Spatial Shift Research Articles

Insect communities under skyglow: diffuse night-time illuminance induces spatio-temporal shifts in movement and predation.

Artificial light at night (ALAN) is predicted to have far-reaching consequences for natural ecosystems given its influence on organismal physiology and behaviour, species interactions and community composition. Movement and predation are fundamental ecological processes that are of critical importance to ecosystem functioning. The natural movements and foraging behaviours of nocturnal invertebrates may be particularly sensitive to the presence of ALAN. However, we still lack evidence of how these processes respond to ALAN within a community context. We assembled insect communities to quantify their movement activity and predation rates during simulated Moon cycles across a gradient of diffuse night-time illuminance including the full range of observed skyglow intensities. Using radio frequency identification, we tracked the movements of insects within a fragmented grassland Ecotron experiment. We additionally quantified predation rates using prey dummies. Our results reveal that even low-intensity skyglow causes a temporal shift in movement activity from day to night, and a spatial shift towards open habitats at night. Changes in movement activity are associated with indirect shifts in predation rates. Spatio-temporal shifts in movement and predation have important implications for ecological networks and ecosystem functioning, highlighting the disruptive potential of ALAN for global biodiversity and the provision of ecosystem services. This article is part of the theme issue 'Light pollution in complex ecological systems'.

Predicting the geographical distribution of the Persian leopard, Panthera pardus tulliana, a rare and endangered species

The endangered Persian Leopard, Panthera pardus tulliana, is a top predator and keystone species whose small, fragmented population is still distributed across the Zagros Mountain regions of northeastern Iraq. Their population is under threat from habitat loss and fragmentation, illegal hunting, prey depletion, minefields, and conflicts with humans. Conservation efforts require accurate information on the current and future distribution patterns of this species. Therefore, this study aimed at establishing new baseline data based on the maximum entropy model (Maxent) combined with GIS techniques, field surveys (i.e., camera traps, kill reports, carcasses), and relevant environmental variables obtained from multiple sources. Modeling demonstrated that the current suitable habitat distribution of the species comprises 12.4 % (6318 km2) of the total area of the study area (50971 km2). Of these suitable areas, 0.8 % (431 km2) were categorized as high suitable, 3.8 % (1935 km2) as medium suitable, and 7.8 % (3953 km2) as low suitable. Overall, as demonstrated by modeling under the preselected environmental predictors, the suitable habitat distribution of the Persian Leopard would contract by 1.3 % (666 km2) and 1.7 % (843 km2) in 2070 under the RCP2.6 and RCP8.5 climate change scenarios, respectively. There would be a latitudinal shift, and the distance between the current and future centroids would be around 43.492 km. This spatial shift would be mostly towards the Zagros Mountains in the northeast of Iraq, alongside the Iran-Iraq border. The most important variables that contributed significantly to the distribution of the species across the study area included slope (47.3 %), temperature seasonality (bio4) (27.9 %), land cover (7.7 %), human population density (4.2 %), soil pH (2.7 %), temperature (Bio2) (2.7 %), and NDVI (1.8 %). These results could have great implications for establishing strategic protected areas not only for the target species of this study but for a wide range of plant communities and prey species (e.g., goats, wild boar) across the mountain ecosystem.

Refining Connection through Detachment: Deictic Shifts in Elizabeth Bishop’s Poems

Elizabeth Bishop’s poems are characterized by the observer’s detachment in the description. In her poems, the observer usually concentrates on the details of object s and tries to rise above the immediate context , thus refining a new connection between self and the world. By analyzing the spatial and relational shift s in Bishop’s poe ms, this study argues that the dei ctic shift not only presents the change of cognition in the observer’s mind but also helps the observer shape the perception and enter into the imagined world.

