Dr. Thomas Kiebacher

Worldwide, the increasing threat of extinction looms over numerous species due to global change. How can we preserve these species for future generations, especially when their environmental requirements are scarcely understood? Germany holds a particular responsibility for the moss species Schistidium spinosum, classified as critically endangered by the International Union for Conservation of Nature (IUCN).

This project bridges the gap between fundamental research and conservation efforts. We investigate the causes of rarity and endangerment, as well as the genetic status of populations, to derive specific conservation measures. Our aim is to demonstrate, how integrative approaches involving interconnected processes and collaboration among researchers and conservation authorities can swiftly and sustainably stabilize species at high risk of extinction.

Supported by Naturschutzfond Baden-Württemberg

The epiphytic moss species Orthotrichum philibertii encompasses, to current knowledge, both Mediterranean and disjunct occurrences in Scandinavia, subject to vastly different ecological conditions. In this project, we investigate whether genetic and morphological differentiation underlies the ecological breadth within this broadly defined species. Initial findings suggest that the morphological concept of O. philibertii encompasses multiple species.

Climate warming leads to a shift in the distribution ranges of species and to changes in the composition of plant communities. The dynamics of these changes have been intensively studied for vascular plants. In contrast, little is known about how bryophytes react to the changing conditions, even though they are the second largest group of land plants and provide important ecosystem services, including carbon and water balance. Since bryophytes differ fundamentally from vascular plants in their ecophysiological properties, it can be assumed that they will also be affected differently by climate warming. Due to their poikilohydry, they are in direct exchange with the atmosphere and thus may react more directly to ongoing warming. In addition, they have much smaller diaspores and may therefore follow the shifting climate more rapidly.

In a comparative study, we analysed changes in bryophyte and vascular plant communities in more than 1000 permanent plots of the Biodiversity Monitoring Switzerland (https://biodiversitymonitoring.ch). The plots cover an altitudinal gradient of almost 3,000 m and have been surveyed regularly since 2001. Initial results indicate that the two species groups differ significantly in their response to climate warming and that the elevational gradient plays a decisive role in this.

Project partners: Hintermann & Weber AG (Reinach, Switzerland), University of Zurich UZH

The cosmopolitan genus Schistidium Bruch & Schimp. (Grimmiaceae) is one of the most species-rich groups of mosses with about 150 recognised taxa. Most species are rock-dwelling and make a decisive contribution to biodiversity through their ability to colonise extreme sites both in the mountains and at secondary sites in urban habitats. In this ongoing research topic, we are investigating this globally insufficiently researched genus from various points of view.

Our data show that current taxonomic concepts vastly underestimate the species diversity of the genus. Even in well-studied areas such as the Alps and Scandinavia, there are still undescribed species that are well delimited morphologically and genetically. The proportion of cryptic species is still largely unknown.

Another research topic are the evolutionary processes that have led to the extraordinary radiation of the genus which will shed light on general patterns of speciation in haploid land plants. Most Schistidium species are thought to have evolved in the context of glacial fluctuations, and phylogenetic data indicate ongoing speciation processes. We are following evidence that homoploid hybridisation events play an important role in this process.

The phylogeny of Schistidium is poorly understood. Current concepts are based on phylogenetic inference with a limited set of markers, show discordance with morphological concepts, and are most likely biased by processes such as incomplete lineage sorting and gene transfer. By using genetic data from all three genome regions (nucleus, chloroplasts, mitochondria) we explore the evolutionary history of the genus and provide a reliable phylogeny.

Project partners: Norwegian Institute of Bioeconomy Research NIBIO

Cryptic species are species that are reproductively isolated but cannot be distinguished morphologically, or only vaguely. Through the application of genetic methods, more and more such species are being discovered in bryophytes and they seem to account for a considerable part of the diversity. In many cases, however, it is unclear how such species have evolved, for example, when the isolation cannot be explained by geographical patterns. In this project, we investigate to whether adaptation to different substrates can explain cryptic speciation in the moss genus Dicranum.

Project partners: University of Zurich UZH

While the floristic connections between western North America and eastern Asia across the Bering Bridge is one of the best-studied biogeographical relationships, the connections between the southern Rocky Mountains and Central Asia have received little attention. Using genetic data, we study this connection for mosses and liverworts.

Project partners: Norwegian Institute of Bioeconomy Research NIBIO, University of Zurich UZH, Peter Gruber (Salzburg, Austria)

In the liverwort genus Scapania the leaves are composed of 2 lobes which are usually connected by a keel in a characteristic way for the genus. Only a few taxa have unkeeled leaves and these were assigned to a separate subgenus Jensenia by 20^th century taxonomists. Currently, such taxa are considered to be forms of a single highly variable species, S. obcordata, which occurs in Arctic and boreal regions in habitats characterised by periodic disturbances. The discovery of Scapania plants with unkeeled leaves in the Alps makes it necessary to revise the current phylogenetic concept, as our analyses indicate that the plants from the Alps are not closely related to S. obcordata. To this end, we use an integrative approach and combine genetic analyses with morphological data, taking into account the ecology of the taxa.

In this project, we investigate an undescribed and morphologically unique taxon of the Grimmiaceae that may represent a hybrid. While the taxon is gametophytically close to species of the genus Grimmia, the sporophyte characteristics indicate a close relationship with Schistidium. By sequencing chloroplast and nuclear markers, we test the hybridisation hypothesis.

Project partners: University of Zurich UZH

Climate change is one of the major threats to biodiversity and there is still a lot of uncertainty about how plants can adapt to and survive in the rapidly changing matrix of habitats. This project addresses key evolutionary processes in early land plants that are relevant in this context. First, it explores two poorly understood processes, homoploid hybridisation and immediate introgression to evaluate their importance by linking them to ecological innovations and selective signals. To achieve this, we build phylogenetic networks and apply tests such as invariants-based methods and simulations. Second, it will infer plant responses that can be expected under the ongoing warming scenario by reconstructing the phylogeographical history and adaptive evolution that species underwent following the last glacial maximum.

We address these topics using the bryophyte genus Schistidium. This model encompasses a swarm of pioneer species adapted to colonize bare rock surfaces including artificial substrates such as concrete and asphalt. This ability allows these species to buffer the effect of climate change by colonizing deglaciated and desertified land. The dominance of the haploid generation in this lineage facilitates the detection of evolutionary signals, speeds up purifying selection and the high reproductive effort favours hybridisation events.

The project builds on extensive preliminary analysis assessing genome sizes and ecological and morphological divergence in the proposed model system. We will perform high throughput target capture and double-digest restriction site-associated sequencing to generate genomic data of coding and non-coding regions from all three parts of the genome (nuclear, plastid, mitochondrial).

Project partners: Swedish Museum of Natural History, Norwegian Institute of Bioeconomy Research NIBIO, University of Liège, University of Zurich UZH