Migration Routes Research Articles

Microplastics in wastewater and the role of local wastewater treatment stations in controlling microplastic pollution: a case study from Vietnam.

Wastewater has been identified as one of the main contributors to microplastic (MP) pollution in aquatic environments. Hence, this study investigates the presence, characteristics of MPs in wastewater sample types (industrial, domestic, and medical wastewater), and also the removal efficacy of MPs by local wastewater treatment stations. Overall, industrial wastewater showed a higher MP abundance level at 60,881 ± 48,154 items/m3, compared to domestic and medical wastewater with values of 31,494 ± 10,142 items/m3 and 35,453 ± 13,186 items/m3, respectively. Fiber and fragment were the main shapes observed among the MPs found in all wastewater samples, and the dominant form was microfiber, ranging from 63 to 97.5% of total MPs. The performance of local wastewater treatment stations showed varied efficiencies in MP removal, ranging between 15.8 ± 5 and 90.2 ± 1.3%. Domestic wastewater treatment stations showed lower MP removal effectiveness, at 43.9 ± 13.1%, while treatment stations receiving industrial and medical wastewater achieved 59.5 ± 20.7 and 69.6 ± 22.1% of removal efficiencies, respectively. As estimated, 2.9 × 1010 microplastic items could be emitted to the water bodies around Hanoi every day, which MPs originated from domestic wastewater accounted for 80.3% due to its high discharge volume and inadequate treatment capacity. Optimization of the septic tank system operation and the sewage sludge treatment processes could prevent secondary contamination of MPs, while an additional primary sedimentation step could improve the overall MP elimination efficacy of the studied treatment stations. The results from this study suggested that more in-depth investigations were required for a proper understanding of the migration routes of MPs from different anthropogenic activities to wastewater.

Effects of ramp width variation on the hydraulic conditions of spillway that affect downstream migrating fish

An experimental investigation was conducted to elucidate the effects of a 45º upstream spillway ramp with varying spanwise width ratios (10%, 25%, 50%) on the turbulent flow characteristics used to guide fish downstream. A particle image velocimetry system was employed to acquire the velocity field in several vertical and spanwise planes and analyze various statistics including mean velocities, spatial velocity gradient, Reynolds stresses and turbulent kinetic energy. The results indicate that the flow topology depends significantly on the ramp width ratio. However, regardless of the width ratio, a recirculation region was observed near the foot of the spillway and a smaller one formed upstream of the ramp. For the 10% ramp width ratio, the smaller recirculation bubble accompanied by the lower velocity, spatial velocity gradient and turbulent kinetic energy along the test channel generate a more favorable pathway for downstream migrating fish. Although a partial-width ramp (i.e., 10% width ratio) is less costly and easier to retrofit compared to a full-width ramp, it creates some spanwise inhomogeneity which may impact the migration route and time of some fish species, particularly those that swim close to the riverbed.

Climate change and migratory patterns of Fulani Herdsmen in Nigeria

Purpose Climate change has emerged as a significant global challenge with far-reaching parallel implications, especially in regions where resource scarcity has led to various conflicts and displacement of people. This research aims to investigate the specific dynamics of Fulani Herdsmen’s migratory patterns as well as the socio-economic and security implications of such migration. Design/methodology/approach This study relied on secondary data from published and unpublished sources. A qualitative research design was adopted and data was collected from scholarly works such as journals and reports published by various governmental organisations and NGOs. Findings In Nigeria, the intersection of climate change and resource competition has notably affected the Fulani Herdsmen, a predominantly nomadic pastoralist group. The changing climate, marked by erratic rainfall, prolonged droughts and desertification, has disrupted traditional migration routes, compelling the Fulani Herdsmen who are constantly in search of grazing lands to migrate thereby, often leading to conflicts with sedentary populations. Originality/value While previous studies have explored the relationship between climate change, resource scarcity and conflict, this research seeks to investigate the specific dynamics of Fulani Herdsmen’s migratory patterns and the socio-economic and security implications of such migration. Using the eco-violence theory of Homer-Dixon and the push-pull migration theory of Lee as the theoretical framework, this study analyses how climate change-induced migration has exacerbated tensions between herdsmen and host communities. The research emphasises the need for effective legal and policy frameworks to mitigate these conflicts, proposing sustainable strategies for promoting peaceful coexistence and resilience among affected populations.

