Range Of Species Research Articles

The Origin of The Problem: Characterization of Paraguayan Septoria steviae, Causal Agent of Septoria Leaf Spot of Stevia Based on Multi-Locus Sequence Analysis.

Septoria leaf spot is a significant disease affecting cultivated stevia, potentially reducing yields by > 50%. The disease is caused by Septoria steviae, first identified in 1978 in Japan as a new pathogen of stevia. Understanding the origin of S. steviae could clarify how it spread to new production areas. To investigate this, twelve isolates of Septoria sp. were obtained from stevia's native range in the Amambay forests and field plantings in Paraguay from 2018 to 2020. These isolates underwent colony morphology and molecular characterization of Actin, β-Tubulin, Calmodulin, ITS, LSU, RPB2, and TEF1α loci. GenBank sequences from S. steviae isolates collected in France, Japan, and the United States (USA) were included. Multi-locus sequence phylogenetic analysis generated a maximum likelihood (ML) tree. The morphological characteristics of Paraguayan isolates were similar to previously reported S. steviae type cultures from Japan. The ML analysis showed that Paraguayan isolates formed a monophyletic group with S. steviae isolates from France, Japan, and the USA. During blotter tests, pycnidia and cirri of S. steviae were observed on multiple stevia seed surfaces from different sources. Further characterization confirmed viable pathogenic conidia of S. steviae. This observation suggests that S. steviae could be associated with stevia seed, possibly spreading from the center of origin to other countries. This research is the first to genetically characterize S. steviae from Paraguay and propose its potential spread mechanism from the center of origin to the rest of the world.

Impact of stage-specific limb function exercises guided by a self-management education model on arteriovenous fistula maturation status.

The exercise of limb function is the most economical and safe method to promote the maturation of arteriovenous fistula (AVF). However, due to the lack of a unified exercise standard in China, many patients have insufficient awareness of the importance of AVF, leading to poor effectiveness of limb function exercise. The self-management education model can effectively promote patients to take proactive health-related actions. This study focuses on the characteristics of patients during the peri-AVF period and conducts a phased limb function exercise under the guidance of the self-management education model to observe changes in factors such as the maturity of AVF. To assess the impact of stage-specific limb function exercises, directed by a self-management education model, on the maturation status of AVFs. This study is a randomized controlled trial involving 74 patients with forearm AVFs from the Nephrology Department of a tertiary hospital in Sichuan Province, China. Patients were randomly divided into an observation group and a control group using a random number table method. The observation group underwent tailored stage-specific limb function exercises, informed by a self-management education model which took into account the unique features of AVF at various stages, in conjunction with routine care. Conversely, the control group was given standard limb function exercises along with routine care. The assessment involves the maturity of AVFs post-intervention, postoperative complications, and the self-management level of the fistula in both groups patients. Analyses were conducted using SPSS version 23.0. Count data were represented by frequency and percentage and subjected to chi-square test comparisons. Measurement data adhering to a normal distribution were presented as mean ± SD. The independent samples t-test was utilized for inter-group comparisons, while the paired t-test was used for intra-group comparisons. For measurement data not fitting a normal distribution, the median and interquartile range were presented and analyzed using the Wilcoxon rank sum test. At the 8-wk postoperative mark, the observation group demonstrated significantly higher scores in AVF symptom recognition, symptom prevention, and self-management compared to the control group (P < 0.05). However, the variance in symptom management scores between the observation and control groups lacked statistical significance (P > 0.05). At 4 wk after the operation, the observation group displayed a superior vessel diameter and depth from the skin of the drainage vessels in comparison to the control group (P < 0.05). While the observation group did manifest elevated blood flow rates in the drainage vessels relative to the control group, this distinction was not statistically significant (P > 0.05). By the 8-wk postoperative interval, the observation group outperformed the control group with notable enhancements in blood flow rates, vessel diameter, and depth from the skin of drainage vessels (P < 0.01). Seven days following the procedure, the observation group manifested significantly diminished limb swelling and an overall reduced complication rate in contrast to the control group (P < 0.05). The evaluation of infection, thrombosis, embolism, arterial aneurysm stenosis, and incision bleeding showed no notable differences between the two groups (P > 0.05). By the 4-wk postoperative juncture, complications between the observation and control groups were statistically indistinguishable (P > 0.05). Stage-specific limb function exercises, under the guidance of a self-management education model, amplify the capacity of AVF patients to discern and prevent symptoms. Additionally, they expedite AVF maturation and mitigate postoperative limb edema, underscoring their efficacy as a valuable method for the care and upkeep of AVF in hemodialysis patients.

