Meise Botanic Garden

Radulaceae is one of the most isolated lineages of leafy liverworts. This family contains three genera and between 200 and 350 extant species worldwide. Most species belong to the genus Radula, which is subdivided into five subgenera and remains taxonomically challenging. In the framework of an integrative taxonomic revision of Radulaceae in tropical America, we are paying special attention to understudied features that may be taxonomically informative, such as spores. Here, we perform the first palynological evaluation of sixteen species of Radulaceae. The spores were processed by standard palynological techniques and described using light and electron microscopy. The spores of Radulaceae are isomorphic monads, apolar in species of the genus Radula and cryptopolar in Cladoradula, usually small to medium-sized, rarely large, inaperturate, with a circular to slightly elongated outline. The spore surface is ornamented with rounded elements, here called Granulate-type ornamentation, or with elongated elements, called Echinate-type ornamentation, and shows differences in each species. The palynological data, especially spore ornamentation, can make an important contribution to Radulaceae taxonomy for separating species or groups of species. The groups found here, however, do not fully correspond to generic and infrageneric circumscriptions as supported by molecular-phylogenetic evidence.

Aim Considering the importance of microclimate in maintaining the diversity of epiphytic bryophytes, we investigated epiphytic bryophytes along an elevational gradient in the subtropical forest of eastern China to unravel the diversity patterns of epiphytic liverworts and mosses along the elevational gradients and the roles of forest microclimates, topographic variables and host plant composition attributes in shaping these elevational diversity patterns. Location Tianmushan National Nature Reserve, Zhejiang, China. Taxon Epiphytic bryophytes. Methods Species diversity patterns of liverworts and mosses were compared based on an inventory of 16 plots along an elevational gradient from 367 to 1470 m. In situ microclimatic data of air temperature and moisture were collected under constant monitoring for over 3 years. Spatial linear models and structural equation models were used to assess the relative roles of the environmental variables in shaping the patterns of species diversity along elevation. Results We found that epiphytic liverwort and moss richness showed different elevational patterns; overall richness patterns of epiphytic bryophytes were largely driven by mosses. Epiphytic mosses exhibited a decline, followed by a hump‐shaped pattern of species richness with increasing elevation, while epiphytic liverworts showed a mid‐elevation plateau with a richness maximum between 800 and 1300 m. Forest microclimate, topography and host plant composition attributes influence epiphytic moss and liverwort patterns differently and interact in a complex way. Overall, species richness of epiphytic liverworts was most strongly affected by microclimate (mean annual air temperature of growing season) and of epiphytic mosses richness by topography (slope). Further, epiphytic liverwort species richness was more influenced by temperature than moisture. Main Conclusions This study highlights the importance of collecting climatic factors at a fine scale (microhabitats) for understanding the patterns and drivers of bryophyte diversity. Further, our findings demonstrate the differences between liverworts and mosses in terms of their response to different environments in the forest ecosystem.

Aim Greenland is among the most rapidly changing regions on Earth, with climate change having a profound impact on its terrestrial ecosystems. Here, moss‐associated diatoms hold great potential as sensitive biological indicators to monitor responses to climate change, but their diversity, community structure and biogeography remain virtually unexplored. Our study, thus, aims to (1) explore the diversity and community structure of moss‐associated diatoms in Greenland and (2) assess the environmental and spatial variables driving their geographic distribution, establishing a baseline for their use as bio‐indicators of climate change. Location Greenland, spanning a gradient from high to subarctic regions. Taxon Moss‐associated diatoms (Bacillariophyta). Methods LM and SEM analysis was conducted on 175 terrestrial moss samples collected from preserved herbarium material and fresh samples (1988–2021) from high, low and subarctic localities in Greenland. Biogeographical distributions, biodiversity patterns and community structure were examined in relation to environmental and spatial factors using Kruskal–Wallis, Spearman's Rank, ordination, SIMPROF and variation partitioning analyses. Results A total of 544 diatom taxa (66 genera) were identified, with nearly half potentially new to science. Community structure was predominantly influenced by moisture, pH, conductivity and temperature. Local variation in microclimate and bedrock, thus, explained more variation in the diatom communities than latitude‐related environmental gradients. Surprisingly, temperature had a negative impact on diatom richness, probably due to its adverse effect on moisture, highlighting the vulnerability of Arctic moss diatoms to global warming. Main Conclusions This study provides the first comprehensive analysis of Greenland's moss‐associated diatoms, highlighting their high diversity and sensitivity to environmental changes. Our findings underscore their potential as indicators for monitoring climate change in the Arctic, with moisture, pH, conductivity and temperature being critical factors influencing their communities, laying the groundwork for future research and monitoring efforts.