Prevalence, Composition, and Behaviour of Humpback Whale (Megaptera novaeangliae) Groups Containing Multiple Mother–Calf Pairs in East Australia

Humpback whale (Megaptera novaeangliae) mothers and their calves predominantly avoid social interactions with conspecifics. However, observations from East Australia indicate that mother–calf pairs occasionally associate with other mother–calf pairs. We investigated the prevalence, composition, and behaviour of multiple-mother-calf (multi-MC) groups in East Australia from 2009 to 2023. In 2009 and 2010, data were collected from two tropical breeding areas (Port Douglas and the Whitsunday Islands) and two coastal migratory locations (Hervey Bay and Eden). No multi-MC groups were detected in Port Douglas out of 15 calf groups observed. Only one (4%) of 23 calf groups encountered in the Whitsunday Islands was a multi-MC group. In Hervey Bay, seven (4%) multi-MC groups were recorded out of 180 calf groups; while in Eden, seven (11%) out of 63 calf groups were multi-MC groups. Between 2009 and 2023, 978 calf groups were encountered in Hervey Bay over 12 years, including 56 (6%) multi-MC groups; while 39 (13%) out of 293 calf groups encountered in Eden over six years were multi-MC groups. Multi-MC groups exhibited more social behaviours compared to single MC groups. Social behaviour was common in both Hervey Bay and Eden; however, groups in Hervey Bay displayed lower arousal behaviours, consistent with the area’s importance as a resting habitat for whales. We did not detect behavioural differences in multi-MC groups with or without escort whales. These findings suggest that humpback whale mothers may gradually socialise their calves by forming multi-MC groups, with an increasing prevalence along the southerly migration route as calves mature. While multi-MC groups have only been detected in Australia to date, it is possible that they occur elsewhere, particularly if social development is a key driver of the phenomenon. Our results enhance our understanding of humpback whale mother–calf sociality and highlight the importance of migration routes for calf social development.

Molecular evolution and geographic migration of severe fever with thrombocytopenia syndrome virus in Asia.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a recently identified tick-borne virus that has emerged in the twenty-first century. Its primary clinical manifestations include fever and thrombocytopenia, and its high morbidity and mortality rates have garnered significant attention. It is crucial to have a comprehensive understanding of the spatial and temporal characteristics of SFTSV migration in order to prevent and control this disease. The SFTSV strains from East Asian countries in GenBank during 2017-2023 were collected and analyzed with phylogenetic and Bayesian methods. Phylogenetic analysis showed that SFTSV can be categorized into five genotypes (A, B, C, D, and E), with 24 recombination events and 15 reassortment events identified. This represented a higher number than previously observed. The results of our study indicated that SFTSV first diverged around 1785. We categorized the migration of SFTSV into two distinct periods, and identified the centers of spread and migration routes of SFTSV in each period. We propose that the eastern migration routes of migratory birds played a pivotal role during the initial stages of virus transmission, functioning as a primary conduit for the dispersal of the virus across the sea. The eastern and central migratory routes were similarly pivotal in subsequent phases of virus transmission. The results of the study showed that Japan was the first region where the virus originated and became endemic, and that the virus spread widely among countries. Elucidating the spatial and temporal characteristics of SFTSV migration will help prevent and control SFTS.