Changes in the spatial patterns of avian migrations: Evidence, mechanisms and causes

AbstractAimsUnderstanding the suite of environmental changes impacting migration and disentangling these from the dependencies between migratory stages is fundamental to understanding the drivers and mechanisms causing spatial shifts to migratory bird distributions. In this review, our objectives are to: (i) provide evidence of spatial change at all migratory stages, (ii) identify the key mechanisms driving change, (iii) discuss how anthropogenic change influences migratory patterns, (iv) highlight interdependencies between migratory stages and (v) offer a framework for understanding migratory pattern changes.LocationMigratory land birds globally.MethodsWe defined a literature search to find examples of spatial changes in avian migrations and their underlying mechanisms. From the top 1000 search results, sorted by relevance, we retained 81 papers published between 1991 and 2020.ResultsSpatial shifts in migratory bird distributions occur throughout the annual cycle, but patterns vary across taxa and migratory stages. Since avian migrants occupy multiple sites across the annual cycle, environmental change has particularly complex repercussions for their distributions. Multiple environmental changes can affect distributions at each migratory stage due to fitness asymmetries between migratory strategies and individuals responding flexibly to environmental changes within and across generations. Spatial changes at one stage (e.g. breeding) can also trigger further indirect spatial changes at other stages (e.g. stopovers) due to dependencies between stages.ConclusionsTo understand the drivers and mechanisms underpinning spatial changes, comprehensive year‐round distributional data are crucial for observing change across multiple migratory stages and disentangling competing drivers. Biologging technology could elucidate the mechanisms causing changes to individual‐level strategies and uncover fitness asymmetries between strategies. Ultimately, gaining a clearer understanding of spatial changes will aid in predicting distributional responses to anthropogenic change in migratory birds. This is paramount for mitigating the effects of anthropogenic change and assessing future population viability within this vulnerable and extensive taxonomic group.

Spatiotemporal modulations in acoustics: From nonreciprocity to mechanical computing

Spatially graded materials have been a cornerstone of acoustic metamaterials for decades, enabling wave manipulation across different length scales. Likewise, structures with time-varying material properties have gained traction in wave filtering applications. Put together, systems exhibiting concurrent spatial and temporal modulations of one or more parameters (e.g., stiffness or phase) can unlock an array of new features ranging from nonreciprocal propagation to frequency-dependent wave beaming. In this talk, we will introduce the notion of dynamic phase gradients, i.e., a spatial phase shift between neighboring elements (of a metasurface) or transducers (of a phased array) which also varies in time. Through theory and experiments, we will demonstrate that the resultant systems are capable of (a) generating multiple scattered harmonics of a single input which simultaneously propagate in different directional lanes, each carrying a unique frequency footprint, and (b) exhibiting non-identical beaming patterns in transmission and reception by breaking time invariance. We will present an application of this concept in the development of a mechanical neural network via reconfigurable elastic metasurfaces, designed to perform a computational task. Since the frequency channels of a spatiotemporally-modulated metasurface are independently tunable, they can be assigned distinct tasks, thus allowing parallel operations in mechanical computing systems.

Diagnosing the relationship between the Madden–Julian Oscillation and United States severe convective weather outbreaks

AbstractThe Madden–Julian Oscillation (MJO) is the leading intraseasonal mode of tropical variability and has been connected to influences in extratropical weather. Recently, the MJO has been gaining traction as a useful teleconnection for extending severe weather outbreak forecast lead time. However, the MJO's intraseasonal, planetary‐scale is far from the meso‐ or micro‐scale severe weather phenomena, making identifying links between the two more difficult. In our study, we use severe weather outbreaks comprising all three main hazards (wind, hail and tornadoes), which are typically linked to a synoptic‐scale system. Outbreaks are devised using kernel density estimation and were used to determine spatial shifts for each of the eight phases of the MJO in each month. A total of 15 months/phases indicated a significant spatial shift. In the spring and summer months (March–August), southerly shifts are more likely to occur in MJO phases 7–8 and 1–3, while northerly shifts are more likely in phases 4–6. In the cool season (September–February), only 3 month/phase groups indicated significant shifts, two shifting west and one north. Composite analysis showed the likely link between the MJO and these outbreak shifts was rooted in Rossby wave breaking and generation of a Rossby wave source induced by the barotropic vorticity advection from the MJO convection. These resulting wave breaks and wave trains led to changes in the storm track (amplitude and location) that resulted in a more favourable synoptic‐scale pattern for severe weather over the United States that deviated from the climatologically favourable region.