A new species of Xylaria is described based on morphological characters of both sexual and asexual morphs, and molecular data based on nuclear rDNA internal transcribed spacer, α-actin, β-tubulin and RNA polymerase subunit II sequences. Xylaria aurantiorubroguttata is characterized by the presence of both upright, cylindrical, long- stipitate and globose to subglobose, short-stipitate stromata, immature stromatal stages producing at first orange and then red drops, and ascospores with a slightly oblique, straight half spore-length germ slit. We provide also new morphological descriptions for X. haemorrhoidalis (holotype) and X. anisopleura (isosyntype), two Xylaria species belonging to X. polymorpha complex together with X. aurantiorubroguttata.

Scanning electron microscopy has revealed variation in the ultrastructure of distinctive isolated pores in or near the central area of raphid diatoms, with different types of pores being restricted to phylogenetic groups. Thus, the widespread use of the term stigma for all such pores not only hides the structural diversity but also obscures the phylogenetic distribution of the different types. This paper provides images of the different types of isolated pores, particularly refining the discrimination of variants within the Cymbellales, and reveals some interesting ecological patterns. Revised definitions of stigmata and stigmoids are proposed, together with the recognition and definition of another type of stigmoid. The restricted distribution of more precisely defined pore types shows the importance of consistent use of terminology and its relevance to phylogenetic studies.

DNA collections are a valuable type of Natural Science collection, enabling the validation of past research, serving as a source for new genomic studies and supporting ex situ conservation. The DiSSCo Flanders DNA collection working group, aiming to advance and "unlock" their DNA collections, identified the need for: 1) actively sharing best practices regarding the management of DNA collections; and 2) providing guidance on how to bring theory into practice. By combining best practice examples from within the working group with available literature and brainstorming ideas, the working group co-created two outputs, referred to as: the "Challenges" and the "Key". The Challenges are a list of obstacles to DNA collection management, which shape the structure of the linked Key and can also be used to spark discussion amongst stakeholders. The Key is a tool that guides users through the maturation process of their DNA collection in a standardised way. It stimulates holistic growth, breaks down the needed work into manageable steps and helps to decide priorities during the process. Furthermore, the Key facilitates communication with both internal stakeholders and external DNA collection managers. The Key distinguishes itself from other self-assessment tools in several ways: it includes (re)investigation of the collection’s purpose and context; it is specialised for DNA collections; it delivers concrete goals linked to relevant information and shared experience; and it is inclusive, targeting all Natural Science DNA collections, regardless of their context or size.

The forests of the Amazon basin are threatened by climate and land use changes. Due to the transition towards a drier climate, moisture-dependent organisms such as canopy epiphytes are particularly affected. Even if the topography in the Amazon lowland is moderate, mesoscale nocturnal katabatic flows result from cold air production related to radiative cooling. From a certain level of mass the cold air starts to flow downslope towards the valley centers leading to temperature inversions. The resulting cooling in the valleys drives localized fog formation in the valleys at night. This correlates with high epiphyte abundance and diversity in the valleys, which is much less pronounced upslope. The underlying temperature dynamics are, however, not sufficiently included in coarse-resolution reanalysis models such as ERA5-Land. Since high resolution climate data are needed e.g. for proper niche modeling of locally distributed species such as canopy epiphytes, downscaling models such as microclima have been developed and include micro- and mesoscale effects. However, it is unclear how well the elevation-related diurnal course of air temperature can be simulated. Here, we test functions for downscaling coarse-resolution temperature data to high spatial resolution data implemented in the R-package microclima for the South American tropical lowland forests. To do so we compared microclima-downscaled ERA5-Land air temperature data with meteorological station data. We found that the microclima functions only properly detect 73 temperature inversions out of 412 nocturnal cold air drainage (CAD) events during the dry season study period and only 18 out of 400 during the wet season with default settings. By modifying default values such as the emissivity threshold and time frames of possible CAD condition detection, we found 345 of 412 CAD events during the dry season and 177 out of 400 during the wet season. Despite problems with the distinction between CAD and non-CAD events the microclima algorithms show difficulties in correctly modeling the diurnal course of the temperature data and the amplitudes of elevational temperature gradients. For future studies focusing on temperature downscaling approaches, the modules implemented in the microclima package have to be adjusted for their usage in tropical lowland forest studies and beyond.

