Structuring Factor Research Articles

DIAGNOSTICS OF EXTERNAL ENVIRONMENT EFFECTS UPON ENTERPRISE COMPETITIVE POSITIONS IN THE CONTEXT OF ITS ECONOMIC SECURITY

The article reveals the nature of a competitive enterprise, identifies the external environment factors affect the enterprise competitive position and provides insights on the enterprise economic security concept. In thus study, the essence of the enterprise economic security category is viewed as a specifically built system of preventive measures aimed at conducting targeted permanent activities to ensure sustainable efficient enterprise performance through effective management of negative impact factors that affect hider its successful operation. The paper provides the analysis of a range of external factors that can damage the enterprise economy along with suggesting the structuring of external factors of competitiveness with regard to each stage of the enterprise business plan implementation. The functional objectives of the enterprise economic security and specifics of shaping the economic security diagnostics system are discussed. The study also offers the review on the methods used to diagnose the environment effects on the enterprise competitive position in the context of its economic security. It is argued that the most significant indicators estimated by a number of selected criteria (structural elements) of a business competitive position within the system for enterprise economic security diagnostics are the following: the level of security by the financial component, the level of security by personnel component, the level of security by innovation and technology component, the level of security by political and legal component, the level of security by analytical information component and the level of security by economic component. The paper also suggests the methods and tools for business economic security diagnostics and explores the key objectives of the enterprise economic security management system.

Helminth Community Structure of the Gray Four-Eyed Opossum Philander opossum (Mammalia: Didelphidae) in the Neotropical Portion of Mexico

Studies on helminth communities associated with didelphids are scarce; the majority of works have focused at taxonomic level. To increase the ecological knowledge of these host-parasite associations, during March (dry season) of 3 consecutive years (2013-2015) a total of 49 adults of the gray four-eyed opossum (Philander opossum) was collected in the Neotropical portion of Mexico (Agua Fría, Chiapas State) and examined for helminths. The main objectives of this study were to describe the infra- and component communities of helminths associated with P. opossum and to compare the helminth fauna of the Mexican population of this host species with those studied in French Guiana and in other Mexican terrestrial didelphids. The helminthological record of this host consisted of 12 species: 7 taxa of Nematoda, 3 of Trematoda, 1 Cestoda, and 1 Acanthocephala. Eight of the 12 taxa have been previously recorded in Didelphidae and 4 represent accidental infections ( Glossocercus sp., Stomylotrema vicarium, Spirura mexicana and Acanthocephala gen. sp.). Diet of hosts is the main structuring factor of the communities (92% of the helminth species were recruited through ingestion). Forty-eight hosts were parasitized by at least 1 helminth species; Rhopalias coronatus was the most prevalent and abundant species in the hosts sampled. No significant differences were found in global prevalence among the helminth species present in all samplings, considering host sex and year. The dominance exerted by R. coronatus led to low values of evenness and diversity at both community levels. No significant differences were observed in composition of helminth species among the 3 sampling years regarding sex. The results of our study showed changes in helminth abundance at infracommunity level; during the first sampling these changes are explained by species with direct life cycle ( Viannaia sp. and Cruzia tentaculata), whereas in last 2 surveys the explanation can be attributed to species with heteroxenous life cycles (particularly R. coronatus, Duboisiella proloba, and Turgida turgida). Thirty-three percent of the helminth species recorded in P. opossum in Agua Fría is shared with the other 2 terrestrial species of didelphids sampled in different sites of Mexico: Didelphis marsupialis and Didelphis virginiana. In contrast, samples from French Guiana and Agua Fría, differ in terms of helminth fauna, confirming that the helminth communities of opossum species inhabiting the same locality show higher levels of taxonomic similarity than communities of conspecific marsupials allopatrically distributed.

