Northern Sites Research Articles

Contrasting patterns of water use efficiency and annual radial growth among European beech forests along the Italian peninsula

Tree mortality and forest dieback episodes are increasing due to drought and heat stress. Nevertheless, a comprehensive understanding of mechanisms enabling trees to withstand and survive droughts remains lacking. Our study investigated basal area increment (BAI), and δ13C-derived intrinsic water-use-efficiency (iWUE), to elucidate beech resilience across four healthy stands in Italy with varying climates and soil water availability. Additionally, fist-order autocorrelation (AR1) analysis was performed to detect early warning signals for potential tree dieback risks during extreme drought events. Results reveal a negative link between BAI and vapour pressure deficit (VPD), especially in southern latitudes. After the 2003 drought, BAI decreased at the northern site, with an increase in δ13C and iWUE, indicating conservative water-use. Conversely, the southern sites showed increased BAI and iWUE, likely influenced by rising CO2 and improved water availability. In contrast, the central site sustained higher transpiration rates due to higher soil water holding capacity (SWHC). Despite varied responses, most sites exhibited reduced resilience to future extreme events, indicated by increased AR1. Temperature significantly affected beech iWUE and BAI in northern Italy, while VPD strongly influenced the southern latitudes. The observed increase in BAI and iWUE in southern regions might be attributed to an acclimation response.

Variability in molecular composition and optical absorption of atmospheric brown carbon aerosols in two contrasting urban areas of China

Atmospheric brown carbon (BrC) aerosols were investigated at two urban sites in southern (Hefei) and northern (Shijiazhuang) China during summer and winter of 2019–2020 to explore regional variability in their compositional and optical properties. Organic matter in ambient PM2.5 samples were characterized at molecular level using ultrahigh performance liquid chromatography coupled with a diode array detector and an Orbitrap mass spectrometer. Although the molecular composition of organic aerosols varied substantially over different ambient environments, they were mainly composed by CHO and CHON species in positive ionization mode while CHO and CHOS species in negative mode. The mass absorption coefficients of BrC aerosols at wavelength range 250–450 nm were relatively higher for winter samples in both cities and for Shijiazhuang samples in both seasons, partly attributed to the higher concentration levels of anthropogenic air pollutants in these environments. The absorption Ångström exponents further revealed that BrC aerosols in winter seasons and in Shijiazhuang had a greater capacity of absorption at shorter wavelengths. A total of 26 BrC species with strong absorption were unambiguously identified from different environments, which mainly consisted of CHO, CHON, and CHN species and had higher degrees of unsaturation and lower degrees of oxidation. The presence and abundance of these BrC species varied dynamically across the seasons and cities, with a greater number of species presented in the winter of Shijiazhuang. The BrC species together contributed 12–26 % in the total absorbance of light-absorbing organic components at 250–450 nm. This study highlights the regional differences in BrC properties influenced by the sources and atmospheric processes, which should be taken into account to assess their climate impacts.

The spatiotemporal distribution of river bank erosion events and their drivers in seasonally frozen regions

River bank erosion supplies sediments to river systems, sustaining many river functions. To properly understand and ultimately model river bank erosion, we have to know the temporal and spatial distributions at which it occurs. This is especially challenging in cold-climate regions where a large variety of processes occur that contribute to river bank erosion. We therefore obtained a one-year dataset, using buried soil sensors, on bank erosion and its forcing parameters with a high temporal resolution to answer the question: what are the temporal and spatial distributions of river bank erosion in cold climate regions and what are the forcing conditions causing these distributions? We measured soil movements at multiple river bank sites throughout Finland and compared the movement times with soil moisture, soil and air temperature and discharge information. This analysis showed that there is no clear temporal distribution of bank movement in the Southernmost investigated site, while in the more Northern field sites soil movement was most frequent around the freezing and thawing periods. At one field site an additional period with an increased frequency of soil movement events is likely caused by reindeer during summer months. This research used a new type of dataset of soil temperature, moisture and movement. This unique dataset allowed us to identify individual soil movement events and helps to better understand river bank erosion and by extension fluvial systems in cold-climates.