Introduced species shed friends as well as enemies

Many studies seeking to understand the success of biological invasions focus on species’ escape from negative interactions, such as damage from herbivores, pathogens, or predators in their introduced range (enemy release). However, much less work has been done to assess the possibility that introduced species might shed mutualists such as pollinators, seed dispersers, and mycorrhizae when they are transported to a new range. We ran a cross-continental field study and found that plants were being visited by 2.6 times more potential pollinators with 1.8 times greater richness in their native range than in their introduced range. Understanding both the positive and negative consequences of introduction to a new range can help us predict, monitor, and manage future invasion events.

Distribution analysis of rare earth elements in fine‐grained CAIs of the Allende meteorite using multiple‐spot femtosecond LA‐ICP‐MS

ABSTRACTCalcium–aluminum‐rich inclusions (CAIs) in chondrites are one of the oldest materials in the solar system. Presence of refractory minerals in CAIs suggests that they formed thorough a condensation process from nebular gas of solar composition. In particular, fine‐grained CAIs (FGs) have escaped melting after condensation, and thus, the elemental distribution of rare earth elements (REEs) in FG minerals provides key information for elucidating the condensation processes. Although the REE abundances of FG fragments have been investigated in previous studies, the distribution of REEs in individual FG constituent minerals remains poorly explored. Here, we demonstrate the utility of laser imaging of REE distribution in CAIs by analyzing five FGs found in the Allende CV3 chondrite using multiple‐spot femtosecond laser ablation (msfsLA)‐ICP‐MS. The msfsLA‐ICP‐MS imaging system allows for a rapid acquisition of a wider range of REE distributions than previously achieved by Secondary ion mass spectrometry‐based imaging techniques. Out of the five FGs examined in this study, three showed the homogeneous REE patterns, while the other two indicated variable REE patterns within each FG. These observations presumably reflect differences in the chemical processes experienced by the FGs, and indicate that multi‐step chemical processes were recorded in some of the FGs. The msfsLA‐ICP‐MS imaging technique can characterize the elemental distribution of individual FGs under the comparable spatial resolution with high‐analysis throughput, and thus, it is an effective new method for advancing the taxonomy of FGs, which will improve our understanding of the physicochemical conditions that prevailed in the early solar system.

Can local ecological knowledge establish conservation baselines for the Critically Endangered Blue‐crowned Laughingthrush?

Abstract Designing conservation interventions for rare species can be hindered by a lack of relevant data. Local ecological knowledge (LEK) has potential to provide rapidly collected, cost‐effective data across large spatio‐temporal scales, but has rarely been used as a source of conservation‐relevant information for the Asian Songbird Crisis. The Blue‐crowned Laughingthrush (Pterorhinus courtoisi; BCLT) is a Critically Endangered passerine found only in southeastern China. It is unclear why the species' breeding range and global population are extremely small, as it occurs in human‐occupied forest‐agricultural landscapes similar to surrounding environments across southern China. We conducted systematic range‐wide interviews on BCLT (n = 519) to collect novel information on the species' temporal and spatial distribution, and on potential human activities and landscape changes associated with its presence or absence. Recognition of BCLT was moderate (45.0% of respondents reported sightings), with sightings within the previous 18 months across the study area, within and beyond their known distribution. Over half of known breeding villages were confirmed by LEK data, and nesting was reported from two villages with no previous breeding records. BCLT trapping was reported across the study landscape, mostly from the last decade and associated with trappers from urban centres. BCLT trapping and lack of fengshui forest were associated with sites where BCLTs did not breed. Breeding sites were associated with increases in vegetable gardens over respondents' lifetimes, and other sites within the species' range were associated with decreases in bush/scrub. We demonstrate that LEK can identify potential threats, new breeding sites and landscape changes correlated with species presence or absence for threatened birds affected by the Asian songbird crisis. This study provides the first evidence of ongoing trapping as a threat to BCLT, and remedial measures are urgently required across the region. Read the free Plain Language Summary for this article on the Journal blog.

