Numerical Dominance Research Articles

Individual Plant-Soil Feedback Effects Influence Tree Growth and Rhizosphere Fungal Communities in a Temperate Forest Restoration Experiment

Plant-soil feedbacks and the soil legacy effects that create them have important implications for community composition and restoration. However, relatively few field trials test the influence of soil legacy effectsplant-soil feedbacks, especially on longer-lived species, such as trees. Here we present a field restoration experiment with 10 ectomycorrhizal fungal tree species native to eastern North America. Trees were inoculated with soils collected from conspecifics in the field or from a heterospecific: Quercus rubra. Fagus grandifolia stem elongationFollowing 16 months of growth in the field, Carya ovata diameter increase was significantly increased greater in trees receiving the by heterospecific inoculant.tion following 16 months of growth in the field, and Tthis negative plant-soil feedback is consistent with its C. ovata’s natural co-occurrence with Q. rubra. Conversely, Quercus macrocarpa diameter increase and Carya cordiformis height increase were was significantly greater when inoculated with conspecific soils, and this positive plant-soil feedback is consistent with its their numerical dominance in natural communities. We found no evidence for phylogenetic Janzen-Connell effects or conservation of soil mutualists across tree species. We also quantified differences in soil fungal community structure with next generation sequencing methods (Illumina MiSeq) following 16 months in the field. Shannon’s diversity of fungal taxa was greater in heterospecific soils of seven of our nine experimental species, consistent with a diversifying influence of heterospecific Quercus rubra soil inocula. However, only one genus, Ulmus, exhibited differences in fungal community composition derived from conspecific and heterospecific sources, suggesting a stronger effect of focal tree species than of soil inocula source. The relatedness among focal tree species also influenced fungal community composition, with tree families and genera displaying different fungal communities. We suggest that future experiments should determine whether more diverse tree and fungal communities might have enhanced ecosystem functioning in tree restoration sites.

Stochastic Expansions Maintain the Clonal Stability of CD8+ T Cell Populations Undergoing Memory Inflation Driven by Murine Cytomegalovirus

CMV is an obligate and persistent intracellular pathogen that continually drives the production of highly differentiated virus-specific CD8+ T cells in an Ag-dependent manner, a phenomenon known as memory inflation. Extensive proliferation is required to generate and maintain inflationary CD8+ T cell populations, which are counterintuitively short-lived and typically exposed to limited amounts of Ag during the chronic phase of infection. An apparent discrepancy therefore exists between the magnitude of expansion and the requirement for ongoing immunogenic stimulation. To address this issue, we explored the clonal dynamics of memory inflation. First, we tracked congenically marked OT-I cell populations in recipient mice infected with murine CMV (MCMV) expressing the cognate Ag OVA. Irrespective of numerical dominance, stochastic expansions were observed in each population, such that dominant and subdominant OT-I cells were maintained at stable frequencies over time. Second, we characterized endogenous CD8+ T cell populations specific for two classic inflationary epitopes, M38 and IE3. Multiple clonotypes simultaneously underwent Ag-driven proliferation during latent infection with MCMV. In addition, the corresponding CD8+ T cell repertoires were stable over time and dominated by persistent clonotypes, many of which also occurred in more than one mouse. Collectively, these data suggest that stochastic encounters with Ag occur frequently enough to maintain oligoclonal populations of inflationary CD8+ T cells, despite intrinsic constraints on epitope display at individual sites of infection with MCMV.

Distribution of cyprinids in the stream during their spring upstream migration

The researches were carry out by stationary and mobile hydroacoustic computerized complexes in the floodplain-riverbed complex of the Irtysh River (Western Siberia, Russian Federation). It was established that during the migration period during the spring flood, patterns of distribution of fish in the stream are observe due to the size-taxonomic characteristics of the fish population and the physiological capabilities of the organism of fish. With an increase in the flow velocity characteristic from the near bank part of the river to its midstream, the proportion of cyprinids in the watercourse decreases, and the proportion of fish with body sizes> 15 cm increases. The number of fish smaller at high-speed sections of the river increases with an increase in water temperature, which in turn indicates the increasing physiological capabilities of representatives of Cyprinidae family. Absolute numerical dominance of migratory fish and the largest proportion of cyprinids were observed in the low velocity section of the river, located closer to the shore. The indicator of the proportion of cyprinids have a direct strong correlative relationship with the temperature factor (0.70-0.73, P<0.05).