Long-Term Assessment of Morocco’s Offshore Wind Energy Potential Using ERA5 and IFREMER Wind Data

Offshore wind energy is a promising resource for renewable energy development. Reanalysed wind data are unmatched by other wind data sources in providing a long-term assessment of wind power potential. In this study, 10 of the selected offshore locations close to the Moroccan coast were used to evaluate the ERA5 wind reanalysis dataset against the IFREMER-blended observational dataset covering the years 1993–2016. The ERA5 wind data’s capacity to represent wind variability in the area was confirmed by the results of the statistical methodologies used. All the reanalysed data scored better at capturing the observed wind variability at the southern sites than at the northern ones, where the wind variability was more complex. In a long-term evaluation from 1981 to 2020, the wind power potential in the Moroccan Atlantic coast was found to be very stable except in the northern sites and between Agadir and Bou Arich. Seven of the 10 sites considered were ranked as promising sites for offshore wind power generation, with wind power densities above 420 W/m2 at 100 m in height. Additionally, the change in signs in the variability toward the middle of the ERA5 record, which was seen at all locations and was also evident in the observations, did not significantly affect the yearly wind power density. However, the seasonal distribution of the latter was modified according to the local features of the seasonal variability.

The direct and indirect radiative effects of sea salt aerosols over the western Pacific using an online-coupled regional chemistry-climate model with a developed sea salt emission scheme

The direct and indirect radiative effects of sea salt aerosols (SSA) over the western Pacific Ocean of East Asia for the year 2014 are investigated by using an online-coupled regional chemistry-climate model (RIEMS-Chem) with a developed sea salt emission scheme (G03SSTRH) by considering the effects of sea surface temperature (SST) and relative humidity (RH) on sea salt generation. Model comparison with observations at coastal and island sites demonstrates the G03SSTRH scheme apparently improve model simulation for sea salt concentration, with the overall model-observation bias for PM10 concentration reduced from 29% to 16% and more evident improvement at northern sites of the western Pacific. It is noteworthy that compared to the experiment with the old SSA emission scheme (G03), the G03SSTRH experiment substantially alters the spatial distribution of mass concentration and radiative effects of sea salt, shifting the maximum value center from the ocean northeast of Japan to the southern parts of the western Pacific with the maximum value increasing to some extent. SSA exerts a negative radiative effect at the top of atmosphere (TOA), in which direct radiative effect (DRESSA) dominates over indirect radiative effect (IRESSA) in the western Pacific. The oceanic and annual mean DRESSA, IRESSA, and total radiative effect (TRESSA) are estimated to be −1.22 W/m2, −0.46 W/m2, and −1.65 W/m2, respectively, from the G03SSTRH experiment, which are 16%, 5%, and 12% stronger than those from the G03 experiment, and the seasonal mean DRESSA in G03SSTRH are approximately 45% and 32% higher than those in G03 in summer and autumn. Distinct seasonality of SSA radiative effects is revealed in the G03SSTRH experiment, showing stronger DRESSA and IRESSA in summer and autumn than those in spring and winter, in marked contrast to the little seasonality in the G03 experiment. This study provides a comprehensive regional estimation of radiative effects induced by SSA and reveals the significant effect of different SSA emission schemes on both mass concentration, radiative effects and seasonal variation of SSA over the western Pacific.

