylus, Quercetum mixtum (QM) trees, and probably also Picea and Alnus. Picea as well as QM trees were further expanding during the Early Atlantic. Picea was the dominant tree during the Late Atlantic and Fagus started to spread towards its end. Abrupt expansion of Abies marks the Subboreal. A high degree of afforestation (Abies, Fagus, Picea) was characteristic for the Early Subatlantic. During Late Subatlantic, pollen of synanthropic plants appears. Phases of the lake biotope development were defined on the basis of coccal green algae and Isoëtes.

What do Holocene sediments in Petuniabukta, Spitsbergen reveal?

“…However, the ecological conditions for Tardigrada are not well known yet. Similar findings were reported from Arctic regions (Svalbard) by Jankovská (1991), high altitudes in the Andes by Montoya et al (2010) or from late glacial sediments from the Czech Republic (Jankovská 1990(Jankovská , 2006. The con− tinuous presence of Tardigrada remnants, and also the occurrence of moss−domi− nated vegetation, indicate that water was accumulating there since the terrace up− lift and then formed into a shallow lake.…”

Quaternary environmental history of the Čejčské Lake (S. Moravia, Czech Republic)

“…Laka in the Šumava Mts, others are still lakes e.g. the Černé Lake (Břízová 1991a(Břízová , b, 1993(Břízová , 1995(Břízová , 1996Jankovská 2000), the Čertovo Lake (Břízová 1996), the Prášilské Lake (Břízová 1999(Břízová , 2000Břízová in Hruška et al 1999, Hruška et al 2000, the Plešné Lake (Jankovská 2006), and in Bavaria, the Great and Small Javorské lakes, the Rachel Lake and the mountain lakes in the Krkonoše Mts, e.g. the Wiełki Staw Lake - situated on the Polish side (Břízová 1999, Břízová in Hruška et al 1999, Hruška & Břízová 2007.…”

Element fluxes in watershed-lake ecosystems recovering from acidification: Plešné Lake, the Bohemian Forest, 2001–2005

“…Details on the current forest and understory vegetations and their development are given by SVOBODA et al (2006a, b) and JANKOVSKÁ et al (2006), respectively. Since 2004, the forest has been damaged by a bark beetle infestation covering ∼40% of its area.…”