Imprints of ecological processes in the taxonomic core community: an analysis of naturally replicated microbial communities enclosed in oil.

It is widely assumed that a taxonomic core community emerges among microbial communities from similar habitats because similar environments select for the same taxa bearing the same traits. Yet, a core community itself is no indicator of selection because it may also arise from dispersal and neutral drift, i.e. by chance. Here, we hypothesize that a core community produced by either selection or chance processes should be distinguishable. While dispersal and drift should produce core communities with similar relative taxon abundances, especially when the proportional core community, i.e. the sum of the relative abundances of the core taxa, is large, selection may produce variable relative abundances. We analyzed the core community of 16S rRNA gene sequences of 193 microbial communities occurring in tiny water droplets enclosed in heavy oil from the Pitch Lake, Trinidad and Tobago. These communities revealed highly variable relative abundances along with a large proportional core community (68.0 ± 19.9%). A dispersal-drift null model predicted a negative relationship of proportional core community and compositional variability along a range of dispersal probabilities and was largely inconsistent with the observed data, suggesting a major role of selection for shaping the water droplet communities in the Pitch Lake.

Adaptive monitoring in action-what drives arthropod diversity and composition in central European beech forests?

Recent studies suggest that arthropod diversity in German forests is declining. Currently, different national programs are being developed to monitor arthropod trends and to unravel the effects of forest management on biodiversity in forests. To establish effective long-term monitoring programs, a set of drivers of arthropod diversity and composition as well as suitable species groups have to be identified. To aid in answering these questions, we investigated arthropod data collected in four Hessian forest reserves (FR) in the 1990s. To fully utilize this data set, we combined it with results from a retrospective structural sampling design applied at the original trap locations in central European beech (Fagus sylvatica) forests. As expected, the importance of the different forest structural, vegetation, and site attributes differed largely between the investigated arthropod groups: beetles, spiders, Aculeata, and true bugs. Measures related to light availability and temperature such as canopy cover or potential radiation were important to all groups affecting either richness, composition, or both. Spiders and true bugs were affected by the broadest range of explanatory variables, which makes them a good choice for monitoring general trends. For targeted monitoring focused on forestry-related effects on biodiversity, rove and ground beetles seem more suitable. Both groups were driven by a narrower, more management-related set of variables. Most importantly, our study approach shows that it is possible to utilize older biodiversity survey data. Although, in our case, there are strong restrictions due to the long time between species and structural attribute sampling.

Phytoplankton species composition as bioindicator in the largest fragmented channel of the Pearl River, China.

To test the serial discontinuity concept (SDC) predictions in a regulated river ecosystem, environmental parameters and phytoplankton community structure were determined in a subtropical river (China) which was regulated by 11 cascade dams. Our results showed that total phosphorus (TP) and silicate during the wet period in several dams supported the SDC predictions. Variations of phytoplankton species composition in several cascade dams, such as Datengxia (DTX) and Changzhou (CZ), also supported the SDC predictions. Moreover, the stations near the dams showed the maximum or minimum values of total species numbers in each cascade segment. Predictive model indicated that the types of phytoplankton decreased in the middle reaches, conforming to SDC predictions. In the whole system of cascading dams, an increase in silicate concentration and phytoplankton communities in the downstream was also consistent with SDC predictions. Therefore, these findings aligned with the SDC predictions in the aspects of both single dam and whole cascade dam system to some extent. In future research, our aim is to further investigate the effects of cascade damming on additional phytoplankton-related indices in this aquatic ecosystem. We hope to gather more comprehensive data to fully validate the SDC predictions.

Metagenome reveals the possible mechanism that microbial strains promote methanogenesis during anaerobic digestion of food waste.

For better understanding the mechanism of microbial strains promoting methane production, four strains Hungatella xylanolytica A5, Bacillus licheniformis B1, Paraclostridium benzoelyticum C2 and Advenella faeciporci E1 were inoculated into anaerobic digestion systems. After bioaugmentation, the cumulative methane production of A5, B1, C2 and E1 groups elevated by 11.68%, 8.20%, 18.21% and 15.67% compared to CK group, respectively. The metagenomic analysis revealed that the species diversity and uniformity of the experimental groups was improved, and hydrolytic acidifying bacteria, represented by Clostridiaceae, Anaerolineaceae and Oscillospiraceae, and methanogens, such as Methanotrichaceae and Methanobacteriaceae, were enriched. Meanwhile, the abundance of key genes in carbohydrate, pyruvate and methane metabolism was increased in the inoculated groups, providing reasonable reasons for more methane production. The strengthening mechanism of microbial strains in this study offered a theoretical foundation for selecting a suitable bioaugmentation strategy to solve the problems of slow start-up and low methane production in anaerobic digestion.

