Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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A mobilities perspective on migration in the context of environmental change
Wiegel, Hanne ; Boas, Ingrid ; Warner, Jeroen - \ 2019
Wiley Interdisciplinary Reviews: Climate Change 10 (2019)6. - ISSN 1757-7780
discourse - environmental change - immobility - migration - mobility

Academic, political, and policy debates about the connection between environmental change and human migration have long focused on migration drivers and outcomes, resulting in a limited discussion between the discourses of “desolate climate refugees” and “environmental migrants as agents of adaptation.” These perspectives remain dominant, particularly in policy and media circles, despite academic critique and the recent emergence of more diverse approaches. In this intervention, we contribute to the recent turn in environmental migration research by seeking to better ground and pluralize our understanding of how environmental change and human mobility relate. We do so by offering a mobilities perspective that centers on the practices, motives, and experiences of mobility and immobility in the context of environmental change: When and why do people decide to move—or not to move—in response to environmental changes? How do they cope with migration pressures? Where do they move, under what conditions, and who can or must stay behind? This approach attends to the diverse aspirations and differential capabilities that underlie particular practices of movement or nonmovement, reflecting both individual characteristics as well as interconnections with uneven power relations across local, regional, and global scales. A mobilities approach offers a starting point for an expanded research agenda on environmental im/mobilities. This enables academic analysis and policy discussion of the human (im)mobility-environmental change nexus to become better attuned to the actual practice and heterogeneous needs of those affected. This article is categorized under: Climate and Development > Social Justice and the Politics of Development Vulnerability and Adaptation to Climate Change > Values-Based Approach to Vulnerability and Adaptation.

Data from: Agricultural pastures challenge the attractiveness of natural saltmarsh for a migratory goose
Dokter, A.M. ; Fokkema, Wimke ; Ebbinge, B.S. ; Olff, H. ; Jeugd, Henk P. van der; Nolet, B.A. - \ 2018
NIOO-KNAW
pastures - saltmarsh - brent geese - human-goose conflict - accelerometer - GPS tracking - intertidal - habitat switching - migration - fuelling
Broad-scale land conversions and fertilizer use have dramatically altered the available staging area for herbivorous long-distance migrants. Instead of natural land, these birds rely increasingly on pastures for migratory fuelling and stopover, often conflicting with farming practices. To be able to predict and manage birds’ future habitat use, the relative advantages and disadvantages of natural (e.g. saltmarsh, intertidal) versus anthropogenic staging sites for foraging need to be understood. 2. We compared the migratory staging of brent geese on saltmarsh and pasture sites in spring. Food quality (nitrogen and fibre content), intra-specific antagonistic behaviour, and body weight were quantified at nearby sites in simultaneous seasons. Individuals were tracked with high-resolution GPS and accelerometers to compare timing of migration and time-budgets during fuelling. 3. On pastures, birds rested more and experienced higher ingestion rates, similar or superior food quality and reduced antagonistic interactions than on saltmarsh. 4. Brent geese using fertilized grasslands advanced their fuelling and migration schedules compared to those using saltmarsh. Pasture birds reached heavy weights earlier, departed sooner, and arrived in the Arctic earlier. 5. Intertidal mudflats were frequently visited by saltmarsh birds during the day, and available food there (algae, some seagrass) was of higher quality than terrestrial resources. Availability of intertidal resources was an important factor balancing the otherwise more favourable conditions on pastures relative to saltmarsh. 6. Policy implications: Disadvantages of longer foraging effort, more antagonistic interactions and delayed fuelling schedules on traditional saltmarshes may cause a trend of geese exchanging this traditional niche in favour of pastures, especially in a warming climate that requires advancement of migratory schedules. However, the high quality of intertidal forage allows it to complement terrestrial foraging, potentially removing the incentive for habitat switches to pastures. The relatively high quality of green algae and seagrass, and birds’ remarkable preference for these resources when available, provides a key for managers to create landscapes that can sustain this specialist’s intertidal lifestyle. To keep natural habitats attractive to staging geese with the purpose to prevent conflicts with farming practices, management actions should focus on conservation and restoration of saltmarsh and especially intertidal habitat.
Limiting the high impacts of Amazon forest dieback with no-regrets science and policy action
Lapola, David M. ; Pinho, Patricia ; Quesada, Carlos A. ; Strassburg, Bernardo B.N. ; Rammig, Anja ; Kruijt, Bart ; Brown, Foster ; Ometto, Jean P.H.B. ; Premebida, Adriano ; Marengo, José A. ; Vergara, Walter ; Nobre, Carlos A. - \ 2018
Proceedings of the National Academy of Sciences of the United States of America 115 (2018)46. - ISSN 0027-8424 - p. 11671 - 11679.
adaptation - agriculture - ecosystem services - hydroelectricity generation - migration