Physical characteristics of deep learning-based image processing software in computed tomography: a phantom study.

This study aimed to assess the image characteristics of deep-learning-based image processing software (DLIP; FCT PixelShine, FUJIFILM, Tokyo, Japan) and compare it with filtered back projection (FBP), model-based iterative reconstruction (MBIR), and deep-learning-based reconstruction (DLR). This phantom study assessed the object-specific spatial resolution (task-based transfer function [TTF]), noise characteristics (noise power spectrum [NPS]), and low-contrast detectability (low-contrast object-specific contrast-to-noise ratio [CNRLO]) at three different output doses (standard: 10mGy; low: 3.9mGy; ultralow: 2.0mGy). The processing strength of DLIPFBP with A1, A4, and A9 was compared with those of FBP, MBIR, and DLR. The standard dose with high-contrast TTFs of DLIPFBP exceeded that of FBP. Low-contrast TTFs were comparable to or lower than that of FBP. The NPS peak frequency (fP) of DLIPFBP shifts to low spatial frequencies of up to 8.6% at ultralow doses compared to the standard FBP dose. MBIR shifted the most fP compared to FBP-a marked shift of up to 49%. DLIPFBP showed a CNRLO equal to or greater than that of DLR in standard or low doses. In contrast, the CNRLO of the DLIPFBP was equal to or lower than that of the DLR in ultralow doses. DLIPFBP reduced image noise while maintaining a resolution similar to commercially available MBIR and DLR. The slight spatial frequency shift of fP in DLIPFBP contributed to the noise texture degradation suppression. The NPS suppression in the low spatial frequency range effectively improved the low-contrast detectability.

Shifts in species dominance related to spatial assemblages and variation in environmental parameters in a tropical mangrove estuary

A shift in species dominance in the mangrove microalgae community in Cross River Estuary System (CRES), Nigeria, was carried out during the wet season to highlight the microalgae structure, identify potential indicators, and evaluate the water quality variation. Plankton samples were collected at sixteen selected sampling sites along the river. Diatoms showed the highest number of species (240 species), contributing more than 70% of the total microalgae abundance. Cluster analysis of the microalgae community delimits the CRES into three sections; upper (UCRS), middle (MCRS), and lower (LCRS) communities. The spatial shift in the microalgae community showed that the green algae (Eudorina elegans and Hylotheca dissiliens) dominated the UCRS communities, while diatoms dominated the MCRS (Polymyxus coronalis and Actinocyclus normanii) and LCRS (A. normanii and A. octonarius). The principal component analysis showed that the UCRS was influenced by turbidity and nitrate, while the MCRS and LCRS were characterized by phosphate, electrical conductivity, and salinity/total dissolved solids. The similarity percentage (SIMPER) analysis showed that Surirella tenera and Hylotheca dissiliens contributed >3.5% inter site dissimilarity between the UCRS and LCRS microalgae community. The redundancy analysis revealed that some microalgae species such as Odontella mobiliensis, Coscinodiscopsis jonesiana, A. normanii, and A. octonarius responded positively to salinity change and ammonia concentration in the estuary, while S. tenera, P. coronalis, Bacillaria paxilifer, Navicula transitans, Cyclotella meneghiniana, Humidophila contenta, Melosira granulata, Aulacoseira herzogii, Eudorina elegans, H. dissiliens, Mougeotia sp., and Dinobryon sertularia responded positively to turbidity, nitrate, and phosphate concentration. This study illustrates that CRES inhabit rich biodiversity of microalgae which some taxa could be used as indicators of the environmental changes in marine waters.