Melani McAlister. The Kingdom of God Has No Borders: A Global History of American Evangelicals.

The role of American missionaries during the nineteenth and early twentieth centuries has been widely studied, but far less attention has been given to the modern American “evangelical” missionary movements abroad since the 1950s. As Melani McAlister shows in The Kingdom of God Has No Borders: A Global History of American Evangelicals, the context is very different. Gone was the hegemony of the European empires, leaving missionaries needing to negotiate their way with anticolonial regimes and independence movements; missionaries also had to deal with the Cold War machinations of both the United States and its Communist adversaries. Gone was the preeminence of the mainline Protestant churches of earlier decades, with 66.5 percent of funding and 85 percent of personnel coming from evangelical sources by 1974; also passing away was the numerical dominance of “white” peoples within global missions, with 70 percent of evangelicals based outside Europe or North America by 2010.

Doing care work on the fly - exploring the unnoticed socio-emotional skills of male ambulance staff.

Prehospital ambulance work is a healthcare arena hitherto neglected by sociologists of health and illness. This is unfortunate because it is an interesting and dynamic area, and in contrast to most healthcare sectors, it is male dominated. Via ethnographic fieldwork, this article examines the particular caring practices and socio-emotional skills that ambulance staff use in practising prehospital care work. The empirical analysis outlines six recurring prehospital practices: medicine work, machine work, scene management, becalming work, communication work and bodywork. Each practice represents a different element of prehospital care practice and is best understood as a repertoire, as many different assemblages of these care practices can work effectively in prehospital situations. The article concludes that despite institutionalised blue-collar masculinity, numeric dominance and scarce formal education in ambulance psychology, male ambulance staff are generally proud and reflexive care practitioners.

Long-term temporal variation in the parasite community structure of metazoans of Pimelodus blochii (Pimelodidae), a catfish from the Brazilian Amazon.

The Amazon represents one of the most complex biomes in the world; however, the temporal variations in parasite community structure of fishes inhabiting this region remain poorly understood. Therefore, processes generating such variations are still unknown. The present study evaluated the long-term temporal variation of communitystructure of metazoan parasites of Pimelodus blochii collected in Iaco River, State of Acre (Southwestern Brazilian Amazon). A total of 196 parasites were collected over a 6-year period (2012-2017). Twenty-four different taxa of parasites were found, of which 5 Monogenea, 11 Nematoda, 3 Digenea, 1 Acanthocephala, 1 Cestoda, and 3 Crustacea. The overall species richness ranged from 4 in 2012 to 17 in 2016, in which nematodes (larvae and adults) showed higher numerical dominance, diversity, and species richness. However, the annual species richness was similar between the study years, except in 2016, where it showed a distinctly higher value. The overall parasite diversity was also different in 2012 and 2016, whereas the overall abundance differed in 2013 and 2017. The prevalence and abundance of some infracommunities of parasites varied over time. The temporal changes in the parasite community structure of P. blochii are probably related to variations in host-related features, i.e., body size and shift in diet composition as well as to the occurrence of parasites with distinct life history and biology (mainly monogeneans, digeneans, and nematodes). This is the first evaluation of a long-term temporal variation in the structure of the parasite community in fish from the Amazon.

