Edge Zone Research Articles

Behavioral responses to riparian and anthropogenic edge effects in mantled howler monkeys (Alouatta palliata) in a disturbed riverine forest.

Fragmented forests contain natural edges, including riparian zones, and anthropogenic edges. Edges generally have lower plant density and fewer large trees than forest interior. Riparian edges, however, contain gap-specialist trees yielding leaves with high protein content, providing primates with important resources. We examined mantled howler monkeys' behavioral responses to riparian and anthropogenic edges at La Suerte Biological Research Station (LSBRS), Costa Rica. We predicted the monkeys would spend more time resting and feeding and less time traveling, and be less spatially cohesive, in both anthropogenic and riparian edges compared to forest interior due to lower resource abundance in edges, and in anthropogenic compared to riparian edge due to higher leaf quality in riparian zones. From 2017 to 2020, we collected data across forest zones on activity and spatial cohesion patterns via focal sampling, recording data every 2min. Howler monkeys were significantly more likely to rest and significantly less likely to travel in both anthropogenic and riparian edges compared to forest interior; however, there were no differences between these edge types. There were significantly more monkeys within a 5-m radius of focal subjects in both anthropogenic and riparian edges compared to forest interior, but no differences between these edge types. While prior research found no differences across zones when only anthropogenic edge and forest interior were compared, results of this study demonstrate that howler monkeys at LSBRS modify their activity patterns in anthropogenic and riparian edge zones compared to forest interior, highlighting the importance of focusing on both natural and anthropogenic edge zones to fully understand primates' behavioral responses in fragmented landscapes.

Wind loading on a low-slope gabled roof: Comparison of field measurements, wind tunnel data, and code provisions

The current wind load provisions for low-slope roofs in the NBCC were established in the 70 s with wind tunnel experiments using analog data technology. These coefficients have remained almost unchanged. As the wind pressure measurement tools have significantly improved during the past 50 years, verification of the original pressure coefficients is required. The National Research Council of Canada (NRC), in collaboration with the Special Interest Group on Dynamic Evaluation of Roofing Systems (SIGDERS) consortium, conducted a wind load investigation to verify the suitability of the current wind load provisions. The investigation was carried out using both field measurements and wind tunnel simulations. An ideal full-scale representation of the low-slope roof specified in building code was instrumented and continuous data was collected for four years. A duplication of the building was evaluated by two wind tunnels to investigate the effect of critical wind directions. The paper presents the efforts made to make field measurements comparable to wind tunnel data and code provisions. It was observed that records with mean wind a speed above 22 mph (10 m/s) reduce the data variability and maximize reliability, which are important features for the code verification process. The goal of this research is to combine multiple sources of data to verify the suitability of wind load provisions on low-slope roofs. The research focuses on NBCC-2020 as an application. Evidence is presented that the NBCC-2020 provisions for the Roof Edge Zone is currently underestimated and needs to be increased. The study suggests taking the opportunity of Edge provision enhancement to merge Corner and Edge into a unique “Perimeter” load provision. The suggested code change addresses the current underestimation of the Edge Zone coefficients (wind load upgrade), and provides construction simplification to minimize roofing failure associated with labour-induced errors during cladding system installation (constructability upgrade).

Influence of relative velocity and contact force between abrasive media and workpiece on material removal in gyro finishing

Gyro finishing is capable of reducing the surface roughness and inducing residual compressive stresses into the edge zone of the component to enhance the fatigue strength. Due to an insufficient understanding of gyro finishing processes, it is not possible to adjust the process result in a knowledge-based manner. In order to understand the mechanisms of action in the process, knowledge of the contact between abrasive media and workpiece is necessary. This paper presents the analysis of the contact conditions and the process state variables between abrasive media and workpiece with two measuring systems. Furthermore, the influence of the contact conditions and the process state variables on the material removal mass was investigated. Therefore, analogy workpieces were machined by gyro finishing using different process state variables and abrasive media specifications. Based on the results, an empirical-analytical model is derived, which is able to describe the material removal mass depending on the contact conditions and the process state variables between abrasive media and workpiece.