Species abundance and density of malaria vectors in Western Thailand and implications for disease transmission.

Understanding the dynamics of malaria vectors and their interactions with environmental factors is crucial for effective malaria control. This study investigated the abundance, species composition, seasonal variations, and malaria infection status of female mosquitoes in malaria transmission and non-transmission areas in Western Thailand. Additionally, the susceptibility of malaria vectors to pyrethroid insecticides was assessed. Entomological field surveys were conducted during the hot, wet, and cold seasons in both malaria transmission areas (TA) and non-transmission areas (NTA). The abundance and species composition of malaria vectors were compared between TA and NTA. The availability of larval habitats and the impact of seasonality on vector abundance were analyzed. Infection with Plasmodium spp. in primary malaria vectors was determined using molecular techniques. Furthermore, the susceptibility of malaria vectors to pyrethroids was evaluated using the World Health Organization (WHO) susceptibility test. A total of 9799 female mosquitoes belonging to 54 species and 11 genera were collected using various trapping methods. The number of malaria vectors was significantly higher in TA compared to NTA (P < 0.001). Anopheles minimus and An. aconitus were the predominant species in TA, comprising over 50% and 30% of the total mosquitoes collected, respectively. Seasonality had a significant effect on the availability of larval habitats in both areas (P < 0.05) but did not impact the abundance of adult vectors (P > 0.05). The primary malaria vectors tested were not infected with Plasmodium spp. The WHO susceptibility test revealed high susceptibility of malaria vectors to pyrethroids, with mortality rates of 99-100% at discriminating concentrations. The higher abundance of malaria vectors in the transmission areas underscores the need for targeted control measures in these regions. The susceptibility of malaria vectors to pyrethroids suggests the continued effectiveness of this class of insecticides for vector control interventions. Other factors influencing malaria transmission risk in the study areas are discussed. These findings contribute to our understanding of malaria vectors and can inform evidence-based strategies for malaria control and elimination efforts in Western Thailand.

Seasonal acoustic presence of marine mammals at the South Orkney Islands, Scotia Sea.

Increased knowledge about marine mammal seasonal distribution and species assemblage from the South Orkney Islands waters is needed for the development of management regulations of the commercial fishery for Antarctic krill (Euphausia superba) in this region. Passive acoustic monitoring (PAM) data were collected during the autumn and winter seasons in two consecutive years (2016, 2017), which represented highly contrasting environmental conditions due to the 2016 El Niño event. We explored differences in seasonal patterns in marine mammal acoustic presence between the two years in context of environmental cues and climate variability. Acoustic signals from five baleen whale species, two pinniped species and odontocete species were detected and separated into guilds. Although species diversity remained stable over time, the ice-avoiding and ice-affiliated species dominated before and after the onset of winter, respectively, and thus demonstrating a shift in guild composition related to season. Herein, we provide novel information about local marine mammal species diversity, community structure and residency times in a krill hotspot. Our study also demonstrates the utility of PAM data and its usefulness in providing new insights into the marine mammal habitat use and responses to environmental conditions, which are essential knowledge for the future development of a sustainable fishery management in a changing ecosystem.

Compositional changes at neighborhood and stand scales during recovery of a tropical lowland rainforest after shifting cultivation on Hainan Island, China.