Distribution of invasive scud, Apocorophium lacustre (Vanhoffen, 1911) in the Illinois Waterway, USA: Do habitat and water quality variables influence spatial distribution and relative abundance?

Apocorophium lacustre – a species of benthic amphipod native to American and European estuaries along the North Atlantic Ocean – has rapidly expanded outside of its native range and is now established in the Illinois, Upper Mississippi, and Ohio river systems, USA. A. lacustre is considered high risk for colonization and disruption of the Laurentian Great Lakes’ benthic communities. To further our understanding of factors influencing A. lacustre distribution and its threat to the Great Lakes, zoobenthic and habitat data were collected from colonization samplers (i.e., rock bags) deployed at 370 sites along the Illinois Waterway. A. lacustre was found in the lower six pools of the Illinois Waterway and was the most abundant amphipod collected in those pools. Our results parallel other studies in that A. lacustre was not observed upstream of Dresden Island Pool, but A. lacustre was found ~11 km farther upstream of any previous records. Generalized linear mixed effects modeling indicated that parameters pertaining to food availability, water quality, and impoundment influenced A. lacustre abundance. Model averaging identified five statistically significant variables: A. lacustre abundance was negatively associated with turbidity, fluorescent dissolved organic matter, and vegetation density and positively associated with temperature and downstream distance (i.e., closer to the next downstream dam). Our findings of what factors influence A. lacustre abundance should be of broad interest to risk assessment and invasion forecasting in other regions where A. lacustre have been or may be introduced.

Landscape influences on thermal sensitivity and predicted spatial variability among brook trout streams in the southeastern USA

AbstractWarming water temperatures as a result of climate change pose a major threat to coldwater organisms. However, the rate of warming is not spatially uniform due to surface‐ground‐water interactions and stream and watershed characteristics. Coldwater habitats that are most resistant to warming serve as thermal refugia and identifying their locations is critical to regional aquatic conservation planning. We quantified the thermal sensitivity of 203 streams providing current and potential habitat for brook trout (Salvelinus fontinalis) across nearly 1000 linear km of their native range in the southern and central Appalachian Mountains region, USA, and characterized their spatial variability with landscape variables available in the National Hydrography Dataset. Using the Bayesian framework, we calculated the maximum slope of the logistic function relating paired weekly mean air temperature and stream temperature as an index of stream thermal sensitivity. Streams differed greatly in thermal sensitivity and those with more resistant water temperature regimes (i.e., thermal refugia) were consistently characterized by southerly latitudes and groundwater input. Landscape variables derived from a principal component analysis explained 16% of the variation in thermal sensitivity, indicating that the existing landscape variables were modestly successful in explaining spatial thermal heterogeneity. Using our model and spatial interpolation, we predicted thermal sensitivity at 8695 stream segments potentially suitable for brook trout in the study region. Thermal refugia were more common southward presumably due to higher elevations, but elsewhere they were also clustered at finer spatial scales. Our analysis informs prioritizing habitat conservation and restoration of this native salmonid and other aquatic organisms that depend on coldwater habitats in a warming world.

