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The 10th International Conference on Serpentine Ecology was held in Nancy, France on June 12–16, 2023. The main goals of the conference were to create a platform for the exchange of ideas and experiences and to promote scientific dialogue among scientists from numerous fields who share expertise in the study of ultramafic habitats worldwide. The proceedings of the conference are being published as two Special Issues of Ecological Research, of which this is the second. In this article, we present the major topics and provide some highlights of the contributions to the 10th International Conference on Serpentine Ecology. [ABSTRACT FROM AUTHOR]

The overabundance of sika deer has become a significant threat to plant communities across Japan. As a result of the deer overgrazing, rare plants are undergoing a demographic bottleneck, leading to a loss of genetic diversity. Genetic diversity is crucial for the reproductive success of self‐incompatible plants, and it also provides evolutionary potential, which increases their long‐term population viability. Therefore, it is essential to appropriately manage the remaining genotypes to conserve local genetic resources. In this study, we exemplify this, via a conservation genetic analysis of Parasenecio peltifolius populations impacted by deer. Genetic data revealed that the small populations confined to isolated refugial sites consisted of effectively single genets. Recent reproductive failures in these populations may be attributed to the loss of genotypic diversity. Despite the bottlenecks, the remaining genets exhibited high individual heterozygosity, which is a good indicator that they have not been affected by severe inbreeding. Hybrid simulations suggested that interpopulation outbreeding between the unique genotypes can be a viable option to promote sexual reproduction and re‐establish genetic diversity within the local populations. Establishing artificial progenies in botanical gardens can serve as a vital genetic resource for the long‐term viability of threatened P. peltifolius populations. [ABSTRACT FROM AUTHOR]

The 10th International Conference on Serpentine Ecology was held in Nancy, France on 12–16 June, 2023. As a major international scientific forum in the field of serpentine (ultramafic) ecology, this conference brings together botanists, zoologists, microbiologists, physiologists, geneticists, geologists, soil scientists, and other applied specialists studying the ecology of ultramafic rocks and soil. A notable aspect of these meetings is the multidisciplinary nature of research on ultramafic biota, including diversity, ecology, evolution, physiology, and applied research in phytotechnologies and conservation. The main goals of the conference were to create a platform for the exchange of ideas and experiences and to promote scientific dialogue among scientists from numerous fields who share expertise in the study of ultramafic habitats worldwide. In this Special Issue we present the major topics and provide some highlights of the contributions to the 10th International Conference on Serpentine Ecology. [ABSTRACT FROM AUTHOR]

Premise: Light is essential for plants, and local populations exhibit adaptive photosynthetic traits depending on their habitats. Although plastic responses in morphological and/or physiological characteristics to different light intensities are well known, adaptive divergence with genetic variation remains to be explored. This study focused on Saxifraga fortunei (Saxifragaceae) growing in sun‐exposed and shaded habitats. Methods: We measured the leaf anatomical structure and photosynthetic rate of plants grown in their natural habitats and in a common greenhouse (high‐ and low‐intensity light experimental sites). To assess differences in ecophysiological tolerance to high‐intensity light between the sun and shade types, we evaluated the level of photoinhibition of photosystem II and the leaf mortality rate under high‐intensity light conditions. In addition, population genetic analysis was conducted to investigate phylogenetic origins. Results: Clear phenotypic differences were found between the sun and shade types despite their recent phylogenetic origin. The leaf anatomical structure and photosynthetic rate showed plastic changes in response to growing conditions. Moreover, the sun type had a well‐developed palisade parenchyma and a higher photosynthetic rate, which were genetically fixed, and a lower level of photoinhibition under high‐intensity light. Conclusions: Our findings demonstrate that light intensity is a selective pressure that can rapidly promote phenotypic divergence between the sun and shade types. While phenotypic changes in multiple photosynthetic traits were plastic, genetic divergence in specific traits related to adaptation to high‐intensity light would be fundamental for ecotypic divergence to different light regimes. [ABSTRACT FROM AUTHOR]

Plant species with overlapping distributions are expected to experience the same historical events. In contrast, species with different preferred habitat types may exhibit incongruent phylogeographic patterns because of their habitat‐dependent demographic changes in spite of their overlapping distributions. On the western side of the Japanese Archipelago, boreal forest and non‐forest vegetation were dominant during the last glacial period; subsequently, temperate forests expanded, and open vegetation (e.g., grasslands) decreased. Such vegetation shifts can result in incongruent phylogeographic patterns among temperate forest and grassland species; however, few phylogeographic studies have investigated this hypothesis. Here, we evaluated the phylogeographic structure of two related Geranium species that occur in grassland (Geranium krameri) and temperate forest (Geranium shikokianum) habitats using chloroplast genome sequencing and nuclear genome‐wide single‐nucleotide polymorphisms genotyping. The phylogeographic structure was stronger for the temperate forest species than the grassland species, despite its currently scattered distribution for grassland species. The observed patterns indicate that the phylogeographic histories of these species were influenced by their habitat configurations since the last glacial period. During the ice age, grasslands in Japan were much more widespread than today; this would have enabled the grassland species to form a continuous distribution, leading to low divergence among regional populations. In contrast, the significant genetic divergence within the forest species can be attributed to the glacial isolation of regional populations. Our genetic results suggest that vegetation transitions have variously controlled the population dynamics of two species with overlapping distributions. [ABSTRACT FROM AUTHOR]

