Thin film structural color is widespread in slime molds (Myxomycetes, Amoebozoa).

Brilliant colors in nature arise from the interference of light with periodic nanostructures resulting in structural color. While such biological photonic structures have long attracted interest in insects and plants, they are little known in other groups of organisms. Unexpected in the kingdom of Amoebozoa, which assembles unicellular organisms, structural colors were observed in myxomycetes, an evolutionary group of amoebae forming macroscopic, fungal-like structures. Previous work related the sparkling appearance of Diachea leucopodia to thin film interference. Using optical and ultrastructural characterization, we here investigated the occurrence of structural color across 22 species representing two major evolutionary clades of myxomycetes including 14 genera. All investigated species showed thin film interference at the peridium, producing colors with hues distributed throughout the visible range that were altered by pigmentary absorption. A white reflective layer of densely packed calcium-rich shells is observed in a compound peridium in Metatrichia vesparium, whose formation and function are still unknown. These results raise interesting questions on the biological relevance of thin film structural colors in myxomycetes, suggesting they may be a by-product of their reproductive cycle.

Cliff-edge forests: Xerothermic hotspots of local biodiversity and models for future climate change.

Cliffs are remarkable environments that enable the existence of microclimates. These small, isolated sites, decoupled from the regional macroclimate, play a significant role in maintaining species biodiversity, particularly in topographically homogeneous landscapes. Our study investigated the microclimate of south-exposed forests situated at the edge of sandstone cliffs in the western part of the North Alpine Foreland Basin in Switzerland and its role in local forest community composition. Using direct measurements from data loggers, as well as vegetation analyses, it was possible to quantify the microclimate of the cliff-edge forests and compare it with that of the surrounding forests. Our results highlighted the significant xerothermic and more variable nature of the cliff-edge forest microclimate, with a mean soil temperature up to 3.72°C warmer in the summer, higher annual (+28%) and daily (+250%) amplitudes of soil temperature, which frequently expose vegetation to extreme temperatures, and an 83% higher soil drying rate. These differences have a distinct influence on forest communities: cliff-edge forests are significantly different from surrounding forests. The site particularities of cliff edges support the presence of locally rare species and forest types, particularly of Scots pine. Cliff edges must therefore be considered microrefugia with a high conservation value for both xerothermic species and flora adapted to more continental climates. Moreover, the microclimate of cliff-edge forests could resemble the future climate in many ways. We argue that these small areas, which are already experiencing the future climate, can be seen as natural laboratories to better answer the following question: what will our forests look like in a few decades with accelerated climate change?

Les falaises sont des milieux remarquables qui permettent l'existence de microclimats. Ces petites surfaces, aux conditions éloignées du climat régional, jouent un rôle important pour la biodiversité, en particulier dans les paysages topographiquement homogènes. Notre étude a porté sur le microclimat de forêts exposées au sud, situées au bord de falaises de molasse, sur le plateau suisse, et sur son rôle dans la composition de la communauté végétale locale. En utilisant des mesures directes provenant d'enregistreurs automatiques de données, ainsi que des analyses de la végétation, il a été possible de quantifier le microclimat des forêts de bord de falaise et de le comparer à celui des forêts environnantes. Nos résultats ont mis en évidence la nature significativement xérothermique et plus variable du microclimat des forêts de bord de falaise, avec une température moyenne du sol jusqu'à 3.72°C plus élevée en été, des amplitudes accrues annuelles (+28%) et journalières (+250%) de la température du sol, qui exposent fréquemment la végétation à des températures extrêmes, et un taux d'assèchement du sol 83% plus élevé. Ces différences ont une influence marquée sur les communautés forestières: les forêts de bord de falaise sont très différentes des forêts environnantes. Elles permettent la présence d'espèces et de types de forêts localement rares, notamment des pinèdes. Les bords de falaise doivent donc être considérés comme des microrefuges à haute valeur de conservation pour les espèces xérothermiques et la flore adaptée à des climats plus continentaux. En outre, le microclimat des forêts de bord de falaise pourrait ressembler au climat futur à bien des égards. Nous soutenons que ces petites zones, qui connaissent déjà le climat futur, peuvent être considérées comme des laboratoires naturels permettant de mieux répondre à la question suivante: à quoi ressembleront nos forêts dans quelques décennies, suite aux changements climatiques?