Effects of seasonal fluctuation of amazon river discharge on the spatial and temporal changes of meiofauna and nematodes in the amazonian coast

In the Amazonian coast seasonal changes of environmental characteristics are the main structuring factors of coastal benthic communities. Spatial and temporal variations in meiofauna and nematofauna were studied during rainy and dry seasons in the coastal zone of the Biological Reserve of Piratuba Lake (Bazil Amazonian coast). At each site (seven sites) five samples were taken in vegetated (inside the mangrove – 100 m from the border) and non-vegetated (outside of the mangrove – 100 m from the border) areas. Each sample was sliced in 0–2 cm, 2–5 cm and 5–10 cm deep layers. Water surface temperature and salinity were determined. Meiofauna was composed of 15 taxa: Nematoda, Copepoda, Ostracoda, Amphipoda, Cladocera, Isopoda, Acari, Polychaeta, Gastropoda, Turbellaria, Rotifera, Loricifera, Nemertea, Kinorhyncha, and Insect larvae. Nematoda (39 genera in 14 families) was the dominant group, accounting for 70% of the total individuals. Daptonema, Neochromadora, Hypodondolaimus, and Dichromadora were dominant. Only salinity significantly changed between seasons and was significantly higher in the dry season. Meiofauna and nematofauna density and richness were lower than those in other mangroves worldwide. The significant changes in meiofauna and nematofauna between seasons and depths were related to higher salinity and food availability during the dry season and more food and oxygen available close to the surface (0–2 cm depth). Meiofauna did not show significant differences between vegetated and non-vegetated areas; however, higher density and richness were generally recorded in the vegetated areas, where food is more abundant, and the substrate is more stable. Non-selective deposit-feeding nematodes were dominant in all areas, seasons and depths. During the rainy season, the second most abundant feeding group was predators/omnivores as a response to an increase in organic detritus, whereas epigrowth feeders were the second most abundant group during dry season due to increased phytoplankton and phytobenthic production.

Microcrustacean metacommunities in urban temporary ponds

Microcrustaceans have a series of adaptations that allow their development in temporary aquatic environments. The colonization and consequent structuring of the communities in these systems is influenced by several environmental and spatial factors. Among them, urbanization is one of the important structuring factors of these communities. Metacommunity theory is an important tool for assessing how local (e.g. environment, competition and predation) and regional/spatial (e.g. dispersion) factors can influence the structure of communities distributed in patches in an area. We evaluated the diversity of the metacommunity of microcrustaceans in two categories of urban aquatic environments, preserved and constructed, looking for how the environmental and spatial factors influenced their diversity. We also sought to verify which beta diversity mechanism explained the dissimilarity between communities. We hypothesized that the richness of taxa would be greater in aquatic environments of preserved areas and in constructed areas there would be a loss of species, thus generating a beta diversity explained by the nestedness pattern. We sampled temporary environments in an urban area, eight in a preserved and six in a construction area. The results showed a clear difference between the two areas, both in environmental characteristics and in the composition of taxa. In relation to the richness of taxa, the areas did not present significant differences, thus rejecting our first hypothesis. The beta diversity was explained mainly by the turnover mechanism, refuting our second hypothesis. This pattern was mainly explained by the difference in the composition of taxa between the preserved and construction area environments.

A shift of ecosystem engineers during the succession of an intertidal benthic community associated with natural and anthropogenic disturbances

Temporal variation and sewage pollution were assessed on the recruitment of two benthic ecosystems engineer species during an experimental succession. The re-colonisation of the spionid polychaete Boccardia proboscidea and the mussel Brachidontes rodriguezii reached a maximum cover recruitment of 80 % after 12 and 20 weeks, respectively in plots cleared in spring. While in plots cleared in autumn B. proboscidea remained dominant from the initial re-colonisation to final successional stages. The settlement of the green algae Ulva hookeriana was facilitated by B. rodriguezii. The spionid polychaete had an abundance peak during spring, replacing B. rodriguezii and dominated the sewage-polluted area. However, the mussel returned to be the dominant species after a wind-wave–storm. An environmental disturbance like the documented storm was an important structuring factor of the studied community, with implications on the intertidal diversity, as it may change the dominance of the ecosystem engineers in the local sewage-impacted area.