A Dynamic Model of Human Limb Selection

Two experiments and a dynamic model forhuman limb selection are reported. In Experiment 1, left-handed and right-handed participants (N = 36) repeatedly used one hand for grasping a small cube. After a clear switch in the cube’s location, perseverative limb selection was revealed in both handedness groups. In Experiment 2, the cubes were presented in a clockwise and counter-clockwise sequence to right-handed participants (N = 15). A spatial shift in the switch point between right-hand use and left-hand use was observed. The model simulates the experiments by implementing the nonlinear multiple-timescale dynamics of the action-selection process underlying limb selection. It integrates two mechanisms that were earlier proposed to underlie this selection aspect of manual activity: limb dominance and attentional information. Finally, the model is used to simulate an influential earlier experiment, by establishing a conceptual link between cross-lateral inhibition asymmetry and the direction and strength of handedness.

On the stability of Leksell Vantage stereotactic head frame fixation in Gamma Knife radiosurgery: a study based on cone-beam computed tomography imaging and the High Definition Motion Management system.

The authors' objective was to investigate the stability of the newly introduced Vantage stereotactic frame fixation in single-fraction Gamma Knife radiosurgery. A total of 255 patients were included in this work and treated with the Vantage frame and Leksell Gamma Knife (LGK) Icon equipped with cone-beam computed tomography (CBCT) imaging. After the frame was mounted on the patient's head, a CT scan was acquired. After the patient was positioned on the couch of LGK, CBCT was acquired to verify the target position before treatment delivery. A second CBCT examination was acquired after treatment delivery to assess intrafractional motion. During treatment delivery, the High Definition Motion Management (HDMM) system was enabled to track a marker on the nose tip of the patient as a surrogate of intracranial motion. The stability of the Vantage frame was deconstructed into two parts: 1) motion between CT and the first CBCT prior to treatment delivery (CT-CBCT1), and 2) motion between CBCT procedures during treatment delivery (CBCT1-CBCT2). Transformation between CT and CBCT1 was given by Leksell GammaPlan, whereas transformation between CBCT1 and CBCT2 required mathematical processing of the transformation and coregistration matrices in the source files. The average CT-CBCT1 displacement vector was 0.31 mm, with a range as great as 1.09 mm, and 89% and 97% of cases were within 0.5 mm and 0.7 mm, respectively. The CBCT1-CBCT2 displacement vectors averaged at 0.09 mm, with 97% of cases being within 0.2 mm. Spatial shift in the posterior direction was evident, with 94% of cases demonstrating this trend and averaging 0.05 mm. This was attributed to increased pressure on the posterior fixation pins. The HDMM displacement vectors presented larger values with an average of 0.4 mm and a range as great as 1.6 mm, and 98% of cases were within 1.0 mm. The correlation between CBCT1-CBCT2 and HDMM displacements was weak, which was attributed to the high stability of the Vantage frame and consequently small target displacements coupled with the sensitivity of HDMM to face mimics. This work demonstrated that the Vantage frame possess the same degree of submillimeter stability as the well-established Leksell Coordinate Frame G (G-frame). Displacements between CT and CBCT1 were 3 times higher than between CBCT1 and CBCT2. A suggested HDMM threshold of 1.2 mm ensures a target accuracy within 0.2 mm in Vantage frame treatments.

