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Biodiversität und Pflanzensystematik

Prof. Dr. Marcus Koch

For the various research projects we are always seeking for enthusiastic students and co-workers (Bachelor- Master- or State exam-thesis):

Selected actual research projects

Principles of Crucifer Evolution: Crucifers (Brassicaceae, Cruciferae) are a large family comprising some 340 genera and approximately 4,000 species. The family includes important crops as well as several model species in various fields of plant research. Meanwhile, we have nearly complete coverage of a molecular-systematic characterization of all genera. And, in addition, numerous phylogenetic hypothesis based on various genes from the plastome, nuclear and mitochondrial DNA are available enabling us to provide first robust and reliable family-wide phylogenetic trees. The Brassicaceae are characterized by frequently occurring hybridization and polyploidization, which, as a consequence, is greatly affecting genome size and structure, but also any mode of speciation. Nonetheless, it is still unclear if the evolution of the Brassicaceae on the various taxonomic/temporal levels and with its evolutionary lineages is mostly or even best explained by multiple radiation events. A fact that can also account for the difficulties to resolve deep phylogenetic relationships within the family. Herein we are aiming to use the actually available knowledge and phylogenetic data and a phylogenetic backbone to address these principle questions of crucifer evolution by adding genome size data across the whole family.

BrassiBase: Tools and biological resources to study characters and traits in the Brassicaceae (DFG - SSP1529) We aim to develop a system of cross-referenced information and resources on Brassicaceae taxonomy, systematics, evolution, chromosome numbers, accurate enumeration of all species, traits and characters and germplasm resources. Biological, molecular and evolutionary knowledge is exponentially increasing in the mustard family (Brassicaceae, Cruciferae). However, because of the complex and overwhelming biological diversity in the family, it is difficult for non-specialists in this plant family to put any research result in a larger evolutionary framework. Many species are remarkable study objects but rarely available. Biological material and resources, either collected directly in the wild or held in germplasm collections, is often taxonomically mis-itentified; and very rarely the material is further characterized and documented. There is also no family-wide and comprehensive survey of character and trait distribution despite the fact that we approached a reliable phylogenetic framework quite recently. In order to close these various gaps and provide the full potential of research focusing on the adaptive characters and character-trait evolution in the Brassicaceae, we will provide a comprehensive documentation of the taxonomy and systematics of the entire family. This will include a database with all the relevant taxonomic, systematic and phylogenetic literature; a comprehensive data collection of characters and traits including all potentially adaptive traits scientists participating in SSP 1529 are interested in; a DNA-based identification tool for genera and species; electronic interactive keys for the identification of genera and species, and a setup of a carefully selected and documented germplasm collection representing the entire family. Basic research will be conducted to provide first and comparative insights into the evolution of characters and traits over the whole family utilizing also the data collected during the project. The results and framework provided herein will be the basis and starting point for other projects focusing in more details on individual characters and traits – inside and outside SSP 1529 “Adaptomics”.

Phylogeography and conservation genetics of the Central European Cochlearia. The genus Cochlearia comprises less than 20 species. There are various polpyloid taxa, but most interestingly are the diploid and ancestral species. Most of them occurr in extreme cold-temperate habitat types (springs, creeks, or high alpine regions) and especially the Central European lowland populations seem to be one of the few examples of cold-adapted plants severely suffering from climate change and global warming. Consequently Cochlearia pyrenaica is one of the most threatend plant species all over Europe. In various countries less then five populations survived. Germany plays an important role in the conservation of this species since most of the populations are found in Bavaria and Baden-Württemberg. We aim to develop a phylogeographic-evolutionary scenario of the whole genus with some particular focus on the conservation genetic status of the species.