The moral geographies of migration maps: spatial order as a normative basis for border control

ABSTRACT The politics of migration management is peppered by maps promoting specific spatial imaginaries of human mobility and its control. These maps are key sites where a space to be bordered is constructed and reaffirmed. Building on the insights of critical cartography, this piece examines the development of maps of ‘migratory routes’ on the part of EU-based actors focusing on FRONTEX's maps and their evolution over time. The role of institutional cartographies is understood as prefiguring sites of the border where action must take place and resources allocated. In this regard, this paper engages the literatures on moral geographies and moral economies to analyze the implicit normative plea in these maps. FRONTEX maps serve as a powerful visualization, such that researchers of migration management cannot avoid referring to the spatial imaginaries they enshrine. These maps are imbued with a moral order of the world that has a strong postcolonial legacy. This order, and the action it requires are referred to as an Accepted Moral Spatial Order. Engaging this spatial order requires a self-reflexive perspective by researchers attuned to how norms and values contribute to knowledge production on borders and the longer histories that underlie these maps of purportedly recent events.

Tracking the Pathways of West Nile Virus: Phylogenetic and Phylogeographic Analysis of a 2024 Isolate from Portugal

Birds are natural hosts for numerous zoonotic viral pathogens, including West Nile virus, which is transmitted by mosquitoes. During migration, birds can act as vectors for the geographic spread of viruses. WNV is endemic in Portugal, causing annual outbreaks, particularly in horses. Here, we report the first detection of an avian WNV strain isolated from a wild bird (Astur gentilis) collected in Portugal in mid-September 2024. Phylogenetic and phylogeographic analyses were conducted to trace the virus’s origin and potential transmission routes, integrating the obtained full-length genomic sequence with a dataset of WNV strains from Africa and Europe (1951–2024). Phylogenetic analysis of 92 WNV sequences spanning lineages 1–5 positioned the 2024 isolate within lineage 1a. Results obtained using phylodynamics-based analysis showed that this isolate likely originated in Africa and reached Portugal via Spain’s Cádiz coast, confirming previously described WNV dispersal patterns between Africa and Europe. The data suggest a migratory route from West Africa to Europe, extending through countries such as Senegal, Mauritania, Morocco, Portugal, Spain, Italy, and France, indicating a reciprocal flow of the virus back into Africa. These transmission routes match the migratory paths of Afro-Palearctic bird species, emphasizing the role of migratory birds in the long-distance spread of WNV.

First record of Pochazia shantungensis (Chou & Lu, 1977) (Hemiptera: Ricaniidae) in Bulgaria: alien and potentially invasive species on Via Pontica

The current study documents the first record of Pochazia shantungensis, an invasive pest species in the Ricaniidae family, within Bulgaria. Two specimens were observed and a single male specimen was collected in Burgas, marking a significant expansion in the distribution of this species. Known for its adaptability and agricultural impact, P. shantungensis represents a potential threat to native flora and crop systems. This paper provides details on the collection site, specimen identification, and the possible role of the Via Pontica migratory route in the introduction of P. shantungensis to Bulgaria. A comparable radiation pathway in a different non-native species of the same family, Orosanga japonica (Melichar, 1898), is discussed in the paper. Given the recent spread of P. shantungensis into the Western Palaearctic region, monitoring and further studies are recommended to assess its impact on local ecosystems.

Migration of wheat stripe rust from the primary oversummering region to neighboring regions in China

Changing climate and changes in cropping systems have greatly affected outbreaks of plant diseases. Wheat stripe rust is a disease posing a threat to global wheat production, caused by Puccinia striiformis f. sp. tritici (Pst). Pst oversummering regions play a crucial role in the emergence of new races in China. To unveil the migration pattern of oversummering to adjacent regions, we develop a set of KASP-SNP marker from 28 Pst whole-genome sequences to investigate the population structure in the oversummering and its adjacent regions. A set of 19 Chinese wheat differentials is used to characterize the virulence patterns of 308 sampled Pst isolates. By integrating virulence characterization, population genetic analysis, air trajectory simulation and field disease monitoring, two main Pst dispersal routes are identified. Inocula from Eastern Qinghai are dispersed to Western and Eastern Liupan Mountain, and reach Guanzhong Plain. The second route originates from Middle Gansu, then through Longnan, and reaches the Guanzhong Plain via Eastern Liupan Mountain. Both dispersal routes result in Pst inoculum spreading to the Huang-Huai-Hai region, the main wheat-growing region in China. The proposed migration routes can be used to develop disease management strategies at a regional and national scale.

