Meise Botanic Garden

Chemistry-based tracing techniques are increasingly used for combating illegal timber trade, but they are currently limited by the small and fragmented reference datasets available. We introduce a model that integrates data from multiple tree genera while accounting for statistical differences between them. Our model accurately predicts the harvest location even when relevant data are unavailable in some areas, by leveraging data from other genera. Our approach could lower reference sampling costs and enable tracing in situations where new samples cannot be collected, such as during armed conflict. Chemistry-based techniques for identifying the harvest location of timber are becoming increasingly important for enforcing timber trade regulations. However, their application has been limited by the need for reference samples from all species across all areas of interest. We investigate whether combining reference data from multiple taxonomic groups can improve timber harvest location determination in regions where reference data is scarce by using the shared natural variability in isotopic composition across species. We extend the harvest location model of Mortier et al. to jointly model isotope ratios and trace element concentrations in wood from different genera. This is achieved by a new covariance function that accounts for shared patterns of spatial variation between genera. We evaluate our approach on 1020 tree samples from four economically important genera (Betula, Fagus, Pinus, Quercus) across 12 Eastern European countries. The multi-genus model substantially outperforms the single-genus model when little or no data for that genus is available in the focus area. When data from all genera are available across the study area, the multi-genus model achieves similar performance to the single-genus model. Our approach strengthens the applicability of timber tracing methods by enabling accurate predictions in areas where sample collection is not currently feasible due to political, logistical and/or security-related challenges, provided that pre-existing samples from other genera are available.

Societal Impact Statement Collections of dried plant specimens (herbaria) provide an invaluable resource for the study of many areas of scientific interest and conservation globally. Digitisation increases access to specimens and metadata, enabling efficient use across a broad spectrum of research. The value of physical specimens is enhanced by digitisation, but these specimens remain fundamental for the study of traits not yet captured digitally. We investigate the requirements for physical access and the curation and facilities needed to maximise specimen use and value. We present recommendations to ensure that specimens and data are both fully accessible to support research into global challenges. Summary Herbarium management has traditionally focused on providing direct access to the physical specimens, but this scope must now expand to also embrace digital collections. Advances in technologies such as artificial intelligence and high‐throughput genomics are increasing the amount of information that can be extracted from specimens, and it is becoming commonplace to provide digital access to specimen images and collection metadata. These developments are facilitating the use of herbarium collections to inform conservation planning and in studies plant and fungal taxonomy, distribution and evolution. This paper examines how herbaria are transitioning from physical specimen‐centric collection management practices to increasingly digitised curation, and the effects that digital availability of data are having on demands for physical access. We provide a set of recommendations to institutions holding herbarium collections. We emphasise the critical importance of further digitising herbaria of all sizes; the need to ensure that historical inequalities in deposition of specimens are not perpetuated; and that the capacity to utilise new technologies must be further developed, especially in biodiverse regions from which most herbarium collections are derived. To improve access to collection data, herbarium managers need to more rigorously adopt community‐agreed data standards, and more strongly support open access platforms such as the Global Biodiversity Information Facility either directly or through regional coalitions. As digitisation and open data access increase, herbaria will need to offer users with seamless hybrid access to physical and digital records while continuing to develop their collections to advance research and conservation.

Parasite infections beyond the traditionally reported host range may point to previously unrecognized host–parasite dynamics. In this study, we investigated the host range of the ectoparasitic fungus Rickia wasmannii (Ascomycota, Laboulbeniales), which has to date been documented mainly on the cuticle of Myrmica ant workers. We first assessed the prevalence of infections in workers and then screened for infections in wingless and winged sexuals, larvae, and arthropod associates from 41 nests across four Myrmica species. Seven colonies were infected, with all workers carrying thalli. Wingless (reproductive) queens, winged (virgin) queens, and males were detected in three of these colonies and were all infected (5, 40, and 55 individuals, respectively), representing the first records of R. wasmannii on winged sexuals. A small proportion of larvae (18 out of 340 specimens) and mites (24 out of 1951 individuals) in the infected colonies carried thalli, as well as one individual of the specialized myrmecophilous beetle Lomechusa emarginata (Staphylinidae). We observed a single mature R. wasmannii thallus on a larva, while all thalli on arthropod associates were immature. Overall, our findings indicate that R. wasmannii can infect multiple Myrmica castes within the shared nest microhabitat. Infections on larvae and arthropod associates also occurred occasionally, but were characterized by low thallus densities and/or the absence of mature thalli.

Background and aims – The genus Lejeunea, with about 375 accepted species, is one of the most species-rich and intricate genera of liverworts. Here, we present the first integrative, worldwide infrageneric classification of Lejeunea based on morphology and molecular-phylogenetic analyses. Material and methods – Maximum likelihood analysis and Bayesian inference of sequences from two chloroplast regions (trnL-trnF, rbcL) and the nuclear ITS region of about 35% of the species, combined with morphological evidence. Key results and conclusions – The phylogenetic analyses revealed numerous robust clades within two major lineages, corresponding to subgenera Lejeunea and Crossotolejeunea. Integrating molecular phylogenetic evidence and morphological data, we describe 15 sections: four in subg. Lejeunea (sect. Glaucescentes, sect. Lamacerinae, sect. Lejeunea, sect. Macrolejeunea) and 11 in subg. Crossotolejeunea (sect. Apolejeunea, sect. Crossotolejeunea, sect. Echinocolea, sect. Flavae, sect. Heterolejeunea, sect. Inflatolejeunea, sect. Minutilobae, sect. Nanolejeunea, sect. Papillolejeunea, sect. Sordidae, sect. Xenantholejeunea). Four sections have a neotropical distribution, three are pantropical, two are pantropical and extend into temperate regions, two are Afro-American, two are Asian, one is Asian-Australasian, and one has a tropical amphi-Pacific range.

Common-environment experiments are important to study genetically based phenotypic variation within and among plant populations. Such experiments can be performed in an experimental garden, greenhouse, or climate chamber. However, phenotypic expression may be strongly affected by the environmental conditions and influenced by parental and storage effects. In particular, when the expression of genetically based phenotypic variation depends on the environment (G × E interaction), it can strongly influence conclusions. In this study, we assessed the effects of three different growth facilities - outdoor garden, greenhouse, and climate chamber - on phenotypic expression. We compared ancestral and descendant genotypes of the same population of Leontodon hispidus. We further evaluated differences in phenotypic expression between plants grown after one (F1) vs. two (F2) intermediate generations. As expected, we observed strong differences among plants growing in different environments (i.e., facilities). More importantly, we found that descendants had larger rosettes than ancestors only in the greenhouse and they flowered later than ancestors exclusively in the climate chamber, indicating G × E interactions. We did not find significant differences between different intermediate generations within the growth facilities. Overall, our study demonstrates that environmental variation among growth facilities can determine both the presence and magnitude of phenotypic differences. Consequently, differences observed in certain experimental settings may be overestimated compared with expression under natural conditions. Concluding, we recommend combining greenhouse and growth chamber resurrection experiments with field experiments to obtain a more comprehensive understanding of evolutionary changes.