| 1. |
- Bengtsson, Daniel, et al.
(författare)
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Age and sex determination of mallards Anas platyrhynchos in autumn
- 2016
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Ingår i: Ornis Svecica. - 1102-6812 .- 2003-2633. ; 26, s. 61-81
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Tidskriftsartikel (refereegranskat)abstract
- The mallard is a well-known and important species in migration ecology, game management,and epidemiology. Males and females are generally easily told apart, whereas ageing isproblematic, due to individual timing of the moult cycle and lack of easily defined agecriteria. From examination and photographic documentation of mallards caught within a longtermringing program at Ottenby Bird Observatory (56°12′N, 16°24′E), we describe ninecharacters of plumage and bare parts to be used for ageing mallards in autumn. The reliabilityof these characters was tested by letting experienced bird ringers determine putative age ofbirds from photos. Age determination from any single character proved to be uncertain, as therate of correctly assigned mallard photos of each character was in the range of 51-85% formales and 48-89% for females. For both sexes, the lowest figure represented post-humeralsand the highest represented tertials. Rectrices, tertial coverts, and greater coverts also hadreasonably high scores (71-85%). With all characters at hand, 91% of the males and 95% ofthe females were correctly identified to age. As young mallards, with the progress of prebreedingmoult (completed from October onwards), acquire tail and tertials identical to adults,untypical individuals are better not assigned to an age category.
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| 2. |
- Bengtsson, Daniel, et al.
(författare)
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Does influenza A virus infection affect movement behaviour during stopover in its wild reservoir host?
- 2016
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Ingår i: The Royal Society. - : The Royal Society. - 2054-5703. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- The last decade has seen a surge in research on avian influenza A viruses (IAVs), in part fuelled by the emergence, spread and potential zoonotic importance of highly pathogenic virus subtypes. The mallard (Anas platyrhynchos) is the most numerous and widespread dabbling duck in the world, and one of the most important natural hosts for studying IAV transmission dynamics. In order to predict the likelihood of IAV transmission between individual ducks and to other hosts, as well as between geographical regions, it is important to understand how IAV infection affects the host. In this study, we analysed the movements of 40 mallards equipped with GPS transmitters and three-dimensional accelerometers, of which 20 were naturally infected with low pathogenic avian influenza virus (LPAIV), at a major stopover site in the Northwest European flyway. Movements differed substantially between day and night, as well as between mallards returning to the capture site and those feeding in natural habitats. However, movement patterns did not differ between LPAIV infected and uninfected birds. Hence, LPAIV infection probably does not affect mallard movements during stopover, with high possibility of virus spread along the migration route as a consequence.
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| 3. |
- Bengtsson, Daniel, et al.
(författare)
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Movements, Home-Range Size and Habitat Selection of Mallards during Autumn Migration
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:6
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Tidskriftsartikel (refereegranskat)abstract
- The mallard (Anas platyrhynchos) is a focal species in game management, epidemiology and ornithology, but comparably little research has focused on the ecology of the migration seasons. We studied habitat use, time-budgets, home-range sizes, habitat selection, and movements based on spatial data collected with GPS devices attached to wild mallards trapped at an autumn stopover site in the Northwest European flyway. Sixteen individuals (13 males, 3 females) were followed for 15-38 days in October to December 2010. Forty-nine percent (SD = 8.4%) of the ducks' total time, and 85% of the day-time (SD = 28.3%), was spent at sheltered reefs and bays on the coast. Two ducks used ponds, rather than coast, as day-roosts instead. Mallards spent most of the night (76% of total time, SD = 15.8%) on wetlands, mainly on alvar steppe, or in various flooded areas (e.g. coastal meadows). Crop fields with maize were also selectively utilized. Movements between roosting and foraging areas mainly took place at dawn and dusk, and the home-ranges observed in our study are among the largest ever documented for mallards (mean = 6,859 ha; SD = 5,872 ha). This study provides insights into relatively unknown aspects of mallard ecology. The fact that autumn-staging migratory mallards have a well-developed diel activity pattern tightly linked to the use of specific habitats has implications for wetland management, hunting and conservation, as well as for the epidemiology of diseases shared between wildlife and domestic animals.