Meeting rising quality standards while at the same time addressing climate challenges will make the commercial cultivation of Robusta coffee increasingly difficult. Whereas breeding new varieties may be an important part of the solution, such efforts for Robusta lag behind, with much of its genetic diversity still unexplored. By screening existing field genebanks to identify accessions with desirable traits, breeding programs can be significantly facilitated. This study quantifies the morphological diversity and agronomic potential of 70 genotypes from the INERA Coffee Collection in Yangambi, Democratic Republic of the Congo. We measured 29 traits, comprising vegetative, reproductive, tree architecture, and yield traits. Classification models were applied to establish whether these traits could accurately classify genotypes based on their background. Furthermore, the agronomic potential and green bean quality of the genotypes were studied. While significant variation in morphological traits was observed, no combination of traits could reliably predict the genetic background of different genotypes. Genotypes with promising traits for green beans were identified in both ‘Lula’ and ‘Lula’ – Wild hybrids, while promising yield traits were found in ‘Lula’ – Congolese subgroup A hybrids. Additionally, certain ‘Lula’ – Wild hybrids showed low specific leaf area and stomatal density, indicating potential fitness advantages in dry environments, warranting further study. Our findings highlight the agronomic potential of underexplored Robusta coffee genotypes from the Democratic Republic of the Congo and indicate the need for further screening to maximize their value.

The Sahara and the Sahel are currently experiencing an increase in rainfall during the rainy season, possibly related to the strengthening of the hydrological cycle induced by global warming. However, the slowdown of the Atlantic Meridional Overturning Circulation (AMOC) might be able to counteract this trend, decreasing the North African monsoon rainfall in a timely, but highly uncertain, manner. During the early and mid-Holocene, the Sahara and the Sahel experienced a wet phase that offers a good analogue for testing the impact of an AMOC perturbation on the climate of this area. Here, we document this wet phase based on the sediment record of Lake Yoa from the central Sahara spanning the last 10,800 years at annual to decadal resolution. This record shows abrupt droughts at 8.2 kyr BP and at 6.3 kyr BP, which interrupted the humid period for a few decades. By modelling precipitation changes in the Lake Yoa area over the Holocene, we support the idea that these droughts were triggered by a slowdown of the AMOC. These results suggest that ongoing AMOC changes could severely weaken the African monsoon on decadal time scales. This process will reduce or even counteract the observed precipitation increase in these areas, highlighting the crucial need for reducing uncertainty in the rapidity of future AMOC weakening.

We introduce the database of European vascular plant red lists, a compilation of red list categories designated to taxa during in-country conservation assessments. Version 1.0 of the database is a standalone static dataset with open access in an end-user friendly format. Its aim is to fulfil the objectives of European Cooperation in Science and Technology (COST) Action 18201, ConservePlants. The database synthesizes data across 42 red lists from 41 countries, with participation of 39 out of a total of 44 European countries and two additional Mediterranean countries. The database contains 51,109 records representing 21,481 original taxonomic names with 37 different red list categories. During data harmonisation, 20,312 of the original taxonomic names were assigned to 17,873 unique accepted taxonomic names with scientific authorships across 184 families, 1650 genera and 15,593 species; and red list categories were standardised to 13 unique categories. We see this database as a source of information in diverse plant conservation activities and suitable for various stakeholders.

Keetia gordonii sp. nov. (Rubiaceae - Vanguerieae) a new species of forest liana from Gabon, is described and illustrated. The new species shows all the diagnostic characters of Keetia , such as pyrenes opening by an apical cap and seeds with tanniniferous endosperm, both of which are unrecorded in other genera of the tribe, flowers with a long-exserted style and erect anthers and a (usually) climbing habit. However, it is unique in the genus for its corolla with dense, appressed, brown hairs externally (vs glabrous or with a few hairs towards the apex), its glabrous disk (vs variously pubescent) and its seeds with a continuous tanniniferous layer in the outer part (vs with tanniniferous areas forming radial bands, or diffuse). Keetia gordonii is assigned to the Keetia hispida group of Guineo-Congolian African species. It is the first endemic Keetia species to be described from Gabon, although several others are awaiting description. On current evidence, the species appears to have six locations and is threatened by forest clearance. It is provisionally assessed using the IUCN (2012) standard as Vulnerable [VU B2ab(i,ii,iii,iv,v)].