Abstract B030: DNA methylation profiling identifies subset of low-grade endometrial neoplasms with poor response to progestin therapy

Abstract Purpose: We aimed to investigate the DNA methylation profile of low-grade endometrial neoplasms before and after progestin therapy. Methods: This is a retrospective cohort of patients with endometrial intraepithelial neoplasia/atypical hyperplasia (EIN/AH) and grade 1 endometrial endometrioid carcinoma (EEC) treated with progestin therapy. DNA was extracted from 24 formalin-fixed paraffin-embedded (FFPE) tumors before and 19 tumors after progestin therapy (median interval between specimens: 12.1 months). Methylation profiling was performed using the Illumina Infinium Methylation EPIC array. Laser-capture microdissection was used to enrich samples with low tumor content. Results: Twenty-four patients with a median age of 38 years were included. Majority of patients were nulligravid (58%), and self-identified as non-Hispanic (83%) and white (42%). Ten patients had a diagnosis of EIN/AH, while 14 were grade 1 EEC. Ten cases showed complete response, 7 partial responses, 8 showed no response between the pre- and post-treatment samples. Ten patients had regression of disease on follow-up, while 9 showed persistent tumor. In 5 patients, clinical outcome could not be assessed due to short time of exposure (<6 months). Unsupervised clustering based on top 3,000 differentially methylated sites (DMS) in 24 pre-treated tumors identified 2 different groups. Cluster 1 (n= 11) was composed of significantly older patients (p=0.047; median age: 39 vs 37 years) and more likely to have EEC on histologic examination (p=0.016; 100% vs 54%). Tumors in Cluster 1 were more likely to show absence of pathologic response following progestin therapy (p= 0.038; 55% vs 8%). Although no statistical significance was reached regarding clinical outcome (p=0.2), patients in Cluster 1 showed regression of disease in only 29% of cases (2/7), while in Cluster 2, 67% of patients showed regression of tumor (8/12). There was no difference regarding gravidity, race/ethnicity, body mass index, type of progestin, and follow-up time. KEGG pathways analysis revealed that the most significantly different pathways between the 2 clusters were: maturity onset diabetes of young, neuroactive ligand-receptor interaction, and signaling pathways regulating pluripotency of stem cells. Pairwise differential DNA methylation analysis between 15 pairs of pre- and post-treatment samples that passed quality control showed a hypermethylation effect of progestin therapy in the majority of DMS, including sites in open sea, northern and southern shores and shelves. Although there were sites in CpG islands with a hypermethylation pattern after treatment, progestin therapy had a predominantly hypomethylation effect on CpG islands. The gene set enrichment based on DMS showed significant change in genes mostly related to cell-cell adhesion following progestin therapy. Conclusion: DNA methylation profiling identifies a subset of EIN/AH and grade 1 EEC with poor response to progestin therapy. The methylation landscape of these low-grade neoplasms undergoes changes after progestin treatment. Citation Format: Lawrence H. Lin, Kyriaki Founta, Nyasha Chambwe, Deborah F. DeLair. DNA methylation profiling identifies subset of low-grade endometrial neoplasms with poor response to progestin therapy [abstract]. In: Proceedings of the AACR Special Conference on Endometrial Cancer: Transforming Care through Science; 2023 Nov 16-18; Boston, Massachusetts. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(5_Suppl):Abstract nr B030.

Analysing direct air capture for enabling negative emissions in Germany: an assessment of the resource requirements and costs of a potential rollout in 2045