Understanding compositional changes during secondary forest recovery is crucial for effective restoration efforts. While previous research has predominantly focused on shifts in species composition at the stand scale, this study delves into the recovery dynamics in three compositional aspects of location (neighbor distances), size (tree diameters), and species (tree species) at both stand and neighborhood scale. The investigation spans nine chronosequence plots within a tropical lowland rainforest ecosystem after shifting cultivation, including three each for young-secondary forests (18-30 years), old-secondary forests (60 years), and old-growth forests (without obvious human interference). The quantification of location, size, and species composition involved categorized neighbor distances (Near, Moderate, Far-distance), tree diameters (Small, Medium, Large-tree), and tree species (Pioneer, Intermediate, Climax-species) into three groups, respectively. Compositional changes at the stand scale (plot) were directly based on these groups, while at the neighborhood scale, assessment involved combination types of these groups within a neighborhood (comprising three adjacent trees). At the stand scale, neighbor distances shifted from Near to Moderate and Far, tree diameters transitioned from Small to Medium and Large, and tree species of Pioneer gave way to Climax. Meanwhile, at the neighborhood scale, there was a notable decline in the aggregations of Near-distance (N), Small-tree (S), and Pioneer-species (P), while the mixtures of Far and Moderate-distance (F-M), Large and Small-tree (L-S), and Climax and Intermediate-species (C-I) experienced a marked increase. The compositional change exhibited a recovery pattern, with the fastest recovery in neighbor distances, followed by tree diameters and tree species. Moreover, compositional recovery in tree diameters and tree species at the neighborhood scale generally lagged behind that at the stand scale. The study suggests that rapid restoration of secondary forest can be achieved by different targeted cutting according to the recovery stages, aimed at reduce the Pioneer-species, Small-tree and Near-distance in neighborhood. Our findings underscore that analyzing the compositional changes in three aspects at two scales not only provides a profound understanding of secondary forest recovery dynamics, but also offers valuable insights for guiding practices in the restoration of degraded forest ecosystems.

Metal pollution drives earthworm biodiversity in urban lawns.

Urban soils represent hotspots of metallic trace elements (MTEs) pollution. Despite the critical impact of soil organisms on soil ecosystem services, there is limited understanding regarding the effects of MTE levels in urban soils on these organisms. This is particularly surprising considering that earthworms, key organisms for soil ecosystems, are commonly used in MTE toxicity tests. This research investigates the impact of MTE pollution on earthworm communities in lawns within the city of Paris. In this study, we sampled a comprehensive array of earthworm communities, totalling 965 individuals from 13 distinct species belonging to Lumbricus, Aporrectodea, Allolobophora and Octolasion genera. These communities were collected from three different locations within 18 parks. At these sites, we assessed the concentrations of eight metals and metalloids in the soil (As, Cd, Cr, Cu, Zn, Ni, Pb and Hg), along with selenium concentrations and eight fundamental soil parameters, to examine the association between earthworm communities and soil attributes. Median MTE concentrations exceeded recommended statutory limit values by approximately 20 % (0.6 mg/kg Cd), 30 % (36.8 mg/kg Cu), 40 % (122.0 mg/kg Zn), and up to 90 % (0.6 mg/kg Hg and 99.7 mg.kg Pb). Nevertheless, these concentrations exhibited considerable variability both between and within parks, correlating with variations in earthworm community structures. Specifically, our results highlight that Cu concentrations in the soil explain about 6 % of the variation in the assemblage of earthworm species. Our findings underscore the importance of considering MTE pollution levels to enhance our comprehension of earthworm distribution in urban environments and its effects on the ecosystem services provided by urban lawns.

All insects matter: a review of 160 entomology cases from 1993 to 2007 in Switzerland-part I (Diptera).

Necrophagous Diptera are the most important group of insects used for the purposes of forensic entomology. While the most utilized fly family in this context is the family Calliphoridae, there are several other families that can be of great importance during real-case investigations. This article analyzes the necrophagous flies of all families recorded from 160 real cases in Switzerland between 1993 and 2007. A total of 56 species belonging to 16 families was identified with Calliphoridae being the most dominant family (90.63% of all cases), followed by Muscidae (26.25%), Sarcophagidae (19.38%), Phoridae (14.38%), and Fanniidae (12.50%). For specimens that were difficult to identify morphologically, a new PCR primer has been specifically designed for the amplification of a short, informative COI barcode in degraded museum samples of forensically important Diptera taxa. The richest family in terms of species was the family Muscidae with 16 species. Fannia fuscula (Fallen) and Fannia monilis (Haliday) were recorded from human cadavers for the first time. The study highlights the importance of different fly families in forensic investigation, enhancing our comprehension of their prevalence and dispersion in real cases in Central Europe. The results pave the way for additional exploration, especially regarding the involvement of less frequently observed species in forensic entomology.