Large uncertainties still dominate the hypothesis of an abrupt large-scale shift of the Amazon forest caused by climate change [Amazonian forest dieback (AFD)] even though observational evidence shows the forest and regional climate changing. Here, we assess whether mitigation or adaptation action should be taken now, later, or not at all in light of such uncertainties. No action/later action would result in major social impacts that may influence migration to large Amazonian cities through a causal chain of climate change and forest degradation leading to lower river-water levels that affect transportation, food security, and health. Net-present value socioeconomic damage over a 30-year period after AFD is estimated between US dollar (USD) $957 billion (×109) and $3,589 billion (compared with Gross Brazilian Amazon Product of USD $150 billion per year), arising primarily from changes in the provision of ecosystem services. Costs of acting now would be one to two orders of magnitude lower than economic damages. However, while AFD mitigation alternatives-e.g., curbing deforestation-are attainable (USD $64 billion), their efficacy in achieving a forest resilience that prevents AFD is uncertain. Concurrently, a proposed set of 20 adaptation measures is also attainable (USD $122 billion) and could bring benefits even if AFD never occurs. An interdisciplinary research agenda to fill lingering knowledge gaps and constrain the risk of AFD should focus on developing sound experimental and modeling evidence regarding its likelihood, integrated with socioeconomic assessments to anticipate its impacts and evaluate the feasibility and efficacy of mitigation/adaptation options.

Agricultural pastures challenge the attractiveness of natural saltmarsh for a migratory goose
Dokter, Adriaan M. ; Fokkema, Wimke ; Ebbinge, Barwolt S. ; Olff, Han ; Jeugd, Henk P. van der; Nolet, Bart A. - \ 2018
Journal of Applied Ecology 55 (2018)6. - ISSN 0021-8901 - p. 2707 - 2718.
accelerometer - brent geese - GPS tracking - habitat switching - human–goose conflict - migration - pastures - saltmarsh

Broad-scale land conversions and fertilizer use have dramatically altered the available staging area for herbivorous long-distance migrants. Instead of natural land, these birds rely increasingly on pastures for migratory fuelling and stopover, often conflicting with farming practices. To predict and manage birds’ future habitat use, the relative advantages and disadvantages of natural (e.g. saltmarsh, intertidal) versus anthropogenic staging sites for foraging need to be understood. We compared the migratory staging of brent geese on saltmarsh and pasture sites in spring. Food quality (nitrogen and fibre content), antagonistic behaviour, and body weight were quantified at nearby sites in simultaneous seasons. Individuals were tracked with high-resolution GPS and accelerometers to compare timing of migration and time budgets during fuelling. On pastures, birds rested more and experienced higher ingestion rates, similar or superior food quality and reduced antagonistic interactions than on saltmarsh. Brent geese using fertilized grasslands advanced their fuelling and migration schedules compared to those using saltmarsh. Pasture birds reached heavy weights earlier, departed sooner, and arrived in the Arctic earlier. Intertidal mudflats were frequently visited by saltmarsh birds during the day, and available food there (algae, some seagrass) was of higher quality than terrestrial resources. Availability of intertidal resources was an important factor balancing the otherwise more favourable conditions on pastures relative to saltmarsh. Synthesis and applications. Disadvantages of longer foraging effort, more antagonistic interactions and delayed fuelling schedules on traditional saltmarshes may cause geese to exchange this traditional niche in favour of pastures, especially in a warming climate that requires advancement of migratory schedules. However, due to its high quality, intertidal forage can complement terrestrial foraging, potentially removing the incentive for habitat switches to pastures. The relatively high quality of green algae and seagrass, and birds’ remarkable preference for these resources when available, provides a key for managers to create landscapes that can sustain this specialist’s intertidal lifestyle. To keep natural habitats attractive to staging geese with the purpose of preventing conflicts with farming practices, management actions should focus on conservation and restoration of saltmarsh and especially intertidal habitat.