Adaptive divergence and genetic vulnerability of relict species under climate change: a case study of Pterocarya macroptera.

BACKGROUND AND AIMS: Understanding adaptive genetic variation and whether it can keep pace with predicted future climate change is critical in assessing the genetic vulnerability of species and developing conservation management strategies. The lack of information on adaptive genetic variation in relict species carrying abundant genetic resources hinders the assessment of genetic vulnerability. Using a landscape genomics approach, this study aimed to determine how adaptive genetic variation shapes population divergence and to predict the adaptive potential of Pterocarya macroptera (a vulnerable relict species in China) under future climate scenarios. METHODS: We applied restriction site-associated DNA sequencing (RAD-seq) to obtain 8244 single-nucleotide polymorphisms (SNPs) from 160 individuals across 28 populations. We examined the pattern of genetic diversity and divergence, and then identified outliers by genetic differentiation (FST) and genotype-environment association (GEA) methods. We further dissected the effect of geographical/environmental gradients on genetic variation. Finally, we predicted genetic vulnerability and adaptive risk under future climate scenarios. KEY RESULTS: We identified three genetic lineages within P. macroptera: the Qinling-Daba-Tianmu Mountains (QDT), Western Sichuan (WS) and Northwest Yunnan (NWY) lineages, which showed significant signals of isolation by distance (IBD) and isolation by environment (IBE). IBD and IBE explained 3.7-5.7 and 8.6-12.8 % of the genetic structure, respectively. The identified GEA SNP-related genes were involved in chemical defence and gene regulation and may exhibit higher genetic variation to adapt to the environment. Gradient forest analysis revealed that the genetic variation was mainly shaped by temperature-related variables, indicating its adaptation to local thermal environments. A limited adaptive potential was suggested by the high levels of genetic vulnerability in marginal populations. CONCLUSIONS: Environmental gradient mainly shaped the population differentiation of P. macroptera. Marginal populations may be at high risk of extinction, and thus proactive management measures, such as assisted gene flow, are required to ensure the survival of these populations.

Shining a light on species delimitation in the tree genus Engelhardia Leschenault ex Blume (Juglandaceae).

Enhanced efficacy in species delimitation is critically important in biology given the pending biodiversity crisis under global warming and anthropogenic activity. In particular, delineation of traditional classifications in view of the complexity of species requires an integrative approach to effectively define species boundaries, and this is a major focus of systematic biology. Here, we explored species delimitation of Engelhardia in tropical and subtropical Asia. In total, 716 individuals in 71 populations were genotyped using five chloroplast regions, one nuclear DNA region (nrITS), and 11 nuclear simple sequence repeats (nSSR). Phylogenetic trees were constructed and relationships among species were assessed. Molecular analyses were then combined with 14 morphological characteristics of 720 specimens to further explore the species boundaries of Engelhardia. Integrating phylogenetic and morphological clusters provided well-resolved relationships to delineate seven species. The results suggested that: first, that E. fenzelii, E. roxburghiana, E. hainanensis, E. apoensis, and E. serrata are distinct species; second, E. spicata var. spicata, E. spicata var. aceriflora, E. spicata var. colebrookeana, and E. rigida should be combined under E. spicata and treated as a species complex; third, E. serrata var. cambodica should be raised to species level and named E. villosa. We illuminated that bias thresholds determining the cluster number for delimiting species boundaries were substantially reduced when morphological data were incorporated. Our results urge caution when using the concepts of subspecies and varieties in order to prevent confusion, particularly with respect to species delimitation for tropical and subtropical species. In some cases, re-ranking or combining subspecies and/or varieties may enable more accurate species delimitation.

Velocity of the falling dispersal units in Zelkova abelicea: remarkable evolutionary conservation within the relict tree genus.