LandS: Vegetation modeling based on Ellenberg's ecological indicator values.

We present LandS, a new version of the Gras Model. The Gras Model was designed to simulate grassland development at local scales based on Ecological Indicator Values (EIVs) for different grassland management practices. In LandS, we complemented the existing set of EIVs with a second set representing several environmental factors: light, moisture, temperature, soil pH and nitrogen, also known as Ellenberg's EIVs. These new EIVs make the model more versatile and applicable to a wide range of sites across Central Europe. For example, it can be used on sites with dry or moist, acidic or calcareous soils in grassland or forest environments. We have also improved the implementation of the model by introducing version control and moving species and site-specific variables to data input files, so that species sets can be easily swapped for application in new study sites. We demonstrate the use and behavior of the model in two simulation experiments exploring interactions mediated by Ellenberg's EIVs, using input files to apply the model to different landscapes. We also provide detailed guidance on species selection and calibration, and discuss model limitations.•LandS is an improved version of the GraS Model for simulating vegetation development at the local scale.•It includes Ellenberg-like indicator values for environmental variables for inverse prediction of species occurrence and composition.•The model is now flexible enough to be used for study sites throughout Central Europe, using data input files for species initialization.

Simulation and prediction of changes in tree species composition in subtropical forests of China using a nonlinear difference equation system model.

Changes in tree species composition are one of the key aspects of forest succession. In recent decades, significant changes have occurred in the tree species composition of subtropical forests in China, with a decrease in coniferous trees and an increase in broad-leaved trees. This study focuses on Zhejiang Province, located in the subtropical region of China, and utilizes seven inventories from the National Continuous Forest Inventory (NCFI) System spanning 30 years (1989-2019) for modeling and analysis. We categorized tree species into three groups: pine, fir, and broadleaf. We used the proportion of biomass in a sample plot as a measure of the relative abundance of each tree species group. A novel nonlinear difference equation system (NDES) model was proposed. A NDES model was established based on two consecutive survey datasets. A total of six models were established in this study. The results indicated that during the first two re-examination periods (1989-1994, 1994-1999), there was significant fluctuation in the trend of tree species abundance, with no consistent pattern of change. During the latter four re-examination periods (1999-2004, 2004-2009, 2009-2014, 2014-2019), a consistent trend was observed, whereby the abundance of the pine group and the fir group decreased while the abundance of the broad-leaved group increased. Moreover, over time, this pattern became increasingly stable. Although the abundances of the pine group and the fir group have been steadily declining, neither group is expected to become extinct. The NDES model not only facilitates short-term, medium-term, and even long-term predictions but also employs limit analysis to reveal currently obscure changing trends in tree species composition.

Grazing intensity effects on rangeland condition and tree diversity in Afar, northeastern Ethiopia.

This study assessed the effects of different grazing pressures (light, moderate and heavy) on rangeland condition and woody species diversity in northeastern Ethiopia. Rangeland condition was analyzed using common protocols for the assessment of semi-arid rangelands. A total of 4 grasses, 5 herbs, 1 sedge and 14 tree and/or shrub species were identified. Results show that grazing intensity had detrimental effects on condition of the rangeland, and caused undesirable changes in herbaceous species composition. The contribution of undesirable plants to herbaceous aboveground biomass was particularly high (40 %) compared to the 30 % contributed by highly desirable species. Nearly all measures of range condition were negatively affected by grazing. Grass composition, number of seedlings and age distribution, basal and litter cover, soil erosion and compaction decreased significantly as grazing intensity increased. Species richness and diversity (Hill numbers) of woody plants were reduced significantly by grazing. The overall condition of the rangeland was generally poor. The pastoralists perceived that recurring droughts, heavy continuous grazing and inappropriate management interventions, and bush encroachment were the main contributing factors that led to overgrazing and rangeland deterioration in the area. In conclusion, our study shows that livestock grazing in northeastern Ethiopia degrade range condition and woody vegetation, and its effects are sever under moderate and heavy grazing. Management measures such as resting of the rangelands preferably with stock exclusions for 6-12 months or protecting heavily degraded or sensitive areas from livestock activity and reseeding may be the viable options to mitigate declines in range conditions.

Effects of Natural Habitat and Season on Cursorial Spider Assemblages in Mediterranean Vineyards.