Neutral and functionally important genes shed light on phylogeography and the history of high-altitude colonization in a widespread New World duck
Lozano-Jaramillo, Maria ; McCracken, Kevin G. ; Cadena, Carlos Daniel - \ 2018
Ecology and Evolution 8 (2018)13. - ISSN 2045-7758 - p. 6515 - 6528.
adaptation - hypoxia - migration - natural selection

Phylogeographic studies often infer historical demographic processes underlying species distributions based on patterns of neutral genetic variation, but spatial variation in functionally important genes can provide additional insights about biogeographic history allowing for inferences about the potential role of adaptation in geographic range evolution. Integrating data from neutral markers and genes involved in oxygen (O2)-transport physiology, we test historical hypotheses about colonization and gene flow across low- and high-altitude regions in the Ruddy Duck (Oxyura jamaicensis), a widely distributed species in the New World. Using multilocus analyses that for the first time include populations from the Colombian Andes, we also examined the hypothesis that Ruddy Duck populations from northern South America are of hybrid origin. We found that neutral and functional genes appear to have moved into the Colombian Andes from both North America and southern South America, and that high-altitude Colombian populations do not exhibit evidence of adaptation to hypoxia in hemoglobin genes. Therefore, the biogeographic history of Ruddy Ducks is likely more complex than previously inferred. Our new data raise questions about the hypothesis that adaptation via natural selection to high-altitude conditions through amino acid replacements in the hemoglobin protein allowed Ruddy Ducks to disperse south along the high Andes into southern South America. The existence of shared genetic variation with populations from both North America and southern South America as well as private alleles suggests that the Colombian population of Ruddy Ducks may be of old hybrid origin. This study illustrates the breadth of inferences one can make by combining data from nuclear and functionally important loci in phylogeography, and underscores the importance of complete range-wide sampling to study species history in complex landscapes.