The State of Knowledge of CCA Diversity in the Caribbean Coral Reefs

Crustose coralline algae (CCA) are a diverse and ecologically important species found in most of the world’s oceans. The current lack of taxonomic knowledge and relative abundance compromises our ability to predict species diversity numbers and, thus, their ecological roles and impacts on coral reefs. To gather a better understanding of the state of knowledge of crustose coralline algae taxonomy in the Caribbean, 107 different research papers, and other primary and secondary literature were studied; any source with taxonomical information, species identification, or genetic markers for identification was recorded. All Genebank codes were collected and sorted by supposed species marker and then ran through the National Center of Biotechnology Information. The location these genetic markers were gathered from was compared to the natural habitat range of the species, based on the Algaebank habitat description. Of the supposed 83 described species of crustose algae in the Caribbean, based on morphological characteristics, only 24 total were confirmed by DNA markers. This leaves at least 59 species of CCA to be confirmed in the Caribbean Sea with molecular markers. This indicates the importance of DNA barcode survey studies to assess the accurate diversity of this group in the region. With this limited knowledge apparent, it should be seen that a CCAs phylogenetic and taxonomical review must be done. An in-depth assessment should be conducted on CCA collections to identify the Caribbean species correctly and thus know their biodiversity in local habitats.

Title: Cross-sectional associations between nutrient intake and tooth decay in older Australian men: The Concord Health and Ageing in Men Project.

Poor nutrition is a risk factor for dental decay in younger people. However, except for sugar it is unclear if this is true in older age groups. The aim of this study was to analyze the possible associations between overall dietary intake of nutrients and diet quality and presence of dental decay in community dwelling older men. A cross-sectional analysis of a longitudinal study with a standardized validated diet history assessment and comprehensive oral health examination in 520 community dwelling men (mean age: 84 years) participating in the Concord Health and Ageing in Men Project. Nutrient Reference Values (NRVs) were used to determine if individual micronutrients and macronutrients were meeting recommendations. Acceptable Macronutrient Distribution Ranges (AMDR) were attained for fat and carbohydrate intakes and were incorporated into a dichotomous variable to determine if the participants were consuming a high fat and low carbohydrate diet. Diagnosis of coronal caries was based on visual criteria and inspection and was completed on each of the five coronal surfaces. Root surface caries was textual changes across four root surfaces. This diagnosis was used to categorize participants by presence and severity of coronal and root caries. Adjusted logistic regression showed not meeting the recommended intakes for thiamin (odds ratio (OR): 2.32 95% confidence interval (CI) 1.15 - 4.67), and zinc (OR: 3.33, 95% CI 1.71 - 6.48) were associated with presence of severe root decay. Adjusted analysis also showed that participants who were outside the recommended AMDR for fat (OR: 0.61, 95% CI 0.38 - 0.98), and those who consumed a high fat and low carbohydrate diet (OR: 0.56, 95% CI 0.35 - 0.91) were less likely to have coronal tooth decay. Our study shows associations between micronutrients and macronutrients and coronal and root surface decay. Although this study cannot prescribe causality or be generalized to all older adults, diet has a possible association with dental decay in older men.

Extralimital terrestrials: A reassessment of range limits in Alaska's land mammals.

Understanding and mitigating the effects of anthropogenic climate change on species distributions requires the ability to track range shifts over time. This is particularly true for species occupying high-latitude regions, which are experiencing more extreme climate change than the rest of the world. In North America, the geographic ranges of many mammals reach their northernmost extent in Alaska, positioning this region at the leading edge of climate-induced distribution change. Over a decade has elapsed since the publication of the last spatial assessments of terrestrial mammals in the state. We compared public occurrence records against commonly referenced range maps to evaluate potential extralimital records and develop repeatable baseline range maps. We compared occurrence records from the Global Biodiversity Information Facility for 61 terrestrial mammal species native to mainland Alaska against a variety of range estimates (International Union for Conservation of Nature, Alaska Gap Analysis Project, and the published literature). We mapped extralimital records and calculated proportions of occurrences encompassed by range extents, measured mean direction and distance to prior range margins, evaluated predictive accuracy of published species models, and highlighted observations on federal lands in Alaska. Range comparisons identified 6,848 extralimital records for 39 of 61 (63.9%) terrestrial mainland Alaskan species. On average, 95.5% of Alaska Gap Analysis Project occurrence records and ranges were deemed accurate (i.e., > 90.0% correct) for 31 of 37 species, but overestimated extents for 13 species. The International Union for Conservation of Nature range maps encompassed 68.1% of occurrence records and were > 90% accurate for 17 of 39 species. Extralimital records represent either improved sampling and digitization or actual geographic range expansions. Here we provide new data-driven range maps, update standards for the archiving of museum-quality locational records and offer recommendations for mapping range changes for monitoring and conservation.