Biomphalaria glabrata (SAY, 1818) AS A PARATENIC HOST OF Angiostrongylus vasorum (BAILLET,1866) KAMENSKY, 1905.

Biomphalaria glabrata (SAY, 1818) AS A PARATENIC HOST OF Angiostrongylus vasorum (BAILLET,1866) KAMENSKY, 1905.

Migrating hoverflies as potential food source for co-migrating insectivorous birds

Most migrating birds must replenish energy reserves during migration. Food availability significantly influences migratory routes and can even force migrants to detour, but still little is known about potential co-migration between insectivorous birds and their insect prey. To address this gap, we focused on day-flying insects and the insectivorous birds migrating through the Červenohorské sedlo mountain pass, Czech Republic. During four seasons of insect and bird trapping, using Malaise trap and mist-nets, respectively, we recorded 23 094 birds of 80 species and 35 087 migrating hoverflies (Syrphidae) of 47 species. We found a strong temporal correlation between the number of migrating hoverflies and insectivorous birds crossing the mountain pass. The observed pattern suggests that a similar phenomenon may occur in lowlands, where both groups stop over before and after crossing the mountains. These stopovers may provide migratory birds with abundant and reliable food resources. We also found that hoverflies comprised 88% of the biomass of all trapped insects, making them the most abundant potential prey of migrating birds. Our results outline the co-migration of birds and hoverflies and shed light on possible predator–prey dynamics during migration.

A Revision of the Maastrichtian Exogyrinae Subfamily from the Kallankurichchi Formation, Ariyalur Sub-basin, India — Taxonomy and Palaeobiogeographic Implications

ABSTRACT Oysters are commonly found in marine Jurassic-Cretaceous deposits worldwide, prompting extensive taxonomic studies that have led to inconsistencies in their identification. The present study re-evaluates the Exogyrinae subfamily with an extensive database from the Maastrichtian Kallankurichchi Formation. We identified four species belonging to three genera of the Exogyrinae subfamily-Rhynchostreon cauveryensis sp. nov., Aetostreon sp. indet., Ceratostreon flabellatum and Ceratostreon pliciferum. While the genus Rhynchostreon has previously been reported from the Cenomanian of India, this study reports a new species of the genus Rhynchostreon, R. cauveryensis sp. nov., from the Maastrichtian Kallnakurichchi Formation. Also, this is the first record of the genus Aetostreon in India as well as the first report of Ceratostreon flabellatum from this region. We also present a morphologic revision of the previously described Ceratostreon pliciferum from the Kallankurichchi Formation. Geometric morphometric analysis was employed to quantify and compare the detailed morphology of R. cauveryensis sp. nov. and Ceratostreon pliciferum. In the present study, the paleobiogeographic distributions of the studied taxa were also investigated to trace their potential migration routes. The findings enhance our understanding of the morphology and migration history of the Exogyrinae subfamily during the Late Cretaceous.

Survival, Travel Time, and Use of Migration Routes by Juvenile Steelhead in a Modified River Estuary

Survival, Travel Time, and Use of Migration Routes by Juvenile Steelhead in a Modified River Estuary

Sex-specific variation in breeding-ground departure decisions and detection rates during southbound migration in West Atlantic Flyway Whimbrels (Numenius phaeopus)

Understanding movement ecology of long-distance migrants is essential for effective conservation. We showed that West Atlantic Flyway Whimbrels (Numenius phaeopus) depart their breeding grounds at different times based on breeding latitude, sex, and nest fate. Whimbrel may exhibit sex-specific preferences in migration, with males favoring oceanic routes, or molt strategies, with males losing glued-on tags earlier than females. We radio-tracked 45 birds from two study sites 710 km apart, with 30 detected after departure. The northern population departed significantly later than the southern population. Successful males in the north tended to depart later than the other groups. Detection probability declined with time after departure, and males were less likely to be detected than females. Seven females, but no males, were detected in one location for more than 1 day. Birds detected in the Maritime Provinces were not detected farther south, while all other birds were detected farther south along the Western Atlantic coast. This suggests that birds detected in the Maritimes may continue with overwater flights to their wintering areas. Our results are the first to suggest that there may be sex-specific preferences for migration routes, or molt strategies in Whimbrel, implying the need for more complex conservation actions.