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| 4. |
- Bengtsson, Daniel
(författare)
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Stopover Ecology of Mallards : Where, when and how to do what?
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The mallard (Anas platyrhynchos) is the most numerous and widespread duck in the northern hemisphere and a model species in ecology and harvest management. Migration is a crucial life stage for many birds and understanding the drivers of migration has important implications for conservation biology and assessment of animal population responses to global changes. Furthermore, mallard migration is a fundamental determinant of the epidemiology of many diseases of major relevance for both animal and human health. For example, it is the reservoir host for influenza A viruses (IAV), a widespread zoonosis causing mortality and economic damage. Improved knowledge of mallard behaviour during migration and the impacts of infection in mallards is needed to determine the role of wild birds in global IAV dynamics.This thesis focuses on mallard stopover ecology, an explicitly important part of the annual life cycle that is not well understood. The study area was southern Öland, SE Sweden, where mallard stopover behaviour was scrutinized by a combination of telemetry and ringing data analyses. Specifically, habitat preferences, movements, and emigration decisions were studied in-depth. Potential effects of low pathogenic avian influenza (LPAIV) infection on movement parameters were also investigated. Radio-tracking revealed that stopover mallards adhered to a strict diel pattern, in which they spent the days resting along the coast, visited crop fields at dawn and dusk, and foraged on inland water bodies during the darkest night hours. Notably, the importance of residual maize, as well as small ephemeral wetlands on the unique alvar steppe habitat that predominates on Öland, was previously unknown. LPAIV infection status did not affect movement behaviour, highlighting the possible risk of spread of IAV from wild mallards to poultry along the migratory flyway. Through capture-mark-recapture modelling, it was confirmed that weather, particularly wind direction, was the most important determinant of departure from the stopover site. In contrast, the body condition of departing mallards was less crucial. Taken together, the research presented in this thesis contributes to improved knowledge about mallard stopover ecology and its role in LPAIV disease dynamics.
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| 5. |
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| 6. |
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| 7. |
- Hammar, Olle, 1985-
(författare)
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The Mystery of Inequality : Essays on Culture, Development, and Distributions
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Essay I (with Daniel Waldenström): We estimate trends in global earnings dispersion across occupational groups by constructing a new database that covers 68 developed and developing countries between 1970 and 2018. Our main finding is that global earnings inequality has fallen, primarily during the 2000s and 2010s, when the global Gini coefficient dropped by 15 points and the earnings share of the world’s poorest half doubled. Decomposition analyses show earnings convergence between countries and within occupations, while within-country earnings inequality has increased. Moreover, the falling global inequality trend was driven mainly by real wage growth, rather than changes in hours worked, taxes or occupational employment.Essay II: I analyze the relationship between individualism and preferences for redistribution, using variation in immigrants’ countries of origin to capture the impact of cultural values and beliefs on personal attitudes towards income redistribution and equality. Using global individual-level survey data, I find strong support for the hypothesis that more individualistic cultures are associated with lower preferences for redistribution. At the same time, cultural assimilation in this dimension seems to take place relatively fast.Essay III (with Paula Roth and Daniel Waldenström): We provide new evidence on income inequality levels and trends in Sweden from 1968 to 2016. By combining data from tax and population registers, we construct a new dataset that includes the distribution of pre-tax total and post-tax disposable income for the full Swedish population since 1968. Our results indicate that the 1980s was the decade with the lowest level of overall income inequality in Sweden, while income inequality as measured by top income shares for the very top has increased steadily over the studied period.Essay IV (with Katarzyna Burzynska): We apply a panel of 331 microfinance institutions from 37 countries to investigate the relationship between social beliefs and microfinance financial performance over the period of 2003–2011. We find that microfinance institutions in countries with higher levels of trust and more collectivist culture have lower operating and default costs and charge lower interest rates. These results provide the first large cross-country evidence that social beliefs are important determinants of microfinance performance.
