Synthesis and Mesomorphic Properties of Liquid Crystals with 5-(4-Alkoxyphenylethynyl)tropolone.

New troponoid liquid crystals with 5-(4-alkoxyphenylethynyl)tropolone cores were synthesized. The 5-(4-alkoxyphenylethynyl)tropolones were obtained by the palladium-catalyzed cross-coupling of 5-iodotropolone with 4-alkoxyphenylacetylenes. The 2-alkoxy-5-(4-alkoxyphenylethynyl)tropones (1A) showed enantiotropic smectic phases, such as smectic A, C, and B. The 2-(4-alkoxy)benzoyloxy-5-(4-alkoxyphenylethynyl)tropones (1B) had enantiotropic nematic and smectic C phases. The 2-alkoxytropone derivatives (1A) had higher clearing temperatures and lower melting points than the corresponding benzene derivatives (2A). However, the 2-(4-alkoxybenzoyl)tropone derivatives (1B) had lower clearing temperatures and higher melting points than the corresponding benzene derivatives (2B).

Hill-Chao numbers allow decomposing gamma multifunctionality into alpha and beta components.

Biodiversity-ecosystem functioning (BEF) research has provided strong evidence and mechanistic underpinnings to support positive effects of biodiversity on ecosystem functioning, from single to multiple functions. This research has provided knowledge gained mainly at the local alpha scale (i.e. within ecosystems), but the increasing homogenization of landscapes in the Anthropocene has raised the potential that declining biodiversity at the beta (across ecosystems) and gamma scales is likely to also impact ecosystem functioning. Drawing on biodiversity theory, we propose a new statistical framework based on Hill-Chao numbers. The framework allows decomposition of multifunctionality at gamma scales into alpha and beta components, a critical but hitherto missing tool in BEF research; it also allows weighting of individual ecosystem functions. Through the proposed decomposition, new BEF results for beta and gamma scales are discovered. Our novel approach is applicable across ecosystems and connects local- and landscape-scale BEF assessments from experiments to natural settings.

Long-term Consequences on Soil Fungal Community Structure: Monoculture Planting and Natural Regeneration.

Understanding the regeneration and succession of belowground communities, particularly in forests, is vital for maintaining ecosystem health. Despite its importance, there is limited knowledge regarding how fungal communities change over time during ecosystem development, especially under different forest restoration strategies. In this study, we focused on two restoration methods used in northern Japan: monoculture planting and natural regeneration. We examined the responses of the fungal community to monoculture plantations (active tree planting) and naturally regenerated (passive regeneration) forests over a 50-year chronosequence, using natural forests as a reference. Based on DNA metabarcoding, we assessed the richness of fungal Operational Taxonomic Units (OTUs) and their dissimilarity. Our findings revealed that soil fungal richness remained stable after natural regeneration but declined in monoculture plantations, from 354 to 247 OTUs. While the compositional dissimilarity of fungal assemblages between monoculture plantations and natural forests remained consistent regardless of the time since tree planting, it significantly decreased after natural regeneration, suggesting recovery to a state close to the reference level. Notably, the composition of key functional fungal groups-saprotrophic and ectomycorrhizal- has increasingly mirrored that of natural forests over time following passive natural regeneration. In summary, our study suggests that monoculture plantations may not be effective for long-term ecosystem function and service recovery because of their limited support for soil fungal diversity. These results underscore the importance of natural regeneration in forest restoration and management strategies.

Biodiversity modeling advances will improve predictions of nature's contributions to people.

Accurate predictions of ecosystem functions and nature's contributions to people (NCP) are needed to prioritize environmental protection and restoration in the Anthropocene. However, our ability to predict NCP is undermined by approaches that rely on biophysical variables and ignore those describing biodiversity, which have strong links to NCP. To foster predictive mapping of NCP, we should harness the latest methods in biodiversity modeling. This field advances rapidly, and new techniques with promising applications for predicting NCP are still underutilized. Here, we argue that employing recent advances in biodiversity modeling can enhance the accuracy and scope of NCP maps and predictions. This enhancement will contribute significantly to the achievement of global objectives to preserve NCP, for both the present and an unpredictable future.