Population genomics of the invasive Northern Giant Hornet Vespa mandarinia in North America and across its native range

The northern giant hornet Vespa mandarinia (NGH) is a voracious predator of other insect species, including honey bees. NGH’s native range spans subtropical and temperate regions across much of east and southeast Asia and, in 2019, exotic populations of the species were discovered in North America. Despite this broad range and invasive potential, investigation of the population genomic structure of NGH across its native and introduced ranges has thus far been limited to a small number of mitochondrial samples. Here, we present analyses of genomic data from NGH individuals collected across the species’ native range and from exotic individuals collected in North America. We provide the first survey of whole-genome population variation for any hornet species, covering this species’ native and invasive ranges, and in doing so confirm likely origins in Japan and South Korea for the two introductions. We additionally show that, while this introduced population exhibited strongly elevated levels of inbreeding, these signatures of inbreeding are also present in some long-standing native populations, which may indicate that inbreeding depression alone is insufficient to prevent the persistence of NGH populations. As well as highlighting the importance of ongoing monitoring and eradication efforts to limit the spread of this species outside of its natural range, our data will serve as a foundational database for future genomic studies into introduced hornet populations.

EMC+GD_C: circle-based enhanced motion consistency and guided diffusion feature matching for 3D reconstruction

AbstractRobust matching, especially the number, precision and distribution of feature point matching, directly affects the effect of 3D reconstruction. However, the existing methods rarely consider these three aspects comprehensively to improve the quality of feature matching, which in turn affects the effect of 3D reconstruction. Therefore, to effectively improve the quality of 3D reconstruction, we propose a circle-based enhanced motion consistency and guided diffusion feature matching algorithm for 3D reconstruction named EMC+GD_C. Firstly, a circle-based neighborhood division method is proposed, which increases the number of initial matching points. Secondly, to improve the precision of feature point matching, on the one hand, we put forward the idea of enhancing motion consistency, reducing the mismatch of high similarity feature points by enhancing the judgment conditions of true and false matching points; on the other hand, we combine the RANSAC optimization method to filter out the outliers and further improve the precision of feature point matching. Finally, a novel guided diffusion idea combining guided matching and motion consistency is proposed, which expands the distribution range of feature point matching and improves the stability of 3D models. Experiments on 8 sets of 908 pairs of images in the public 3D reconstruction datasets demonstrate that our method can achieve better matching performance and show stronger stability in 3D reconstruction. Specifically, EMC+GD_C achieves an average improvement of 24.07% compared to SIFT-based ratio test, 9.18% to GMS and 1.94% to EMC+GD_G in feature matching precision.

An analysis of the impact of nanofluids on the cooling effectiveness of pin and perforated heat sinks

In the presented numerical study, the effect of the use of mono and hybrid (CuO/Water at 2% volume concentration and CuO + Fe/Water (1% CuO + 1% Fe)) type nanofluid in heat sinks designed in new geometric structures used to increase the processor cooling performance was investigated. The geometries used are circular, triangular, square, hexagonal, square, and hexagonal, and their perforated structures and their effects on a total of eight geometries were analyzed. In addition to these, the rate of improving the temperature distribution and heat transfer in the heat sink, i.e., the Performance Evaluation Criterion (PEC), was also examined. According to the results obtained, the lowest thermal resistance value is seen in the circular cross-section with Rth = 0.289 K/W, while the highest thermal, i.e., cooling performance is seen in the triangular perforated structure with Rth = 0.63 K/W and at the lowest pressure inlet condition. In terms of temperature distribution, the most uniform distribution was obtained between 311.82 and 308.98 K in the circular section. The most interesting result in terms of the results was the PEC = 1.4 for the triangular hole structure in the heat transfer improvement performance. The main reason for this is that the range of the temperature distribution shown is very high (319–311.5K).

