Local Migration Patterns Research Articles

Migration response to an immigration shock: evidence from Russia’s aggression against Ukraine

Abstract This article examines the impact of the massive and unexpected inflow of Ukrainians that resulted from Russia’s aggression in 2014 on local migration patterns in Poland. For identification, I use an instrumental variable approach drawing on unique historical data on the forced resettlement of Ukrainians in Poland after World War II. The results show that the regional inflow of immigrants, while crowding out internal in-migration, decreases both internal and international out-migration of the local population. I provide supportive evidence that the decrease in out-migration is due to an enlargement of local labor markets.

Mundane urban (im)mobilities: work, domestic, and family lives of migrant building workers in China

ABSTRACT Interdisciplinary research from China has generated a wealth of quantitative and qualitative insights into trans-, national, regional, and local migration patterns over long and short distances through attention to diverse topics, socio-economic groups, and case-study locations. Our contribution in this paper is to advance recent critical work that is directing focus from rural-to-urban “circular movements” toward more complex spatialities and temporalities. To add value to that project, we not only engage with studies of urban (im)mobilities per se but also elaborate productive new avenues from across interdisciplinary mobilities research. Specifically, we draw on feminist, materialist, and more-than-representational thinking to highlight the contingent relatedness of migrants’ daily lives across diverse work, domestic, and family times/spaces both within and beyond cities. In doing so, we show how exploration of mundane urban (im)mobilities offers new insights to challenge binary depictions of city/countryside, home/destination, movement/stasis, belonging/marginalization, and moored/unmoordness. The conclusion signposts new research opportunities.

Phylogeography and climate-associated morphological variation in the endemic white oakQuercus deserticola(Fagaceae) along the Trans-Mexican Volcanic Belt

Mexico is a center of diversification for the genus Quercus, with an important number of taxa occurring along the Trans-Mexican Volcanic Belt (TMVB). However, the impact of the interaction between historical and current climatic variation and geological heterogeneity in the TMVB on the genetic and phenotypic diversification within oak species has been scarcely investigated. We used chloroplast DNA microsatellites and a geometric morphometrics analysis of leaf shape to understand differentiation between populations of Quercus deserticola Trel., which inhabits dry highlands along the TMVB. Ecological niche modeling for present-day conditions and projections into past scenarios were performed to evaluate the influence of environmental variables on the evolutionary history of the species. Results showed high genetic diversity (hS= 0.774) and high genetic structure (RST= 0.75) and the morphological subdivision of populations into two clusters, corresponding to the west/south and east/north sectors of the Q. deserticola geographic distribution. Ecological niche modeling indicated that the potential distribution of the species has remained similar from the late Pleistocene to the present. Seemingly, the phylogeographic structure of the species has been shaped by low seed-mediated gene flow and mostly local migration patterns. In turn, leaf shape is responding to climate differences either through phenotypic plasticity or local adaptation.

Using robust correlation matching to estimate sand-wave migration in Monterey Submarine Canyon, California

Sandwave migration rate is of critical importance for the hydrodynamic research as well as the coastal engineering application. To acquire this information, the correlation matching algorithm is applied in this paper. By searching for similar seafloor areas between multi-temporal digital terrain models, the migration rate can be estimated. To account for the impact of the morphological distortion as well as outliers in the survey data, the correlation matching is adjusted based on the robust estimation theory. By executing the correlation matching based on the least median square criterion, a robust initial estimate is obtained. Afterwards, the potential outliers are detected based on the initial matching result, and the corresponding weights are adjusted to zero. Finally, correlation matching is executed with the updated weights. With the above procedure, the impact of outliers can be accounted for. The developed method is applied on the bathymetry time-series data collected in Monterey Canyon, California. Comparison shows that the presented algorithm significantly improves the credibility of the estimation. The generated migration vector field not only reveals the main tendency of the migration rate in the region, but also highlights the unique local migration patterns, which is helpful for understanding the mechanism of the sandwave migration.

Exploring how residential mobility and migration influences teenage pregnancy in five rural communities in California: youth and adult perceptions

Teenage birth rates among young people aged 15–19 years in California, USA, have declined from 47 births per 1000 in 2000 to 24 per 1000 in 2013. Nevertheless, the US counties with the highest teenage birth rates are predominantly rural and have a high proportion of Latinos/as. We conducted 42 interviews with key stakeholders and 12 focus groups with 107 young people in five rural communities to better understand local migration patterns and their influence on intermediate and proximate variables of pregnancy, such as interaction with role models and barriers to access contraception. The migration patterns identified were: residential mobility due to seasonal jobs, residential mobility due to economic and housing changes and migration from other countries to California. These patterns affect young people and families’ interactions with school and health systems and other community members, creating both opportunities and barriers to prevent risky sexual behaviours. In rural areas, residential mobility and migration to the USA interconnect. As a result, young people dually navigate the challenges of residential mobility, while also adapting to the dominant US culture. It is important to promote programmes that support the integration of immigrant youth to reduce their sense of isolation, as well as to assure access to sexual health education and reproductive health services.

Network-Based Analysis on Orthogonal Separation of Human Plasma Uncovers Distinct High Density Lipoprotein Complexes.