Direct air capture (DAC) combined with subsequent storage (DACCS) is discussed as one promising carbon dioxide removal option. The aim of this paper is to analyse and comparatively classify the resource consumption (land use, renewable energy and water) and costs of possible DAC implementation pathways for Germany. The paths are based on a selected, existing climate neutrality scenario that requires the removal of 20 Mt of carbon dioxide (CO2) per year by DACCS from 2045. The analysis focuses on the so-called “low-temperature” DAC process, which might be more advantageous for Germany than the “high-temperature” one. In four case studies, we examine potential sites in northern, central and southern Germany, thereby using the most suitable renewable energies for electricity and heat generation. We show that the deployment of DAC results in large-scale land use and high energy needs. The land use in the range of 167–353 km2 results mainly from the area required for renewable energy generation. The total electrical energy demand of 14.4 TWh per year, of which 46% is needed to operate heat pumps to supply the heat demand of the DAC process, corresponds to around 1.4% of Germany's envisaged electricity demand in 2045. 20 Mt of water are provided yearly, corresponding to 40% of the city of Cologne‘s water demand (1.1 million inhabitants). The capture of CO2 (DAC) incurs levelised costs of 125–138 EUR per tonne of CO2, whereby the provision of the required energy via photovoltaics in southern Germany represents the lowest value of the four case studies. This does not include the costs associated with balancing its volatility. Taking into account transporting the CO2 via pipeline to the port of Wilhelmshaven, followed by transporting and sequestering the CO2 in geological storage sites in the Norwegian North Sea (DACCS), the levelised costs increase to 161–176 EUR/tCO2. Due to the longer transport distances from southern and central Germany, a northern German site using wind turbines would be the most favourable.

Dietary flexibility of the greater bamboo lemur (Prolemur simus), a specialized feeder, in eastern Madagascar.

The degree of dietary flexibility in primates is species specific; some incorporate a wider array of resources than others. Extreme interannual weather variability in Madagascar results in seasonal resource scarcity which has been linked to specialized behaviors in lemurs. Prolemur simus, for example, has been considered an obligate specialist on large culm bamboo with >60% of its diet composed of woody bamboos requiring morphological and physiological adaptations to process. Recent studies reported an ever-expanding list of dietary items, suggesting that this species may not be an obligate specialist. However, long-term quantitative feeding data are unavailable across this species' range. To explore the dietary flexibility of P. simus, we collected data at two northern sites, Ambalafary and Sahavola, and one southern site, Vatovavy, from September 2010 to January 2016 and May 2017 to September 2018, respectively. In total, we recorded 4022 h of behavioral data using instantaneous sampling of adult males and females from one group in Ambalafary, and two groups each in Sahavola and Vatovavy. We recorded 45 plant species eaten by P. simus over 7 years. We also observed significant differences in seasonal dietary composition between study sites. In Ambalafary, bamboo was the most frequently observed resource consumed (92.2%); however, non-bamboo resources comprised nearly one-third of the diet of P. simus in Sahavola and over 60% in Vatovavy. Consumption of all bamboo resources increased during the dry season at Ambalafary and during the wet season at Vatovavy, but never exceeded non-bamboo feeding at the latter. Culm pith feeding was only observed at Ambalafary, where it was more common during the dry season. We identify P. simus as a bamboo facultative specialist capable of adjusting its feeding behavior to its environment, indicating greater dietary flexibility than previously documented, which may enable the species to survive in increasingly degraded habitats.

Measurements of biologically effective solar radiation using erythemal weighted broadband meters.

In this paper, we describe conversion factors (CF) for the calculation of biologically effective irradiances (BEI) from erythemal irradiance for three effects: photosynthesis of previtamin D3, psoriasis healing, and inactivation of the SARS-Cov-2 virions. CFs were empirically derived from measurements of spectral solar ultraviolet (UV) radiation during all sky conditions at four mid-latitude sites in the Northern Hemisphere, namely Aosta, Belsk, Reading, and San Diego. These CFs were found to depend on solar zenith angle (SZA) and total column ozone, but are largely independent (within ± 5% for SZA < 60°) of local conditions such as surface albedo, visibility and other local atmospheric patterns. The values of these empirical CFs are consistent with analytical CFs derived with radiative transfer calculations (model FastRT) for clear-sky and overcast conditions. To validate these analytical CFs, one-hour radiant exposures for the three biological effects were calculated from erythemal measurements at Reading between 2012 and 2021 and compared with similar exposures calculated directly from the spectral UV measurements. The two datasets agreed within 10% for SZA < 65°, demonstrating the utility of the conversion method. These results suggest that the proposed analytical CFs can be used with confidence to estimate radiant exposures for the three biological effects from measurements of the UV Index at any northern mid-latitude site.