Autochthony and insecure land tenure : the spatiality of ethnicized hybridity in the periphery of post-conflict Bukavu, DRC
Overbeek, Fons van; Tamás, Peter A. - \ 2018
Journal of Eastern African Studies 12 (2018)2. - ISSN 1753-1055 - p. 290 - 309.
autochthony - DR Congo - hybridity - migration - post-conflict - Urbanization
This article analyzes the interaction of the traces of war with institutional hybridity in shaping the use of space in the periphery of Bukavu, in the eastern Democratic Republic of Congo. In peri-urban Bukavu, the urbanization of previously rural areas has created an uncertain mixture of land allocation mechanisms that are not adequately explained by representation in terms of a clash or mixture of statutory and customary law. This hybridity has created uncertainty for both newcomers and early settlers in which the othering and violence required to justify both encroachment on, and the protection of, land are supported by discourses of autochthony. Large parts of peri-urban Bukavu, in particular the area of Kasha, are gradually being balkanized by quasi-voluntary socio-spatial practices of segregation by ethnicities whose existence and salience are constantly, and at times forcibly, re-negotiated. While initially perceived as a safe haven, the city’s periphery is becoming an area of acute insecurity.
Bat 1: Estimate of bat populations at the southern North Sea : Supporting note to ZDV report no. 2016.031 Migration bats at the southern North Sea
Lagerveld, S. ; Limpens, H.J.G.A. ; Schillemans, M.J. ; Scholl, M. - \ 2017
Den Helder : Wageningen Marine Research (Wageningen Marine Research report C014.17) - 14
chiroptera - migration - offshore - wind farms - north sea - migratie - windmolenpark - noordzee
To close the knowledge gap described above, or better said in order to make a start to overcome this crucial lack of insight into (sub)population sizes, RWS commissioned the Bats_1 study as part of the Wind op Zee Ecological Programma (Wozep; in English: Wind at Sea Ecological Programme), a multi-annual research programme initiated in view of the realisation of new offshore wind farms under the SER agreement (2013). Aim of the Bat_1 desk study is to estimate the extent to which (sub)populations of Nathusius’ Pipistrelle and possibly other relevant bat species, expressed in terms of numbers of individuals, use migration routes across the southern North Sea (SNS)1. This information is of great importance to be able to make better estimates of what the Potential Biological Removal (PBR) values are of Nathusius’ Pipistrelle and possibly other bat species, knowing that these values depend on the size of the (sub)populations to be considered.
Telemetry for migratory bats : a feasibility study
Lagerveld, Sander ; Janssen, René ; Manshanden, Jasper ; Haarsma, Anne-Jifke ; Vries, Simon de; Brabant, Robin ; Scholl, Michaela - \ 2017
Den Helder : Wageningen Marine Research (Wageningen Marine Research report C011/17) - 58
chiroptera - migration - telemetry - offshore - wind farms - biomonitoring - feasibility studies - north sea - netherlands - migratie - telemetrie - windmolenpark - biologische monitoring - haalbaarheidsstudies - noordzee - nederland
Herkomst en migratie van Nederlandse edelherten en wilde zwijnen : een basiskaart van de genetische patronen in Nederland en omgeving
Groot, G.A. de; Spek, G.J. ; Bovenschen, J. ; Laros, I. ; Meel, Tom van; Jansman, H.A.H. - \ 2016
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2724) - 71 p.
cervus elaphus - sus scrofa - migration - genetic variation - wildlife conservation - netherlands - migratie - genetische variatie - wildbescherming - nederland
De laatste jaren worden in toenemende mate incidentele waarnemingen van edelherten en wilde zwijnen buiten de toegewezen leefgebieden gedaan. De vraag is vervolgens of dit om natuurlijke immigratie vanuit (niet-omrasterde) leefgebieden in binnen- of buitenland gaat en waar ze dan vandaan zijn gekomen, of dat het een ontsnapt of losgelaten dier betreft. Om deze vraag in de toekomst in voorkomende gevallen effectief te kunnen beantwoorden, stelde Alterra in opdracht van BIJ12 – Faunafonds en Vereniging Het Edelhert een landelijke genetische referentiedatabase op van de zwijnen- en edelhertenpopulaties in Nederland en nabijgelegen populaties in België en Duitsland. In dit rapport worden de mogelijkheden van deze databases voor herkomstbepalingen nader onderzocht. Tevens geeft dit onderzoek, op basis van de verkregen databases, een overzicht van de genetische vitaliteit van de Nederlandse populaties van beide soorten met betrekking tot diversiteit, inteeltrisico’s en uitwisselingsmogelijkheden.
Effect straatverlichting op paddentrek
Grunsven, R.H.A. van; Joosten, K. ; Creemers, R. - \ 2015
RAVON 17 (2015)3. - p. 56 - 58.
padden - migratie - habitats - habitatfragmentatie - habitatverbindingszones - verlichting - kunstmatige verlichting - wildbescherming - toads - migration - habitat fragmentation - habitat corridors - lighting - artificial lighting - wildlife conservation
Al duizenden jaren gaan padden in het vroege voorjaar ’s nachts op pad naar voortplantingswateren om daar te paren en eieren af te zetten. De wereld om hen heen is in al die jaren sterk veranderd. Wegen doorkruisen hun leefgebied en straatverlichting langs de wegen is eerder regel dan uitzondering. En dat heeft effect op de paddentrek, zo blijkt uit een lichtonderzoek.
Skill selectivity in transatlantic migration : The case of Canary Islanders in Cuba
Juif, Dácil - \ 2015
Revista de Historia Economica - Journal of Iberian and Latin American Economic History 33 (2015)2. - ISSN 0212-6109 - p. 189 - 222.
human capital - institutions - Latin America - migration - numeracy

The skill composition of European migrants to the New World and their contribution to the human capital and institutional formation in destination countries are popular topics in economic history. This study assesses the skill composition of 19th century transatlantic migrants to Cuba. It finds that nearly half of the European immigrants originate from the Spanish province of the Canary Islands, which displays the lowest literacy and numeracy rates of Spain. Even within this province, those who left belonged to the least skilled section of the population. By promoting the influx of a cheap and poorly educated white workforce that replaced African slaves on their sugar estates, large landowners in Cuba contributed to the perpetuation of high economic, political and social inequality.