Wind Loading of Photovoltaic Panels Installed on Hip Roofs of Rectangular and L-Shaped Low-Rise Buildings

Many residential houses in Japan have hip roofs with pitches ranging from 20° to 30°. Recently, roof-mounted photovoltaic (PV) panels have become popular all over the world for environmental conservation. The design of PV systems in Japan is usually based on the Japanese Industrial Standard (JIS) C 8955 (2017). However, the standard does not provide wind force coefficients for PV panels installed near roof edges (up to 0.3 m from the edge) because flow separation at the roof edges causes large up-lift forces on such panels. In this paper, we investigated the wind force coefficients for designing PV panels installed on hip roofs of rectangular and L-shaped low-rise buildings. The roof pitch was set to 25° as a typical value. Rectangular panels were installed almost over the whole roof, including the edge zones. Because the thickness of PV panels and the distance between PV panels and the roof are both as small as several centimeters, it is difficult to make wind tunnel models of PV systems with the same geometric scale as that for buildings. We focused on a numerical simulation using the unsteady Bernoulli equation to estimate the pressures in the space between PV panels and the roof. In the simulation, we used the time histories of wind pressure coefficients on the bare roof, which were measured in a turbulent boundary layer. We propose installing PV panels with small gaps between them along their short sides. The gaps may reduce the wind loads not only on the PV panels but also on the roofing due to pressure equalization. We discuss the optimum gap width from the viewpoint of wind load reduction.

Gulf Stream Position, Width, and Orientation Estimated from HF Radar Radial Velocity Maps off Cape Hatteras, North Carolina

Abstract A method to extract characteristics of the Gulf Stream (GS) surface flow field using high-frequency radar (HFR)–derived currents is described. Radial velocity measurements, from radar installations near Cape Hatteras, North Carolina, serve as input, chosen because of the greater spatial and temporal coverage provided compared to total velocity fields. The landward GS edge, jet axis, orientation, and cyclonic shear zone (CSZ) width are identified along bearings within the radar footprint. The method is applied to observations from two radar installations from November 2014 and provides GS estimates with daily temporal resolution. Results along eight bearings provide a consistent representation of GS variability dominated by the passage of meanders. Average distance to the GS edge along bearings varies from 50 to 100 km; distance estimate quality degrades with range from the radars. Monthly mean GS jet axis locations from satellite sea surface height (SSH) and the algorithm are consistent. Cross correlations between estimates of GS characteristics in the same region vary from 0.37 to 0.73 for the GS edge. Estimates of radar distance to the GS edge are negatively correlated with current velocity measurements nearest the surface from a moored 150-kHz acoustic Doppler current profiler and vary between −0.58 and −0.71. GS CSZ width metrics range from mean values of 29–31 km. Daily GS orientation estimates are affected by the crossing angle of the radial bearing relative to the GS. Lags from the cross correlations of monthly mean properties suggest meander propagation speed estimates increase from 43.2 km day−1 south of the cape, to 136.8 km day−1 just east of it.

Where is the forest core area? Gradients of flora in the ecotone of urban forests in Warsaw

Urban forests are very important ecosystems, performing key cultural services and having crucial regulatory functions. However, naturally valuable areas in cities continue to decline or undergo irreversible transformations. It is necessary to determine the extent of human influence on forest ecosystems in highly urbanized environments. Our study examined the indicators of diversity, naturalness, lability, and stability of flora along transects from edge to center of six urban forests. Furthermore, the shape of gradients of changes and the threshold distance and straightness between forest edge and core for these indicators were measured. Finally, the impact of the number of inhabitants, the degree of protection, and the size and shape of the forests on each indicator separately and their aggregation in the form of the Flora Transformation Index were analyzed. The findings revealed that the gradients of changes were rarely linear and showed a logarithmic or polynomial shape. The most regular gradients were observed for lability and naturalness of flora. The regularity of the shape of the thresholds differed between the studied indicators. The threshold distance was relatively far (93–113 m) and depended heavily on human influence, but forest shape and area were also very important. Our results showed that legal protection, even as a reserve, has no effect in the case of solid human penetration of the forest. Our findings are expected to help determine suitable indicators for defining threshold values, i.e., the size of the edge and core zones of urban forests, which is crucial to the protection of the native plant species pool.