Ecotypic variation in multiple traits of European beech: selection of suitable provenances based on performance and stability

Induced by climate change associated disturbances and further promoted by changes in forest management, the proportion of European beech, a highly competitive climax species, is increasing in Central Europe. However, its climatic stability is questioned by the recent loss of vitality. In this regard, the evaluation of seed sources used for reforestation receives great attention. Here, we present a multi-trait evaluation of height, basal area and stem quality assessed over 25 years for 85 provenances grown at three sites in northern, western and eastern Germany. Considerable provenance differentiation exists, explaining 21% (proportion of trees with acceptable stem form) to 45% (basal area) of the variance on single sites and 20 to 39% across sites, while provenance by environment interactions are absent. On the landscape level, this results in distinct patterns with spatially adjacent provenances showing a similar trait expression. These patterns are highly similar for height and basal area but divergent for stem form. They could be directly linked to geographic variables with multivariate regression tree analysis that captured 58% of the phenotypic variation, delineating eleven ‘ecotypes’ shaped by local adaptation. A selection based on two multi-trait indices gives highly concordant results. Particularly, the intermediate elevations of the central highlands in Western Germany host highly suitable provenances. Lower elevation provenances from continental climates in the south-east profit from the transfer to favorable growing conditions. Since the majority of provenances was already exposed to elevated temperatures compared to their origin during the observation period, this study gives a first indication for the potential benefits of assisted migration facing climate change.

Tracing the Maternal Line in Glacial–Interglacial Migrations of Populus tremuloides: Finding Trees for Future Sustainable Forests by Searching in the Past

Maintaining and planting sustainable forests is fundamental in perpetuating the essential functions of these ecosystems. A central aspect of managing forests for future resilience is the consideration of past migration and evolution of trees using genetic and genomic data to ensure that functionally appropriate diversity is conserved and utilized. In our study, we generated and compared genetic and genomic data from the plastome to better understand phylogeography and molecular evolution in the tree species Populus tremuloides (aspen). With these analyses, we found evidence of divergence and migration between northern and southern sites. Additionally, evidence of deep incomplete plastome sorting across the Salicaceae was found when examining insertion–deletion (indel) sites associated with DNA repair. By examining these indels in plastomic genes with introns across Salicaceae, we found a strong correlation between the abundance of DNA repair with genomic position and transcript abundance. From our findings, we conclude that previously ignored plastomic data are essential in understanding phylogeography and the evolution of key metabolic processes for improved aspen forest planning. Given the propensity of aspen forests to host high levels of biodiversity, rapidly sequester carbon, absorb excess nitrogen, and efficiently regulate snowmelt, improvements to planning and conservation will be highly impactful.

Combining disturbance and competition to control creeping perennial weeds in a field study on three northern European sites

Controlling creeping perennial weeds is challenging throughout all farming systems. The present study distinguished and explored three different methods to control them non-chemically: disturbance with inversion, disturbance without inversion, and competition. Focusing on Cirsium arvense, Elymus repens, and Sonchus arvensis, we conducted a field study (2019–2021) at three northern European sites in Germany, Finland, and Norway. We investigated the effects of the control methods ploughing (inversion disturbance), root cutting (non-inversion disturbance), and cover crops (competition) alone. Root cutting was conducted using a prototype machine developed by “Kverneland”. Eight treatments were tested in factorial designs adapted for each site. Control methods were applied solely and combined. Response variables after treatments were aboveground weed biomass and grain yield of spring cereals. The control method of ploughing was most effective in reducing weed biomass compared to root cutting or cover crops. However, compared to the untreated control, a pronounced additive effect of root cutting and cover crops occurred, reducing weed biomass (−57.5%) similar to ploughing (−66%). Pooled over sites, the response was species-specific, with each species showing a distinct reaction to both control methods. C. arvense was most susceptible to root cutting, followed by E. repens, while S. arvensis showed no susceptibility. Crop yield losses were prevented compared to untreated plots by ploughing (+60.57%) and root cutting (+30%), but not by cover crops. We conclude that the combination of non-inversion disturbance and competition is a promising strategy to reduce the reliance on herbicides or inversion tillage in the management of perennial weeds.