PREMISE: Seed dispersal is extremely important for the recovery and restoration of forest communities. Relict tree genus Zelkova possesses a unique dispersal mechanism: mature fruits fall with the entire twig, and the dried leaves that are still attached function as a drag-enhancing appendage, carrying the fruits away from the parent tree. This singular adaptation has never been investigated in Z. abelicea. METHODS: Drop tests with dispersal units and individual fruits of Z. abelicea were performed in controlled conditions to measure their dispersal velocity and to define their flight mode. RESULTS: Zelkova abelicea uses both slowly falling dispersal units with chaotic motion, as well as fast falling individual fruits using a straight path. The falling velocity of Z. abelicea dispersal units is 1.53 m s-1 , which is virtually identical to that of the East Asiatic Z. serrata (1.51 m s-1 ). In contrast, the falling velocity of individual fruits was 2.74 m s-1 (Z. serrata: 5.36 m s-1 ). CONCLUSIONS: Members of the genus Zelkova, growing today in distant regions, show remarkable evolutionary conservation of the velocity and flight mechanics of their dispersal units. This is surprising because the Mediterranean and East Asiatic Zelkova species have been separated at least 15-20 mya. Zelkova abelicea, although growing in the Mediterranean with completely different forest structure and composition, still uses the same dispersal mechanism. The dispersal capacity of the genus Zelkova is less efficient than that of other wind dispersed trees, and it presumably evolved for short-distance ecological spread and not for long-distance biogeographical dispersal.

Species delimitation in the East Asian species of the relict tree genus Zelkova (Ulmaceae): A complex history of diversification and admixture among species.

Zelkova species, trees of the elm family (Ulmaceae), are part of the Cenozoic relict flora. In western Eurasia, the genus comprises three species that are restricted to disjunct areas (Z. sicula on Sicily, Z. abelicea on Crete and Z. carpinifolia in Transcaucasia). The situation is different in East Asia, where three species (Z. serrata, Z. schneideriana and Z. sinica) have at least partly overlapping distributions. The phylogenetic and phylogeographic status of these East Asian species is still not well understood, mainly since all previous studies used almost exclusively plant material collected in botanical gardens and were based on very small numbers of individuals. Our study is the first based on 33 natural populations covering all important areas with Zelkova species in the Sino-Japanese Floristic Region. Chloroplast and microsatellite markers were used, and Bayesian analyses were run for both types of markers. East Asian Zelkova species cluster into two groups that partially overlap when comparing the two types of markers. For chloroplast markers, the two groups coincide with all Japanese, some Korean and northern Chinese Z. serrata in one group and all other individuals in the other group, regardless of whether they are attributed to Z. serrata, Z. sinica or Z. schneideriana from Korea, mainland China and Taiwan. At the nuclear level, however, the clustering clearly groups all the Z. serrata individuals together, regardless of whether they are from Japan, Korea or China, and the two other species in a second group. This complex genetic pattern in East Asian Zelkova species is most likely due to a combination of ancient diversification and speciation events and more recent hybridization during the last glacial/interglacial retractions and recolonizations. One of the surprising results of our study concerns the populations from Taiwan, which are genetically similar to Z. schneideriana. Thus, their assignation to a separate taxon (Z. tarokoensis) or to a variety of Z. serrata (Z. serrata var. tarokoensis), as currently reported in all local and national floras, might be in need of revision. Furthermore, our results indicate that the East Asian species are more closely related to Z. carpinifolia than to any other Western European species. Haplotypes of Z. sicula and Z. abelicea (Mediterranean region) as well as those of Z. sinica and Z. schneideriana (East Asia) seem to have diversified more recently. The most ancient haplotypes are found among the western Eurasian Z. carpinifolia and the East Asian Z. serrata. This result is in agreement with the carpinifolia and serrata-like morphotypes commonly found in the fossil record.

Molecular Biogeography of Prickly Lettuce (Lactuca serriola L.) Shows Traces of Recent Range Expansion.

Prickly lettuce (Lactuca serriola L., Asteraceae), a wild relative of cultivated lettuce, is an autogamous species which greatly expanded throughout Western and Northern Europe during the last 2 centuries. Here, we present a large-scale biogeographic genetic analysis performed on a dataset represented by 2622 individuals from 110 wild European populations. Thirty-two maternally inherited chloroplast RFLP-markers and 10 nuclear microsatellite loci were used. Microsatellites revealed low genetic variation and high inbreeding coefficients within populations, as well as strong genetic differentiation between populations, which was in accordance with the autogamous breeding system. Analysis of molecular variance based clustering indicated the presence of 3 population clusters, which showed strong geographical patterns. One cluster occupied United Kingdom and part of Northern Europe, and characterized populations with a single predominant genotype. The second mostly combined populations from Northern Europe, while the third cluster grouped populations particularly from Southern Europe. Kriging of gene diversity for L. serriola corroborated northwards and westwards spread from Central (Eastern) Europe. Significant lower genetic diversity characterized the newly colonized parts of the range compared to the historical ones, confirming the importance of founder effects. Stronger pattern of isolation by distance was assessed in the newly colonized areas than in the historical areas (Mantel's r = 0.20). In the newly colonized areas, populations at short geographic distances were genetically more similar than those in the historical areas. Our results corroborate the species' recent and rapid northward and westward colonization from Eastern Europe, as well as a decrease of genetic diversity in recently established populations.