Aspirations and everyday life of single migrant women in Ghana
Tufuor, T. - \ 2015
Wageningen University. Promotor(en): Anke Niehof, co-promotor(en): Hilje van der Horst; Chizu Sato. - Wageningen : Wageningen University - ISBN 9789462575578 - 187
migratie - rurale migratie - ruraal-urbane migratie - platteland - stedelijke gebieden - vrouwen - man-vrouwrelaties - samenleving - gezinsstructuur - ghana - west-afrika - migration - rural rural migration - rural urban migration - rural areas - urban areas - women - gender relations - society - family structure - ghana - west africa

Female labour migrants in West Africa including Ghana have been widely perceived as followers of male relatives. Since the late 1990s, the increasing movement of young women to cities in the region has drawn attention to this phenomenon and this study discovered females as actors in the migration process. Women have been moving from the rural North to the urban South, especially to Accra, to live in the city’s slums. Their migrations are not associational; these journeys are now independently pursued by women with aspirations to realise their ideals of a better life. Female migrations make up a growing share of migrant labour streams within Ghana. Among the migrants who arrive in Accra every day there is an increasing number of single young women as well as divorced women and neglected as wives from the North of Ghana. Economic explanations do not fully account for such moves, because men and women perform different productive and reproductive roles within the northern households. The varying degrees of gender and intra-household inequality and the women’s anticipation of life changes after migration spur the motivations and aspirations behind the journeys.

This study on single migrant women (SMW) was conducted in two sites. The first site was in four districts in the Northern Region with its capital Tamale. The Dagomba are the pre­dominant ethnic group here. They practise subsistence farming and most of them are Muslims. The second study site was the Old Fadama (OF) market in Accra. By tracking the migrant women from the North to OF, the study connected the spaces of area of origin and area of destination in the migration process. A mixed-methods approach was applied in data collection, combining qualitative methods such as focus group discussion, case study and life history with a survey in the OF market.

While in the past the restrictions on women’s sexuality and autonomy prevented women from migrating alone, now northern households provide an incentive for young women to migrate. The women cited a gain in autonomy and freedom as the most important motivation for their move. In the household of their fathers or future husbands in the North, their autonomy is constrained. However, through their earnings in Accra, the women prepare themselves for an expensive religious marriage ceremony, invest in housing or education and also buy modern goods. Young migrant women from the rural Dagomba communities primarily engage in accumulating goods for their dowry, whereas older women accumulate capital for investment in their children’s education. The older women who have no plans anymore of returning to the North to marry, especially those who are successful in Accra and have achieved the status of ‘market mummies’, seek enjoyment in the present but also use their wealth to secure construction of rooms of their own in the North. The women save money, assemble housewares and send remittances with their own independent income.

In Accra, most young women engage in petty trading. In the OF market in Accra these single migrant women from the North generate livelihoods through the adoption of both market and non-market based strategies by extending and prioritising moral obligations to community members beyond their immediate households, instead of just focusing on maximisation of profits. Communities of old and young market women have built a ‘moral community economy’ through, among others, engaging in reciprocal labour, gift giving, and childcare and food sharing. This contributes positively to household food security and social well-being among the market women and migrant settlers in the OF community. SMW’s livelihood generation is sustained through social relations among women, in which also age, ethnicity and regional background play crucial roles. SMW give support to and receive benefits from the community through moral obligations and ethnic commitment. The analysis of these strategies contributes to the understanding of the intersections of household, livelihood strategies, gender and markets in urban settings.

In Accra, these women not only need to find income earning activities, they also have to reinvent themselves as consumers because of the abundant and varied consumption options in Accra as compared to the North. Through consumption of food, hairdos and leisure activities, they shape their new urban identities. However, through consumption they also try to secure the desired next phase in their life course. Despite earning very modest amounts of money with activities such as hawking or food vending, SMW save for their future and adapt their consumption to enable such savings. They save in money and in kind, buying items to set up their own hearths in the North for the preparation of meals, an iconic married woman’s activity, and to be able to enter a preferred, i.e. religious, marriage. They also spend money on dressing, styling their hairdos and looking good in order to attract suitable marriage candidates. Alternatively, the successful older women in the market place invest in conspicuous consumption to enact their informal position of ‘market mummies’, women who are well established and suitable mentors to more recent arrivals. The women shape their own life courses through consumption. The consumption practices SMW engage in are crucial for understanding the dynamics of single migrant women’s agency.