Direct Evidence of Standing Internal Tide West of the Luzon Strait Observed by a Large-Scale Observation Array

Abstract Using a large-scale observation array of 27 simultaneous pressure-recording inverted echo sounders (PIESs), the standing wave features of the mode-1 M2 internal tide west of the Luzon Strait (LS) were identified. These features exhibited nonmonotonic spatial phase shifts and half-wavelength amplitude modulation, resulting in spatially varying amplitudes under PIES observations, which have not been previously observed in field observations west of the LS. Satellite altimeter measurements also identified standing-wave patterns consistent with the PIES observations. These patterns emanated from interference between the northwestward and southeastward beams from the LS and the slope of the southern Taiwan Strait, respectively. Near the LS, the two beams superimposed into partial standing waves, whereas the superimposed waves tended to become perfect standing waves near the slope of the southern Taiwan Strait. The nodes and antinodes of the wave shifted under the influence of an anticyclonic eddy. The eddy-induced background current modified the phase speed of the internal tides, and the superimposed standing-wave nodes and antinodes deflected clockwise. The node shifted during three anticyclonic eddy events, and two stations on two sides of the wave node showed opposite variations in amplitude. Significance Statement The internal tidal constituent (M2) propagating in opposite directions can result in standing waves, which have been frequently observed in global oceans but were absent west of the Luzon Strait (LS). Our observations (based on a large-scale array west of the LS) discovered a standing M2 internal tide, which stems from interference between the northwestward beams emanating from the LS and southeastward beams from the slope of the southern Taiwan Strait. Anticyclonic eddies play important roles in adjusting the amplitude of internal tides by deflecting the standing-wave nodes and antinodes clockwise. The study facilitates the understanding of the energy distribution and mixing processes west of the LS and provides a fresh perspective on the dynamic relationship between mesoscale perturbations and internal tides.

Sixty-years of community-science data suggest earlier fall migration and short-stopping of waterfowl in North America

Abstract Worldwide, migratory phenology and movement of many bird species is shifting in response to anthropogenic climate and habitat changes. However, due to variation among species and a shortage of analyses, changes in waterfowl migration, particularly in the fall, are not well understood. Fall migration phenology and movement patterns dictate waterfowl hunting success and satisfaction, with cascading implications on economies and support for habitat management and securement. Using 60 years of band recovery data for waterfowl banded in the Canadian Prairie Pothole Region (PPR), we evaluated whether fall migration timing and/or distribution changed in Mallard (Anas platyrhynchos), Northern Pintail (A. acuta), and Blue-winged Teal (Spatula discors) between 1960 and 2019. We found that in the Midcontinent Flyways, Mallards and Blue-winged Teal migrated faster in more recent time periods, whereas Northern Pintail began fall migration earlier. In the Pacific Flyway, Mallards began fall migration earlier. Both Mallards and Northern Pintails showed evidence of short-stopping in the Midcontinent Flyways. Indeed, the Mallard and Northern Pintail distribution of band recovery data shifted 180 and 226 km north, respectively, from 1960 to 2019. Conversely, Blue-winged Teal recovery distributions were consistent across years. Mallards and Northern Pintails also exhibited an increased proportion of band recoveries in the Pacific Flyway in recent decades. We provide clear evidence that the timing and routes of fall migration have shifted over the past 6 decades, but these phenological and spatial shifts differ among species. We suggest that using community-science data collected by hunters themselves to explain one of the group’s major concerns (changes in duck abundance at traditional hunting grounds), within the environmental lens of climate change, may help lead to further engagement and two-way dialogue to support effective waterfowl management for these culturally and ecologically important species.