Can zooplankton grazing affect the functional features of phytoplankton in subtropical shallow lakes? - Experiment in situ in the south of Brazil

Herbivory in aquatic environments reflects the organization of trophic webs as a structuring factor in the communities of prima-ry producers. We experimentally evaluated the influence of grazing by zooplankton and by different predator groups on the abundance and biomass of phytoplankton and morphologically-based functional groups (MBFGs), in a subtropical floodplain shallow lake (Brazil). We tested if different grazing levels modify the structure of the phytoplankton, considering that higher zooplankton abundance reduces the abundance and biomass of phytoplankton and the MBFGs. We used five treatments (5 L) with different zooplankton abundance and five replicas to represent an increasing grazing gradient. Sampling of phytoplankton and zooplankton was carried out after 24 hours, in each treatment. The zooplankton abundance presented significant differences among treatments (F = 11.79; p < 0.01), showing the evident grazing gradient in the experiment. Rotifers dominated all the treatments, followed by copepods, although their abundance decreased at the end of the experiment. In contrast, cladoceran abundance increased. An inverse and significant relationship was observed between zooplankton and rotifer abundances and MBFG III abundance (β = -0.85, p < 0.01; r2 = 0.32; β = -0.54; p < 0.01; r2 = 0.29, respectively), showing an effective preda-tor-prey interaction. Many positive and significant relationships were also observed among the grazers and the prey. The increase of the abundance and biovolume of phytoplankton was related to the bottom-up mechanisms, the rapid population growth of prey, and the short time of the experiment. The change in the MBFGs’ contribution was related to the increase in the zooplankton and group abundance, grazer competition and exploitative competition among the MBFGs. The experiment contributes to the knowledge on an important part of the trophic dynamics among planktonic communities in subtropical floodplain shallow lakes

Detailed Mapping of Hydrothermal Vent Fauna: A 3D Reconstruction Approach Based on Video Imagery

Active hydrothermal vent fields are complex, small-scale habitats hosting endemic fauna that changes at scales of centimeters, influenced by topographical variables. In previous studies, it has been shown that the distance to hydrothermal fluids is also a major structuring factor. Imagery analysis based on two dimensional photo stitching revealed insights to the vent field zonation around fluid exits and a basic knowledge of faunal assemblages within hydrothermal vent fields. However, complex three dimensional surfaces could not be adequately replicated in those studies, and the assemblage structure, as well as their relation to abiotic terrain variables, is often only descriptive. In this study we use ROV video imagery of a hydrothermal vent field on the southeastern Indian Ridge in the Indian Ocean. Structure from Motion photogrammetry was applied to build a high resolution 3D reconstruction model of one side of a newly discovered active hydrothermal chimney complex, allowing for the quantification of abundances. Likewise, the reconstruction was used to infer terrain variables at a scale important for megabenthic specimens, which were related to the abundances of the faunal assemblages. Based on the terrain variables, applied random forest model predicted the faunal assemblage distribution with an accuracy of 84.97 %. The most important structuring variables were the distances to diffuse- and black fluid exits, as well as the height of the chimney complex. This novel approach enabled us to classify quantified abundances of megabenthic taxa to distinct faunal assemblages and relate terrain variables to their distribution. The successful prediction of faunal assemblage occurrences further supports the importance of abiotic terrain variables as key structuring factors in hydrothermal systems and offers the possibility to detect suitable areas for Marine Protected areas on larger spatial scales. This technique works for any kind of video imagery, regardless of its initial purpose and can be implemented in marine monitoring and management.

Crop Residues in Wheat-Oilseed Rape Rotation System: a Pivotal, Shifting Platform for Microbial Meetings.

Crop residues are a crucial ecological niche with a major biological impact on agricultural ecosystems. In this study, we used a combined diachronic and synchronic field experiment based on wheat-oilseed rape rotations to test the hypothesis that plant is a structuring factor of microbial communities in crop residues, and that this effect decreases over time with their likely progressive degradation and colonisation by other microorganisms. We characterised an entire fungal and bacterial community associated with 150 wheat and oilseed rape residue samples at a plurennial scale by metabarcoding. The impact of plant species on the residue microbiota decreased over time and our data revealed turnover, with the replacement of oligotrophs, often plant-specific genera (such as pathogens) by copiotrophs, belonging to more generalist genera. Within a single cropping season, the plant-specific genera and species were gradually replaced by taxa that are likely to originate from the soil. These changes occurred more rapidly for bacteria than for fungi, known to degrade complex compounds. Overall, our findings suggest that crop residues constitute a key fully-fledged microbial ecosystem. Taking into account this ecosystem, that has been neglected for too long, is essential, not only to improve the quantitative management of residues, the presence of which can be detrimental to crop health, but also to identify groups of beneficial microorganisms. Our findings are of particular importance, because the wheat-oilseed rape rotation, in which no-till practices are frequent, is particularly widespread in the European arable cropping systems.