After migration, SMW are more likely to exert influence on the timing of their marriage and the choice of the partner. In the place of origin there are transformations of the gendered subjectivities women experience after having produced livelihoods away from home. The investigation of the reintegration experience of SMW who return to their place of origin revealed the everyday experience of returned migrant women within their households in rural northern Ghana. The study found the household to be an ‘arena of everyday life’; the word arena indicates dynamics and even struggle. These are visible in the provision for daily needs, and also in the income generating activities the women try to initiate to exercise their agency in generating livelihood. In this household arena, we recognized the gender dynamics around decision-making on livelihood generation as key to under­standing the reintegration experience of returned migrant women. The analysis drew on feminist geographers’ insights of gender as process situated in a specific place. Critical attention was paid to how gender and household are co-constituted, to shed light on the multiple and contradictory ways in which gender, livelihood, and household are constructed.

Applying the lens of gender as situated process enabled capturing the significance of everyday micro transformations, resulting in a framework that wove together the domains of gender, household and livelihood. Contingent formations of intra-household dynamics revealed variations in the ways subjection and activation are enacted. The boundaries of women’s triple shifts (household work, farming, income generation) are not fixed but are constantly negotiated. On an everyday basis women have to juggle multiple subjectivities, such as being wives, daughters-in-law, mothers and petty commodity producers and traders. They do the work their husbands and senior women require them to do in order to secure their marriage, which is considered a lifelong security in this specific context, but they try to set limits to this work.

The general conclusion this study highlights is that the young women in the North successfully negotiate to realize their aspirations to migrate and, upon return, both subject themselves to the domestic and patriarchal order and contest it by using the means and skills they acquired to improve their bargaining position. This causes cracks in the prevailing order, which suggest the malleability of the patriarchal system. The observed processes underpin the relevance of conceptualising migration as an intrinsic factor in broader processes of development and social transformation.