Natural habitats adjacent to vineyards are presumed to have a positive effect on the diversity of natural enemies within the vineyards. However, these habitats differ in vegetation structure and seasonal phenology and in turn could affect the species composition of natural enemies. Here, we compared the species richness and diversity and the composition of spider assemblages in several locations within three commercial vineyards and the nearby natural habitats in a Mediterranean landscape in northern Israel. We sampled spiders by means of pitfall traps in early and in late summer. Both the time in the season and the habitat (natural versus vineyard) affected spider species richness and diversity. More species were found in early summer (47) than in late summer (33), and more occurred in the natural habitat (34 species) than in the vineyards (27-31 species). Fifteen species were found exclusively in the natural habitat, and only 11 species were shared by the vineyards and natural habitat, four of which were the most abundant and geographically widely distributed species in the samples. In late summer, spider diversity in the natural habitat was higher than within the vineyards: the spider assemblages in the vineyards became dominated by a few species late in the crop season, while those of the natural habitat remained stable. Overall, the natural habitat differed in assemblage composition from all within-vineyard locations, while the three locations within the vineyard did not differ significantly in assemblage composition. Season (early vs. late summer), however, significantly affected the spider assemblage composition. This study documents the large diversity of spiders in a local Mediterranean vineyard agroecosystem. Over 60% of the known spider families in the region occurred in our samples, highlighting the importance of this agroecosystem for spider diversity and the potential for conservation biocontrol, where natural habitats may be a source of natural enemies for nearby vineyards.

Road Impact on Plant Colonization in the Arid Timanfaya National Park.

Roads have the potential to alter local environmental conditions, such as the availability of water and nutrients, and rapidly create suitable habitats for the establishment of both native and non-native plant species, transforming the ecosystems. This is a challenge in Timanfaya National Park and Los Volcanes Natural Park on Lanzarote Island, protected areas that have experienced primary succession after recent volcanic eruptions. In arid ecosystems, changes in abiotic conditions along roadsides might facilitate colonization and plant growth. We analyzed the effect of roads and road type on plant species composition and richness at a spatiotemporal scale. Vascular plant species were systematically recorded at three distances from the road edge on both sides, across fourteen zones in the wet and dry seasons, for three years. Results showed that there were slight differences on species composition depending on the distance to the road edge, as well as on the zones. Species richness was also determined by the interaction of the position, zones, and season, being higher at the road edge. Furthermore, zones with higher traffic intensity showed a higher presence of both native and non-native species. This study highlights the importance of the awareness about the road impacts on species composition by enhancing the colonization capacity of species while facilitating the entry of invasive ones. Good management practices regarding infrastructures in natural protected areas are crucial for the conservation of their unique flora, landscapes, and natural succession processes.

Response of Aboveground Net Primary Production, Species and Phylogenetic Diversity to Warming and Increased Precipitation in an Alpine Meadow.

The uncertain responses of aboveground net primary productivity (ANPP) and plant diversity to climate warming and increased precipitation will limit our ability to predict changes in vegetation productivity and plant diversity under future climate change and further constrain our ability to protect biodiversity and ecosystems. A long-term experiment was conducted to explore the responses of ANPP, plant species, phylogenetic α-diversity, and community composition to warming and increased precipitation in an alpine meadow of the Northern Tibet from 2014 to 2019. Coverage, height, and species name were obtained by conventional community investigation methods, and ANPP was obtained using observed height and coverage. Open-top chambers with two different heights were used to simulate low- and high-level climate warming. The low- and high-level increased precipitation treatments were achieved by using two kinds of surface area funnel devices. The high-level warming reduced sedge ANPP (ANPPsedge) by 62.81%, species richness (SR) by 21.05%, Shannon by 13.06%, and phylogenetic diversity (PD) by 14.48%, but increased forb ANPP (ANPPforb) by 56.65% and mean nearest taxon distance (MNTD) by 33.88%. Species richness, Shannon, and PD of the high-level warming were 19.64%, 9.67%, and 14.66% lower than those of the low-level warming, respectively. The high-level warming-induced dissimilarity magnitudes of species and phylogenetic composition were greater than those caused by low-level warming. The low- rather than high-level increased precipitation altered species and phylogenetic composition. There were significant inter-annual variations of ANPP, plant species, phylogenetic α-diversity and community composition. Therefore, climate warming and increased precipitation had non-linear effects on ANPP and plant diversity, which were due to non-linear changes in temperature, water availability, and/or soil nutrition caused by warming and increased precipitation. The inter-annual variations of ANPP and plant diversity were stronger than the effects of warming and especially increased precipitation on ANPP and plant diversity. In terms of plant diversity conservation and related policy formulation, we should pay more attention to regions with greater warming, at least for the northern Tibet grasslands. Besides paying attention to the responses of ANPP and plant diversity to climate change, the large inter-annual changes of ANPP and plant diversity should be given great attention because the large inter-annual variation indicates the low temporal stability of ANPP and plant diversity and thus produces great uncertainty for the development of animal husbandry.

