Evolution of Landplants & Development of Terrestrial Ecosystems"

The evolution of land plants and the development of terrestrial ecosystems are closely interconnected. The colonisation of terrestrial habitats in the early Palaeozoic, the rapid development of the flora in the Devonian as well as the evolutionary success of the angiosperms in the Cretaceous caused an overall change of terrestrial ecosystems. Land plants always had various interactions with microorganisms, insects and other animals, they shaped and changed ecosystems and had strong influence on the world's climate.

In Alexander Schmidt's research group land plants of the Earth history are therefore studied with regard to their palaeoenvironment. Non-vascular and vascular plants as well as fungi of terrestrial palaeoecosystems are the main research focus. The investigation of amber fossils are hereby most important since fossil tree resins also preserved those taxa which are otherwise rarely or never preserved. Cryptogams and phanerogams were preserved in the places where they lived and together with many other syntopic organisms. Amber fossils are predestined for the research on palaeoecosystems because of the excellent preservation, often in several developmental stages as well as the possibility to draw conclusions on interactions between organisms.

Fossil resins of different epochs from all over the world are screened for inclusions of fungi, algae, bryophytes, protozoans and remnants of higher plants. The scientific investigation of fossils of different groups of organisms allows comprehensive insights into the biota of Mesozoic and Cenozoic forests. Our main focus is on members of the otherwise only rarely preserved lower trophic levels of the terrestrial palaeoecosystems. We pursue questions on the stability of microbiocoenoses and the interactions between higher plants with microorganisms and animals. Furthermore, we try to reconstruct biocoenoses and food webs.

The particular excellent preservation of soft-bodied microorganisms in amber allows direct comparison of the fossils to morphological determinable extant taxa at genus and species level. Groups with previously poor fossil record can therefore now be enclosed in interdisciplinary approaches incorporating palaeontological and molecular methods. Molecular phylogenies obtained from DNA sequence analyses of modern taxa are calibrated with well-dated amber microfossils and the origin of groups and evolutionary rates through time are estimated. Various genera of liverworts and ascomycetes are hereby subject of current investigation. The results will shed new light on the understanding of stability and change of terrestrial ecosystems in the Mesozoic and Cenozoic.