Analysis of nuclear microsatellites reveals limited differentiation between Colchic and Hyrcanian populations of the wind-pollinated relict tree Zelkova carpinifolia (Ulmaceae).

UNLABELLED: • PREMISE OF THE STUDY: The Caucasus represents one of the world's biodiversity hotspots and includes the climatic refugia Hyrcan on the southern coast of the Caspian Sea and Colchis on the eastern coast of the Black Sea, where different species survived during the Quaternary climatic oscillations. We evaluated the genetic diversity of the relict tree Zelkova carpinifolia shared between the two refugia and distributed throughout the Caucasus and adjacent areas.• METHODS: Specimens were collected from 30 geographical sites in Azerbaijan, Georgia, Iran, and Turkey and screened for variability at eight nuclear microsatellite loci. The genetic diversity among and within populations was assessed using a set of statistical measures.• KEY RESULTS: We detected 379 different genotypes from a total of 495 individuals with varying degrees of clonal reproduction at the different sites. Low to intermediate levels of genetic diversity were observed at all sites, and strong differentiation between sampling sites was absent. In addition, we observed no clear genetic differentiation between the Colchis and Hyrcan. Bayesian clustering of the genotypes revealed three populations with high levels of admixture between the sampling sites.• CONCLUSIONS: The lack of strong genetic structure of studied populations of Z. carpinifolia contrasts with a previous study based on chloroplast markers and suggests that long-distance pollen dispersal is an important factor of gene flow among populations of Z. carpinifolia. The present study does not reveal any particular site with particularly isolated genotypes that would deserve more attention for conservation purposes than others, although some sites should be considered for further investigation.

Understanding Arctic-Alpine Plants from Ecological and Evolutionary Perspectives.

Conditions in arctic and alpine ecosystems impose great challenges on the plants and other organisms that live there [...].

Complete Chloroplast Genomes of Four Oaks from the Section Cyclobalanopsis Improve the Phylogenetic Analysis and Understanding of Evolutionary Processes in the Genus Quercus.

Quercus is a valuable genus ecologically, economically, and culturally. They are keystone species in many ecosystems. Species delimitation and phylogenetic studies of this genus are difficult owing to frequent hybridization. With an increasing number of genetic resources, we will gain a deeper understanding of this genus. In the present study, we collected four Quercus section Cyclobalanopsis species (Q. poilanei, Q. helferiana, Q. camusiae, and Q. semiserrata) distributed in Southeast Asia and sequenced their complete genomes. Following analysis, we compared the results with those of other species in the genus Quercus. These four chloroplast genomes ranged from 160,784 bp (Q. poilanei) to 161,632 bp (Q. camusiae) in length, with an overall guanine and cytosine (GC) content of 36.9%. Their chloroplast genomic organization and order, as well as their GC content, were similar to those of other Quercus species. We identified seven regions with relatively high variability (rps16, ndhk, accD, ycf1, psbZ-trnG-GCC, rbcL-accD, and rpl32-trnL-UAG) which could potentially serve as plastid markers for further taxonomic and phylogenetic studies within Quercus. Our phylogenetic tree supported the idea that the genus Quercus forms two well-differentiated lineages (corresponding to the subgenera Quercus and Cerris). Of the three sections in the subgenus Cerris, the section Ilex was split into two clusters, each nested in the other two sections. Moreover, Q. camusiae and Q. semiserrata detected in this study diverged first in the section Cyclobalanopsis and mixed with Q. engleriana in the section Ilex. In particular, 11 protein coding genes (atpF, ndhA, ndhD, ndhF, ndhK, petB, petD, rbcL, rpl22, ycf1, and ycf3) were subjected to positive selection pressure. Overall, this study enriches the chloroplast genome resources of Quercus, which will facilitate further analyses of phylogenetic relationships in this ecologically important tree genus.

