21 resultados para Live Migration
Resumo:
Habitat fragmentation produces patches of suitable habitat surrounded by unfavourable matrix habitat. A species may persist in such a fragmented landscape in an equilibrium between the extinctions and recolonizations of local populations, thus forming a metapopulation. Migration between local populations is necessary for the long-term persistence of a metapopulation. The Glanville fritillary butterfly (Melitaea cinxia) forms a metapopulation in the Åland islands in Finland. There is migration between the populations, the extent of which is affected by several environmental factors and variation in the phenotype of individual butterflies. Different allelic forms of the glycolytic enzyme phosphoglucose isomerase (Pgi) has been identified as a possible genetic factor influencing flight performance and migration rate in this species. The frequency of a certain Pgi allele, Pgi-f, follows the same pattern in relation to population age and connectivity as migration propensity. Furthermore, variation in flight metabolic performance, which is likely to affect migration propensity, has been linked to genetic variation in Pgi or a closely linked locus. The aim of this study was to investigate the association between Pgi genotype and the migration propensity in the Glanville fritillary both at the individual and population levels using a statistical modelling approach. A mark-release-recapture (MRR) study was conducted in a habitat patch network of M. cinxia in Åland to collect data on the movements of individual butterflies. Larval samples from the study area were also collected for population level examinations. Each butterfly and larva was genotyped at the Pgi locus. The MRR data was parameterised with two mathematical models of migration: the Virtual Migration Model (VM) and the spatially explicit diffusion model. VM model predicted and observed numbers of emigrants from populations with high and low frequencies of Pgi-f were compared. Posterior predictive data sets were simulated based on the parameters of the diffusion model. Lack-of-fit of observed values to the model predicted values of several descriptors of movements were detected, and the effect of Pgi genotype on the deviations was assessed by randomizations including the genotype information. This study revealed a possible difference in the effect of Pgi genotype on migration propensity between the two sexes in the Glanville fritillary. The females with and males without the Pgi-f allele moved more between habitat patches, which is probably related to differences in the function of flight in the two sexes. Females may use their high flight capacity to migrate between habitat patches to find suitable oviposition sites, whereas males may use it to acquire mates by keeping a territory and fighting off other intruding males, possibly causing them to emigrate. The results were consistent across different movement descriptors and at the individual and population levels. The effect of Pgi is likely to be dependent on the structure of the landscape and the prevailing environmental conditions.
Resumo:
The aim of this thesis is to examine migration of educated Dominicans in light of global processes. Current global developments have resulted in increasingly global movements of people, yet people tend to come from certain places in large numbers rather than others. At the same time, international migration is increasingly selective, which shows in the disproportional number of educated migrants. This study discovers individual and societal motivations that explain why young educated Dominicans decide to migrate and return. The theoretical framework of this thesis underlines that migration is a dynamic process rooted in other global developments. Migratory movements should be seen as a result of interacting macro- and microstructures, which are linked by a number of intermediate mechanisms, meso-structures. The way individuals perceive opportunity structures concretises the way global developments mediate to the micro-level. The case of the Dominican Republic shows that there is a diversity of local responses to the world system, as Dominicans have produced their own unique historical responses to global changes. The thesis explains that Dominican migration is importantly conditioned by socioeconomic and educational background. Migration is more accessible for the educated middle class, because of the availability of better resources. Educated migrants also seem less likely to rely on networks to organize their migrations. The role of networks in migration differs by socioeconomic background on the one hand, and by the specific connections each individual has to current and previous migrants on the other hand. The personal and cultural values of the migrant are also pivotal. The central argument of this thesis is that a veritable culture of migration has evolved in the Dominican Republic. The actual economic, political and social circumstances have led many Dominicans to believe that there are better opportunities elsewhere. The globalisation of certain expectations on the one hand, and the development of the specifically Dominican feeling of ‘externalism’ on the other, have for their part given rise to the Dominican culture of migration. The study also suggests that the current Dominican development model encourages migration. Besides global structures, local structures are found to ve pivotal in determining how global processes are materialised in a specific place. The research for this thesis was conducted by using qualitative methodology. The focus of this thesis was on thematic interviews that reveal the subject’s point of view and give a fuller understanding of migration and mobility of the educated. The data was mainly collected during a field research phase in Santo Domingo, the Dominican Republic in December 2009 and January 2010. The principal material consists of ten thematic interviews held with educated Dominican current or former migrants. Four expert interviews, relevant empirical data, theoretical literature and newspaper articles were also comprehensively used.
