Dr. Holger Thüs

Many lichens are known for their very small growth rates, but there are notable exceptions. Within the Wart lichen family (Verrucariaceae/Ascomycota) there are small and rapidly growing species living on rarely flooded embankments, on natural screes and on anthropogenic materials, e.g. building rubble and plastic. External or microscopic features are often inadequate for the clear identification of these lichens, and the genetic fingerprint is sometimes the only viable option for an unambiguous identification. The distribution, abundances and the breadth of ecological niches of these species is still poorly understood. The ongoing work will provide an improved basis for evaluating these species in a new edition of the Red List of Lichens of Baden-Württemberg, testing their suitability as bio-indicators for assessing the stability of river beds and screes, and providing answers to the question of why they are successful as pioneers in disturbed habitats.

Within SMNS: Thüs H. (PI), Klüßendorf, J. (PhD student)

External cooperations with: Keller, C. (WSL, Birmensdorf / CH), Orange, A. (NMW, Cardiff), Killmann, D., Fischer, E. (University of Koblenz-Landau), Schiefelbein, U. (University of Rostock), Vondrak, J. (Pruhonice/CZ)

Publications:

Vondrák, J, Svoboda, S., Malíček, J., Palice, Z., Kocourková, J., Knudsen, K., Mayrhofer, H., Thüs, H., Schultz, M., Košnar, J., Hofmeister, J. (2022) Cinderella turns ino a princess – an exceptional hot-spot of lichen diversity in a long-inhabited European landscape.  –  Preslia 94: 143–181. doi.org10.23855/preslia.2022.143

Thüs H., Killmann D., Leh B., Fischer E. (2018) Verrucaria hunsrueckensis (Verrucariaceae, lichenized Ascomycota), a new rare species with exceptionally slender ascospores from Germany. – Phytotaxa, 345: 26–34. https://doi.org/10.11646/phytotaxa.345.1.3

The biodiversity of aquatic and subaquatic lichens increases under cooler conditions. So far, this assumption has been almost entirely based on species concepts which are limited to the analysis of external or microscopic features. However, as soon as genetic characters of lichen-forming fungi and the associated algae are examined, it turns out that hitherto differentiated morphospecies often disintegrate into several different, sometimes not even closely related evolutionary lines. To what extent the previous hypotheses about biodiversity patterns can be confirmed or if they have to be changed in light of new genetic data is an open question. The answers to this question have implications for the assessment of expected impacts of global climate and land use change on lichen ecosystem functions, their threat assessment and reliable diagnostics for the lichens as raw material for pharmaceutical research.

Cooperations with: Perez-Ortega, S. (Real Jardín Botanico de Madrid), Fryday, A. (Michigan State Univ.), Heidmarsson, S. (Univ. Akureyri), Gueidan, C. (CSIRO, Canberra), Orange, A. (National Museum of Wales, Cardiff), Spribille, T. (Univ. Alberta), Shivarov, V. (Univ. Sofia), Nascimbene, J. (Univ. Bologna), Schiefelbein, U. (Univ. Rostock), Gonzales, F. (UNED, San José), Schiefelbein , U. (Univ. Greifswald), Flakus, A. (Univ. Krakow), Pykälä, J. (Helsinki), Skaloud, P. (Charles Univ. Prag).

Publications:

Spribille, T., Fryday, A., Pérez-Ortega, S., Svensson, M., Tønsberg, T., Ekman, S., Holien, H., Resl, P., Schneider, K., Stabentheiner, E., Thüs, H., Vondrák, J, Sharman, L. (2020) Lichens and associated fungi from Glacier Bay National Park, Alaska.  – The Lichenologist, 52 (2), 61–181. doi.org/10.1017/S0024282920000079

Shivarov V., Denchev C., Thüs H. (2018) Ecology and distribution of Dermatocarpon (Verrucariaceae, Ascomycota) in the catchment areas of two Bulgarian rivers. – The Lichenologist, 50: 679–690.https://doi.org/10.1017/S0024282918000452.

Fryday A., Thüs H. (2017) The genus Xenolecia (Lecideaceae s. lat., Lecanoromycetidae inc. sed.), including a second species in the genus from Campbell Island, New Zealand. – The Lichenologist,49: 365–372. doi: 10.1017/S0024282917000287

Scienceblog

Tropical forests are among the world's top habitats with the highest species numbers of lichen-forming fungi worldwide. New species are constantly being described, and it is not uncommon to find undescribed new species in the course of ecologic studies. Under these conditions, protocols developed in temperate regions, which as a rule require a determination at the species or genus level, can only be implemented locally and at great expense of effort. A possible alternative is the use of functional groups, an assessment of the functional diversity of lichens aimed at ecosystem functions. This approach does not require an exact determination of the lichen genera or species. Together with the London Natural History Museum, we have investigated randomly selected forest areas in primary and secondary forests in the northeast of the island of Borneo and compared the results obtained using a taxonomic approach with those of a method using functional groups. As a by-product of the taxonomic approach, we are contributing to the description of new species from one of the hotspots of global biodiversity.