Introduction Although drought resistance of a plant may be achieved through morphological, structural, physiological, cellular, and molecular adaptations, most studies remain limited to quantifying the effect of drought on biomass. Methods Using a highthroughput phenotypic imaging system, we evaluated the drought resistance of 151 bean accessions (Phaseolinae; Fabaceae) in an explorative approach, by quantifying five different traits simultaneously: biomass, water use efficiency (WUE), relative water content (RWC), chlorophyll content (NDVI), and root/shoot ratio. Since crop wild relatives are important resources for breeding programs, we analyzed both wild and cultivated accessions, most of which have never been evaluated for drought resistance before. Results We demonstrate that the five traits are affected very differently by drought in the studied accessions, with significant correlations existing only between the biomass and WUE indicators (r=0.39), and between the RWC and NDVI indicators (r=0.40). When grouping accessions by subgenus or by species, large intraspecific and withinsubgenus variation was found. For this reason, we performed a cluster analysis, which grouped the accessions into five distinct clusters with similar response profiles. We also correlated the drought resistance for each accession to local climate variables at their original collection sites. The biomass, WUE, and RWC indicators were significantly correlated to annual precipitation (r=0.40, r=0.20, r=0.22, respectively), confirming that accessions from arid environments are generally more drought resistant. Discussion Our results demonstrate that the drought resistance of Phaseolinae beans is a multifaceted characteristic and cannot be simply quantified through biomass. Furthermore, the broader knowledge of the drought resistance of the accessions studied here may prove an invaluable resource for future crop production.

Abstract Aim To evaluate the patterns of stream diatom beta diversity in islands vs. continents across scales, to relate community similarities with spatial and environmental distances and to investigate the role of island characteristics in shaping insular diatom beta diversity. Location Africa, America, Europe, and Pacific. Time period Present. Major taxa studied Stream diatoms. Methods We compared diatom beta diversity between islands and continents at large scales (within biogeographic region) in two study regions (America and Europe) and at small scales (within islands or equivalent areas in continents) in three regions (Africa, America, and Europe) by partitioning beta diversity into turnover and nestedness components. We used a partial Mantel test and distance-decay curves to assess how diatom beta diversity on islands and continents is affected by spatial and environmental distances. Finally, using island data from all four regions, we evaluated the relationship between island beta diversity and island latitude, area, age, and isolation using linear models. Results At large scales, mean dissimilarities were higher on islands than in continents in Europe but lower in America. At smaller scales, the differences varied mostly depending on island isolation. Beta diversity was mainly caused by species turnover. Partial Mantel test and distance-decay curves revealed that spatial and environmental distances shaped diatom beta diversity at large, but not at small scales. Moreover, diatom beta diversity on islands was affected by island latitude, age, and isolation, but not by island area. Main conclusions Diatom beta diversity on islands vs. continents and its responses to spatial and environmental factors are scale- and region-dependent. Incomplete colonisation, evolutionary processes and environmental filtering likely contribute to insular beta diversity, which further varies with island latitude, age, and isolation. This study sheds new light on beta diversity of microorganisms on islands and suggests that beta diversity should be explicitly considered in island biogeographical research.

While there is growing recognition of the importance of traditional knowledge in science, these perspectives remain underrepresented in research publications. However, the synthesis of these approaches has tremendous potential to improve our understanding of wildlife and ecosystems. Toward realizing this aim, we combined local traditional knowledge with molecular classification techniques to investigate “soil scratching” behavior in western lowland gorillas in two localities in Republic of Congo, the Goualougo Triangle and the Djéké Triangle. Daily observations of four gorilla groups for nearly a decade revealed that soil scratching is a foraging strategy to access a deer truffle species, identified here as Elaphomyces labyrinthinus. We also conducted group scans to calculate the time gorillas spent foraging for deer truffles and video focal observations to assess foraging efficiency. There was considerable variation in soil scratching across groups. It was most common in Buka’s group, followed by Kingo’s group and Mététélé’s group. Truffle foraging was rarely observed in the Loya-Makassa group. While the overall distribution of deer truffles seemingly determines the occurrence of this behavior across populations, we found indications of social influences on soil scratching within populations. For example, an adult female transferred from a group in which the behavior was rare to another group where it is common and adjusted her frequencies of soil scratching to that of her new group. Finally, these findings were included in an ecological impact assessment of the Djéké Triangle that prompted conservation managers to shift the location of tourism-associated construction to safeguard this putative cultural behavior.