Hourly variation of environment and copepod community of the Ganges River Estuary of India: Perspectives on sampling estuarine zooplankton

High-resolution ecological databases are only rarely available for tropical estuaries, so details of their ecological variability are often poorly understood. We studied 12 h of continuous variability salinity, water temperature, pH, dissolved oxygen, NO3–N, and the copepod community (size > 200 μm) of the Ganges River Estuary (GRE) of India. We hypothesized that short-term environmental variability affects copepod community and its most and least abundant populations. We recorded twenty-nine copepod species, in terms of size the largest was Eucalanus elongatus (3.5–5 mm) and the smallest was Oithona brevicornis (0.4–0.51 mm). Spatial variability of the environment was not statistically significant. Site-specific temporal variability of salinity, water temperature, pH and dissolved oxygen was statistically significant but only a few of those variables affected the diversity and evenness of the copepod community. Bestiolina similis and Paracalanus parvus were among the most abundant and E. elongatus and Acrocalanus gibber were among the least abundant copepods of the GRE. Site-specific rank-abundance revealed that the numerical dominance of specific copepod changed within small (~500 m) spatial scale. Abundant copepods were mostly omnivores; a few large ones were carnivores whereas most others including the least abundant forms were herbivores. Population abundance of B. similis remained unaffected by temporal variability of environment. Compared to day time abundance of Paracalanus parvus increased in the dark and in relatively cooler waters showing evidence of its diel vertical movements. Abundance of E. elongatus increased in higher salinity, demonstrating its affinity towards the marine environment. Abundance of A. gibber showed significant temporal associations with different environmental variables. Variability exists within the copepod community in terms of diversity, abundance, size class, and feeding habits. For a better management of the ecological resources of this estuary we suggest not to overlook microscopic ecological changes of the lower trophic levels.

Ammonia Oxidizers as Biological Health Indicators of Elevated Zn and Cu in Poultry Litter Amended Soil

Ammonia-oxidixing bacteria (AOB) and archaea (AOA) mediate the first and rate-limiting step of nitrification and are responsive to agricultural management practices. These two attributes make them ideal indicators of biological soil health. We conducted a laboratory incubation study to determine their response to elevated levels of zinc (Zn) and copper (Cu) in poultry litter treated soil at three substrate concentrations: 0 (low), 50 (medium) and 100 (high) mg ammonium ($$ {\mathrm{NH}}_4^{+} $$-N) kg−1 soil. Nitrification potential (NP) was measured to characterize changes in their function in which 1-octyne was used to separate their contributions. Quantitative polymerase chain reaction was used to measure their abundance by targeting amoA. Increasing Zn from 21 to 250 mg kg−1 resulted in large reductions in AOB (78%) and AOA (85%) abundance at the high $$ {\mathrm{NH}}_4^{+} $$ level over 28 days. Likewise, increasing Cu from 20 to 120 mg kg−1 significantly reduced AOB (92%) and AOA (63%) abundance at the high $$ {\mathrm{NH}}_4^{+} $$ level over 28 days. The relative contribution of AOB to NP was significantly higher than that of AOA in both Zn (~60%) and Cu (~70%) treated soils despite the numerical dominance of AOA over AOB. Overall, results indicate that elevated levels of Zn and Cu depressed AOB and AOA abundance and function and that their effect was dependent on availability of $$ {\mathrm{NH}}_4^{+} $$. The results also indicated that AOB are functionally more important than AOA under elevated Zn and Cu concentrations and that management practices to improve N use efficiency should focus on AOB under this condition.

Factors linked to interannual variation in the metazoan parasite communities of black skipjack, Euthynnus lineatus (Pisces: Scombridae)