Taxonomic Composition and Salinity Tolerance of Macrozoobenthos in Small Rivers of the Southern Arid Zone of the East European Plain.

This study investigated the species composition, distribution, and salinity tolerance of macrozoobenthos in 17 small rivers in the southern arid region of the East European Plain, which are characterized by a small channel gradient, slow-flowing or stagnant water bodies, and a wide range of water salinity, varying between 0.18 and 30 g L-1. In total, 156 taxa were found, among which 66 were Diptera species. The study revealed that the formation of benthic communities in the rivers is influenced by natural factors of the catchment basins, including the flat landscape with sparsely developed relief differentiation, climate aridity, and the widespread occurrence of saline soils and groundwater, largely related to the sedimentation of the ancient Caspian Sea and modern climate changes. These conditions are favorable for the occurrence of lacustrine macrozoobenthic species in freshwater, euryhaline, and halophilic ecological groups. The investigation revealed a decrease in species richness in response to an increase in water salinity. The five identified halophilic species Tanytarsus kharaensis, Glyptotendipes salinus, Cricotopus salinophilus, Chironomus salinarius, and Palpomyia schmidti can be used as indicators of river ecosystem salinization.

Combining Multiple Plant Attributes to Reveal Differences in Community Structure in Two Distant Deserts in Central Asia.

International interest is growing in biodiversity conservation and sustainable use in drylands. Desert ecosystems across arid Central Asia are severely affected by global change. Understanding the changes in a plant community is an essential prerequisite to revealing the community assembly mechanism, vegetation conservation, and management. The knowledge of large-scale spatial variation in plant community structure in different Central Asian deserts is still limited. In this study, we selected the Taukum (TD, Kazakhstan) and the Gurbantunggut (GD, China) deserts as the research area, with similar latitudes despite being nearly 1000 km apart. Thirteen and 15 sampling plots were set up and thoroughly investigated. The differences in community structure depending on multiple plant attributes (individual level: plant height, canopy diameter, and plant volume, and community level: plant density, total cover, and total volume) were systematically studied. TD had a better overall environmental status than GD. A total of 113 species were found, with 68 and 74 in TD and GD, respectively. The number of species and plant attributes was unequally distributed across different families and functional groups between deserts. The values of several plant attributes, such as ephemerals, annuals, dicotyledons, and shrubs with assimilative branches in GD, were significantly lower than those in TD. The Motyka indices of six plant attributes (26.18-38.61%) were higher between the two deserts than the species similarity index (20.4%), indicating a more robust convergence for plant functional attributes. The community structures in the two deserts represented by different plant attribute matrices demonstrated irregular differentiation patterns in ordination diagrams. The most variance in community structure was attributed to soil and climatic factors, while geographic factors had the smallest proportion. Consequently, the community structures of the two distant deserts were both different and similar to an extent. This resulted from the long-term impacts of heterogeneous environments within the same region. Our knowledge is further deepened by understanding the variation in community structure in different deserts on a large spatial scale. This therefore provides valuable insights into conserving regional biodiversity in Central Asia.

Comparison of species composition and community characteristics of Quercus forests on south and north slopes of Taibai Mountain, China.