DO Toxic Invasive Prey Become a Toxin Source for Native Consumers?

Toxic organisms can become food that potentially harms consumers. When these organisms become invasive species, the harm often turns to a serious threat that disrupts native ecosystems. On the other hand, there are consumers that can exploit toxic organisms for food and sequester intact toxins from them for the consumers' own chemical defense. Therefore, it can be expected that toxic invasive prey can become a toxin source for native consumers. Here, we focused on the relationship between toads, which are one of the major toxic invasive organisms and possess bufadienolides (BDs), and Rhabdophis snakes, which sequester BDs from toads. On Sado Island, Japan, R. tigrinus is native, but no toads had inhabited this island until Bufo japonicus formosus was introduced as a domestic invasive species in 1963 and 1964. At present, invasive toads are distributed only in the southwestern part of the island. We collected a total of 25 and 24 R. tigrinus from areas allopatric and sympatric with toads, respectively. Then, we investigated the possession of BDs and the BD profile of these snakes. We found that only R. tigrinus sympatric with toads possessed BDs, whereas all snakes allopatric with toads lacked BDs. Based on the characteristics of the BD profile, the toxin source was identified as B. j. formosus. Our findings show that a new case of impact caused by toxic invasive species, i.e., "toxin supply to native consumers from invasive prey", could occur.

Synergistic effects of succession and microtopography of moraine on the fungal spatial diversity in a glacier forefield.

Primary succession and microtopography result in environmental changes and are important processes influencing the community assembly of soil fungi in the Arctic region. In glacier forefields that contain a series of moraine ridges, both processes contribute synchronously to fungal spatial diversity. To reveal the synergistic effects of succession and microtopography, we investigated the fungal community structure and environmental variables in the moraines of the Arklio Glacier, Ellesmere Island. The study sites were established at four locations from the top to the bottom of the ridge slope within each of the three moraine ridges of different post-glacial ages. The location-dependent community composition was equally diverse in both the initial and later stages of succession, suggesting that successional time could alter the effects of microtopography on the fungal community. Moreover, our results suggest that fungal communities at different locations follow different successional trajectories, even if they have passed through the same time lapse. Such a synergistic effect of succession and microtopography of moraines does not allow for parallel changes in fungal communities among moraines or among locations, suggesting that the moraine series contributes substantially to fungal spatial diversity in the glacier forefield.

Giving fair credits to efforts in science and policy.

International collaborations aim to solve global environmental issues. Academic work and science-policy interfaces are instrumental in this pursuit, although scholars often overlook their significance. There is a need for fair credit distribution, transparency, and diversity in academia and policy reports. Recognizing these factors can enhance inclusivity and equity, driving solutions.

Leaf-level coordination principles propagate to the ecosystem scale.

Fundamental axes of variation in plant traits result from trade-offs between costs and benefits of resource-use strategies at the leaf scale. However, it is unclear whether similar trade-offs propagate to the ecosystem level. Here, we test whether trait correlation patterns predicted by three well-known leaf- and plant-level coordination theories - the leaf economics spectrum, the global spectrum of plant form and function, and the least-cost hypothesis - are also observed between community mean traits and ecosystem processes. We combined ecosystem functional properties from FLUXNET sites, vegetation properties, and community mean plant traits into three corresponding principal component analyses. We find that the leaf economics spectrum (90 sites), the global spectrum of plant form and function (89 sites), and the least-cost hypothesis (82 sites) all propagate at the ecosystem level. However, we also find evidence of additional scale-emergent properties. Evaluating the coordination of ecosystem functional properties may aid the development of more realistic global dynamic vegetation models with critical empirical data, reducing the uncertainty of climate change projections.

Clarifying the effect of biodiversity on productivity in natural ecosystems with longitudinal data and methods for causal inference.