Changing dimensions of cultural consumption? The space of lifestyles in Switzerland from 1976 to 2013

In the present study we trace transformations of the Swiss space of lifestyles during the past four decades. The sociological discussion suggests that lifestyle practices were once structured by a highbrow-lowbrow distinction, whereas today cultural omnivorism, eclecticism, broad engagement, or cosmopolitanism should be prevalent. Furthermore, Bourdieu’s homology thesis claims that cultural consumption is closely linked with class structures, which is contested by recent individualisation arguments. So, we ask two questions here: First, what are the main axes of the Swiss space of lifestyles and how do they develop over time? Second, how does the association between the space of lifestyles and the space of social positions evolve over time? We find that cultural practices in Switzerland are primarily structured by a dimension differentiating between engagement in a wide range of activities and disengagement, followed, secondly, by a highbrow-popular distinction. Accordingly, we identify an “inactive”, an “intense highbrow” and a “moderate eclectic” consumption pattern. Although this configuration is quite stable over time, structural correlates of lifestyles are changing. Most importantly, indicators of vertical social position like education or occupational status are correlated with broad cultural engagement today, whereas they have been correlated with highbrow activities in the 1970s. Instead, age emerged as the main structuring factor of highbrow-popular disparities.

PRACTICES OF UKRAINIAN TRADITIONAL WEDDING RECONSTRUCTION IN THE BEGINNING OF THE XXI c.

This article is devoted to the issue, which usually slips away from the scholar`s glance – to attempts of traditional Ukrainian wedding or its elements reconstruction in contemporary conditions. The article`s source base consists of the author`s field researches, interviews, video and photo materials. The author pays attention to the real weddings in “folk style” as well as to the local variants of the wedding, staged by folklore ensembles.The main purpose of the article is to examine such practices in aspects of their functionality, process, material and interaction content and, at last, factors that structure the situation of reconstruction and allow to recognize it among other collective actions. To reach the last aim frame-analysis, developed by E. Goffman, is used.The motivations of the reconstructors can be different: participation in some festival or competition in case of staged performances; sincerely desire, connected with professional or extra-professional interests in case of the real “ethnographical weddings”. However, in the latter case participators often realize their activity as some extraordinary behavior, deserving for some self-irony.The author makes conclusion that wedding rite`s reconstructions fluctuate between two pairs of social senses. First of all, it seems that real “ethnographical weddings” often have connotation of the averaged “Ukrainian” wedding, despite they appeal to the certain social and historical variant of the wedding – traditional peasant wedding of the XVIII and XIX centuries. The second pair of senses is the wedding as it is and performance – in the “real” weddings it is notable actualized.The research shows that in many cases reconstruction of traditional wedding can be understood as a collage, made from different sources. Besides that such structuring factors of this situation are defined: locality of reconstruction, presence of alien spectators, scenario, filming and demand in concentrate format. If the “ethnographical wedding” has schematic view, it draws near to the frame of performance. And the more detailed it is, the closer to the traditional wedding it becomes. Wedding reconstructions in Ukraine represent all spectrum between these two frames. Opposed to some historiographical positions, real weddings in “folk style” isn`t only illusion of reality or authenticity. In contemporary circumstances they can reach forms, senses and importance of traditional wedding, although it seems impossible to define some “formula” of successful synthesis of ethnographical material in certain reconstruction.

Structurally Controlled Cellular Architectures for High-Performance Ultra-Lightweight Materials.

The design and synthesis of cellular structured materials are of both scientific and technological importance since they can impart remarkably improved material properties such as low density, high mechanical strength, and adjustable surface functionality compared to their bulk counterparts. Although reducing the density of porous structures would generally result in reductions in mechanical properties, this challenge can be addressed by introducing a structural hierarchy and using mechanically reinforced constituent materials. Thus, precise control over several design factors in structuring, including the type of constituent, symmetry of architectures, and dimension of the unit cells, is extremely important for maximizing the targeted performance. The feasibility of lightweight materials for advanced applications is broadly explored due to recent advances in synthetic approaches for different types of cellular architectures. Here, an overview of the development of lightweight cellular materials according to the structural interconnectivity and randomness of the internal pores is provided. Starting from a fundamental study on how material density is associated with mechanical performance, the resulting structural and mechanical properties of cellular materials are investigated for potential applications such as energy/mass absorption and electrical and thermal management. Finally, current challenges and perspectives on high-performance ultra-lightweight materials potentially implementable by well-controlled cellular architectures are discussed.