Resumo:
The European Union has agreed on implementing the Policy Coherence for Development (PCD) principle in all policy sectors that are likely to have a direct impact on developing countries. This is in order to take account of and support the EU development cooperation objectives and the achievement of the internationally agreed Millennium Development Goals. The common EU migration policy and the newly introduced EU Blue Card directive present an example of the implementation of the principle in practice: the directive is not only designed to respond to the occurring EU labour demand by attracting highly skilled third-country professionals, but is also intended to contribute to the development objectives of the migrant-sending developing countries, primarily through the tool of circular migration and the consequent skills transfers. My objective in this study is to assess such twofold role of the EU Blue Card and to explore the idea that migration could be harnessed for the benefit of development in conformity with the notion that the two form a positive nexus. Seeing that the EU Blue Card fails to differentiate the most vulnerable countries and sectors from those that are in a better position to take advantage of the global migration flows, the developmental consequences of the directive must be accounted for even in the most severe settings. Accordingly, my intention is to question whether circular migration, as claimed, could address the problem of brain drain in the Malawian health sector, which has witnessed an excessive outflow of its professionals to the UK during the past decade. In order to assess the applicability, likelihood and relevance of circular migration and consequent skills transfers for development in the Malawian context, a field study of a total of 23 interviews with local health professionals was carried out in autumn 2010. The selected approach not only allows me to introduce a developing country perspective to the on-going discussion at the EU level, but also enables me to assess the development dimension of the EU Blue Card and the intended PCD principle through a local lens. Thus these interviews and local viewpoints are at the very heart of this study. Based on my findings from the field, the propensity of the EU Blue Card to result in circular migration and to address the persisting South-North migratory flows as well as the relevance of skills transfers can be called to question. This is as due to the bias in its twofold role the directive overlooks the importance of the sending country circumstances, which are known to determine any developmental outcomes of migration, and assumes that circular migration alone could bring about immediate benefits. Without initial emphasis on local conditions, however, positive outcomes for vulnerable countries such as Malawi are ever more distant. Indeed it seems as if the EU internal interests in migration policy forbid the fulfilment of the PCD principle and diminish the attempt to harness migration for development to bare rhetoric.
Resumo:
Muuttaessaan maasta toiseen ihminen kohtaa useita rajoja. Ylittäessään kohdemaan valtion rajan hän kulkee läpi ensimmäisestä maahanmuuton portista. Toinen raja erottaa tilapäiset asukkaat pysyvistä: tämän maahanmuuton toisen portin läpikulkemisen myötä yksilö pääsee osalliseksi sosiaalisista oikeuksista. Maahanmuuton viimeisestä portista kuljettuaan yksilö saavuttaa kyseisen valtion kansalaisuuden. (Hammar 1990, 21.) Tässä pro gradu -tutkielmassa tarkastelen toisen maahanmuuton portin aukeamista ja sosiaaliturvan piiriin pääsyä odottavien maahan-muuttajien kokemuksia. Käytän tarkastelussa sosiaalisen kansalaisuuden ja marginaalisuuden käsitteitä. Tutkielmassa selvitän, miten sosiaali- ja terveyspalveluiden sekä toimeentuloturvan ulkopuolelle jääminen vaikuttaa maahanmuuttajien arkeen ja miten he kokevat osallisuutensa ja jäsenyytensä yhteiskunnassa. Tutkimus on lähtökohdiltaan fenomenologis-hermeneuttinen ja sovellan lähestymistapana ko-kemuksiin keskittyvän narratiivista tutkimusta. Tutkimusaineisto on koottu kevään 2011 aikana ja se koostuu 10 teemahaastattelusta. Haastateltavien maahanmuuton keinot ja syyt vaihtelivat: he olivat saapuneet Suomeen perhesyistä, työn vuoksi tai hakeakseen turvaa. Haastateltavat tavoitettiin Helsingin Diakoniaopiston, Pro-tukipisteen, Kansainvälisen seurakunnan ja tuttava-verkostojen kautta. Aineiston analyysi toteutettiin sisällönanalyysillä Atlas-ohjelman avulla syksyn 2011 aikana. Toisen maahanmuuton portin aukeamisen odottaminen oli raskaaksi: tuota aikaa leimasi epä-varmuus, tyhjyys ja yksinäisyys. Sosiaaliturvan ulkopuolella jääminen aiheutti osalle haastatel-tavista taloudellisia vaikeuksia sekä ongelmia terveydenhuollon palveluiden piiriin pääsemisessä. Toisaalta apua hakeneet haastateltavat olivat sitä lopulta saaneet. Auttamistyön ammattilaiset ja maistraatti saivat haastateltavien kertomuksissa portinvartijan aseman. Kaikille sosiaaliturvan ulkopuolelle jääminen ei ollut ongelma vaan he kokivat sosiaaliturvan puutetta suuremmaksi ongelmaksi työnteko-oikeuden puuttumisen. Kuulumisen ja ulkopuolisuuden kokemus voivat olla läsnä samanaikaisesti, ja kuulumisesta neuvotellaan jatkuvasti esimerkiksi sosiaalisessa kanssakäymisessä tai palveluita hakiessa. Insti-tutionaaliset käytännöt ja poiskäännyttämisen kokemukset tuottavat marginaalisia identiteettejä. Tasavertainen oikeus sosiaaliturvaan vahvistaa kokemusta kuulumisesta ja kodista. Sosiaaliturva ei kuitenkaan yksin määritä kuulumisen ja kodin kokemusta vaan siihen vaikuttavat myös muut tekijät. Näistä tärkeimmät ovat kehon fyysinen sijoittuminen Suomeen, perhe- ja ystä-vyyssuhteet, työ, asunto ja rasismin kokemukset.