Leverages for on-farm innovation from farm typologies? An illustration for family-based dairy farms in north-west Michoacán, Mexico
Cortez Arriola, J. ; Rossing, W.A.H. ; Amendola Massiotti, R.D. ; Scholberg, J.M.S. ; Groot, J.C.J. ; Tittonell, P.A. - \ 2015
Agricultural Systems 135 (2015). - ISSN 0308-521X - p. 66 - 76.
impact assessment - management - diversity - systems - scale - indicators - households - migration
Knowledge on farm diversity provides insight into differences among farms, enables scaling from individual farm to farm population level and vice versa, and has been used in the definition of recommendation domains for introduction of novel technologies. Farm diversity can be broadly described in terms of resource endowment and resource use strategy, or in other words, in terms of scale and intensity of production. Measuring intensity of production requires much greater monitoring effort than measuring scale of production, and often only proxies of production intensity are used. Using data from a regional farm survey and from intensive on-farm monitoring the question addressed in this paper is to which extent results of farm surveys that measure primarily scale of production can inform on-farm interventions aimed at improving farm performance. The survey included a random sample of 97 out of 664 smallholder dairy farmers in a community in north-west Michoacán, Mexico. Farm types were identified by a combination of Principal Component Analysis to reduce the dimensionality of the dataset, followed by Cluster Analysis. The survey was complemented with detailed analyses of costs, revenues and productivity on 6 farms over the course of one year. Survey results revealed considerable variation among the dairy farms in land area, livestock units, amount of hired labour, and infrastructure and equipment, which led to the distinction of 4 farm types. Indicators for animal health management and feeding strategies were uniform across the 4 types. The farm types matched the distinction of family-based and semi-intensive farm types used in Mexico. The detailed analyses of the individual farms belonging to the different types, however, revealed differences in resource use strategies reflected in differences in animal productivity, labour productivity and return to labour. Differences in animal productivity and labour productivity were explained by stocking rate, albeit in different ways. Return to labour was strongly related to cost of feed. Profitability was negative for all farms and was on most farms related to high external feedstuff costs, which constituted 59–89% of the feed cost of the animal ration. The results indicate that in addition to variables reflecting resource endowment or scale of production, typologies that aim to inform on-farm interventions need to consider farm characteristics that reflect intensity of production. Which variables should be selected will need to be determined in a preliminary assessment. To enhance internal resource use efficiency as was the purpose in the current study, candidate variables expressing intensity could include the share of external feed in the ration and proxies of internal resource use, e.g. reflected in crop and milk yields. Opportunities for on-farm innovation arising from the analyses are discussed from the perspective of labour flexibility, low costs and use of internal resources.
Tunnels for toads = Hoe effectief zijn paddentunnels?
Ottburg, F.G.W.A. ; Grift, E.A. van der - \ 2015
Alterra, Wageningen-UR
padden - universitair onderzoek - migratie - habitatverbindingszones - monitoring - efficiëntie - diergedrag - wildpassages - toads - university research - migration - habitat corridors - efficiency - animal behaviour - wildlife passages
Het aanleggen van paddentunnels onder een weg helpt padden bij het oversteken van anders dodelijke wegen. Maar als je wilt weten hoe effectief ze zijn, moet je niet alleen kijken hoeveel dieren de tunnels gebruiken, maar ook hoeveel dieren dat niet doen. Fabrice Ottburg en Edgar van der Grift leggen het belang van hun onderzoek uit in een filmpje.
Minor differences in body condition and immune status between avian influenza virus-infected and noninfected mallards: a sign of coevolution?
Dijk, J.G.B. van; Fouchier, R.A.M. ; Klaassen, M. ; Matson, K.D. - \ 2015
Ecology and Evolution 5 (2015)2. - ISSN 2045-7758 - p. 436 - 449.
a virus - anas-platyrhynchos - natural antibodies - stable hydrogen - wild birds - vice-versa - ducks - patterns - migration - isotopes
Wildlife pathogens can alter host fitness. Low pathogenic avian influenza virus (LPAIV) infection is thought to have negligible impacts on wild birds; however, effects of infection in free-living birds are largely unstudied. We investigated the extent to which LPAIV infection and shedding were associated with body condition and immune status in free-living mallards (Anas platyrhynchos), a partially migratory key LPAIV host species. We sampled mallards throughout the species' annual autumn LPAIV infection peak, and we classified individuals according to age, sex, and migratory strategy (based on stable hydrogen isotope analysis) when analyzing data on body mass and five indices of immune status. Body mass was similar for LPAIV-infected and noninfected birds. The degree of virus shedding from the cloaca and oropharynx was not associated with body mass. LPAIV infection and shedding were not associated with natural antibody (NAbs) and complement titers (first lines of defense against infections), concentrations of the acute phase protein haptoglobin (Hp), ratios of heterophils to lymphocytes (H:L ratio), and avian influenza virus (AIV)-specific antibody concentrations. NAbs titers were higher in LPAIV-infected males and local (i.e., short distance) migrants than in infected females and distant (i.e., long distance) migrants. Hp concentrations were higher in LPAIV-infected juveniles and females compared to infected adults and males. NAbs, complement, and Hp levels were lower in LPAIV-infected mallards in early autumn. Our study demonstrates weak associations between infection with and shedding of LPAIV and the body condition and immune status of free-living mallards. These results may support the role of mallards as asymptomatic carriers of LPAIV and raise questions about possible coevolution between virus and host.