Phylogeography and the evolutionary history of Hypericum perforatum L. The genus Hypericum is a morphologically and ecologically highly diverged and large group of more than 460 species. Several species are wide-spread in Eurasia and dominate in lowland habitats not affected by extreme environmental factors. Hypericum perforatum and H. maculatum are representative examples with a largely overlapping distribution area, but the first one tends to prefer drier habitats, while the second species is distributed even in boreal Eurasian regions. We aim to unravel the evolutionary history of these two wide-spread lowland species during the pleistocene (phylogeography) and to characterize genetical contact zones reflecting actual and past geneflow between both. We would like to test if this evolutionary scenario of the wide-spread lowland species confirm patterns of refuge areas and principle migration routes revealed from the analysis of woody plants, annuals, arctic-alpine representatives and others. It is very likey that hybridization and reticulation played a role in the evolution of different morpho- and cytotypes in H. perforatum as well as in H. maculatum, and it is also obvious, that there is ongoing geneflow between both species groups. This project is embedded in a larger research network focusing on the evolution and systematics of Hypericum in general, but selecting H. perforatum and closest relatives as model to focus on evolutionary important traits and characters. The results from this study are a prerequisite to discuss the evolution of one important trait in Hypericum, namely apomixis, the propagation via seeds produced without sexuality. This study will provide fundamental information about 1) centres of genetic diversity, 2) migration routes and source areas of genetic variation, 3) hybridization and suture zones, and 4) temporal estimates of diversification. All these information can be linked with the trait apomixis within populations actually analysed in detail and should answer questions about 1) multiple origin and constitution of apomixis (in space and time), 2) transmission of the trait via hybrid bridges, and 3) temporal dynamics of adaptation and transition from sexual to asexual propagation and vice versa.

Conservation Biology and Genetics of Cheddar Pink - Artenschutzprogramm Pfingstnelke, Naturschutzfond BW (in coll. with the Federal State BW and NHM STU) The Cheddar Pink (Dianthus gratianopolitanus) is an endemic element of the Central European flora. Its distribution centers are located in the French, Swiss and German Jura mountains. Furthermore, there are numerous relic populations throughout Europe, found in low elevation mountain areas, ranging from France and Belgium to the Czech Republic and Poland in the East. A distribution outpost is found in the UK (Somerset: Mendip Hills). The Cheddar Pink is growing on shallow, humus-poor soils, at habitats with high light intensities, such as margins of acclivities, rocky outcrops and cliffs. The plant is frequently found on limestone (dolomite). In the northeast of its distribution range, populations are frequently found on schistous gravel, sandstone, diabase or greenstone and serpentine. Occasionally the Cheddar Pink manages to penetrate into pine forests adjacent to its rocky habitat. In Brandenburg, Germany, D. gratianopolitanus var. sabulosa is found in pine forest on sandy soils. mkoch_pid198_b1_L.jpgIn France and Switzerland the species is found at elevations between 500 and 1600 m asl. Outside these areas, the species occurs at much lower elevations. It is important to notice, that the habitat type colonized by the Cheddar Pink is almost exclusively highly endangered and characterized by very specific species assemblages. This is especially true for rocky outcrops and cliffs as well as serpentine habitats. It is also important to realize that these rock and cliff habitats are mostly NON-alpine. Consequently, con-sidering the large and native Central European distribution range, the Cheddar Pink can be regarded as a “flagship species” for many of these habitat types. Further investigation is necessary to illucidate the Cheddar Pink’s eligibility to serve as target species in nature conservation and action plans. The Cheddar Pink is endangered troughout its whole distribution area. The different factors causing this severe threat can be roughly categorized as follows: 1) vegetation encroachment, 2) human recreational activities – especially climbing, or hiking close to cliff sides, 3) genetic and autecological effects caused by very small and isolated, populations. Especially factors 1 and 2 are surprising at first, for today, most populations are located in nature reserves. However, especially these habitats suffer largely from successional processes towards closed woodlands. And as a curiosity one population in Lower Saxony (sünteln, Niedersachsen) occurs on rocks surronded by avalanche forest, which is a major conflict of objectives.  The distribution pattern demonstrates that Germany and Switzerland share particular responsibility for any longterm preservation and action plans. Populations in Germany are especially noteworthy for they display an exceptionally broad ecological amplitude (e.g. adaptation to a wide range of different soil types). As a consequence, populations in Germany must be regarded as central to any conservation strategy. Although the highly endangered Dianthus gratianopolitanus is neither protected as annex species to the FFH-EU directive nor protected under the Berne convention, in most countries strict national protection guidelines are given. Our project on conservation genetics and evolution of the Cheddar Pink is based on these various aspects. At first glance, the continuous Central European distribution indicates only little differentiation. However, edaphic factors indicate a major geographical split, separating a major area harbouring populations on limestone (Jura mountains in Switzerland, France and Germany), from northeastern populations, with many satellite populations remaining scattered throughout Central Europe. The project aims to answers several open, but important questions regarding genetic diversity, distribution and evolutionary history, but also regarding systematics and taxonomy. These datasets are virtually important to develop effective conservation management strategies for Dianthus gratianopolitanus