AbstractMarine parasite communities can exhibit temporal and spatial changes in response to seasonal and local variations in several biotic and abiotic environmental factors. Limited attention has been given to the influence of abiotic factors, so their effects on parasite community structure remain unclear. A total of 496 specimens of Euthynnus lineatus were collected over a 7‐year period (2012–2018) from Acapulco Bay, Mexico. Their parasite communities were analyzed to determine if they experience interannual variations due to local biotic and abiotic factors. Thirty‐three metazoan parasite species were recovered and identified: four species of Monogenea (adults); 16 of Digenea (one larvae and 15 adults); two of Acanthocephala (adults); two of Cestoda (larvae); three of Nematoda (two larvae and one adult); and six of Crustacea (three Copepoda, and three Isopoda). Species richness was greatest among the digeneans, which represented 48% of the total species recovered, followed by the crustaceans (19% of total species). Species richness at the component community level (14–24 species) was similar to reported richness in other small tuna species. The component communities and infracommunities of E. lineatus exhibited a similar pattern: high species richness and diversity, and numerical dominance by a single species, mainly by one of the didymozoids Allopseudocolocyntotrema claviforme or Pseudocolocyntotrema yaito. Parasite community structure and species composition varied among sampling years. Variations were possibly caused by a combination of abiotic and biotic factors which generated notable changes in the infection levels of several component species during the study period. These communities may therefore be unpredictable in terms of structure and species composition, as has been suggested for other communities of marine parasites.

Drifting in the Caribbean: Hints from the intertidal bivalve Isognomon alatus

Settlement of most marine benthic invertebrates is intrinsically linked to the end of the pelagic life, but for a few, the transition to the benthos can be less well-defined. Early metamorphosed postlarvae of temperate and subtropical bivalves are known to delay final settlement, i.e., undergo secondary migrations, until detecting specific habitat cues. Here, we test the hypothesis that postlarval drifting occurs as well in tropical systems, being mediated by the nutritional quality of nearshore waters. We monitored early stages of the flat tree oyster Isognomon alatus on the Caribbean coast of Panama, and observed successive numerical dominance of late-stage larvae (pediveligers) and postlarvae (juvenile drifters) of this isognomonid in the water column. Of all the pelagic individuals collected, 19% corresponded to juvenile drifters, suggesting that conditions favoring juvenile drifting were present at the time of sampling and/or juvenile drifting may be commonplace for this species. During 23 consecutive sampling days, we detected a single settlement peak of long-term drifters that followed a decrease in sea-surface salinity. The shell morphology of juveniles revealed that first settlement for I. alatus takes place after theoretical competence, when prodissoconch II exceeds c. a. 300 μm. A shift in nearshore trophic conditions was detected after settlement, with particulate matter dominated by tracers of microalgae and vascular plant matter shifting to tracers for detritic matter and bacterial load. Essential fatty acids comprised 28% of the seston, yet, were minimally accumulated by I. alatus pediveligers (2% of energetic reserves). We highlight the importance of accounting for juvenile drifters of I. alatus on settlement estimates, as the spatial distribution of late larval stages and/or early settlers might not reflect their final distribution. This information is key to manage, exploit and/or conserve natural stocks.

Palynological assemblage from the lower Cenomanian plant-bearing Lagerstätte of Jaunay-Clan-Ormeau-Saint-Denis (Vienne, western France): Stratigraphic and paleoenvironmental implications

We describe here the palynological content from the lower Cenomanian plant-rich site of Jaunay-Clan (Vienne, western France), a site that previously yielded exceptional leaf impressions. Altogether, 184 species of palynomorphs have been identified, and two palynological intervals were recognized in the sedimentary sequence. The lower interval is characterized by the taxonomical and numerical dominance of spores of Gleicheniaceae, Cyatheales, and Anemiaceae, while the upper interval is characterized by an abrupt increase in the abundance of Classopollis and the appearance of dinocysts. This shift in the palynological composition, coupled with paleobotanical observations, is interpreted as reflecting a transition from a calm freshwater environment, with occasional droughts to an environment more open to very occasional marine inputs, such as an inner lagoon.The association of Tehamadinium coummia, Trichodinium spinosum, Tricolpites nemejcii, Retitricolporites decorosus, and Microreticulatiporites sacalii, coupled with the absence of Normapolles pollen grains, suggests that the Jaunay-Clan assemblage is early Cenomanian in age, corroborating the previous determination based on lithological and paleontological proxies. However, the Jaunay-Clan palynoflora is considered to be slightly younger than the numerous earliest Cenomanian assemblages described from Charente-Maritime, owing to its resemblance with mid-lower Cenomanian palynofloras from western France. The paleoflora and palynoflora from Jaunay-Clan are similar to other assemblages found in the upper Albian of Spain (Teruel Province), and in the Cenomanian of France and Czech Republic (Peruc-Korycany Formation, La Buzinie, Archingeay). The combined Jaunay-Clan palynoflora and paleoflora is considered to be the most diversified Cenomanian paleobotanical-palynological assemblage described so far in Western Europe.