Aims: Quaternary climate changes dramatically affected species' distributions and thus impacted genetic diversity patterns, particularly for rear‐edge populations. Empirical studies have shown the southernmost (rear‐edge), fragmented populations of Japanese woody plants can harbour high genetic diversity owing to their origin in southern glacial refugia. The effect of Holocene climate warming on rear‐edge populations has, however, rarely been demonstrated. We assessed whether the genetic structure of populations of temperate plants in Japan can be interpreted to show legacies of both icy (Last Glacial Maximum, LGM) and warm (Holocene) climates. Location: Japanese Archipelago. Taxon: Hemerocallis middendorffii (Asphodelaceae). Methods: Population genetic profiles of 737 individuals from 41 populations were analysed to examine population structure and past population demography, using 12 EST‐SSR markers. Present and past suitable habitat areas during the LGM and the Holocene climatic optimum were estimated by ecological niche modelling (ENM). Reconstructed palaeodistribution was combined with population genetics to statistically predict population demographics in relation to past climate changes. Results: Genetic analysis of the 41 populations revealed 6 regional population groups. Four groups widely dominating the northern–central ranges harboured high genetic diversity, whereas genetic divergence within the groups was low. In contrast, the two groups at the southwestern edge were geographically and genetically isolated, and they showed the lowest genetic diversity. The estimated palaeodistributions showed a decrease in the suitable range during the Holocene in comparison with that at the LGM, and only habitat suitability in the Holocene was able to predict the genetic diversity across the range. Main conclusions Populations at the centre of the current distribution harbour high genetic diversity because they remained stable during both cold and warm periods. However, habitat fragmentation and population decline in relation to climate warming during the Holocene resulted in genetic isolation and impoverishment of the rear‐edge populations. [ABSTRACT FROM AUTHOR]

Fagus L. is a key component in temperate deciduous broadleaf forests of the Northern Hemisphere. However, its biogeographic history has not been examined under the framework of a fully resolved and reasonably time‐calibrated phylogeny. In this study, we sequenced 28 nuclear single/low‐copy loci (18 555 bp in total) of 11 Fagus species/segregates and seven outgroups. Phylogenetic trees were reconstructed using both concatenation‐based (maximum parsimony, maximum likelihood, and Bayesian inference) and coalescent‐based methods (StarBEAST2, ASTRAL). The monophyly of two subgenera (Fagus and Engleriana) and most sections was well supported, except for sect. Lucida, which was paraphyletic with respect to sect. Longipetiolata. We also found a major phylogenetic conflict among North American, East Asian, and West Eurasian lineages of subgen. Fagus. Three segregates that have isolated distribution (F. mexicana, F. multinervis, and F. orientalis) were independent evolutionary units. Biogeographic analysis with fossils suggested that Fagus could have originated in the North Pacific region in late early Eocene. Major diversifications coincided with a climate aberration at the Eocene/Oligocene boundary and the global cooling since mid‐Miocene. The late Miocene accelerated global cooling and the Pleistocene glaciations would have driven beeches into East Asia, North America, and West Eurasia. Meanwhile, range reduction and extinction in high latitudes, central Asia, and western North America converged to form the beech modern distribution pattern. This study provides a first attempt to disentangle the biogeographic history of beeches in the context of a nearly resolved and time‐calibrated phylogeny, which could shed new insights into the formation of the temperate biome in the Northern Hemisphere. [ABSTRACT FROM AUTHOR]

The Ogasawara Islands, representing an oceanic island ecosystem in Japan, have a notably high rate of endemic species akin to other oceanic islands globally. Pittosporum parvifolium is a critically endangered shrub with only four remaining individuals in its natural habitat on the Ogasawara Islands. Current conservation efforts encompass both in situ and ex situ approaches for P. parvifolium . However, these efforts face challenges stemming from the lack of critical conservation information. Therefore, we explored P. parvifolium 's genetic diversity and implications for conservation. We utilized simple sequence repeat markers to scrutinize genetic diversity within both in situ and ex situ populations, revealing notably rich diversity among both. The in situ genetic diversity was significantly high despite the few extant individuals. In addition, many of the ex situ peculiar genotypes were absent in individuals conserved in situ. This investigation also provides insights into the reproductive strategies and combinations of selfing and outcrossing. The results of the present study recommend conservation to maximize genetic diversity in P. parvifolium by promoting cross-pollination among in situ individuals and by introducing individuals with unique genotypes into ex situ stocks., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Author(s). Ecology and Evolution published by John Wiley & Sons Ltd.)

Extreme environments and plants thriving in them, known as extremophytes, offer promising platforms for studying the diverse adaptive mechanisms that have evolved in plants. However, research on adaptation to extreme environments is still limited to those environments where model species or their relative can survive. Fumarole fields, an extreme environment often overlooked, are characterized by multi-hazardous abiotic stressors, including atmospheric contamination (high concentration of H2S, SO2, and CO2), high soil temperature (~60℃), and strong soil acidification (pH=2-3). These conditions make fumarole fields a rich source for studying stress tolerance mechanisms in plants. In this review, we highlight the recent ecological, physiological, and genomic advances involved in fumarole field adaptation, and discuss the forward avenues. The studies outlined in this paper demonstrate that the extreme levels of abiotic stressors found in fumarole fields make them unparalleled field laboratories for studying the unknown stress tolerance mechanisms, warranting further genomic assessments. Some studies succeeded in identifying genes associated with fumarole field adaptation and shedding light on evolutionary implications; however, they have also encountered challenges such as limited genome resources and high genetic differentiation from related species and/or neighboring populations. To overcome such difficulties, we propose integrating ecophysiological and genomic approaches, drawing from the recent studies in other extreme environments. We expect that further studies in the fumarole fields will contribute to broadening our general knowledge of the limits of life., (© The Author(s) 2024. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site–for further information please contact journals.permissions@oup.com.)