@phdthesis{Barthelmes2010,
  author    = {Alexandra Barthelmes},
  title     = {Vegetation dynamics and carbon sequestration of Holocene alder (Alnus glutinosa) carrs of NE Germany},
  journal    = {Vegetation dynamics and carbon sequestration of Holocene alder (Alnus glutinosa) carrs of NE Germany},
  url       = {https://nbn-resolving.org/urn:nbn:de:gbv:9-000789-8},
  year      = {2010},
  abstract  = {Black alder (Alnus glutinosa [L.] Gaertn.) is the predominant tree species on nutrient-rich peatlands in mid-latitude Europe where alder carrs cover large areas. Widespread even-aged stocks and difficult regeneration in shade lead to the assumption that alder carrs perform a cyclic alternation with open vegetation types. Since alder wood peat has rarely been object of palaeoecological research, little is known about the long-term dynamics of alder carrs. To reconstruct peat forming vegetation, vegetation dynamics and carbon sequestration rates of Holocene alder carrs, four profiles of alder wood peat from NE Germany were analysed on micro- and macrofossils. Because of poor pollen and macrofossil preservation, additional non-pollen palynomorphs (NPPs: wood, fungal, algal and invertebrate remains) were studied for sharper reconstruction of vegetation and environmental conditions. A multitude of previous unpublished non-pollen palynomorphs were introduced (with morphological description, digital photography, identification, ecological indication), which extended the approach of analysis of non-pollen palynomorphs to eutrophic and forested sites. All studied alder wood peat deposits show alternations of primary alder carr or willow scrub peat and secondary displacement peat of alder roots grown into previously deposited sedge fen peat. Therefore, cyclic vegetation development of alder carrs, willow scrubs and sedge fens can be deduced as common feature of long-term forested fens in NE Germany. These long-term vegetation dynamics were in the analysed cores predominantly driven by increased groundwater discharge into the mire, resulting from human disturbance of the surrounding woodlands that partly interfered with climatic shifts. Although alder wood peat is widespread in mid-latitude Europe, it rarely has been subject of palaeoecological research and data on the long term carbon accumulation rates (LORCA in t C ha-1 yr-1) of alder carrs are very rare. To determine long-term accumulation rates bulk density measurements are combined with radiocarbon datings. We found LORCA values of 31 to 58 g m-2 y-1 in very wet willow scrub vegetation, 48 to 96 g m-2 y-1 for displacement peats, 31 to 44 g m-2 y-1 in very wet alder carrs (mean water level: 15-0 cm above surface) and 50 to 126 g m-2 y-1 in wet alder carrs (mean water level: 0-10 cm below surface). The high LORCA of peat accumulated in the latter carrs is likely related to the much higher production of highly decomposition resistant wood roots (lignin) in absence of long-term flooding. Long-term C-accumulation rates in alder carrs are surprisingly high in comparison to boreal forested peatlands, approaching LORCAs of tropical peat swamp forests.},
  language  = {de}
}