Are Forced Migrant Trajectories Path-Dependent? A Markov Analysis

This study evaluates whether the trajectories of forced migrants, specifically Syrian refugees moving towards Germany, exhibit path dependency—meaning that their migration decisions are influenced by past events and their previous migration experiences. Using data from the IAB-BAMF-SOEP survey of refugees, this article investigates whether these migration trajectories adhere to a Markov process, where the likelihood of future migrations depends solely on the current state. By employing global and local Markov score tests, the article systematically tests the Markov assumption across different migration routes, focusing on Turkey, Lebanon, and Egypt as transit countries. The findings indicate that shorter, reactive migrations from Syria to Lebanon and Turkey exhibit path dependency, meaning their likelihood is influenced by recent events. Conversely, longer, logistically complex migrations, such as from Syria to Egypt and from transit countries to Germany, adhere to the Markov property, suggesting path independence. This distinction highlights the impact of route difficulty and destination accessibility on migration behaviors. The implications of the findings are also significant for the use of the Markov property in computational models of migration. Researchers should exercise caution when applying the Markov assumption indiscriminately across different migration contexts, as its validity can vary based on external factors such as policy changes and route accessibility.

Repeatable Selection on Large Ancestry Blocks in an Avian Hybrid Zone.

Hybrid zones create natural tests of genetic incompatibilities by combining loci from 2 species in the same genetic background in the wild, making them useful for identifying loci involved in both intrinsic and ecological (extrinsic) isolation. Two Swainson's thrush subspecies form a hybrid zone in western North America. These coastal and inland subspecies exhibit dramatic differences in migration routes; their hybrids exhibit poor migratory survival, suggesting that ecological incompatibilities maintain this zone. We used a panel of ancestry informative markers to identify repeated patterns of selection and introgression across 4 hybrid populations that span the entire length of the Swainson's thrush hybrid zone. Two repeatable patterns consistent with selection against incompatibilities-steep genomic clines and few transitions between ancestry states-were found in large genetic blocks on chromosomes 1 and 5. The block on chromosome 1 showed evidence for inland subspecies introgression while the block on chromosome 5 exhibited coastal subspecies introgression. Some regions previously associated with migratory phenotypes, including migratory orientation, or exhibiting misexpression between the subspecies exhibited signatures of selection in the hybrid zone. Both selection and introgression across the genome were shaped by genomic structural features and evolutionary history, with stronger selection and reduced introgression in regions of low recombination, high subspecies differentiation, positive selection within the subspecies, and on macrochromosomes. Cumulatively, these results suggest that linkage among loci interacts with divergent selection and past divergent evolution between species to strengthen barriers to gene flow within hybrid zones.

Multimodal imaging of a case of intraretinal silicone oil in an eye with retinochoroidal coloboma: Insights into possible routes of migration.

We report multimodal imaging of intraretinal silicone oil in a case operated for coloboma-associated retinal detachment (RD) and provide imaging based anatomical insights of the route on entry of intraretinal emulsified silicone oil droplets. A 19-year-old male presented with gradual onset diminution of vision in right eye for several years with worsening for 1 month. The patient was evaluated with examination, multimodal imaging, including fundus photography, optical coherence tomography, multicolor imaging, and green reflectance imaging. The right eye showed large inferonasal chorioretinal coloboma sparing the fovea, with dull foveal reflex on color fundus photography, loss of foveal contour with multiple hyperreflective dots predominantly collected in the outer nuclear layer in the foveal region on optical coherence tomography, greenish hue in the foveal region with feather-like projections on multicolor imaging, and crystalline deposits on green reflectance imaging. This was diagnosed as collection of intraretinal silicone oil post-RD surgery in a case of chorioretinal coloboma. We highlight a possible pathway for the intraretinal entry of emulsified silicone oil particles in a case of chorioretinal coloboma.