Which Cyclaneusma minus morphotypes are responsible for needle cast of Pinus spp. in Slovakia?

AbstractCyclaneusma needle cast (CNC) is a needle disease which caused deterioration of vitality and reduction in the growth of pines. The disease is caused by the ascomycetous fungus Cyclaneusma minus, which has two well-described morphotypes; C. minus simile and C. minus verum. The distribution and host range of C. minus simile and verum was determined from needle samples and isolates collected throughout Slovakia from 2014 to 2020. Samples from 111 localities, 11 pine host species and 245 trees collected in different types of planting were analysed. It was found, that both morphotypes are present, but C. minus verum is predominantly responsible for CNC in urban and forest plantings in Slovakia. C. minus verum was positively detected in more than 88% of collected samples, whereas C. minus simile was only in four samples from three localities. Morphotype-specific primers were sufficiently sensitive even for new pine-host species. The host range of C. minus simile and C. minus verum was enriched worldwide. C. minus verum was observed in nine host species, whereas C. minus simile was identified only in one. Cyclaneusma niveum was also recorded and its presence was confirmed through DNA sequencing.

Environment, intraspecific lineages and geographic range jointly shape the high morphological variability of Dikerogammarus villosus (Sowinsky, 1894) (Crustacea, Amphipoda): a successful aquatic invader across Europe

AbstractPhenotypic variability is a key factor promoting the establishment and spread of invasive populations in new environments. The Ponto-Caspian region contains a diverse endemic fauna known for its exceptional environmental plasticity, with many species invading European waters. However, the extent to which the environment shapes the phenotypic variability of these successful invaders remains poorly understood. We test to what extent the environment, intraspecific lineage affinity and geographic range interact and shape the variability of ecologically relevant functional morphological traits of the amphipod, Dikerogammarus villosus. Our results show the highest differentiation among environments, with an enhancement of predation-related traits in brackish waters relative to freshwaters. Differentiation among lineages and ranges (native/invaded) was smaller, occurring in traits related to locomotion and food processing. Although we uncovered an overall increase in variability outside the native range, the dynamics of morphological change were lineage-specific: the Western Lineage (invading via the River Danube) underwent a shift towards increased appendage length, while the Eastern Lineage (invading via the River Dnieper) underwent a significant overall morphospace expansion. We conclude that D. villosus exhibits a remarkable morphological variability across Europe that is influenced by the interplay between the environment as well as its evolutionary and invasion history.

Effects of Eucalyptus wood and leaf litter on saproxylic insects in the southeastern United States

Although Eucalyptus is widely planted outside its native range for timber and pulp production, the effects of these exotic plantations on biodiversity relative to native semi-natural forests or plantations of native tree species remain incompletely understood. Here, we compare the diversity of saproxylic beetles (Coleoptera) and true bugs (Hemiptera) between non-native Eucalyptus benthamii Maiden and Cambage (Camden white gum) and native Pinus taeda L. (loblolly pine) stands on the upper Coastal Plain of South Carolina, U.S.A. We sampled insects emerging from logs of both species placed in both stand types after 1, 2, 6, and 12 months in the field. Beetle and true bug richness and diversity were both significantly lower from eucalypt than from pine wood. Moreover, the two communities were compositionally distinct. Whereas pine supported many species of host-specific phloeoxylophagous beetles, most species collected from eucalypts were mycophagous or predatory taxa capable of utilizing a wide range of hosts. Species richness did not differ between logs placed in eucalypt vs. pine stands but Shannon’s diversity was significantly higher in the eucalypt stands, possibly due to greater sun exposure in the latter. Contrary to a previous study, we found no support for the idea that eucalypt litter reduces the diversity of saproxylic insects. Our findings add to the growing body of evidence that non-native plantations are less favorable to biodiversity than those consisting of native tree species.