Low Genetic Variability of the Tundra Vole in Lithuania.

The distribution and spread of the tundra vole (Alexandromys oeconomus) in Lithuania have been documented over the last 70 years, but the genetic diversity of the species has not been studied. In this study, we examined A. oeconomus trapped in three sites in northern and western Lithuania using mtDNA sequence analysis of the cytb and control region. The western and northern sites are separated by anthropogenic landscape barriers. The western site is subject to regular spring flooding. Phylogenetic analyses of the studied individuals placed them in the Central European phylogroup, suggesting that Lithuanian A. oeconomus originated from northeastern Poland. In Lithuania, the genetic diversity of A. oeconomus at both mtDNA loci was relatively low (Hd < 0.6, π < 0.002) compared to that found in other European samples (Hd = 0.833-0.958; π = 0.00402-0.01552). Individuals analyzed in Lithuania were genetically different from samples collected in Poland and Northern Europe (ΦST > 0.15, p < 0.05). The genetic divergence between the western and northern samples of A. oeconomus in Lithuania, together with the low genetic variability among the voles studied, provides new insights into the phylogeography of the species and the influence of barriers on the colonization of the country.

The prevalence of HDV among HBsAg-positive populations with and without HIV-1 in China

BackgroundExisting research has provided evidence of changes in hepatitis delta virus (HDV) prevalence worldwide. This study aimed to investigate the prevalence and molecular characteristics of HDV to elucidate its spread in China. MethodsA total of 3,000 samples were collected from 2,241 HBV monoinfections and 759 HBV/HIV-1 coinfections across 13 sites in northern, southern, western, and southwestern China. Serological and virological prevalence were determined by detecting anti-HDV antibodies and HDV RNA. ResultsThe study revealed a 2.63% (95% CI: 2.06–3.21) seroprevalence of HDV among HBV infections in China, exhibiting regional variation. HDV seroprevalence was notably higher at 7.91% (95% CI: 5.98–9.83) in HBV and HIV-1 coinfections. Region and HIV-1 infection were identified as risk factors for HDV infection. Virological prevalence was 0.67% (95% CI: 0.38–0.96) in HBV infections and 2.24% (95% CI: 1.18–3.29) in HBV/HIV-1 coinfections. The predominant HDV genotype in China was HDV-2a, followed by HDV-1. Participants with anti-HDV positivity demonstrated significantly higher proportions of abnormal liver dysfunction and elevated HBV DNA load (P < 0.001) compared to anti-HDV-negative participants. ConclusionsThis study highlights the HDV epidemic in China, sheds light on its geographical distribution and high-risk populations, and provides insights for developing strategies to manage the spread of HDV in the country.

Spatio-temporal interactions between the red fox and the wolf in two contrasting European landscapes

Relationships among carnivore species are complex, potentially switching from competition to facilitation on a context-dependent basis. Negative associations are predicted to increase with latitude, due to limited resources emphasising competition and/or intra-guild predation. Accordingly, a stronger negative correlation between large- and meso-carnivore abundances should be expected at higher latitudes, with a substantial spatio-temporal partitioning favouring interspecific coexistence. Human presence may influence spatio-temporal relationships between (meso)carnivore species, as it can be perceived as a risk factor, but anthropogenic food can also provide an important additional food resource. Using camera-trap data, we studied the spatio-temporal associations between two of the most widespread carnivores in Europe, i.e., the red fox and wolf. We compared their monthly/daily spatio-temporal partitioning between two different landscapes: Białowieża Primeval Forest (Poland) and the Mediterranean Maremma Regional Park (Italy). We predicted a stronger interspecific partitioning, as well as more attraction of red foxes to humans in the northern site (Poland). Temporal activity patterns of the two carnivores overlapped in both sites, and their detection rates were positively associated, even though in weaker way in Poland. We observed a positive spatial association of red foxes with human activity in Białowieża, but not in Maremma. This association occurred only at a monthly temporal scale and disappeared at a daily scale, suggesting some disturbance in the shorter term. Our results provided partial support to our predictions and suggest that, despite the ecological differences between our study areas, only weak differences in wolf-fox relations were observed, suggesting that red fox responses to wolves may be relatively comparable over large spatial scales.