Effects of Forest Fragmentation on the Volume of Wood Resources in Managed, Pine-Dominated Forests in Poland

Forest fragmentation is a widespread phenomenon that directly or indirectly affects the processes that take place both in forest ecosystems and in their immediate surroundings. So far, many studies confirm its negative effects, especially on biodiversity. On the other hand, there are few studies that address the effects of forest fragmentation on the amount of accumulated biomass or carbon, as well as on the characteristics of wood resources in managed forests. Therefore, issues related to timber production, which are important from the point of view of multifunctional forest management, are omitted. The aim of our research was to add to the knowledge in this area. In particular, we focused on assessing the impact of forest fragmentation on wood resources based on an analysis of edge effects in forest patches (units formed by combining forest fragments characterized by structural connectivity). Vector data describing the topography of forest fragments in Poland and the results of the National Forest Inventory (NFI) from 2015–2019 were used as material for solving this problem. The results of our research showed that the effects of fragmentation on managed pine stands depend on the age of the stand and the fertility of the habitat. In young stands growing on barren or strongly barren habitats, growing stock volume turned out to be significantly higher in the edge zone. In older stands, especially on moderately fertile habitats, significantly higher resources were found in the interior zone of forest patches. Habitat quality also had a significant effect on the amount of carbon accumulated. In strongly barren habitats, higher carbon mass was found in edge zones, while in moderately fertile habitats, stands had higher carbon volume in the interior zone. Our results illustrate that forest fragmentation is a very complex process that can increase or reduce wood resources, depending on the age of the stand and the quality of the habitat. From the standpoint of measurable benefits, it was concluded that protection from the negative effects of fragmentation should focus primarily on older stands and more fertile habitats.

High-fidelity modeling of turbulent shear flow downstream of a 3-D airfoil with spanwise ice contamination leading stall

The characteristics of turbulent shear flow downstream of NACA23012 airfoil with ridge-ice contamination leading stall are investigated in this paper. A low-dissipated compressible N–S solver is employed to simulate its unsteadiness via Improved Delayed Detached Eddy Simulation (IDDES) with sufficient spatial and temporal resolution. Nonlinear phenomena of eddy dynamics, such as vortex pairing, shedding, merging and breaking down, are fully resolved with extremely fine grid scale over 0.2 billion. The calculated Reynolds number based on the airfoil chord length is near 2.1×106. High-fidelity results show that the turbulent shear stream quickly develops into tubular geometry after leaving the ridge. The shedding-off tubular geometries quickly show anisotropy, twist in all directions, and finally decomposed into turbulence. Large-scale structural interaction is found above the trailing edge zone, determined by the shedding-off vortex and the rolling-up flow from the lower surface of the airfoil. Using POD and DMD analysis, we make sense it as the cause of low-frequency oscillation of the shear layer and even the lift fluctuation.

Effects of joint heat distribution on material flow and microstructure in continuous drive friction welding of 45 # steel

Continuous drive friction welding (CDFW) is an economical and productive method for joining similar metals. In this study, 45 # steel was joined via CDFW, and the material heat distribution, flow behaviour, flash formation and fracture mode were investigated via experiments and simulations. The bar was divided into three zones in the direction of radius (R), the R zone near the axis, the edge zone at the edge of the R and the 0.5 R zone between the R zone and edge zone. The maximum flow velocity and temperature of the joint first appeared in the 0.5 R zone, and as the friction continued, the maximum temperature moved to the edge zone, followed by flash. When the friction time was 9 s, the maximum tensile strength was 674 MPa, the fracture mode was the coexistence of ductile and brittle and the fracture location had an obvious boundary. Ductile fracture occurred in the R zone, and the flash took a lot of heat, brittle fracture occurred in the 0.5 R and edge zones. The maximum microhardness of the joint is 295 HV in the weld zone, and the microhardness decreased in the partially deformed zone. When the friction time was appropriate, the heat distribution was uniform and sufficient, and the grains exhibited a significant degree of dynamic recrystallisation refinement.