Causal effects of biodiversity on ecosystem functions can be estimated using experimental or observational designs - designs that pose a tradeoff between drawing credible causal inferences from correlations and drawing generalizable inferences. Here, we develop a design that reduces this tradeoff and revisits the question of how plant species diversity affects productivity. Our design leverages longitudinal data from 43 grasslands in 11 countries and approaches borrowed from fields outside of ecology to draw causal inferences from observational data. Contrary to many prior studies, we estimate that increases in plot-level species richness caused productivity to decline: a 10% increase in richness decreased productivity by 2.4%, 95% CI [-4.1, -0.74]. This contradiction stems from two sources. First, prior observational studies incompletely control for confounding factors. Second, most experiments plant fewer rare and non-native species than exist in nature. Although increases in native, dominant species increased productivity, increases in rare and non-native species decreased productivity, making the average effect negative in our study. By reducing the tradeoff between experimental and observational designs, our study demonstrates how observational studies can complement prior ecological experiments and inform future ones.

Identity of the holotype and type locality of Rhabdophis leonardi (Wall, 1923) (Colubridae: Natricinae), with notes on the morphology and natural history of the species in southwestern China.

The original description of Natrix leonardi (currently Rhabdophis leonardi) by Frank Wall in 1923, based on a specimen from the "Upper Burma Hills," lacked important morphological details that have complicated the assignment of recently collected material. Furthermore, although the holotype was never lost, its location has been misreported in one important taxonomic reference, leading to further confusion. We report the correct repository of the holotype (Natural History Museum, London), together with its current catalog number. We also describe key features of that specimen that were omitted from the original description, and provide new details on the morphology of the species, including sexual dichromatism unusual for the genus, based upon specimens from southern Sichuan, China. Rhabdophis leonardi is distinguished from its congeners by the following characters: 15 or 17 DSR at midbody and 6 supralabials; distinct annulus around the neck, broad and red in males, and narrow and orange with a black border in females; dorsal ground color light green or olive; some lateral and dorsal scales possessing black edges, the frequency of black edges gradually increasing from anterior to posterior, forming irregular and ill-defined transverse black bands; eye with prominent green iris; black ventral spots with a red edge, most numerous at midbody but extending halfway down the length of the tail. In southwestern China, this species is frequently found at 1730-2230 m elevation. It has been documented to prey upon anuran amphibians, including toads. A recently published phylogenetic analysis showed this species to be deeply nested with the genus Rhabdophis, as a member of the R. nuchalis Group. That analysis also revealed the existence of two closely related but geographically distinct subclades in the molecular analysis, one of which may represent an unnamed taxon.

Vegetation as a key driver of the distribution of microbial generalists that in turn shapes the overall microbial community structure in the low Arctic tundra.

Understanding the variability of microbial niches and their interaction with abiotic and biotic factors in the Arctic can provide valuable insights into microbial adaptations to extreme environments. This study investigates the structure and diversity of soil bacterial communities obtained from sites with varying vegetation coverage and soil biogeochemical properties in the low Arctic tundra and explores how bacteria interact under different environmental parameters. Our findings reveal differences in bacterial composition and abundance among three bacterial niche breadths (specialists, common taxa, and generalists). Co-occurrence network analysis revealed Rhizobiales and Ktedonobacterales as keystone taxa that connect and support other microbes in the habitat. Low-elevation indicators, such as vascular plants and moisture content, were correlated with two out of three generalist modular hubs and were linked to a large proportion of generalists' distribution (18%). Structural equation modeling revealed that generalists' distribution, which influenced the remaining microbial communities, was mainly regulated by vegetation coverage as well as other abiotic and biotic factors. These results suggest that elevation-dependent environmental factors directly influence microbial community structure and module formation through the regulation of generalists' distribution. Furthermore, the distribution of generalists was mainly affected by macroenvironment filtering, whereas the distribution of specialists was mainly affected by microenvironment filtering (species-engineered microbial niche construction). In summary, our findings highlight the strong top-down control exerted by vegetation on generalists' distribution, which in turn shapes the overall microbial community structure in the low Arctic tundra.

Perspective: sustainability challenges, opportunities and solutions for long-term ecosystem observations.