Migrant Workers or Working Women? Comparing Labour Supply Policies in Post-War Europe

ABSTRACTWhy did some European countries choose migrant labour to expand their labour force in the decades that followed World War II, while others opted for measures to expand female employment via welfare expansion? The paper argues that gender norms and the political strength of the left were important structuring factors in these choices. Female employment required a substantial expansion of state intervention (e.g. childcare; paid maternity leave). Meanwhile, migrant recruitment required minimal public investments, at least in the short term, and preserved traditional gender roles. Using the contrasting cases of Sweden and Switzerland, the article argues that the combination of a weak left (labour unions and social democratic parties) and conservative gender norms fostered the massive expansion of foreign labour and a late development of female labour force participation in Switzerland. In contrast, more progressive gender norms and a strong labour movement put an early end to guest worker programmes in Sweden, and paved the way for policies to promote female labour force participation.

Canopy-Forming Macroalgae Facilitate Recolonization of Sub-Arctic Intertidal Fauna and Reduce Temperature Extremes

Ice can be an important structuring factor physically removing intertidal flora and fauna. At high latitudes in particular, the removal of canopy-forming algae by ice scour may be important as their canopy may serve to modify the extreme environment for marine organisms at low tide. We simulated the effect of ice scouring by manipulating the biomass of the canopy-forming algae Ascophyllum nodosum in a sub-Arctic fjord (‘Full canopy’, ‘Reduced canopy’, ‘Bare (start)’, ‘Bare (annual)’). Over a three-year period, we quantified key physical parameters and the recolonization of flora and fauna to test the hypothesis that A. nodosum and rock rugosity facilitate recolonization of sub-Arctic intertidal fauna and that potential facilitation could rely on an ability of A. nodosum canopy to modify air temperature and ice scour. Finally, we estimated the recovery period of A. nodosum canopy height to pre-disturbance levels based on estimated early growth rates. We found that A. nodosum canopy facilitated higher species richness and recolonization of dominating faunal species (Littorina saxatilis, Littorina obtusata, Mytilus edulis and Semibalanus balanoides), and also significantly reduced the high temperatures in summer and raised the low temperatures in winter. The abundance of M. edulis and A. nodosum recolonization increased significantly with rock rugosity and the recovery of A. nodosum canopy height was estimated to a minimum of 15 years. We conclude that algal canopy and rock rugosity play key roles in structuring sub-Arctic intertidal communities, likely by modifying environmental stress such as extreme temperature, desiccation, and by increasing the settling surface and the habitat complexity. As the distribution of canopy-forming algae is expected to shift northward, they may act as a key habitat facilitating a northward colonization of intertidal fauna in the Arctic. We highlight the importance of considering scales relevant to biological communities when predicting impacts of climate change on distributional patterns and community structure in the Arctic intertidal.

The spatial scaling of impact in edaphic and plant factors on the structuring of the soil macrofauna community

In this paper, the role of edaphic factors and plant, as well as the spatial variables was revealed in the structuring of the forest biogeocenosis soil macrofauna community in the river Dnepr arena within the nature reserve of Dnepr-Orelsky (Ukraine). 44 species of soil animals were found in the test polygon after manual sorting of soil samples. The density of the soil macrofauna in studied polygon is 321.5 ± 43.2 ind./m2. It is shown that the soil macrofauna community is structured under the influence of edaphic, plant and spatial factors. The role of these factors is different at fine-scale, medium-scale and broad-scale spatial levels. The variation of the community structure under the influence of edaphic and plant factors can be classified as deterministic processes, which is carried out within the framework of the ecological niche theory. The spatial component of the variation can be attributed to the result of the neutral nature of the factors. However, it should be noted that the spatial variation of plant community also is subject to the deterministic and neutral control. This manifests itself in the spatial structuring of plant factors. The spatial variation of soil properties has a similar nature. Soil as environment undergoes structuring influence of vegetation, where there are spatial patterns of soil properties. Scale effects of variation in space manifest themselves in different ways for the representatives of different ecological groups of macrofauna. For litter forms the most characteristic spatial patterns on large and medium-scale level, and for proper soil and burrowing forms - on fine-scale level.