The spatial consistency and repeatability of migratory flight routes and stationary sites of individual European nightjars based on multiannual GPS tracks

BackgroundThe degree to which avian migrants revisit the same sites to replicate routes from previous years has received more and more attention as the possibilities of tracking small to medium-size birds over multiple annual cycles have improved. Repeated measurements of individuals with an appropriate sampling resolution can potentially inform about their navigation and migration strategies and to what extent observed variation within and between individuals may reflect the selective potential in the population.MethodsWe analysed the annual space-use of European nightjars Caprimulgus europaeus tracked with GPS-loggers in multiple years between northern Europe and southern Africa. We quantified spatial consistency of stationary sites and variation, repeatability, and latitudinal correlations in route choice and also investigated barrier-associated changes of within- and between-individual longitudinal variation in flight routes.ResultsWe found that the nightjars consistently used the same breeding and wintering sites. In contrast, the birds generally varied their migration routes between years, and we could only rarely confirm site fidelity to stopover sites. Nevertheless, route variation within individuals remained low for most of both autumn and spring migration, while the between individual variation generally was larger, resulting in a high repeatability in flight routes. Although we found extensive spatial autocorrelation in both seasons across latitudes, we detected significant changes in longitudinal variation associated with the passage of ecological barriers enroute. Potential intermediate goal areas were visited prior to the crossing of the Mediterranean Sea and the Sahara Desert in both seasons. In spring, within-individual route variability dropped to a few tens of kilometres at the initiation of the Sahara crossing but increased to maximum over the barrier.ConclusionsThe nightjars incorporate individual-specific space use within their annual cycle that allows for a degree of flexibility during migration, possibly driven by the energetic benefits of allowing adaptive wind drift while airborne. Our data demonstrate how topography and spatial autocorrelation of positions influence flight path variability that may diminish or reinforce individuality in route choice. Hence, this study highlights that identifying and quantifying past and present external influences on emergence of realised routes can be critical for distinguishing the genetic basis and environmental variation in migration.

Racialized and moral‐religious politics of migrant acompañamiento: Informal hosting as local care entrepreneurship along migration routes

AbstractThis article contributes to understanding contemporary processes of racialization in the Central American migration landscape by looking at the residential reception of increasingly diverse groups of people on the move. Based on research in southern Honduras, it argues that we need to disentangle the racialized and religious politics involved with informal spaces of assistance or acompañamiento in contexts where migrants tend to stay temporarily. Engaging with the notion of acompañamiento through the hosting practices of ordinary citizens shows how racialization gets produced and reinforced in tandem with religious teachings, entrepreneurial considerations, and local migration anxieties. The article concludes that racialization is shaped through the histories and inequalities of place and confirms the intersectional nature of racialization, which incorporates religious identities and hierarchies. Highlighting how the challenges of acompañamiento help attend to shared experiences of injustice and persistent inequalities of human mobility, the article also contributes to broadening migrant trajectory research to the communities that surround migration routes.

Race in place: scales of difference along the Balkan Route of migration

ABSTRACT This paper is an ethnographic examination of race, racialization, and racism among members of a Muslim post-Yugoslav population who have not emigrated – who stayed “in place” – but whose location just outside EU borders has brought people from outside Europe to their community as illegalized migrants along the Balkan Route to the EU. Residents of Bihać and the northwest region of Bosnia–Herzegovina make sense of how racial hierarchies position both them and the migrants, and in turn how racism functions in their society, through overlapping and simultaneously imagined global, regional, and local scales. Distancing from racism based on Bosnia’s specific positioning was common, while local racializing hierarchies such as those that inferiorize the Roma were often understood through frameworks of ethnicity. This made possible a simultaneous identification with “Europe” and whiteness and a distancing from racial thinking and racism as a problem of the “west” even through divergent stances towards migrants.