Plant species dominance increases pollination complementarity and plant reproductive function.

Worldwide, anthropogenic change is causing biodiversity loss, disrupting many critical ecosystem functions. Most studies investigating the relationship between biodiversity and ecosystem functioning focus on species richness, predominantly within the context of productivity-related functions. Consequently, there is limited understanding of how other biodiversity measures, such as species evenness (the distribution of abundance among species), affect complex multitrophic functions such as pollination. We explore the effect of species evenness on the ecosystem function of pollination using a controlled experiment with selected plants and insects in flight cages. We manipulated the relative abundances of plant and pollinator species, while holding species richness, composition, dominance order, and total abundance constant. Then, we tested how numerical species evenness affected network structure and consequently, seed production, in our artificial communities. Contrary to our expectation, numerical dominance in plant communities increased complementarity in pollinator use (reduced pollinator sharing) among plant species. As predicted by theory, this increased complementarity resulted in higher seed production for the most dominant and rare plant species in our cages. Our results show that in a controlled experimental setting, numerical species evenness can alter important aspects of plant-pollinator networks and plant reproduction, irrespective of species richness, composition, and total abundance. Extending this understanding of how species evenness affects ecosystem functioning to natural systems is crucial as anthropogenic disturbances continue to alter species' abundances, likely disrupting ecosystem functions long before extinctions occur.

Fish Assemblage Structure in Al-Huwaizah marsh southern of Iraq after inscribed on the World Heritage List

The fish assemblage structure in Al-Huwaizah marsh, southern of Iraq was assessed. Fish samples collected monthly by different fishing means from period December 2017 to November 2018. A total of 28959 individual of fish belonging to 9 families and 19 species were collected, 11 of them of native species and 8 of alienspecies. The numerical dominance index value (D3) of the highest three abundant species comprised 74.26% of the total fish caught, included Planiliza abu (Al-Keshny) 38.2% ; Coptodon zilli (Tilapia red abdomen) 29.41% and Carassius auratus (Prussian carp) 6.65%. The total weight of fish caught 2,190,680 tan, highest weight 312,242kg achieved in July, while lowest weight 41,590 kg found in September. The weight dominance index value (D3) of the highest three species in weight recorded 1,409,973 tan of the total weight of fish caught included C. zilli(Tilapia red abdomen) 659,994 kg , S. triostegus (Jerry fresh water) 495,784 kg and O. aureus (Blue tilapia) 245,195kg.The annual rate value for diversity, richness and evenness indices amounted 1.88, 1.75 and 0.64, respectively. Some of physical and chemical properties were studied such as water temperature which ranged from 11.5°C in January to 31.02°C in August month, dissolved oxygen ranged from 2.24 mg/l in September to 9.9mg/l in February, salinity varied from 1.37‰ in November to 3.76‰ in September and pH which ranged from 7.4 in June to 8.15 in December.Jaccard Similarity Index (Ss%) was used to know the similarity degree between the monthly catch samples. Also associations between distribution of fish species and the environmental variables were quantified by using canonical correspondence analysis (CCA).