Dry grasslands and thorn-cushion communities of Armenia: a first syntaxonomic classification

Aim: To provide the first syntaxonomic, plot-based classification of the dry grasslands and thorn-cushion communities in Armenia. Study area: Armenia. Methods: We sampled 111 vegetation plots (10 m2) and recorded environmental and structural parameters. We collected additional 487 relevés from surrounding countries for a broad-scale comparison. We used modified TWINSPAN to derive a syntaxonomic classification system, whose units were then compared among each other regarding species composition, structure, site conditions and distribution. Results: The classification of Armenian vegetation plots resulted in a 12-cluster solution. Unsupervised classification of the broad-scale dataset yielded five main groups, which were used for the high-level syntaxonomic assignments of the Armenian data. We assigned about half of the plots of the Armenian dataset to the Festuco-Brometea, while the remaining represented a potential new class, preliminarily called “Ziziphora tenuior-Stipa arabica grasslands”. Most of the syntaxa below class level are new to science, therefore we provide formal descriptions of three orders (Plantagini atratae-Bromopsietalia variegatae, Onobrychido transcaucasicae-Stipetalia pulcherrimae, Cousinio brachypterae-Stipetalia arabicae), four alliances (Acantholimono caryophyllacei-Stipion holosericeae, Artemision fragrantis, Onobrychido michauxii-Stipion capillatae, Onobrychido transcaucasicae-Stipion pulcherrimae) and six associations. We found significant differences in the topographic, climatic and soil characteristics, and structural parameters, species life forms and distribution range types between the grassland types at different syntaxonomic levels. The mean species richness was 47.3 (vascular plants: 46.8, bryophytes: 0.4, lichens: 0.1). Conclusions: We found remarkable differences of the Armenian dry grasslands from the previously known units and described most of the higher syntaxa and all the associations as new to science. Our study provides arguments for a potential new class of Ziziphora tenuior-Stipa arabica grasslands separate both from the Euro-Siberian Festuco-Brometea and the Anatolian Astragalo-Brometea. Finally, we found plot scale richness of vascular plants clearly above the Palaearctic average of dry grasslands and that of non-vascular plants clearly below, which calls for further biodiversity analyses. Taxonomic reference: Euro+Med (2023) for vascular plants, Hodgetts et al. (2020) for bryophytes, Nimis et al. (2018) for lichens except for Xanthoparmelia camtschadalis (Ach.) Hale. Abbreviations: EDGG = Eurasian Dry Grassland Group; DCA = detrended correspondence analysis; ICPN = International Code of Phytosociological Nomenclature (Theurillat et al. 2021); TWINSPAN = two-way indicator species analysis.

Assessment of hydrological baseline condition and its alteration in Athabasca River Basin, Canada

Study regionAthabasca River Basin (ARB), Canada. Study focusThis study aimed to characterize the flow regime of the ARB, a basin with diverse hydroclimatic and geological characteristics. Forty-two different flow indicators from the Indicators of Hydrological Alteration (IHA) and Cold regions Hydrological Indicators of Change (CHIC) were employed. The natural range of these indicators was established for the baseline period (1961–1990), and subsequent alterations during the recent period (1991–2020) were systematically examined. Principal Component Analysis (PCA) was applied to identify pivotal indicators shaping the basin's flow regime. In addition, trends of key indicators were examined at eight distinct locations within the basin. New hydrological insights for the study regionThe findings indicate spatiotemporal variation between the basin's upper and lower parts. The upstream region exhibited an earlier peak flow (9 days), an earlier ice break-up (17 days), and a shorter ice cover duration (22 days) compared to the downstream region. Increased winter and spring flow have led to an augmentation of annual flow by 3.8 % in the upper region. In contrast, downstream flow experienced a decline throughout the year (11.38 %), which was found to be statistically significant at a rate of 3.24 m3/s/year. Alteration analysis revealed a shift toward the 'low category' (below their defined baseline range) for most indicators in the recent period, underscoring a transition towards a diminishing flow regime, with an overall alteration ranging at low to moderate levels (19–38 %). Late summer flow reduction (8–25 %) can have critical implications, given the rising water demand in the basin. The study identified eleven key indicators encapsulating the basin's flow regime variability range. It was found that ice cover, its break-up, and spring freshet significantly influence the flow regime of the basin. The findings from this study will assist decision-makers in making more informed decisions for the holistic management of water resources in the basin.