Foredune‐forming grass and plant diversity show contrasting responses along the southeastern United States coast after hurricane disturbance

AbstractAimsLatitudinal gradients in plant communities are well studied, yet how these fundamental ecological patterns influence ecosystem recovery after extreme weather events remains largely unknown. In coastal foredunes, we investigated how the cover of a key dune‐building grass (Uniola paniculata), vegetation diversity and vegetation cover vary along a short latitudinal gradient during recovery from hurricane disturbance.LocationSoutheastern USA.MethodsWe surveyed 24 sites, from central Florida to north Georgia (&gt;400 km), four times over 18 months. General linear mixed‐effect models were used to unravel patterns of vegetation responses across latitude.ResultsVegetation properties showed countervailing patterns across the latitudinal gradient. While vegetation richness, functional diversity and total cover generally declined, Uniola cover increased with increasing latitude. Further, the latitude–richness relationship strengthened while the latitude–functional diversity relationship was invariant with increasing time since the hurricane disturbance. Meanwhile, the latitude–Uniola association was seasonally dependent and strongest in the summer. Latitude also influenced diversity–cover relationships: vegetation cover was positively related to species richness at lower latitudes, while it was positively associated with functional diversity only at northern sites. We found no relationship between species richness or functional diversity and increases in cover between time steps; however, recruitment of new species and functional groups was associated with increases in vegetation cover between time steps at northern sites.ConclusionsOur study highlights the temporal dynamism and contrasting patterns along latitudinal gradients exhibited by key engineering species and overall plant diversity in foredunes — a crucial line of coastal protection — exposed to hurricane disturbances. These results suggest a need for greater integration of latitudinal and diversity effects into our understanding of coastal dune resilience. They also highlight the potential benefits of enhancing dune plant biodiversity, particularly in areas where the dune‐building grasses that are classically employed in restoration (e.g., Uniola) are unfavoured, to accelerate the re‐establishment of well‐vegetated dunes.

Microbiome variation at the clam-sediment interface may explain changes in local productivity of Chamelea gallina in the North Adriatic sea

BackgroundThe clam Chamelea gallina is an ecologically and economically important marine species in the Northwestern Adriatic Sea, which currently suffers from occasional, and still unexplained, widespread mortality events. In order to provide some glimpses in this direction, this study explores the connections between microbiome variations at the clam-sediment interface and the nutritional status of clams collected at four Italian production sites along the Emilia Romagna coast, with different mortality incidence, higher in the Northern sites and lower in the Southern sites.ResultsAccording to our findings, each production site showed a peculiar microbiome arrangement at the clam-sediment interface, with features that clearly differentiate the Northern and Southern sites, with the latter also being associated with a better nutritional status of the animal. Interestingly, the C. gallina digestive gland microbiome from the Southern sites was enriched in some health-promoting microbiome components, capable of supplying the host with essential nutrients and defensive molecules. Furthermore, in experiments conducted under controlled conditions in aquaria, we provided preliminary evidence of the prebiotic action of sediments from the Southern sites, allowing to boost the acquisition of previously identified health-promoting components of the digestive gland microbiome by clams from the Northern sites.ConclusionsTaken together, our findings may help define innovative microbiome-based management strategies for the preservation of the productivity of C. gallina clams in the Adriatic Sea, through the identification and maintenance of a probiotic niche at the animal-sediment interface.