Extending the moral economy beyond households: Gendered livelihood strategies of single migrant women in Accra, Ghana
Tufuor, T. ; Niehof, A. ; Sato, C. ; Horst, H.M. van der - \ 2015
Women's Studies International Forum 50 (2015). - ISSN 0277-5395 - p. 20 - 29.
institutions - migration - survival - poverty - porters
This article highlights how single migrant women (SMW) from rural northern Ghana generate livelihoods through the adoption of both market and non-market based strategies by extending and then prioritising moral obligations to community members beyond their immediate households instead of focusing on maximisation of profits. The setting is the Old Fadama market in Accra, Ghana. Communities of old and new SMW build a “moral community economy” through, amongst others, engaging in reciprocal labour, gift giving, childcare and food sharing. Our study reveals the importance of this moral community economy to SMW's livelihood generation and how it is sustained through social relations amongst women, in which also generation, ethnicity and regional background, play crucial roles. SMW give support to and receive benefits from the community through moral obligations and ethnic commitment. The analysis of these strategies contributes to the understanding of the intersections of household, livelihood strategies, gender and markets in urban settings.
Pilot study on behaviour of sharks around Saba using acoustic telemetry - Progress report 2014
Winter, H.V. ; Vink, D. ; Beek, I.J.M. van - \ 2015
IJmuiden : IMARES (Report / IMARES Wageningen UR C026/15) - 21
haaien - saba - zeereservaten - telemetrie - migratie - verspreiding - universitair onderzoek - sharks - marine protected areas - telemetry - migration - dispersal - university research
Worldwide many shark populations are in strong decline mainly due to fisheries. Population status of sharks in the Caribbean is still poorly known. In order to be able to take effective measures to protect sharks, insight in their spatial behaviour during different life stages is required. Do marine parks enhance shark populations and if so at what scale? This pilot study mainly aims at determining the feasibility of using telemetry around Saba and at a later stage at the Saba Bank and surrounding islands, e.g. what logistics and which co-operation, catching and deployment methods are required to set-up telemetric experiments for target shark species, and to get a first insight of the scale of movement patterns of the target shark species.
Thermal regime, predation danger and the early marine exit of sockeye salmon Oncorhynchus nerka
Katinic, P.J. ; Patterson, D.A. ; Ydenberg, R.C. - \ 2015
Journal of Fish Biology 86 (2015)1. - ISSN 0022-1112 - p. 276 - 287.
british-columbia - atlantic salmon - temperature - water - river - populations - mortality - migration - pacific - energetics
Marine exit timing of sockeye salmon Oncorhynchus nerka populations on the Haida Gwaii Archipelago, British Columbia, Canada, is described, with specific focus on Copper Creek. Marine exit in Copper Creek occurs¿>¿130¿days prior to spawning, one of the longest adult freshwater residence periods recorded for any O. nerka population. Copper Creek presents an easy upstream migration, with mild water temperatures (7 to 14°¿ C), short distance (13·1¿km) and low elevation gain (41¿m) to the lake where fish hold prior to spawning. An energetic model estimates that
Gender mainstreaming and rural development policy; the trivialisation of rural gender issues
Bock, B.B. - \ 2015
Gender, Place & Culture : a Journal of Feminist Geography 22 (2015)5. - ISSN 0966-369X - p. 731 - 745.
european-union - mobilities - areas - state - work - eu - challenges - migration - politics - family
This paper considers gender mainstreaming of the EU Rural Development Programme. The EU promotes the gender mainstreaming of rural development policies because retaining women in rural areas is seen as crucial to the long-term viability of rural areas. A review of literature and scan of policy documents demonstrates that few rural development plans address gender issues, and generally only by including some separate projects for women. Little is done to address the systemic features of gender inequality and to realise inclusive developments that address the needs of all social groups. The de-politicisation of rural gender issues results in policy makers ticking the obligatory gender box without envisioning any real change in the agenda or process of rural development policy making. I argue that a more fruitful way to go forward is to re-politicise gender in rural development and to tease out at the local level how changing gender relations and rural development coincide.
Neandertal Admixture in Eurasia Confirmed by Maximum-Likelihood Analysis of Three Genomes
Lohse, K. ; Frantz, L.A.F. - \ 2014
Genetics 196 (2014)4. - ISSN 0016-6731 - p. 1241 - 1251.
ancestral population sizes - dna-sequences - divergence - speciation - history - number - recombination - coalescent - migration - inference
Although there has been much interest in estimating histories of divergence and admixture from genomic data, it has proved difficult to distinguish recent admixture from long-term structure in the ancestral population. Thus, recent genome-wide analyses based on summary statistics have sparked controversy about the possibility of interbreeding between Neandertals and modern humans in Eurasia. Here we derive the probability of full mutational configurations in nonrecombining sequence blocks under both admixture and ancestral structure scenarios. Dividing the genome into short blocks gives an efficient way to compute maximum-likelihood estimates of parameters. We apply this likelihood scheme to triplets of human and Neandertal genomes and compare the relative support for a model of admixture from Neandertals into Eurasian populations after their expansion out of Africa against a history of persistent structure in their common ancestral population in Africa. Our analysis allows us to conclusively reject a model of ancestral structure in Africa and instead reveals strong support for Neandertal admixture in Eurasia at a higher rate (3.4-7.3%) than suggested previously. Using analysis and simulations we show that our inference is more powerful than previous summary statistics and robust to realistic levels of recombination.
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