Yeast Stress Response and Fermentation Efficiency: How to Survive the Making of Wine - A Review

Fermentation predictability and wine quality are directly dependent on wine yeast attributes that assist in the rapid establishment of numerical dominance in the early phase of wine fermentation, and that determine the ability to conduct an even and efficient fermentation to obtain a desirable alcohol degree. It is therefore not surprising that the primary selection criteria applied to most wine yeast strain development programmes relate to the overall objective of achieving an efficient conversion of grape sugar to alcohol and carbon dioxide, at a controlled rate and without the development of off-flavours. Numerous factors influence the fermentation performance of wine yeast. Following a successful inoculation of grape must with an appropriate starter culture strain, the ability of a wine yeast to adapt to and cope with the hostile environment and conditions prevailing in grape juice fermentation are of vital importance to fermentation performance. There is a direct correlation between fermentation efficiency and resistance, which refers to the ability of a yeast strain to adapt efficiently to a changing environment and unfavourable growth conditions. Successful yeast cellular adaptation to changes in extracellular parameters during wine fermentation requires the timely perception (sensing) of chemical or physical environmental parameters, followed by accurate transmission of the information to the relevant compartments of the cell. Chemical parameters perceived during wine fermentation include the availability/concentration of certain nutrients (e.g., fermentable sugars, assimilable nitrogen, oxygen, vitamins, minerals, ergosterol and unsaturated fatty acids) and the presence of inhibitory substances (e.g., ethanol, acetic acid, fatty acids, sulfite, phenolic phytoalexins, mycotoxins, bacterial toxins and agrochemical residues). Signals of a physical nature include temperature, pH, agitation and osmotic pressure. The sensing of these environmental signals is carried out by specific receptor proteins, most of them situated on the cellular surface. Once perceived, the information is transmitted by a network of dedicated, interconnected signal transduction pathways to the relevant cellular compartments which implement the adaptive response, a process referred to as stress response. Intensive research has focused on elucidating the molecular mechanisms involved in responses, which are evolutionarily well conserved. Besides furthering our understanding of the fundamental strategies for adaptation to hostile, industrial environments, and the biological resilience of Saccharomyces cerevisiae, the data are of key importance to the future improvement of wine yeast strains. This review describes the different types of experienced by wine yeast cells during their life cycles, summarises our current knowledge of some of the most important molecular processes required for the survival of the yeast cell, and highlights the potential benefits for future yeast strain development which can be derived from this research.

A Genomic Approach To Identify Klebsiella pneumoniae and Acinetobacter baumannii Strains with Enhanced Competitive Fitness in the Lungs during Multistrain Pneumonia.

Microbial competition is most often studied at the genus or species level, but interstrain competition has been less thoroughly examined. Klebsiella pneumoniae is an important pathogen in the context of hospital-acquired pneumonia, and a better understanding of strain competition in the lungs could explain why some strains of this bacterium are more frequently isolated from pneumonia patients than others. We developed a barcode-free method called "StrainSeq" to simultaneously track the abundances of 10 K. pneumoniae strains in a murine pneumonia model. We demonstrate that one strain (KPPR1) repeatedly achieved a marked numerical dominance at 20 h postinoculation during pneumonia but did not exhibit a similar level of dominance in in vitro mixed-growth experiments. The emergence of a single dominant strain was also observed with a second respiratory pathogen, Acinetobacter baumannii, indicating that the phenomenon was not unique to K. pneumoniae When KPPR1 was removed from the inoculum, a second strain emerged to achieve high numbers in the lungs, and when KPPR1 was introduced into the lungs 1 h after the other nine strains, it no longer exhibited a dominant phenotype. Our findings indicate that certain strains of K. pneumoniae have the ability to outcompete others in the pulmonary environment and cause severe pneumonia and that a similar phenomenon occurs with A. baumannii In the context of the pulmonary microbiome, interstrain competitive fitness may be another factor that influences the success and spread of certain lineages of these hospital-acquired respiratory pathogens.

Unassigned diversity of planktonic foraminifera from environmental sequencing revealed as known but neglected species.