Influence of Metal Working Fluids in Cutting Processes

For the realization of efficient production processes, an understanding of the appropriate application of metal working fluids (MWF) is necessary. In addition to knowledge about the process-related aspect of chip transport and the macroscopic cooling effect, the characteristics and properties of the lubrication film thickness and the cooling conditions in the area of the secondary shear zone on the chip surface, i.e. in the direct vicinity of the material separation, represent a fundamental scientific issue within production technology. In particular, these areas generate a high proportion of heat during machining, so that the local friction phenomena have a significant influence on the resulting edge zone of the produced component and the thermomechanical load on the tool. Currently, there are no numerical models and methods for mapping and predicting the lubrication film thickness that can be used in the sense of a targeted design of the cooling lubricant supply. The aim is to transfer the methods from the field of tribology of machine elements, which have already led to significant knowledge gains in this discipline, to machining and couple them to approaches already established in machining. To this end, experiments on tribometers have been performed as a first step. For example, an oscillating pin-on-plate tribometer was used. In this setup, a steel plate is doing oscillating motion against a fixed ball (diameter of 6 mm) under a defined load. The frictional force is recorded during the test. A MWF in a heated tank is used for the lubricant. Additional investigations on the film thickness were performed on an optical EHL (elasto-hydrodynamic lubrication) tribometer. In this setup, a ball rolls on a glass-disc and the resulting film thickness is measured by interferometry.For comparison, the influence of the MWF on the chip formation process in metal cutting was investigated on a special test rig (machine tool). This test rig allows high speed imaging and force measurements of an orthogonal cutting process while using MWFs. The first results show a reduced contact length between chip and tool as well as lower process forces for processes with MWFs compared to dry cutting processes. In future investigations, this test rig will be applied for the identification of the local friction coefficient between chip and tool. The data gained from the cutting test are compared with the output of the tribological test rigs.

Quantitative Analysis of Land Subsidence and Its Effect on Vegetation in Xishan Coalfield of Shanxi Province

It is of great significance for the monitoring and protection of the original ecological environment in coal mining areas to identify the ground subsidence and quantify its influence on the surface vegetation. The surface deformation and vegetation information were obtained by using spaceborne SAR and Landsat OLI images in the Xishan Coalfield. The relative change rate, coefficient of variation, and trend analysis methods were used to compare the vegetation growth trends in the subsidence center, subsidence edge, and non-subsidence zones; and the vegetation coverage was predicted by the pixel dichotomy and grey model from 2021 to 2025. The results indicated that the proportions of vegetation with high fluctuation and serious degradation were 6.60% and 5.64% in the subsidence center, and its NDVI values were about 10% lower than that in the subsidence edge and non-subsidence zones. In addition, vegetation coverage showed a wedge ascending trend from 2013 to 2020, and the prediction values of vegetation coverage obtained by GM (1,1) model also revealed this trend. The residuals of the predicted values were 0.047, 0.047, and 0.019 compared with the vegetation coverage in 2021, and the vegetation coverage was the lowest in the subsidence center, which was consistent with the law obtained by using NDVI. Research suggested that ground subsidence caused by mining activities had a certain impact on the surface vegetation in the mining areas; the closer to the subsidence center, the greater the fluctuation of NDVI, and the stronger the vegetation degradation trend; conversely, the smaller the fluctuation, and the more stable the vegetation growth.

Modeling of intra-arterial hemodynamics in main arteries atherosclerosis

Abstract Funding Acknowledgements Type of funding sources: None. Aim. To study intra-arterial hemodynamics of the main arteries in atherosclerosis using the original device for modeling of intra-arterial circulation. Material and methods. To study hemodynamics inside an arterial vessel, we used an original device developed by us for modeling of intra-arterial circulation (Document of invention № RU 202780 U1). The main part of the device is a prototype of an artery - a glass tube of a rotameter with a length of 365 mm, an inlet end with a diameter of 20 mm, an outlet end - 16.5 mm. Flexible silicone tubes are attached to the rotameter on both sides, with free ends connected to an electric pump, with various modes of work (imitation of pulse waves at the regular rhythm (RR), extrasystole (ES), atrial fibrillation (AF)). An aqueous solution of glycerin was introduced into a closed system diluted with water corresponding to the viscosity of the blood. A 5 mm long silk thread was alternately installed inside the tube, an intravascular piezoelectric crystal pressure sensor connected to an oscilloscope was injected with a dye - clerical ink. Plastic diaphragms 15 mm long with stenosis of the internal lumen of 50%, 70%, and 90% were alternately hermetically installed in the rotameter. Results. When imitating ES in the first post-extrasystolic contraction (1PEC), the speed of fluid flow through the diaphragms increased in the 1PEC in comparison with the RR. So, with a stenosis of 50%, the speed with a RR was 2.09 m/s, with an ES 0.03 m/s, with 1PEC 3.83 m/s; with 70% stenosis, the speed at RR 3.24 m/s, with ES 0.04 m/s, with 1PEC 5.26 m/s; with 90% stenosis, the speed at RR 8.96 m / s, with ES 0.10 m/s, with 1PEC 12.36 m/s. The pressure increased proportionally to the speed. We observed the appearance of reflected, standing waves in the edge zones of the diaphragm and a turbulent flow of liquid behind the diaphragm. Conclusion. These changes in hemodynamics are characterized by the concept of "hydraulic shock". Intense mechanical effect of 1PEC pressure waves in the marginal zones of the diaphragm can contribute to the further growth and progression of atherosclerosis in arterial vessels. Abstract Figure.