“A nation built on coal”: transcalar memory work at the Big Pit

Welsh and coal heritage may seem synonymous in the context of Welsh identities. One of seven national museums, Big Pit and its associated memory work reflect and shape the intertwined dynamic discourses of Wales and coal for visitors. We explore these discourses through a mixed methodology, highlighting the changing and transcalar nature of Wales itself, particularly the devolution of the tourism, heritage, and culture sector in 1997 from the UK Government to the Welsh Government. How have the discourses of National Museum Wales and Big Pit shifted in conjunction with devolutionary power transfers? This paper reflects upon the complicated and fluid discourses of Welshness within the museum’s landscapes. Migration, the dialectic of capital industrialization, and the romanticization of the banal activity of work are all central to these discourses at the Big Pit. Transcalar relationships of tourism and heritage fuel and challenge these discourses as the Big Pit sits on the edge of a UK National Park, on the European Route of Industrial Heritage, and as a central institution of the Blaenavon Industrial Landscape UNESCO World Heritage Site. These interscalar and geopolitical relationships of memory, heritage, and tourism emerge from our multisensory analysis and speak to questions echoing across the United Kingdom and other multi-nation states navigating spatial and temporal shifts in the geopolitics of their tourism sectors. All industrial heritage sites navigate national identities in overt and covert ways. The relationships between resources, heritage sites, the state, and visitors shape the landscapes of industrial heritage sites and their embeddedness into community and national narratives. As Big Pit has transitioned from a small industrial heritage site managed by the UK-overseen National Museum of Wales towards a major tourist attraction and equal member of the seven-site Welsh-overseen National Museum Wales, we identify geopolitical shifts in coal and national heritage.

Droughts force temporal change and spatial migration of vegetation phenology in the northern Hemisphere

Ecosystems are exposed to continuous shifts in droughts. This shows up as a point on a pixel that moves continuously in a specific direction and angle (spatial migration) to preserve its original climate niche. We currently do not have a good understanding whether ecosystems exposed to droughts are more sensitive to droughts temporal trends or spatial migrations. Using dataset of vapor pressure deficit (VPD), total water storage anomaly (TWSA), and standardized soil moisture index (SSMI), we tested the spatiotemporal sensitivity of vegetation phenology to extreme droughts and compound extreme droughts, respectively. On the temporal scale, we found that the differences in the sensitivity of vegetation phenology to VPD, TWSA, and SSMI were mainly reflected in the lag time. Compared to normal years, however, the start of growing season (SOS) was advanced and the end of growing season (EOS) was delayed in most pixels even under extreme preseason droughts. Such results can be attributed to the extreme atmospheric driving forces. On the spatial scale, the spatial migration velocity of SOS and EOS was best correlated with the extreme atmospheric drought (r = 0.5, p < 0.01) and the extreme soil drought in the third layer (r = 0.43, p < 0.01), respectively. Compared to extreme droughts, however, the effects of compound extreme droughts on the spatial migration of vegetation phenology only produced weak negative feedback (|r| < 0.1, p < 0.01). This indicate that the velocity of vegetation phenology was consistent with the velocity of single extreme droughts. Our results emphasize the temporal sensitivity of droughts on vegetation phenology and the accompanying effects of extreme droughts on the spatial shifts in vegetation phenology.

Spring Temperature Accumulation Is a Primary Driver of Forest Disease and Pest Occurrence in China in the Context of Climate Change

Climatic factors have a strong influence on the occurrence of forest diseases and pests, but few studies have systematically analyzed the influence of spring climatic factors on the occurrence of forest diseases and pests in China. We collected inventory data of forest resources, forest diseases, and pest occurrences and then analyzed the spatial and temporal characteristics of China’s forest diseases and pests from 1992–2019. Next, we took spring temperature accumulations ≥ 10 °C, spring average precipitation, and spring average radiation as the spring climatic factors and analyzed their influence on China’s forest diseases and pests with partial correlation and piecewise trend methods. The results showed that the incidence rate of forest diseases and pests in China had a nonlinear decreasing trend that occurred simultaneously with the growth of forested areas and the increase in forest pest and disease areas. Ultimately, the increase in forest pest and disease areas stabilized at low levels of 1% and 4%, respectively. This change generated a spatial shift from an east–west to a north–south pattern in China. Additionally, the average turning points of forest disease and pest incidence trends in China occurred in 2000 and 2005, where 56.7% and 63.3% of provinces, respectively, experienced significant shifts in forest disease and pest incidence. Finally, spring meteorological elements had a significant role in driving the mechanisms of forest disease and pest incidence in China. Among these, spring temperature accumulation was a major contributor in disease and pest variability in China. However, spring radiation and spring precipitation were important local drivers in Southwest China, though these two factors had two opposing shifts in forest diseases and pests reflected over time. This study systematically analyzed the impact of climate change on the development of forest diseases and pests in China, helping clarify the future control of forest diseases and pests in China.

