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RESEARCH PRODUCT

Möglichkeiten und Grenzen einer Ökosystem-Rekonstruktion am Beispiel des spätpaläozoischen lakustrinen Paläo-Ökosystems. 1. Theoretische und methodische Grundlagen

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In analogy to ecosystems, palaeoecosystems are defined here as the palaeocommunities of a given area and their relationships to the abiotic variables of their respective environments. They are characterized by (a) their species diversity, (b) the trophic structure of their palaeocommunities, based on their food webs, and (c), based on their detailed historical development, ecosystem functions such as stability, resilience, and succession. Due to numerous taphonomic biases, palaeocommunities can only be reconstructed from very few fossil horizons (taphocoenoses). Important conditions for such reconstructions are an uninterrupted vertical sequence of taphocoenoses with little time-averaging, excellent fossilization potential, a minimal percentage of allochthonous species in the taphocoenoses, and reliable evidence concerning the original trophic interactions between the species or trophic guilds of the palaeocommunities. The following topics are discussed in detail: Taphonomic assessment concerning fossilization potential; estimation of autochthonous vs. allochthonous components, and time-averaging; reconstruction of food webs and their interpretation in terms of extant food webs, such as web parameters; various ecosystem functions, especially successions and structuring processes, and the limited possibilities for their reconstruction.