Решение задачи о раскрытии метаном трещин в предельно напряженной зоне пласта

The conditions were studied concerning the cracks opening by in-situ methane in the formation marginal zone during its transition to the maximum stressed state. The calculations are based on the joint use of the fundamental methods of deformable solids mechanics, statics of the flowing medium, and the concept of academician S.A. Khristianovich on the distribution of pressure of intra-layer methane during the movement of the mine face at a constant speed. The stress field of a coal-rock mass containing a seam with a weak interlayer and a working through it, was constructed within the framework of an elastic-plastic problem of the stressed state of a coal-rock mass. It is reduced to the integral equation of the second external boundary value problem of elasticity theory and solved by the boundary element method. The stress distribution in the extremely stressed zone of the formation is constructed by the method of characteristics known in the theory of differential equations. In the model of the ultimate stress state of a structurally homogeneous formation, the limiting zones are formed from the edge itself. In the formation with an unstable interlayer, the interlayer passes to the limiting state first, and at some distance from the edge, the formation itself. After that, the formation and the intermediate layer are deformed as integral whole. The cracks in the formation, which are its slip lines, open when the pressure of in-situ methane exceeds the stresses normal to the contour of the slip line. These stresses are related to the values of the principal stresses found from the solution of the boundary value problem. From this condition, the dimensions of the formation edge zone with free methane surfaces are determined.

Formation of a dark streaky edge defect on galvannealed ultra-high strength steel

To analyze the formation mechanism of a dark streaky edge defect on a hot-dip galvannealed (GA) ultra-high strength steel (UHSS) sheet, multiple metallographic characterizations were performed on samples collected from different processes. It was found that this streaky defect was directly caused by differences in the coating morphology. The coating in the edge zone showed a crater morphology, while the coating in the center zone showed a flatter morphology and uniform coating thickness. Corresponding streaky edge defects were found on the annealed steel prior to hot-dipping and on the pickled steel prior to cold rolling. The root cause was finally traced back to the hot-rolled steel after coiling. A formation mechanism of this defect was proposed based on the evolution of surface microstructures in multiple processes. The difference in the amounts of internal oxides formed in the subsurface of different zones of the hot-rolled strip influenced the pickled steel surface, cold-rolled steel surface, annealed steel surface and the galvannealed coating surface.

ЗНИЖЕННЯ РІВНЯ МАГНІТНОГО ПОЛЯ ПІДЗЕМНОЇ КАБЕЛЬНОЇ ЛІНІЇ НА ВІДПОВІДАЛЬНИХ ДІЛЯНКАХ ЗА ДОПОМОГОЮ КОМПОЗИЦІЙНИХ МАГНІТНИХ ЕКРАНІВ КІНЦЕВОЇ ДОВЖИНИ

In the article, the numerical calculation and analysis of three-dimensional magnetic field of underground power cable line with finite-length magnetic shields used to reduce the level of this field on the ground are carried out. Both fill-up soil and filling soil containing magnetic particles and then having effective magnetic properties (=1÷1000) are proposed to used as magnetic shields. The shielding efficiency is studied for underground 330 kV cable line depending on the dimensions and effective magnetic permeability () of the shields. As shown, the use of filling soil with magnetic properties gives a possibility to reduce the field on the ground five times. This type of shielding is more efficient as compared to magnetic fill-up soil. The computed results reveal the non-monotonic variation of magnetic field on the ground above the soil edge zones. The longitudinal size of these zones is in the order of the depth of the cables. References 16, figures 9.