Sensitivity and response of low-nutrient lakes to post twentieth century environmental change in New Brunswick, Canada

A paleolimnological approach was used at 45 mostly remote, low-nutrient lakes in New Brunswick (NB), Canada, to determine bioindicator responses and lake sensitivity to post twentieth century environmental change. From each undated core we assessed zooplankton (Cladocera) change between discrete time periods using related assemblage metrics, including the rise of Bosmina sp., cladoceran richness, and average assemblage body size. Cladocerans from a pre-industrial interval (20–20.5 cm) were compared to those from a present-day interval (0–0.5 cm). Lakes were then classified as either high- or low-sensitivity based on assemblage metrics, and sensitivity group differences in physical–chemical measures were tested for significance. Compared to pre-industrial times, Bosmina sp. relative abundance increased in 33 of 43 lakes (75% of lakes surveyed) by on average 20%. Body size and rarefied species richness of assemblages decreased significantly. These ecological shifts detected at an important intermediate trophic level are attributable to indirect effects of climate change, although we cannot rule out shifts in fish predation and littoral habitat as additional structuring factors. Eighteen lakes were classified as high-sensitivity lakes and showed significant differences in latitude, surface area, elevation, dissolved calcium and magnesium concentrations, and conductivity compared to 25 low-sensitivity lakes. In high-sensitivity lakes, richness decreased on average by 6 species and body size decreased by 0.2 mm. This study presents a historical context for constructing effective conservation and management efforts at a time of substantial environmental change in low-nutrient NB lakes.

Assessing the phenotypic and genotypic diversity of Sclerotinia sclerotiorum in France

White mould caused by the ascomycete Sclerotinia sclerotiorum affects the production of many economically important crops. The incidence of this disease has recently increased in France, especially in melon crops, which were not affected much in the past. One possible explanation for this situation is the emergence of strains with particular characteristics, including increased aggressiveness to melon. To test this hypothesis, 200 isolates of S. sclerotiorum were collected from six host crops (bean, brassica oilseed rape, carrot, lettuce, melon, witloof chicory) in different regions. They were genotyped with 16 microsatellites markers. A subsample of 96 isolates were assessed for their aggressiveness on melon leaves. Overall, the isolates from melon did not show higher aggressiveness on melon leaves than those which originated from other host plants. Moreover, the melon isolates did not present distinctive genetic characteristics in comparison with those from other crops and shared several of the 128 identified multilocus haplotypes with isolates collected from carrot, witloof chicory and oilseed rape. Furthermore the Bayesian analysis of the genetic structure indicated that the host plant is not a structuring factor of the three genetic clusters identified, and it suggested instead the occurrence of an isolation-by-distance process. Possible consequences of these results for the management of white mould and alternative hypotheses to explain the recent changes in disease incidence are presented.

Microbiota inoculum composition affects holobiont assembly and host growth in Daphnia

BackgroundHost-associated microbiota is often acquired by horizontal transmission of microbes present in the environment. It is hypothesized that differences in the environmental pool of colonizers can influence microbiota community assembly on the host and as such affect holobiont composition and host fitness. To investigate this hypothesis, the host-associated microbiota of the invertebrate eco(toxico)logical model Daphnia was experimentally disturbed using different concentrations of the antibiotic oxytetracycline. The community assembly and host-microbiota interactions when Daphnia were colonized by the disturbed microbiota were investigated by inoculating germ-free individuals with the microbiota.ResultsAntibiotic-induced disturbance of the microbiota had a strong effect on the subsequent colonization of Daphnia by affecting ecological interactions between members of the microbiota. This resulted in differences in community assembly which, in turn, affected Daphnia growth.ConclusionsThese results show that the composition of the pool of colonizing microbiota can be an important structuring factor of the microbiota assembly on Daphnia, affecting holobiont composition and host growth. These findings contribute to a better understanding of how the microbial environment can shape the holobiont composition and affect host-microbiota interactions.

