Kazimierz Tobolski

Palaeoecological evidence for anthropogenic acidification of a kettle-hole peatland in northern Poland

The Holocene developmental history of a small kettle-hole peatland in northern Poland was studied using radiocarbon dating and analyses of pollen, plant macrofossils and testate amoebae with the aim of sorting out the influences of climate change, autogenic succession and human impact. The mire followed the classical succession from lake to a Sphagnum-dominated peatland, but peat accumulation only started about 3000 cal. BP. A rapid shift to wetter conditions, lower pH and higher peat accumulation rate took place about 110—150 years before present, when the vegetation shifted to a Sphagnum-dominated poor fen with some bog plants. While the first shift to a peat-accumulating system was most likely driven by climate, the second one was probably caused by forest clearance around the mire. This shift towards a Sphagnum-dominated vegetation mirrors both in pattern and timing the changes observed in similar situations in North America and New Zealand. While human activities have overall caused the loss of vast expanses of peatlands worldwide in recent centuries, locally they may have also allowed the development of communities that are now ironically considered to have a high conservation value. However, in the case of the site studied the likely anthropogenic shift to bog vegetation was at the expense of a species-rich poor fen, which today has even higher conservation value than ombrotrophic bogs. Thus this study also illustrates the value of palaeoecology for peatland management and biodiversity conservation.

Palaeoecological Studies on the Decline of Cladium mariscus (Cyperaceae) in NE Poland

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 presence 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. mariscus in areas that are influenced significantly by a continental climate. The abundance of Ca2+ cations in the substratum compensates for that climatic factor.

Resilience of plant and testate amoeba communities after climatic and anthropogenic disturbances in a Baltic bog in Northern Poland: Implications for ecological restoration:

This study explores the history of the development of Sphagnum communities in an ombrotrophic peatland – Bagno Kusowo – over the past 650 years, based on high-resolution plant macrofossil and testate amoebae analysis. Our research provided information related to the length of peatland existence and the characteristics of its natural/pristine state before the most recent human impacts. Changes in the Sphagnum communities before human impact could have resulted from climate cooling during the ‘Little Ice Age’ (LIA). In this cold and unstable hydrological period, among vascular plants, Eriophorum vaginatum and Baeothryon caespitosum dominated in the peatland vegetation. Peat-forming Sphagnum communities survived the drainage conducted during the 20th century at the Bagno Kusowo bog. We provide three important messages through this study: (1) testate amoebae reflect similar hydrological trends in two peat cores despite considerable microhabitat variability, (2) average long-term water level 10 cm below the surface should be a target for active bog conservation and (3) sites like Bagno Kusowo are extremely important to preserve the remains of pristine biodiversity (including genetic diversity of plants and protists) that was completely removed from most of the raised bogs in Europe due to human activities, for example, drainage.

Macrofossil Evidence of Early Holocene Presence of Picea abies (Norway Spruce) in NE Poland

Early Holocene presence of Picea abies (Norways spruce) was recorded in NE Poland. Currently it is the westernmost known fossil site of spruce for the Early Holocene (9500–9000 cal. BP) in central-eastern Europe, approximately five thousand years earlier than presumed. For the first time, the occurrence of P. abies was documented by the presence of needles, bud scales and seeds. Picea abies grew on a peatland developed on a mineral peninsula between lakes Kojle and Perty during a period of low water level, when Corylus expanded. The disappearance of P. abies is related to a substantial climate change from continental to oceanic, approximately 9400 cal. BP, which resulted in an increase in humidity, higher water levels, and submergence of the peatland inhabited by P. abies.