Cooperations with: Vairappan, C. (UMS, Kota Kinabalu/Malaysia), Wolseley, P., Eggleton, P., Weerakoon, G. (Natural History Museum , London), Timdal, E., Kistenich, S. (Univ. Oslo)

Publications:

Thüs, H., Wolseley, P., Carpenter, D., Eggleton, P., Reynolds, G., Vairappan, C.S., Weerakoon, G., Mrowicki, R.J. (2021) Key Roles of Dipterocarpaceae, Bark Type Diversity and Tree Size in Lowland Rainforests of Northeast Borneo — Using Functional Traits of Lichens to Distinguish Plots of Old Growth and Regenerating Logged Forests. - Microorganisms 2021, 9(3), 541: 1-21. https://doi.org/10.3390/microorganisms9030541

Ellis, C.J., Asplund, J., Benesperi, R., Branquinho, C., Di Nuzzo, L., Hurtado, P., Martínez, I., Matos, P., Nascimbene, J., Pinho, P., Prieto, M., Rocha, B., Rodríguez-Arribas, C., Thüs, H., Giordani, P. (2021) Functional Traits in Lichen Ecology: A Review of Challenge and Opportunity. – Microorganisms 2021, 9, 766. doi.org/10.3390/microorganisms9040766

Kistenich S. Rikkinen J.K., Thüs H., Vairappan C.S., Wolseley P.A., Timdal E (2018) Three new species of Krogia (Ramalinaceae, lichenized Ascomycota) from the Paleotropic. – MycoKeys, 40: 69–88. https://doi.org/10.3897/mycokeys.40.26025

The Stuttgart factories of the Jobst family were once among the world's leading manufacturing places of the anti-malaria drug quinine. Quinine, extracted from the Cinchona bark (Cinchona spp.), and structurally related other substances, formed the basis for the only effective medicine for the relief of malaria prior to the development of synthetic drugs. Until the first half of the 19th century, the wild populations of the Cinchona trees were almost eradicated in many places due to overexploitation. The resulting shortage and mistakenly (or fraudulently deliberately wrong) declared but weakly effective varieties of Cinchona bark became a life-threatening risk to the patient. Against this background, any reference to the true origin and variety of the Cinchona bark was of great value. Lichens growing on the Cinchona bark played a significant role in this period as proof of the origin and quality of the raw materials for quinine production. Together with colleagues from the Economic Botany Unit at the Royal Botanic Gardens Kew, we try to use today's knowledge of the environmental requirements and distribution of epiphytic lichens to re-assess the reliability of this historical method.

Cooperation with Walker, K., Nesbitt, M. (Economic Botany Unit Kew)

SMNS Cross-cutting topics: Biodiversity Patterns: Species and their Distribution, Free Fields of Research

Mycosporines and Mycosporine-like amino acids (MAAs) are highly effective UV filters and are already being used in various skincare products. They are found in almost all groups of organisms (cyanobacteria, algae, animals, fungi) and are missing only in the land plants. In addition to the sunscreen function, MAAs play additional roles, e.g. in osmoregulation, heat dissipation and the control of development processes. For a long time, MAAs in lichen-forming fungi were only known from those species that use cyanobacteria as a photosynthetic symbiosis partner. It was only a few years ago that MAAs were detected for the first time in a Wart Lichen associated with green algae. Our ongoing research aims to identify new variants of MAAs and to uncover their distribution and role in the chemoecology, evolution and taxonomy of the Wart lichens (Verrucariaceae/Ascomycota).

Cooperation with Chollet-Krugler, M., Boustie, J. (University of Rennes 1), Nguyen, T. (University of Ho Chi Minh City).

Publications:

Chollet-Krugler M., Nguyen T.T.T., Sauvager A., Thüs H., Boustie J. (2019) Mycosporine-Like Amino Acids (MAAs) in Time-Series of Lichen Specimens from Natural History Collections. – Molecules 24 (6), 1070: 1-11. https://doi.org/10.3390/molecules2406107

Le Devehat,F., Thüs, H., Abasque, M.L., Desmail, D., Boustie, J. (2014) [book chapter] Oxidative Stress Regulation in lichens and its relevance for survival in coastal habitats, In: Sea Plants, Elsevier: 471–507.

Lichenised fungi of the genus Heterodermia are particularly diverse in warm regions of the earth. Only a few species are known from Europe and in Germany all occurrences outside the Alps were considered as extinct for a long time. With the support of the Esmée Fairbaine Foundation's "Lost and Found" project of the Royal Botanic Gardens Kew, I have studied the evolution and genetic diversity of Heterodermia species in the English archipelago Isles of Scilly and the mainland of the British Isles. Currently, the relationships of the British populations to representatives of Heterodermia in Central Europe, south of the Alps, in the Azores and in the tropics are examined. I am trying to clarify whether the Heterodermia species which we see in Europe are outposts of widespread and thus less threatened species from a global perspective, or whether there are genetic lineages on our continent that exist only here and for which European countries have a special responsibility.

Cooperation with Cannon, P. (Kew Gardens, London), Bogomazova, K. (Edinburgh RBG), Scheidegger, C. (WSL Birmensdorf / CH), Otte, V. (Senckenberg Research Institute Görlitz) and Citizen Scientists of the British Lichen Society (BLS) and the Bryological-Lichenological Association for Central Europe (BLAM)

SMNS Cross-cutting Topics: Biodiversity Patterns: Species and their Distribution, Biodiversity in the Anthropocene: Model Region Baden-Württemberg