As interest in natural capital grows and society increasingly recognizes the value of biodiversity, we must discuss how ecosystem observations to detect changes in biodiversity can be sustained through collaboration across regions and sectors. However, there are many barriers to establishing and sustaining large-scale, fine-resolution ecosystem observations. First, comprehensive monitoring data on both biodiversity and possible anthropogenic factors are lacking. Second, some in situ ecosystem observations cannot be systematically established and maintained across locations. Third, equitable solutions across sectors and countries are needed to build a global network. Here, by examining individual cases and emerging frameworks, mainly from (but not limited to) Japan, we illustrate how ecological science relies on long-term data and how neglecting basic monitoring of our home planet further reduces our chances of overcoming the environmental crisis. We also discuss emerging techniques and opportunities, such as environmental DNA and citizen science as well as using the existing and forgotten sites of monitoring, that can help overcome some of the difficulties in establishing and sustaining ecosystem observations at a large scale with fine resolution. Overall, this paper presents a call to action for joint monitoring of biodiversity and anthropogenic factors, the systematic establishment and maintenance of in situ observations, and equitable solutions across sectors and countries to build a global network, beyond cultures, languages, and economic status. We hope that our proposed framework and the examples from Japan can serve as a starting point for further discussions and collaborations among stakeholders across multiple sectors of society. It is time to take the next step in detecting changes in socio-ecological systems, and if monitoring and observation can be made more equitable and feasible, they will play an even more important role in ensuring global sustainability for future generations. This article is part of the theme issue 'Detecting and attributing the causes of biodiversity change: needs, gaps and solutions'.

Assessing the importance of species and their assemblages for the biodiversity-ecosystem multifunctionality relationship.

Biodiversity changes, such as decline in species richness and biotic homogenization, can have grave consequences for ecosystem functionality. Careful investigation of biodiversity-ecosystem multifunctionality linkages with due consideration of conceptual and technical challenges is required to make the knowledge practically useful in managing social-ecological systems. In this paper, we introduced different methods to assess perspectives regarding the issue of diversity-multifunctionality, including a possible multifunctional redundancy/uniqueness, and the influences of the number and identity of functions on multifunctionality. In particular, we aimed to align methods with detecting the mechanisms underpinning diversity-multifunctional relationships that are free from statistical biases. Based on a set of novel methods that excluded analytical biases resulting from differences in the number and identities of multiple functions considered, we found that a substantial portion of species disproportionately supported ecosystem functions and that the diversity effects on multifunctionality were more markedly observed when more functions were considered. These results jointly emphasize that individual species are, to some extent, both functionally unique as well as redundant, highlighting the complexity and necessity for managed assemblages to retain high levels of diversity. We also observed that the relative magnitude of uniqueness or redundancy can differ between species and functions and therefore should be defined in a multifunctional context. We further found that only a small subset of species was identified as significantly less important, especially at low levels of multifunctionality. Taken together, given the low level of multifunctional redundancy we identified, we stress that unraveling the hierarchical roles of biodiversity at different levels, such as individual species and their assemblages, should be a high research priority, in both theory and practice.

Global beta-diversity of angiosperm trees is shaped by Quaternary climate change.

As Earth's climate has varied strongly through geological time, studying the impacts of past climate change on biodiversity helps to understand the risks from future climate change. However, it remains unclear how paleoclimate shapes spatial variation in biodiversity. Here, we assessed the influence of Quaternary climate change on spatial dissimilarity in taxonomic, phylogenetic, and functional composition among neighboring 200-kilometer cells (beta-diversity) for angiosperm trees worldwide. We found that larger glacial-interglacial temperature change was strongly associated with lower spatial turnover (species replacements) and higher nestedness (richness changes) components of beta-diversity across all three biodiversity facets. Moreover, phylogenetic and functional turnover was lower and nestedness higher than random expectations based on taxonomic beta-diversity in regions that experienced large temperature change, reflecting phylogenetically and functionally selective processes in species replacement, extinction, and colonization during glacial-interglacial oscillations. Our results suggest that future human-driven climate change could cause local homogenization and reduction in taxonomic, phylogenetic, and functional diversity of angiosperm trees worldwide.

Propensity Score Matching Analysis of the Safety of Completion Total Pancreatectomy for Remnant Pancreatic Tumors Versus that of Initial Total Pancreatectomy for Primary Pancreatic Tumors.