Poleward shifts in the maximum of spring phenological responsiveness of Ginkgo biloba to temperature in China.

Global warming is advancing the timing of spring leaf-out in temperate and boreal plants, affecting biological interactions and global biogeochemical cycles. However, spatial variation in spring phenological responsiveness to climate change within species remains poorly understood. Here, we investigated variation in the responsiveness of spring phenology to temperature (RSP; days to leaf-out at a given temperature) in 2754 Ginkgo biloba twigs of trees distributed across subtropical and temperate regions in China from 24°N to 44°N. We found a nonlinear effect of mean annual temperature on spatial variation in RSP, with the highest response rate at c. 12°C and lower response rates at warmer or colder temperatures due to declines in winter chilling accumulation. We then predicted the spatial maxima in RSP under current and future climate scenarios, and found that trees are currently most responsive in central China, which corresponds to the species' main distribution area. Under a high-emission scenario, we predict a 4-degree latitude shift in the responsiveness maximum toward higher latitudes over the rest of the century. The identification of the nonlinear responsiveness of spring phenology to climate gradients and the spatial shifts in phenological responsiveness expected under climate change represent new mechanistic insights that can inform models of spring phenology and ecosystem functioning.

Spatial Analysis of Cadmium and Lead in Soils of Nagaon District of Assam, India

Aims: The study was carried out in order to find the hotspots of Cadmium and Lead accumulation in the soil due to the anthropogenic activities, so that proper management strategies can be taken on time for their remediation.&#x0D; Study Design: Different geospatial techniques as Normal Q-Q plot, histogram, trend analysis and semi-variogram cloud model is used.&#x0D; Place and Duration of Study: The study was conducted emphasizing basically in high agricultural chemicals dependent Nagaon District of Assam, India, from 2018 to 2021.&#x0D; Methodology: Heavy metals were assessed using a random sampling method with a 5 x 5 km2 grid, and a total of 160 samples were collected from a depth of 0 – 15 cm for soil. Choropleth maps were created to show the distribution and hotspots of pollution.&#x0D; Results: Geospatial analyses from different thematic maps of heavy metals revealed significant vulnerable points of elevated concentrations of Pb (&gt;24.45 mg/kg) and Cd (&gt;0.31 mg/kg) in soil which is presumed to be due to anthropogenic factors. The three-dimensional trend over the distribution of metals throughout the district best fitted the second-order polynomial for Cd, and Pb in soils. Significant numbers of pairs of heavy metal pairs to a certain extent were found to be spatially autocorrelated and all the pairs away from X-axis towards the extreme right corner and far above the axis reflected less influence of local characteristics of the heavy metal. Co-variance cloud with search direction from North to South revealed the existence of spatial autocorrelation and a wider spatial shift of correlation towards the southern direction.&#x0D; Conclusion: The current study provides baseline data to update the mitigation approaches to better manage the heavy metal contamination in soil in the entire district.