Southern pine beetle (Coleoptera: Curculionidae) and its associated insect community: similarities and key differences between northeastern and southeastern pine forests.

We examine consequences of climate-induced range expansion on community composition and diversity within trees attacked by the southern pine beetle (Dendroctonus frontalis Zimmermann). At the northernmost limit of the southern pine beetle range where populations have persisted for multiple years (currently Long Island, NY), we collected and reared bark samples and placed emergence traps on southern pine beetle-attacked pitch pine, Pinus rigida Mill. (Pinales: Pinaceae). From these samples, we quantified southern pine beetle gallery length and emergence as well as the diversity and abundance of all associated insects including known and suspected competitors, predators, and parasitoids. We compared our results to that of historic sampling data (1975-1997) in the core of southern pine beetle's range in the southern United States. Key community members were present in both the northern and southern regions; composition and relative abundances differed markedly. A key predator, the clerid beetle Thanasimus dubius (Fabricius) (Coleoptera: Cleridae), was present in similar densities in both regions. Southern pine beetle infested a greater proportion of the length of the tree bole in the North. This increased tree utilization may be a consequence of a lack of resource competition by Ips De Geer (Coleoptera: Curculionidae) engraver beetles, which we found only in very low abundance in the northern sites. We discuss the implications of these results in the context of southern pine beetle range expansion. Continued study of the southern pine beetle community and temporal southern pine beetle dynamics in the North will add to our current knowledge base and aid preservation of rare and ecologically valuable pine barrens of New England.

Local adaptation shapes functional traits and resource allocation in black spruce

Climate change is rapidly altering weather patterns, resulting in shifts in climatic zones. The survival of trees in specific locations depends on their functional traits. Local populations exhibit trait adaptations that ensure their survival and accomplishment of growth and reproduction processes during the growing season. Studying these traits offers valuable insights into species responses to present and future environmental conditions, aiding the implementation of measures to ensure forest resilience and productivity. This study investigates the variability in functional traits among five black spruce (Picea mariana (Mill.) B.S.P.) provenances originating from a latitudinal gradient along the boreal forest, and planted in a common garden in Quebec, Canada. We examined differences in bud phenology, growth performance, lifetime first reproduction, and the impact of a late-frost event on tree growth and phenological adjustments. The findings revealed that trees from northern sites exhibit earlier budbreak, lower growth increments, and reach reproductive maturity earlier than those from southern sites. Late-frost damage affected growth performance, but no phenological adjustment was observed in the successive year. Local adaptation in the functional traits may lead to maladaptation of black spruce under future climate conditions or serve as a potent evolutionary force promoting rapid adaptation under changing environmental conditions.

A comparison of ligatures on gravestones in Scotland, Northern Germany and the French Basque region

Although ligatures have a long history and can be found on a range of artefacts, they are particularly characteristic of gravestone inscriptions of the 17th and 18th centuries in several parts of Western Europe. The grouping of two or more letters as a ligature can be attributed to minimising mason’s costs and workload, or stone brittleness, but it is suggested that their function was primarily a space-saving device. This research, based solely on statistical analysis, suggests that there may be other, possibly more common, reasons as to why they were employed in gravestone inscriptions. Ligatures have an uneven distribution throughout Western Europe. They are especially frequent in gravestone inscriptions from north and south-west Scotland, Northern Germany and the French Basque region. These areas were selected for analysis. Ligatures were recorded from 36 sites in northern and south-western Scotland, 35 sites in Northern Germany and 24 sites in the French Basque region. Frequencies at each site were calculated. The most common ligature in Scotland and north Germany was HE and in the French Basque region it was DE. All ligature frequencies were compared with the frequencies of bigrams in English, German and French to determine whether or not this influenced their frequency in gravestone inscriptions. It was found that there was no evidence of correlation between gravestone ligatures and bigrams in any of the three languages. The possible reasons for the use of ligatures are discussed.