Most research on extant planktonic foraminifera has been directed towards larger species (>0.150 mm) which can be easily manipulated, counted and yield enough calcite for geochemical analyses. This has drawn attention towards the macroperforate clade and created an impression of their numerical and ecological dominance. Drawing such conclusions from the study of such “giants” is a dangerous path. There were times in the evolutionary history of planktonic foraminifera when all species were smaller than 0.1 mm and indeed numerous small taxa, mainly from the microperforate clade, have been formally described from the modern plankton. The significance of these small, obscure and neglected species is poorly characterized and their relationship to the newly discovered hyperabundant but uncharacterized lineages of planktonic foraminifera in metabarcoding datasets is unknown. To determine, who is hiding in the metabarcoding datasets, we carried out an extensive sequencing of 18S rDNA targeted at small and obscure species. The sequences of the newly characterized small and obscure taxa match many of the previously uncharacterized lineages found in metabarcoding data. This indicates that most of the modern diversity in planktonic foraminifera has been taxonomically captured, but the role of the small and neglected taxa has been severely underestimated.

Do mass flowering agricultural species affect the pollination of Australian native plants through localised depletion of pollinators or pollinator spillover effects?

Australian agricultural landscapes are dominated by northern-hemisphere mass flowering species, with the potential to disrupt pollination of adjacent co-flowering plants. In northern-hemisphere systems, mass flowering plants can act as ‘pollinator magnets’. Magnets can reduce the pollination success of adjacent co-flowering neighbours by drawing pollinators from these plants. However, magnets can also produce pollination ‘spillover-effects’ through increased pollinator movements to adjacent co-flowering taxa, potentially either increasing pollination or impacting it through transfer of mixed-species pollen. The impact of agricultural species on co-flowering plants in Australia is unknown. Native Australian plants evolved with unique pollinators and yet agricultural pollination is dominated by the exotic honeybee Apis mellifera. We tested how distance (to 250 m) from each of two populations of Lavender (Lavandula spp.) (2 years), Nectarines (Prunus persica var. nucipersica or var. nectarina) (1 year) and the pasture weed Paterson’s Curse (Echium plantagineum) (2 years) affected pollinator diversity and abundance within experimental arrays of native and northern-hemisphere plants. For Paterson’s Curse, we tested whether visitation varied when honeybee abundance was experimentally increased. As expected, we found magnets attracted significantly more honeybee visits in all possible comparisons across combinations of species, sites and years. However, contrary to expectation, in 10 of 18 comparisons, co-flowering species supported a slightly higher diversity of pollinators than magnets, with honeybees comprising a significantly lower proportion of flower visitors in 14 comparisons. The exceptions, which included populations of all three magnet species, were cases where honeybees were the only visitor (6 comparisons) or the magnet and co-flowering species were each visited by a single but different pollinator (2 compariosns). Most strikingly, our data provided no evidence of pollinator spillover. More than 95% of all pollinators on co-flowering species carried only their pollen and overall pollinator abundance didn’t vary significantly with distance from magnets at any site or time. Honeybee abundance did not vary significantly with distance from magnets. For Paterson’s Curse, the addition of managed hives increased honeybee abundance on co-flowering species in two of eight cases, but pollinator abundance didn’t vary with distance from the magnet. Overall, we found few direct effects of mass flowering agricultural species on the pollination of either Australian native or exotic neighbours. The lack of spillover-effects may largely reflect the unusually high species fidelity of foraging A. mellifera. However, the numerical dominance of honeybees within Australian agricultural systems may impact pollination at the regional level.

Double Trouble: How Being Outnumbered and Negatively Stereotyped Threatens Career Outcomes of Women in STEM.

Masculine work contexts form an important source of social identity threat for working women. But what aspect of masculine work contexts is most threatening to women’s gender identity at work: A numerical majority of male colleagues (i.e., numerical male dominance), working in a profession in which women are negatively stereotyped (i.e., normative male dominance), or the combination? The current study aimed to disentangle these two aspects of masculine work contexts by testing its combined impact on the experience of gender identity threat among women and men who work in the STEM sector (i.e., Science, Technology, Engineering and Mathematics). A field study was conducted among women (N = 177) and men (N = 630) graduates holding an academic degree in a STEM educational program. Respondents either worked in- or outside the STEM sector (i.e., stronger vs. weaker gender stereotype) and estimated the ratio of men to women in their direct work environment. Results from a Structural Equation Model demonstrated that women in STEM face double trouble: The combination of working almost solely with male colleagues (being outnumbered) and working in the technical sector (where women are negatively stereotyped) predicted the highest levels of experienced gender identity threat, particularly among women who highly identified with their gender group. Gender identity threat, in turn, negatively predicted women’s work engagement and career confidence. Men did not face double trouble: Their experience of gender identity threat was not related to working in a masculine STEM sector. Importantly, considering that the women in this sample already hold a degree in STEM, and have proven their competence in STEM and resilience to gender stereotypes, this research reveals how in naturalistic work settings, prevailing social identity threats continue to affect women’s professional careers.