Anomalous spatial shifts in interface electronic reflection beyond the linear approximation

Anomalous spatial shifts in interface electronic reflection beyond the linear approximation

Projected Strengthening Impact of the Quasi-Biennial Oscillation on the Southern Hemisphere by CMIP5/6 Models

Abstract Using 20 quasi-biennial oscillation (QBO)-resolving models from phases 5/6 of the Coupled Model Intercomparison Project (CMIP5/6), this study examines the projected Southern Hemisphere (SH) extratropical response to the QBO. Nine of the 22 models simulate decelerated circumpolar westerlies during easterly QBO (EQBO) in the historical climate as is observed, though only ∼30% of the observed change is reproduced in the multimodel ensemble mean (MME) of these high-skill models. These high-skill models project an enhanced stratospheric QBO teleconnection for both emissions scenarios. Further, the stratospheric wind anomaly in high latitudes is projected to move to midlatitudes in future scenarios. The climatological subtropical jet is projected to strengthen, while tropical easterlies are projected to weaken. As a consequence, upward wave activity in the future appears to become more sensitive to the QBO phase. Enhanced upward propagation of waves in mid- to high latitudes during EQBO are much stronger in future scenarios than in historical simulations. The anomalous downwelling over the Antarctic, as part of the Brewer–Dobson deep branch response to EQBO, is also projected to strengthen, corresponding to increased warm anomalies. In future scenarios, the areal extent of the deep convective response to EQBO over the Maritime Continent widens and includes a sharper reduction in outgoing longwave radiation, albeit with southward expansion from Indonesia to Australia. The enhancement and spatial shift in the stratospheric polar vortex pathway and tropical convection pathway subsequently lead to changes in the tropospheric QBO signal. An annular mode–like response forms in the troposphere and near-surface in the present climate, whereas this pattern shifts farther equatorward in future projections with circulation anomalies in the tropical Indian Ocean amplifying. Significance Statement The influence of the equatorial stratospheric quasi-biennial oscillation (QBO) has been reported to intensify in the Northern Hemisphere under climate change, even as the QBO wind magnitude weakens. It is still unknown whether the influence of the QBO on the Southern Hemisphere intensifies or weakens in a warm climate. Using simulations from multiple models, this study finds that the influence of the QBO on the Southern Hemisphere is projected to strengthen in most models even as the QBO weakens. Two QBO pathways are explored, including the stratospheric polar vortex route and the tropical convection pathway, both of which are projected to amplify in both the moderate- and high-emissions scenarios. In addition to the amplification of the QBO signals in the Southern Hemisphere extratropics, an equatorward shift of the maximum anomalies is also projected. That is, the maximum easterly anomalies in the Antarctic stratosphere during easterly QBO and the annular mode–like pattern in the troposphere or the near-surface shifts farther equatorward.

Conservation‐relevant reproductive parameters from long‐term tagging of two globally important sea turtle nesting aggregations in Central Africa

Abstract Assessing abundance and monitoring ecology and population trends are of critical importance for animal species of conservation concern. For sea turtles, annual nest counts represent the most common method of estimating population size. However, to develop a better understanding of population trends, these data need to be complemented by other reproductive parameters, which are lacking for many nesting populations across central Africa. To this end, an intensive capture–mark–recapture programme was conducted spanning 21 years (1997–2018) in the most important nesting sites on the Atlantic coast of central Africa (Gabon and Congo) for leatherback (Dermochelys coriacea) and olive ridley (Lepidochelys olivacea) sea turtles. A total of 18,105 encounters of 14,109 D. coriacea individuals and 2678 encounters of 2427 L. olivacea individuals were recorded. Biological and technical parameters such as clutch frequency, inter‐nesting interval, remigration interval, annual survival rate, somatic growth, size trends, tag loss and number of annual nesting females were estimated through a variety of methods and models. The study detected a decline in body size and low survival probability (not due to tag loss) in both species but no clear decline in estimated annual number of nesting females. High fidelity to nesting sites (&lt;30 km for both species) implies that the current conservation strategy, protecting the main nesting areas, could be effective. We recommend that local conservation managers promote: (i) continued monitoring of the nesting activity of the two species through capture–mark–recapture programmes; (ii) continued nest counts at long‐term monitoring sites, which may also detect possible spatial shifts; and (iii) strengthening of cross‐border cooperation between Gabon and Republic of the Congo given the observed connectivity between nesting sites of the two countries.