We examined species composition, community characteristics, diversity, and community similarity of five Quercus communities composed of three Quercus species (Q. variabilis, Q. aliena var. acutiserrata, Q. wutaishanica) on the altitudinal gradient on the south and north slopes of Taibai Mountain. The results showed that there was an altitudinal transition pattern from Q. variabilis pure forest to Q. variabilis-Q. aliena var. acutiserrata mixed forest, Q. aliena var. acutiserrata pure forest, Q. aliena var. acutiserrata-Q. wutaishanica mixed forest and Q. wutaishanica pure forest on the south and north slopes of Taibai Mountain. The main companion species of Quercus community on the north slope were Pinus armandii, Castanea seguinii, and Sorbus alnifolia, and were Pinus tabuliformis, C. seguinii, Carpinus cordata, and Q. spinosa on the south slope. Species richness, woody plant density, and Quercus species dominance on the north slope of Taibai Mountain were higher than those on the south slope. α diversity of tree layer in Quercus community on the south and north slopes of Taibai Mountain increased first, then decreased and then increased with altitude. α diversity of tree layer was higher in mixed forests than pure forests. α diversity of shrub layer was higher than that of tree layer and herb layer in Quercus community on south and north slopes. ß diversity fluctuated greatly along the altitudinal gradient on the south and north slopes, indicating that species composition changed greatly with altitude. Results of redundancy analysis showed that mean warmest month temperature, altitude and tree height accounted for 79.0% of the community diversity on the north slope, and that soil water content, tree height, canopy density and mean annual temperature accounted for 79.6% of the community diversity on the south slope. Overall, Quercus dominance was higher on the north slope of Taibai Mountain, and the substitution distribution pattern of Quercus species was clearer than that on the south slope. Environmental factors related to temperature and precipitation jointly affected α diversity of Quercus communities.

Identification of Intestinal Microbial Community in Gallstone Patients with Metagenomic Next-Generation Sequencing.

Gallstone disease (GD) is one of the most common gastrointestinal diseases worldwide. Nowadays, intestinal microbiota are thought to play important roles in the formation of gallstones. In our study, human fecal samples were extracted for metagenomic next-generation sequencing (mNGS) on the Illumina HiSeq platform, followed by bioinformatics analyses. Our results showed that there was a particular intestinal micro-ecosystem in GD patients. In contrast to healthy people, the sequences of Bacteroidetes, Bacteroides and Thetaiotaomicron were obviously more abundant in GD patients at phylum, genus and species levels, respectively. On the other hand, the glycan metabolism and drug resistance, especially for the ß-lactams, were the most profound functions of gut microbes in GD patients compared to those in normal subjects. Furthermore, a correlation analysis drew out that there existed a significant relationship between the serum levels of biochemical indicators and abundances of intestinal microbes in GD patients. Our results illuminate both the composition and functions of intestinal microbiota in GD patients. All in all, our study can broaden the insight into the potential mechanism of how gut microbes affect the progression of gallstones to some extent, which may provide potential targets for the prevention, diagnosis or treatment of GD.

Use climatic space-for-time substitutions with care: Not only climate, but also local environment affect performance of the key forest species bilberry along elevation gradient.

An urgent aim of ecology is to understand how key species relate to climatic and environmental variation, to better predict their prospects under future climate change. The abundant dwarf shrub bilberry (Vaccinium myrtillus L.) has caught particular interest due to its uphill expansion into alpine areas. Species' performance under changing climate has been widely studied using the climatic space-for-time approach along elevation gradients, but potentially confounding, local environmental variables that vary along elevation gradients have rarely been considered. In this study, performed in 10 sites along an elevation gradient (200-875 m) in W Norway, we recorded species composition and bilberry performance, both vegetative (ramet size and cover) and reproductive (berry and seed production) properties, over one to 4 years. We disentangled effects of local environmental variables and between-year, climatic variation (precipitation and temperature), and identified shared and unique contributions of these variables by variation partitioning. We found bilberry ramet size, cover and berry production to peak at intermediate elevations, whereas seed production increased upwards. The peaks were less pronounced in extreme (dry or cold) summers than in normal summers. Local environmental variables explained much variation in ramet size and cover, less in berry production, and showed no relation to seed production. Climatic variables explained more of the variation in berry and seed production than in ramet size and cover, with temperature relating to vegetative performance, and precipitation to reproductive performance. Bilberry's clonal growth and effective reproduction probably explain why the species persists in the forest and at the same time invades alpine areas. Our findings raise concerns of the appropriateness of the climatic space-for-time approach. We recommend including both climatic and local environmental variables in studies of variation along elevation gradients and conclude that variation partitioning can be a useful supplement to other methods for analysing variation in plant performance.