Zur Rekonstruktion historischer Biodiversität aus archivalischen Quellen: Das Beispiel des Oderbruchs (Brandenburg) im 18. Jahrhundert

Abstract

This study demonstrates the usefulness and efficiency but also the limits of archival sources and collections for the reconstruction of historical biodiversity. The research focuses on the historical biodiversity of the Oderbruch, a floodplain of the river Oder situated in the northeast of Brandenburg (Germany) which was on a large-scale embanked, meliorated and colonised during the 18th century. The large quantity of archival material compiled at that time provides the basis for investigating the levels of biodiversity determinable through archival sources, evaluating the potential of different types of archival sources as well as developing interpretation methods for dealing with often incomplete or indirect archival information. The study focuses on the historical species and community diversity of the floodplain. First, it outlines the overall animal and plant species richness with an emphasis on vertebrates and vascular plants. Second, two case studies analyse the fish community and the grassland communities as they are the most economically important and therefore best documented aspects of historical biodiversity in archival and literary sources of the 18th century Oderbruch. The reconstruction of the fish community relies on species lists, registers of taxes paid in kind, fishing statistics and particularly on the numerous records about the pike (Esox lucius) in the unmeliorated floodplain (among them sales statistics of a specialised Hechtreisser fishermen s guild which mainly marketed pike). The pike represents both top predator and indicator species in freshwater and thus information about its frequency allow inferences as to the composition and biomass of the fish community as well as to associated parameters of biodiversity (e. g. habitat diversity). The grassland communities are reconstructed using diverse records of character species, site conditions, farming styles, hay-yield, stocking rate and livestock type. The results of these two case studies are discussed in relation to reference sites in Germany, East and Southeast Europe which are ecologically similar to the historical Oderbruch. Finally, the study s methodology is assessed in its transferability to other periods, regions as well as to other aspects of historical biodiversity. An outlook provides direction for the practical applicability of the study s reconstructions (e. g. revision and adaptation of current nature conservation strategies).