Freshwater diversity at a biogeographic edge zone: the high-mountain pea-clams of Ethiopia

Mountain ranges are known for their particular level of biodiversity typically including a striking amount of endemism. This has been comparatively well studied for certain mountain ranges worldwide such as the Alps in Europe, the Himalayas in Asia, the Rocky Mountains in North America and the Andes in South America. Apparently, this is not the case for the mountains on the African continent and especially their freshwater fauna. One of Africa’s largest high-elevated regions is the Ethiopian Highlands. The study of freshwater molluscs might potentially allow to provide valuable insights into the interplay of environmental variation and evolutionary change. Here, we present the first genetically based study of Afromontane sphaeriid bivalves in a worldwide phylogenetic framework which allowed us to assess and describe the recent diversity and endemism as well as the fauna’s biogeographic background. Additionally, a new Ethiopian species of Sphaeriidae, Pisidium boessnecki Albrecht & Clewing sp. nov., could be discovered and is formally described here. Our study revealed a total of six sphaeriid species for the restricted study region in the Ethiopian Highlands of which the first two are most likely endemic: Pisidium boessnecki sp. nov., P. ethiopicum, P. cf. kenianum, P. cf. pirothi, P. cf. viridarium, and Pisidium sp. V. Based on the multigene phylogeny generated, we conclude that the observed diversity might have been caused by multiple independent colonization events from Africa. The zoogeographic affinities of all Ethiopian sphaeriids are related to the Afrotropics. The importance of these findings is discussed. http://zoobank.org/urn:lsid:zoobank.org:act:99C2C3A3-533B-4180-BBDD-E4E5A4D28F09

USING THE UNIVERSITY'S ENERGY EFFICIENCY KNOWLEDGE HUB FOR ENERGY RENOVATION AND ENERGY MODERNIZATION OF UNIVERSITY BUILDINGS

BACKGROUND AND OBJECTIVES. The most important socio-economic task in the current period is to transfer Ukraine's economy to an intensive way of development in order to improve the level and quality of life of the population and solve the full range of social problems. Implementation of such a policy dictates the need to solve problems of reconstruction and modernization of buildings and structures, primarily related to the public sphere (including higher education institutions), in order to eliminate the existing inconsistency of the technical condition and functional and consumer qualities of public buildings to current standards and consumer requirements. Therefore, one of the most urgent directions of development of higher educational institutions is the task of providing effective overhaul and reconstruction of buildings, increasing their energy efficiency.METHODS. The theoretical and methodological basis of the study were the fundamental and applied developments of leading domestic and foreign scientists in the theory and practice of management of energy modernization and energy reconstruction of buildings, increasing energy efficiency of buildings. The factual basis of research were the legislative acts of Ukraine in the field of energy efficiency, normative and methodical documents on the modernization and reconstruction of buildings, Directive 2010/31/EC in the field of energy saving. When solving specific tasks the methods of system and comparative analysis, economic-mathematical methods of efficiency evaluation of energy reconstruction and energy modernization projects were used.FINDINGS. The method of calculation of the reduced resistance to heat transfer of the enclosing structures and the shell of the 4th building of Kyiv National University of Technology and Design as a whole taking into account the temperature and humidity conditions in the fencing marginal zones. It is shown that in the enclosure edge zones the heat protective properties decrease resulting in a deterioration of the heat protection of the whole building. Practical recommendations for the design of fencing structures of modern buildings taking into account the temperature-moisture regime are proposed.CONCLUSION. For the analysis of complex processes of moisture transfer in enclosures, a mathematical model based on the moisture potential is most convenient. A certain difference from the thermal potential (temperature) to the definition of the moisture potential allows to diagnose the most general assessment of the moisture regime of exterior and interior fences on the basis of HUB knowledge on energy efficiency. At use of this model it is possible to consider process of moisture exchange in a wide range of humidity and temperature taking into account movement of a moisture as a basis of carrying out energy reconstruction and energy modernization of operating buildings of the university.