Genome Size in the Arenaria ciliata Species Complex (Caryophyllaceae), with Special Focus on Northern Europe and the Arctic.

The main aim of the present study has been the completion of genome size data for the diverse arctic-alpine A. ciliata species complex, with special focus on the unexplored arctic taxon A. pseudofrigida, the north-European A. norvegica, and A. gothica from Gotland (Sweden). Altogether, 46 individuals of these three Nordic taxa have been sampled from seven different regions and their genome size estimated using flow cytometry. Three other alpine taxa in the A. ciliata complex (A. multicaulis, A. ciliata subsp. ciliata, and A. ciliata subsp. bernensis) were also collected and analyzed for standardization purposes, comprising 20 individuals from six regions. A mean 2c value of 1.65 pg of DNA was recorded for A. pseudofrigida, 2.80 pg for A. norvegica, and 4.14 pg for A. gothica, as against the reconfirmed 2c value of 1.63 pg DNA for the type taxon A. ciliata subsp. ciliata. Our results presenting the first estimations of genome sizes for the newly sampled taxa, corroborate ploidy levels described in the available literature, with A. pseudofrigida being tetraploid (2n = 4x = 40), A. norvegica possessing predominantly 2n = 8x = 80, and A. gothica with 2n = 10x = 100. The present study also reconfirms genome size and ploidy level estimations published previously for the alpine members of this species complex. Reflecting a likely complex recent biogeographic history, the A. ciliata species group comprises a polyploid arctic-alpine species complex characterized by reticulate evolution, polyploidizations and hybridizations, probably associated with rapid latitudinal and altitudinal migrations in the Pleistocene-Holocene period.

Typification of the name Ranunculusrionii (Ranunculaceae).

Available information on the typification of the name Ranunculusrionii in the literature is scarce and misleading. Previously claimed type collections indicate Lagger as the collector, but the protologue discusses only the specimens collected by Rion. Original material for the name is identified, the locality of the type collection is specified, Lagger's way of writing herbarium labels for his type specimens is described, the history of the discovery of R.rionii is reviewed, and the name is lectotypified.

A new species of Contarinia (Diptera: Cecidomyiidae) from flower galls on the relict tree Zelkova abelicea (Ulmaceae) endemic to Crete (Greece).

Contarinia ampelitsiae n. sp. Dorchin & Fazan is described as a newly discovered gall-midge species (Diptera: Cecidoymiidae) forming galls in flowers of Zelkova abelicea (Ulmaceae), a tree species endemic to the Mediterranean island of Crete (Greece). Larvae develop within modified filaments of male flowers, contrary to many Contarinia species that develop freely in flowers or in simple flower galls. The species has one generation per year, and its galls are sometimes found in great numbers on individual trees, thus affecting both fruit quantity and weight. This is the first report of a gall midge from Zelkova and the first record of Contarinia from Ulmaceae. Based on its host-plant association and on the barcoding section of the mtCOI gene, this species has no obvious relatives within Contarinia.

Genome Size in the Arenaria ciliata Species Complex (Caryophyllaceae), with Special Focus on A. ciliata subsp. bernensis, a Narrow Endemic of the Swiss Northern Alps.

The genus Arenaria (Caryophyllaceae) comprises approximately 300 species worldwide; however, to date, just six of these taxa have been investigated in terms of their genome size. The main subject of the present study is the A. ciliata species complex, with special focus on A. ciliata subsp. bernensis, an endemic plant occurring in the Swiss Northern Alps. Altogether, 16 populations and 77 individuals of the A. ciliata complex have been sampled and their genome sizes were estimated using flow cytometry, including A. ciliata subsp. bernensis, A. ciliata s.str., A. multicaulis, and A. gothica. The Arenaria ciliata subsp. bernensis shows the highest 2c-value of 6.91 pg of DNA, while A. gothica showed 2c = 3.69 pg, A. ciliata s.str. 2c = 1.71 pg, and A. multicaulis 2c = 1.57 pg. These results confirm the very high ploidy level of A. ciliata subsp. bernensis (2n = 20x = 200) compared to other taxa in the complex, as detected by our chromosome counting and previously documented by earlier work. The genome size and, thus, also the ploidy level, is stable across the whole distribution area of this taxon. The present study delivers additional support for the taxonomic distinctiveness of the high alpine endemic A. ciliata subsp. bernensis, which strongly aligns with other differences in morphology, phylogeny, phenology, ecology, and plant communities, described previously. In affirming these differences, further support now exists to re-consider the species status of this taxon. Upgrading to full species rank would significantly improve the conservation prospects for this taxon, as, because of its precise ecological adaptation to alpine summit habitats, the A. ciliata subsp. bernensis faces acute threats from accelerated climate warming.