 

Research projects at the Botanical Gardens and Herbarium

THE WERNER RAUH HERITAGE PROJECT Prof. Werner Rauh (1913–2000) studied Botany, Zoology, Chemistry and Geology at Leipzig, Innsbruck and Halle (Saale). In 1956 he was appointed as associate Professor of Botany at Heidelberg University. In 1960 he became full Professor and Director of the newly established «Institut für systematische Botanik und Pflanzengeographie», until 2010 Heidelberg Institute for Plant Science (HIP), now part of Centre for Organismal Studies (COS Heidelberg). He held this position until he retired in 1981 and beyond that until 1982.

During his time as director and in his retirement until 1994, he made more than 36 expeditions, mainly to South- and Central-America, as well as to the south of Africa and particularly to Madagascar. From these journeys, he took innumerable plants to the Botanical Gardens Heidelberg, especially succulents, bromeliads and orchids, which are a valuable part of today's living collection and of the Herbarium (HEID). During his expeditions he scribed more than 90 booklets with detailed information not only about the plants collected, but on vegetation and geology of the regions he visited. A total of 8.776 hand written pages with more than 19.000 entries, hardly accessible for research, were scanned in 2008 and 2009 and are now being processed within «The Werner Rauh Heritage Project».

The heart of the project is a relational database to store the heterogenous information found in the field books, as well as to link it to a clear taxonomy and to the garden's database. A number of powerful tools are being developed to enable researchers to search the database for information like collected taxa by name, Rauh's field numbers and the place of collection etc. The central parts of the database are a look-up table with the itineraries of Werner Rauh's journeys (all geographical points to be found in his field books, with the taxa collected or observed) and another table with the taxa entries (all taxa with a field number noted in the field books). Tables with synonyms and basionyms and protologue data are included as well as links to other taxonomic databases, e.g. IPNI and TROPICOS.

«The Werner Rauh Heritage Project »

 

            

 

Selected other projects

Evolution of apomixis in North American Boechera, Kooperation with Tim Sharbel. Over the past years we developed a comprehensive evolutionary model of the diversification of the genus Boechera in space and time. More than 2000 accessions have been analysed and genotyped over the whole North american continent. Additional information was achieved analysing the reproductive mode and the trait apomixis..

Evolution of the genus Draba, Koopearation with Ingrid Jordon. We developed a comprehensive phylogeny of the genus Draba with its more than 350 species. In this collaboration we further focus on biogeographic aspects and unravel the importance of various different modes of the reproductive system triggering the evolution of particular clades within Draba.

Regeneration of limestone grassland in Lower Saxonony. Over the past 25 years we have monitored and evaluated management strategies to restore limestone grasslands in Lower Saxony near Osnabrück. With particular consideration of the soil seed bank these management strategies will be further optimized and developed to guarantee the survival of this unique vegetation type.

Further projects are focusing on the phylogeography and taxonomy of Noccaea caeruelscens agg, the genus genus Aubrieta, terrestrial tillandsia´s, ...

 

Our research is/was funded by various sources such as DFG, BMBF, EU-Synthesis, DAAD and the Humboldt-foundation, the Tschira-foundation as well as from the excellence initiative, and graduate programmes (Landesgraduiertenförderung. HBIGS) and the Naturschutzfond Baden-Württemberg.

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/var/www/cos/ / https://www.cos.uni-heidelberg.de/ Prof. Dr. Marcus Koch