The identification of individuals with hatchery and natural origin in a mixed sample of Amur River chum salmon by Otolith microchemistry

We estimated the proportion of hatchery and natural fall spawning chum salmon returning to the Amur River using chemical markers specific to hatchery-origin fry. We used otolith microchemistry technique to identify fish with artificial origin among returning spawners. First, we found that juveniles of artificial origin had higher values of the Sr:Ca molar ratio of the otoliths’ edge zone compared with juveniles of natural origin, what can be related to the use of rearing feed produced from raw materials of marine origin rich in strontium. Then we observed that most of the spawners from Anyuisky Hatchery and from the Amur River mouth at the start of the spawning migration has also the higher value of Sr:Ca molar ratio of the juvenile zone of otoliths. Also, adults with higher values of the Sr:Ca molar ratio are characterized by a skewed right in the peak of the age distribution. Both, the age structure and phenological shift in the time of spawning migration of individuals with higher value of the used chemical marker corresponds to results of studies on hatchery-produced chum salmon completed at different parts on Northern Pacific. The results of this study will be used in the management of Amur fall chum salmon fisheries, and also demonstrates the necessity of the development of specific measures for increasing the survival of juvenile anadromous salmonids released at large rivers and exposed to prolonged freshwater migration to the ocean. As a further application of the methodology, we plan to identify the markers specific to each of the hatcheries and main spawning tributaries belonging to Amur River catchments. This will be an important step in the evaluation of the contribution of different stocks in mixed fisheries and also in the estimation of the effect of hatchery releases on naturally spawning stocks of Amur fall chum.Following to, our results may indicate the applicability of this approach for the determination of artificial-origin fish in a mixed sample of the Amur fall chum salmon.

Diversity patterns in high‐latitude grasslands

AbstractAimGrasslands of varying land‐use intensity and history were studied to describe and test species richness and compositional patterns and their relationships with the physical environment, land cover of the surrounding landscape, patch geometry, and grazing.LocationThe mainland of Norway.MethodsWe utilized data from the Norwegian Monitoring Programme for Agricultural Landscapes, which recorded vascular plants from 569 plots, placed within 97 monitoring squares systematically distributed throughout agricultural land on the Norwegian mainland. We identified four grassland types: (i) moderately fertilized, moist meadows; (ii) overgrown agricultural land; (iii) cultivated pastures and disturbed ground; and (iv) natural/unfertilized and outfield pastures.ResultsSoil moisture and grazing measures were found to be important in explaining species compositional variation in all grassland types. Richness patterns were best explained by complex and differing combinations of environmental indicators. Nevertheless, negative (nitrogen and light level) or unimodal (pH) responses were similar across grassland types. Vegetation plots adjacent to areas historically and/or currently dominated by mires, forests, or pastures, as well as abandoned and overgrown grasslands, had a slightly higher species richness. Larger grasslands surrounding the vegetation plots had slightly less species than smaller grasslands.ConclusionsThis study demonstrates that data from a national monitoring programme on agricultural grasslands can be used for plant ecological research. The results indicate that climate‐change‐related shifts along moisture and nutrient gradients (increases) may alter both species composition and species richness in the studied grasslands. It is likely that large and contiguous managed (grass)land might affect areas perceived as remnants, probably caused by the transformation to homogeneous (agri)cultural landscapes reducing edge zones, which in turn may threaten the species pool and richness. The importance of land use and land‐cover composition should be considered when planning management actions in extensively used high‐latitude grasslands.

ОСОБЕННОСТИ ПРОСТРАНСТВЕННО-ВРЕМЕННОЙ ИЗМЕНЧИВОСТИ СУММАРНЫХ ТУРБУЛЕНТНЫХ ПОТОКОВ ТЕПЛА НА ГРАНИЦЕ ОКЕАН-АТМОСФЕРА В АТЛАНТИКЕ

The features of the spatial distribution of climate values and the coefficients of linear trends of total tur-bulent heat fluxes are revealed, based on NCEP/NCAR reanalysis data for 1950–2020 for the Atlantic Ocean. Variability of total turbulent heat fluxes is investigated on scales of more than 10 and more than 30 years. It is shown that the trends of average annual total heat fluxes significant at 95% level in most part of the Atlantic Ocean area are negative (except for the western parts of anticyclonic gyres and area of arctic sea ice edge). It is confirmed that the maxima of the low-frequency variability of the total heat fluxes correspond to important energy-active zones of the Atlantic, they are North Atlantic deep-water mass formation region, ice edge zone in the north of the North Atlantic and the Atlantic sector of the Arc-tic Ocean.