Widespread establishment of adventive populations of Leptopilina japonica (Hymenoptera, Figitidae) in North America and development of a multiplex PCR assay to identify key parasitoids of Drosophila suzukii (Diptera, Drosophilidae)

In recent years, there has been an increase in the adventive establishment and spread of parasitoid wasps outside of their native range. However, lack of taxonomic tools can hinder the efficient screening of field-collected samples to document the establishment and range expansion of parasitoids on continent-wide geographic scales. Here we report that Leptopilina japonica (Hymenoptera, Figitidae), a parasitoid of the globally invasive fruit pest Drosophila suzukii (Diptera, Drosophilidae), is now widespread in much of North America despite not having been intentionally introduced. Surveys in 2022 using a variety of methods detected L. japonica in 10 of 11 surveyed USA States and one Canadian Province where it was not previously known to occur. In most surveys, L. japonica was the most common species of D. suzukii parasitoid found. The surveys also resulted in the detection of Ganaspis cf. brasiliensis (Hymenoptera, Figitidae), the recently-released biological control agent of D. suzukii, in six USA States where it had not previously been found. These new detections are likely a result of intentional biological control introductions rather than spread of adventive populations. A species-specific multiplex PCR assay was developed as a rapid, accurate and cost-effective method to distinguish L. japonica, G. cf. brasiliensis, the closely-related cosmopolitan parasitoid Leptopilina heterotoma (Hymenoptera, Figitidae) and other native parasitoid species. This dataset and the associated molecular tools will facilitate future studies of the spread and ecological impacts of these introduced parasitoids on multiple continents.

Characterization and functional evidence for Orf2 of Streptomyces sp. 139 as a novel dipeptidase E

Aspartyl dipeptidase (dipeptidase E) can hydrolyze Asp-X dipeptides (where X is any amino acid), and the enzyme plays a key role in the degradation of peptides as nutrient sources. Dipeptidase E remains uncharacterized in Streptomyces. Orf2 from Streptomyces sp. 139 is located in the exopolysaccharide biosynthesis gene cluster, which may be a novel dipeptidase E with “S134-H170-D198” catalytic triad by sequence and structure comparison. Herein, recombinant Orf2 was expressed in E. coli and characterized dipeptidase E activity using the Asp-ρNA substrate. The optimal pH and temperature for Orf2 are 7.5 and 40 ℃; Vmax and Km of Orf2 are 0.0787 mM·min−1 and 1.709 mM, respectively. Orf2 exhibits significant degradation activities to Asp-Gly-Gly, Asp-Leu, Asp-His, and isoAsp-Leu and minimal activities to Asp-Pro and Asp-Ala. Orf2 contains a Ser-His-Asp catalytic triad characterized by point mutation. In addition, the Asp147 residue of Orf2 is also proven to be critical for the enzyme’s activity through molecular docking and point mutation. Transcriptome analysis reveals the upregulation of genes associated with ribosomes, amino acid biosynthesis, and aminoacyl-tRNA biosynthesis in the orf2 mutant strain. Compared with the orf2 mutant strain and WT, the yield of crude polysaccharide does not change significantly. However, crude polysaccharides from the orf2 mutant strain exhibit a wider range of molecular weight distribution. The results indicate that the Orf2 links nutrient stress to secondary metabolism as a novel dipeptidase E.Key points• A novel dipeptidase E with a Ser-His-Asp catalytic triad was characterized from Streptomyces sp. 139.• Orf2 was involved in peptide metabolism both in vitro and in vivo.• Orf2 linked nutrient stress to mycelia formation and secondary metabolism in Streptomyces.