Coffee processing involves various steps, from harvest to the storage of dried green coffee beans, each of which can significantly affect the beans' chemical composition and sensory qualities. Yet, a comprehensive evaluation that includes the coffee's genetic background and chemical, sensory, and biological aspects is still uncommon for Robusta coffee. Four Robusta ( C. canephora ) genotypes from the Democratic Republic of the Congo were subjected to five different coffee processing methods: Strip-picked, unsorted, sundried cherries; Overripe, sorted, sundried cherries; ripe, sorted, sundried (Natural) cherries; ripe, sorted, Pulped, sundried parchment; and ripe, sorted, wet fermented (Washed), sundried parchment were processed separately. The resulting green beans underwent sensory descriptive cupping, seed germination tests, and metabolite profiling using LC-HRMS. The Pulped and Washed methods produced coffees with higher sensory attributes scores, while the Overripe method was associated with the sensory ‘potato taste’ defect. Washed coffee was characterized by smooth, fruity, cocoa notes, and was negatively correlated with rough mouthfeel, tobacco, and leather flavors. The Pulped and Washed method had significantly higher germination success after four months of storage. The processing method influenced caffeine concentration in green beans, depending on the genotype, while trigonelline levels varied significantly between genotypes but not between processing methods. The grouping of the metabolite profiles of roasted coffee and green beans was consistent with their genetic background rather than the processing method. Overall, we demonstrate that genotype plays a significant role in mediating the outcomes of different processing methods.

The genus Coleus is revised for DR. Congo, Rwanda, Burundi, based on herbarium taxonomy. Ninety-five taxa are reported (89 species, 1 subspecies, 5 varieties). Fifteen new species and one new variety are described (Coleus duvigneaudii, C. esculentus var. kolweziensis, C. hildei, C. kaminaensis, C. kundelunguensis, C. linarioides, C. lisowskii, C. marunguensis, C. minusculus, C. mitwabaensis, C. mystax, C. pengbelensis, C. piscatorum, C. pseudoschizophyllus, C. ruziziensis and C. zigzag). Fourteen species are newly recorded in DR. Congo and two species are newly recorded in Burundi. Four new combinations are made (Coleus betonicifolius var. kasomenensis, C. esculentus var. densus, C. esculentus var. primulinus and C. parvifolius). Ten names are lectotypified. One name is neotypified. Thirteen new synonyms are reported. Particular attention is paid to the Coleus bojeri complex. Three names are resurrected to accommodate the extensive variation patterns in Central Africa (C. chevalieri, C. collinus and C. heterotrichus); their distribution in Africa is outlined and the circumscription of C. bojeri is amended accordingly. Fifteen taxa are endemic to the study region. A determination key is provided.

The Afrotropics are experiencing some of the fastest urbanisation rates on the planet but the impact of city growth on their rich and unique biodiversity remains understudied, especially compared to natural baselines. Little is also known about how introduced species influence β‐diversity in these contexts, and how patterns coincide with native ranges of species. Here we investigated how tree assemblages of the endemic‐rich Afrotropical island of São Tomé differed between urban, rural and natural zones. These were primarily characterised by urban greenspaces, shade plantations, and old‐growth forests, respectively. Based on 81 transects, we assessed biodiversity metrics of endemic, native and introduced species. Tree abundance and species richness were highest in the natural zone, where the composition was most different from the urban zone. The tree community of the rural zone was the most uneven and had the least variation among transects, representing the lowest β‐diversity. The urban zone was dominated by introduced species (57.7%), while the natural zone hosted almost exclusively native species (93.3%), including many endemics (26.1%). The biogeographic realms that species originated from were particularly diverse in the urban zone, with few species from the Afrotropics. In contrast to native and endemic trees, introduced trees were clearly associated with urban and rural expansion, as they were much more abundant and species‐rich in these zones than in the natural zone, facilitating biotic homogenisation. These findings highlight how urban and rural environments are affecting the native tree flora of São Tomé, and the need for conservation measures geared towards globally threatened and endemic tree species. Importantly, these require the protection of natural forests, despite the rising land demands for settlements and agriculture. Ultimately, such action to conserve endemic trees will contribute to global efforts to prevent further biodiversity declines.