BACKGROUND: The safety and feasibility of completion total pancreatectomy (TP) for remnant pancreatic neoplasms remain controversial and are rarely compared with that of initial TP. Thus, we aimed to compare the safety of these two procedures inducing a pancreatic state. METHODS: Patients who underwent TP for pancreatic neoplasms between 2006 and 2018 at our institution were included in this study. Tumor pathologies were classified into three subgroups according to survival curves. We used 1:1 propensity score matching (PSM) to analyze age, sex, Charlson Comorbidity Index, and tumor stage. Finally, we analyzed the primary outcome Clavien-Dindo classification (CDC) grade, risks of other safety-related outcomes, and the survival rate of patients with invasive cancer. RESULTS: Of 54 patients, 16 underwent completion TP (29.6%) and 38 (70.4%) underwent initial TP. Before PSM analysis, age and Charlson Comorbidity Index were significantly higher, and T category and stage were significantly lower for the completion TP group. Upon PSM analysis, these two groups were equivalent in CDC grade [initial TP vs. completion TP: 71.4% (10/14) vs. 78.6% (11/14); p = 0.678] and other safety-related outcomes. Additionally, while the overall survival and recurrence-free survival of patients with invasive cancer were not significantly different between these two groups, the T category and stage tended to be remarkably severe in the initial TP group. CONCLUSIONS: PSM analysis for prognostic factors showed that completion TP and initial TP have similar safety-related outcomes that can be used as a decision-making reference in the surgery of pancreatic tumors.

Surgical Outcomes of Laparoscopic versus Open Hepatectomy for Left Hepatocellular Carcinoma: Propensity Score Analyses Using Retrospective Japanese and Korean Individual Patient Data.

Introduction: This study aimed to compare the prognostic impact of laparoscopic left hepatectomy (LLH) with that of open left hepatectomy (OLH) on patient survival after resection of left hepatocellular carcinoma (HCC). Methods: Among the 953 patients who received initial treatment for primary HCC that was resectable by either LLH or OLH from 2013 to 2017 in Japan and Korea, 146 patients underwent LLH and 807 underwent OLH. The inverse probability of treatment weighting approach based on propensity scoring was used to address the potential selection bias inherent in the recurrence and survival outcomes between the LLH and OLH groups. Results: The occurrence rate of postoperative complications and hepatic decompensation was significantly lower in the LLH group than in the OLH group. Recurrence-free survival (RFS) was better in the LLH group than in the OLH group (hazard ratio, 1.33; 95% confidence interval, 1.03-1.71; p = 0.029), whereas overall survival (OS) was not significantly different. Subgroup analyses of RFS and OS revealed an almost consistent trend in favor of LLH over OLH. In patients with tumor sizes of ≥4.0 cm or those with single tumors, both RFS and OS were significantly better in the LLH group than in the OLH group. Conclusions: LLH decreases the risk of tumor recurrence and improves OS in patients with primary HCC located in the left liver.

Intrinsic Factors Associated with Dietary Toxin Quantity and Concentration in the Nuchal Glands of a Natricine Snake Rhabdophis Tigrinus.

The snake Rhabdophis tigrinus sequesters cardiotonic steroids, bufadienolides (BDs), from ingested toads and stores them in the nuchal glands as defensive toxins. It has previously been shown that there are individual differences in the total quantity of BDs stored in the nuchal glands of adult R. tigrinus and that BD quantities and profiles of R. tigrinus exhibit geographic variation. However, no previous study has examined the total quantity of BDs as a percentage of body mass (relative BD quantity) and the concentration of BDs in the nuchal gland fluid (BD gland concentration). In addition, intrinsic factors that are associated with relative BD quantity and BD concentration have not been examined within a single population. We collected 158 adult snakes from an area of central Japan from May to October and analyzed their BD quantities by UV analysis. We assessed individual differences in BD quantity, relative BD quantity and BD gland concentration. We found that 1) in approximately 60% of the 158 individuals, the BD gland concentration was greater than 50%; 2) body length and body condition are positively correlated with relative BD quantity and BD gland concentration; 3) even in a single population, individual differences of BD quantity are large, and are greater in females than in males; and 4) relative BD quantity and BD gland concentration of females during the gestation season are lower than those during the non-gestation season.