Global Estimation and Mapping of the Conservation Status of Tree Species Using Artificial Intelligence.

Trees are fundamental for Earth's biodiversity as primary producers and ecosystem engineers and are responsible for many of nature's contributions to people. Yet, many tree species at present are threatened with extinction by human activities. Accurate identification of threatened tree species is necessary to quantify the current biodiversity crisis and to prioritize conservation efforts. However, the most comprehensive dataset of tree species extinction risk-the Red List of the International Union for the Conservation of Nature (IUCN RL)-lacks assessments for a substantial number of known tree species. The RL is based on a time-consuming expert-based assessment process, which hampers the inclusion of less-known species and the continued updating of extinction risk assessments. In this study, we used a computational pipeline to approximate RL extinction risk assessments for more than 21,000 tree species (leading to an overall assessment of 89% of all known tree species) using a supervised learning approach trained based on available IUCN RL assessments. We harvested the occurrence data for tree species worldwide from online databases, which we used with other publicly available data to design features characterizing the species' geographic range, biome and climatic affinities, and exposure to human footprint. We trained deep neural network models to predict their conservation status, based on these features. We estimated 43% of the assessed tree species to be threatened with extinction and found taxonomic and geographic heterogeneities in the distribution of threatened species. The results are consistent with the recent estimates by the Global Tree Assessment initiative, indicating that our approach provides robust and time-efficient approximations of species' IUCN RL extinction risk assessments.

Complete Chloroplast Genome of an Endangered Species Quercus litseoides, and Its Comparative, Evolutionary, and Phylogenetic Study with Other Quercus Section Cyclobalanopsis Species.

Quercus litseoides, an endangered montane cloud forest species, is endemic to southern China. To understand the genomic features, phylogenetic relationships, and molecular evolution of Q. litseoides, the complete chloroplast (cp) genome was analyzed and compared in Quercus section Cyclobalanopsis. The cp genome of Q. litseoides was 160,782 bp in length, with an overall guanine and cytosine (GC) content of 36.9%. It contained 131 genes, including 86 protein-coding genes, eight ribosomal RNA genes, and 37 transfer RNA genes. A total of 165 simple sequence repeats (SSRs) and 48 long sequence repeats with A/T bias were identified in the Q. litseoides cp genome, which were mainly distributed in the large single copy region (LSC) and intergenic spacer regions. The Q. litseoides cp genome was similar in size, gene composition, and linearity of the structural region to those of Quercus species. The non-coding regions were more divergent than the coding regions, and the LSC region and small single copy region (SSC) were more divergent than the inverted repeat regions (IRs). Among the 13 divergent regions, 11 were in the LSC region, and only two were in the SSC region. Moreover, the coding sequence (CDS) of the six protein-coding genes (rps12, matK, atpF, rpoC2, rpoC1, and ndhK) were subjected to positive selection pressure when pairwise comparison of 16 species of Quercus section Cyclobalanopsis. A close relationship between Q. litseoides and Quercus edithiae was found in the phylogenetic analysis of cp genomes. Our study provided highly effective molecular markers for subsequent phylogenetic analysis, species identification, and biogeographic analysis of Quercus.

A multifaceted field sampling approach for the management of extremely narrow endemic vascular plant species.