TATAR MUSLIM COMMUNITY OF ASTRAKHAN IN THE EARLY TWENTIETH CENTURY

The article discusses the main features of the Astrakhan Muslim community in the early twentieth century. During this period, Muslims of Russia entered the period of institutionalization of ethnic and religious identity. Astrakhan Muslim community in the period under review was one of the centers of the Muslim Tatar movement in the Russian Empire. At the same time, due to the historical and geographical features of the settlement of the Astrakhan region, the formation of the urban population of the provincial center, the community had a number of characteristic features that could not but aff ect all aspects of life of the mahalla. The work is based on the analysis of archival and published sources, works of local historians and orientalists. Unconditional numerical and material domination of the Tatar ethnic group became decisive in the development of the regional Muslim community. But at the same time, the factor of its polyethnicity had a great infl uence on various aspects of mahalla’s life. Even the Tatars, who formed the basis of the community, came from diff erent provinces and represented diff erent territorial groups of the Turkic-Tatar world. But as part of the Astrakhan Muslim community successfully managed to overcome the ethno-group interests, the isolation of local corporations. Islam has emerged as an integrating core value. Astrakhan mahalla has become an exceptional example of ethnic tolerance among co-religionists and loyalty to state institutions, on the other. Today, when the fl ow of migrants from the North Caucasus republics (primarily Dagestan and Chechnya) is directed to the Astrakhan region and the number of Muslims in the region increases annually, the experience of a century ago is very much in demand for the formation of a new religious identity here.

Energetically relevant predator-prey body mass ratios and their relationship with predator body size.

Food web structure and dynamics depend on relationships between body sizes of predators and their prey. Species‐based and community‐wide estimates of preferred and realized predator–prey mass ratios (PPMR) are required inputs to size‐based size spectrum models of marine communities, food webs, and ecosystems. Here, we clarify differences between PPMR definitions in different size spectrum models, in particular differences between PPMR measurements weighting prey abundance in individual predators by biomass (r bio) and numbers (r num). We argue that the former weighting generates PPMR as usually conceptualized in equilibrium (static) size spectrum models while the latter usually applies to dynamic models. We use diet information from 170,689 individuals of 34 species of fish in Alaskan marine ecosystems to calculate both PPMR metrics. Using hierarchical models, we examine how explained variance in these metrics changed with predator body size, predator taxonomic resolution, and spatial resolution. In the hierarchical analysis, variance in both metrics emerged primarily at the species level and substantially less variance was associated with other (higher) taxonomic levels or with spatial resolution. This suggests that changes in species composition are the main drivers of community‐wide mean PPMR. At all levels of analysis, relationships between weighted mean r bio or weighted mean r num and predator mass tended to be dome‐shaped. Weighted mean r num values, for species and community‐wide, were approximately an order of magnitude higher than weighted mean r bio, reflecting the consistent numeric dominance of small prey in predator diets. As well as increasing understanding of the drivers of variation in PPMR and providing estimates of PPMR in the north Pacific Ocean, our results demonstrate that that r bio or r num, as well as their corresponding weighted means for any defined group of predators, are not directly substitutable. When developing equilibrium size‐based models based on bulk energy flux or comparing PPMR estimates derived from the relationship between body mass and trophic level with those based on diet analysis, weighted mean r bio is a more appropriate measure of PPMR. When calibrating preference PPMR in dynamic size spectrum models then weighted mean r num will be a more appropriate measure of PPMR.