High density lipoprotein (HDL) particles are blood-borne complexes whose plasma levels have been associated with protection from cardiovascular disease (CVD). Recent studies have demonstrated the existence of distinct HDL subspecies; however, these have been difficult to isolate and characterize biochemically. Here, we present the first report that employs a network-based approach to systematically infer HDL subspecies. Healthy human plasma was separated into 58 fractions using our previously published three orthogonal chromatography techniques. Similar local migration patterns among HDL proteins were captured with a novel similarity score, and individual comigration networks were constructed for each fraction. By employing a graph mining algorithm, we identified 183 overlapped cliques, among which 38 were further selected as candidate HDL subparticles. Each of these 38 subparticles had at least two literature supports. In addition, GO function enrichment analysis showed that they were enriched with fundamental biological and CVD protective functions. Furthermore, gene knockout experiments in mouse model supported the validity of these subparticles related to three apolipoproteins. Finally, analysis of an apoA-I deficient human patient's plasma provided additional support for apoA-I related complexes. Further biochemical characterization of these putative subspecies may facilitate the mechanistic research of CVD and guide targeted therapeutics aimed at its mitigation.

The influence of contemporary and historic landscape features on the genetic structure of the sand dune endemic, Cirsium pitcheri (Asteraceae)

Narrow endemics are at risk from climate change because of their restricted habitat preferences, lower colonization ability and dispersal distances. Landscape genetics combines new tools and analyses that allow us to test how both past and present landscape features have facilitated or hindered previous range expansion and local migration patterns, and thereby identifying potential limitations to future range shifts. We have compared current and historic habitat corridors in Cirsium pitcheri, an endemic of the linear dune ecosystem of the Great Lakes, to determine the relative contributions of contemporary migration and post-glacial range expansion on genetic structure. We used seven microsatellite loci to characterize the genetic structure for 24 populations of Cirsium pitcheri, spanning the center to periphery of the range. We tested genetic distance against different measures of geographic distance and landscape permeability, based on contemporary and historic landscape features. We found moderate genetic structure (Fst=0.14), and a north-south pattern to the distribution of genetic diversity and inbreeding, with northern populations having the highest diversity and lowest levels of inbreeding. High allelic diversity, small average pairwise distances and mixed genetic clusters identified in Structure suggest that populations in the center of the range represent the point of entry to the Lake Michigan and a refugium of diversity for this species. A strong association between genetic distances and lake-level changes suggests that historic lake fluctuations best explain the broad geographic patterns, and sandy habitat best explains local patterns of movement.

Prospects for whale shark conservation in Eastern Indonesia through bajo traditional ecological knowledge and community-based monitoring

The whale shark, Rhincodon typus, is a long-lived migratory species inhabiting tropical and warm-temperate waters worldwide. Seasonal aggregations of whale sharks in shallow coastal waters of many countries have led to the development of ecotourism industries. Whale sharks that aggregate seasonally at Ningaloo Reef in Western Australia have a migration range within Indonesian and Southeast Asian waters. However, very little is known about their behaviour, local migration patterns, or potential threats faced in this region. In this study, we investigated traditional ecological knowledge of whale sharks through interviews with Bajo and other fishers from five settlements in the Timor and Roti Islands in eastern Indonesia. We found that there are culturally driven prohibitions and customary beliefs concerning whale sharks among Bajo fishermen, who commonly sight sharks in the Timor Sea, in southern Indonesian and Timor Leste waters. Sightings are most common during the months of August to December. Interviews also indicate a low level of harvesting of whale sharks in the region. The results demonstrate the potential for combining traditional ecological knowledge and new technology to develop whale shark management strategies, and to determine the predictability of whale shark appearances as one vital factor in assessing the potential for development of small-scale whale shark ecotourism initiatives.

Migration of rural families in 19th century southern Sweden. A longitudinal analysis of local migration patterns

Most research on historical migration patterns has focused on more long-range migration processes such as rural–urban, interregional, or intercontinental flows, neglecting the more local migration patterns, which could also have a profound impact on the rural preindustrial economy. This article analyzes the migration of rural families in 19th century southern Sweden using a longitudinal data set at the microlevel. The analysis shows a rather high mobility of families, the overwhelming majority of whom migrated very short distances. Factors determining the migration decision of these families included access to land and social networks and family composition as well as family type. The results clearly show that migration was an important part of the lives of preindustrial families and that the new migration pattern emerging in the second half of the 19th century, when rural–urban as well as international migration increased considerably, was not so much the result of higher mobility in general but rather a response to changing incentives making long distance migration more attractive.

Migratory differences between ecotypes of the snail Littorina saxatilis on Galician rocky shores

Local migration patterns may be crucial to gene flow in species of marine gastropods which do not broadcast pelagic larvae. In some species, dispersal over distances of a few metres may influence micro-scale population structures. We investigated the migration pattern in Galician populations of the snail Littorina saxatilis in which populations of contrasting morphologies occupy different tidal levels of the same rocky shore. Two distinct morphs, one at the upper and one at the lower shore, overlap in distribution in a small mid-shore region where hybrids are produced. We documented the distances and directions of migration of both parental morphs and hybrids 1 month after they had been marked and released at different shore levels. When placed at their native shore level, snails migrated less than about 2m and usually in independent directions. This supports the suggestion of a low local gene flow. At an alien shore level, however, the morphs often moved further and more directionally compared with native morphs. These differences may help to keep the two morphs separated at different shore levels. As fitness of an individual is highest in its native habitat, this seems to be an adaptive strategy.