Extremely narrow endemic plant species (ENEs) are generally connected with microrefugia characterized by particular environmental conditions. In-depth knowledge of the ecological requirements of ENEs is fundamental to plan appropriate conservation measures. Using cross-cutting technology, this paper gives a multifaceted approach to collect on-site data on the ecology of ENEs, defines the protocols for a correct sampling design and describes the type of equipment, the time and expenditure needed. Our sampling approach is based on two orthogonal transects, long enough to extrapolate the whole ecological gradient across the area of occupancy of the target species. Microclimatic data are recorded all along the transects through iButton technology, plus a weather station installed at the intersection of the transects. Microtopographic data are recorded with high-resolution digital elevation model and sub-metric GPS. Edaphic data are recorded along the transects through standard soil analyses and on-site evaluation of the seasonal decomposition rate of organic matter. Additionally, vegetation sampling in 4 m2 plots and on-site germination tests allow to collect data on auto- and synecological factors that regulate the life cycle of the target species. Our approach has proved to be cost-effective and efficient in terms of time spent in the field against the data collected. The most demanding activities were the establishment of the transects and the vegetation sampling. The time spent downloading microclimatic data and testing seed germination was relatively short. Our sampling design allows: (i) to catch as much micro-topographic variability as possible, both within and out of the tolerance range of the target species, (ii) to minimize the risk of recording identical micro-topographic conditions compared with a random sampling scheme, and (iii) to ensure quick and relatively easy retrieval of the plots and the equipment both on a multi-seasonal and multi-annual basis.

Phylogenetics and phylogeography of the monocot genus Baldellia (Alismataceae): Mediterranean refugia, suture zones and implications for conservation.

Aquatic plants, and especially the emblematic genus Baldellia (Alismataceae), are among the most threatened organisms, due to unprecedented human-driven habitat destructions. Therefore protection plans are crucially needed and call for thoroughly documenting the genetic diversity and clarifying the taxonomy of this endangered genus. Our sampling included 282 individuals from 42 natural populations and covered the whole geographical range of the genus, across Europe and the Mediterranean. We combined sequencing of nuclear internal transcribed spacer (ITS) and chloroplastic trnL-ndhF regions with amplified fragment length polymorphism (AFLP) genotyping to investigate the Alismataceae phylogeny, and produce a phylogeography of Baldellia. Our phylogeny strongly supported the monophyly of Baldellia and placed it as the sister clade to Luronium and Alisma, therefore excluding, as previously supposed, a close genetic relatedness to the predominantly neotropical genus Echinodorus. The phylogeography of Baldellia outlined patterns consistent with a hypothesis considering glacial refugia located in the Iberian Peninsula and the Italy/Balkan region from which two distinct genetic lineages re-colonized Europe. These two lineages corresponded respectively to Baldellia ranunculoides (Italy/Balkan derived populations) and Baldellia repens (populations recovered from the Iberian Peninsula refuge), therefore supporting differences outlined between the two taxa in previous ecological and morphological studies. These results allowed clarifying taxonomic uncertainties by confirming the genetic distinctness of B. repens according to B. ranunculoides. A third lineage, Baldellia alpestris, originated and remained endemic to the mountainous regions of the Iberian Peninsula. Unexpectedly, B. repens populations collected in northern Africa, appeared to be genetically distinct from their European counterparts, this calls for further investigation to fully address their genetic and conservation status. Finally, we detected a large hybridization zone in northwestern Europe between B. repens and B. ranunculoides. These results were discussed in light of conservation approaches for Baldellia populations.

Biogeographic Overview of Ulmaceae: Diversity, Distribution, Ecological Preferences, and Conservation Status.

The elm family (Ulmaceae) is a woody plant group with important scientific, societal, and economic value. We aim to present the first biogeographic synthesis investigating the global diversity, distribution, ecological preferences, and the conservation status of Ulmaceae. A literature review was performed to explore the available data for all extant species. Our study made it possible to map the actual global distribution of Ulmaceae with high precision, and to elucidate the centers of diversity, located mainly in China and in the southeastern USA. A detailed comparative analysis of the macroclimatic niche for each species was produced, which shows the general biogeographic pattern of the family and pinpoints the outlier species. The results corroborate recent molecular analyses and support the division of Ulmaceae into two taxonomically, biogeographically, and ecologically well-differentiated groups: the so-called temperate clade with 4 genera and 43 species and the tropical clade with 3 genera and 13 species. The elm family is often described as a typical temperate plant group, however the diversity peak of all Ulmaceae is located in the subtropical zone, and a non-negligible part of the family is exclusively distributed in the tropics. We also noticed that a high proportion of Ulmaceae is linked to humid macro- or microhabitats. Finally, we highlighted that nearly 25% of all Ulmaceae are threatened. Fieldwork, conservation efforts, and research activities are still necessary for this family, particularly for the tropical members and the most endangered species.