Ranking of wetting–drying, plant, and fauna factors involved in the structure dynamics of a young constructed Technosol

Dynamical in situ observation of biological and climatic structuring factors involved in pedogenesis has not previously been possible in a way that would consider the early stages of pedogenesis. If studies have explored the effect of pedogenetic factors on soil structure, none have succeeded in ranking them in view of the intensity of their effects. We propose a novel approach for describing the aggregation process for a constructed Technosol obtained from a process of pedological engineering. We focus on agents including plants, macrofauna, and water, and we use (i) a dynamic in situ observation and (ii) the quantification of the evolution of selected descriptors of pores and aggregates. They are quantified from high-resolution images obtained with the Soilinsight® device. Associating those images with each other, movies of interactions between soil and organisms over a 14-month non-destructive soil evolution experiment are made. Agents influencing aggregation—plant roots, earthworms, and water—can be ranked according to their impact on soil structure. During the studied period of evolution, wetting–drying cycles are the first to operate. The intensity of their action on soil structure is dominant at the very first stages of pedogenesis. Despite this ranking of agents, over the long term, plants and earthworms have a more intense effect on soil structure than wetting–drying cycles. The method applied to observe and quantify soil structure dynamics is thus proposed as a helpful approach to modeling other processes involved in soil functioning and evolution in relation to their ability to fulfill ecosystem services.

Comparing anadromous brown trout Salmo trutta in small, neighbouring catchments across contrasting landscapes: What is the role of environment in determining life-history characteristics?

Study of anadromous brown trout Salmo trutta in Orkney, U.K., burns (small streams) with a common-garden sea in Scapa Flow supports the key role of nutrient availability in fresh water, independent of day length, as a determinant of smolt age, with a systematic increase in mean smolt age from 1 to 3years related inversely to productivity. Whole catchment (8km2 ) population budgets indicated annual smolt production of around 650 individuals from approximately 100 spawners. Egg-to-smolt survival was 0·65%, while marine survival was estimated from mark-recapture to be between 3·5 and 10%. The question of B-type growth (accelerated growth immediately prior to or during smolt migration) was also addressed, with a strong negative correlation between B-type growth and size at end of winter suggesting that this represents a freshwater compensatory growth response. The data obtained indicate the potential importance of small catchments for supporting anadromous Salmo trutta populations and suggest that small runs of spawners (<100 individuals) are adequate to maintain stocks in such situations. Furthermore, they support the key role of freshwater productivity in determining life-history characteristics over small spatial scales, with Orkney providing a useful natural laboratory for future research into metapopulation genetic structuring and environmental factors at a tractable scale.

Habitat-dependent responses of tropical fish assemblages to environmental variables in a marine-estuarine transitional system

Guanabara Bay is located within one of the most populated areas in Brazil, still harbouring a great aquatic biodiversity and supporting important commercial fisheries despite the increased levels of human disturbances. Here, individual and simultaneous effects of water temperature, pH, and salinity on reef-associated and transient fish assemblages in a transitional marine-estuarine zone of Guanabara Bay were addressed. It was predicted that composition and structure of fish assemblages will respond differently to these environmental variables, depending on the species-specific degree of association with rocky substrates. A canonical correspondence analysis applied on all 83 fish species caught revealed that fish assemblages as a whole were mainly driven by salinity and pH, but with no clear trend of species association or seasonal responses. Canonical analysis of principal coordinates revealed a group composed only by reef-associated species, which was separated from a second group of only transient species, but some species of overlapping distribution were also detected (mixed group). Reef-associated species followed mostly a salinity gradient, whereas transient species responded to salinity and temperature, and those of the mixed group were ruled by salinity and pH. Generalized additive models indicated that, except for transient species, fish richness increased with the effects of estuarine waters from inner bay. Our study is the first to highlight the importance of a transitional zone in coastal bays, which can apparently increase the potential of sharing species among marine and estuarine areas, leading thus to positive effects on local biodiversity. We also stress the role of salinity as key structuring factor of the fish assemblages in tropical coastal bays, and its potential to be used, in conjunction with pH and temperature, as a proxy of alternating influence of estuarine and oceanic waters in these systems.