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| 8. |
- Helldin, Jan Olof, et al.
(författare)
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Assessment of traffic noise impact in important bird sites in Sweden : A practical method for the regional scale
- 2013
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Ingår i: Oecologia Australis. - : Oecologia Australis. - 2177-6199. ; 17:1, s. 48-62
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Tidskriftsartikel (refereegranskat)abstract
- Previous research has pointed out the negative impact of traffic noise on wildlife adjacent to major roads, but despite the scientific evidence, the impact of traffic noise in natural environments is rarely assessed, and even more rarely mitigated, in road planning, in Sweden as well as in most other countries. It has been argued that the reason to this shortcoming is the lack of a practical method to assess this impact on natural environments. We developed a desktop method for assessing the traffic noise impact on areas of importance for nature conservation, with special emphasis on important bird sites. The method output is a calculation of the effective habitat loss due to traffic noise for each site, based on dose-effect relationships presented in literature, available GIS data on selected habitat types, official road data, and a simplified model for noise distribution. The method has a dual purpose; to estimate the impact of traffic noise on birds at larger geographic scales, and to identify priority sites for mitigation efforts. We applied the method in two Swedish regions with relatively low or moderate road and traffic densities. The results from these case studies pointed out that i) at regional level, the impact zone covers a small part of the land area (0.6 and 3.3% of lower and higher density regions, respectively), ii) for certain important bird habitat types, >10% of sites are within the impact zone, iii) the impact from traffic noise represents an effective loss of 0.02-1.7% of the total area of the selected habitat types. The latter figures can be taken as estimates of the present conservation debt of traffic noise. The results indicate that traffic noise may have a disproportionate impact on some important bird habitats. Because bird sites are often rich also in other taxa, and in addition tend to be important areas for outdoor recreation, we argue that traffic noise may have a broad impact on nature conservation, and that mitigation efforts should be made to minimize this impact. We discuss the general applicability of the method.
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| 9. |
- Hernandez, Jorge, et al.
(författare)
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Characterization and Comparison of Extended-Spectrum beta-Lactamase (ESBL) Resistance Genotypes and Population Structure of Escherichia coli Isolated from Franklin's Gulls (Leucophaeus pipixcan) and Humans in Chile
- 2013
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Ingår i: PLOS ONE. - : PLoS, Public Library of Science. - 1932-6203. ; 8:9, s. e76150-
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the general level of antibiotic resistance with further analysis of extended-spectrum beta-lactamase (ESBL) prevalence, as well as the population structure of E. coli in fecal flora of humans and Franklin's gulls (Leucophaeus pipixcan) in central parts of Chile. We found a surprisingly high carriage rate of ESBL-producing E. coli among the gulls 112/372 (30.1%) as compared to the human population 6/49 (12.2%.) Several of the E. coli sequence types (STs) identified in birds have previously been reported as Multi Drug Resistant (MDR) human pathogens including the ability to produce ESBLs. This means that not only commensal flora is shared between birds and humans but also STs with pathogenic potential. Given the migratory behavior of Franklin's gulls, they and other migratory species, may be a part of ESBL dissemination in the environment and over great geographic distances. Apart from keeping the antibiotic use low, breaking the transmission chains between the environment and humans must be a priority to hinder the dissemination of resistance.
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| 10. |
- Latorre-Margalef, Neus, et al.
(författare)
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Long-term variation in influenza A virus prevalence and subtype diversity in migratory mallards in northern Europe.
- 2014
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 281:1781, s. 20140098-
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Tidskriftsartikel (refereegranskat)abstract
- Data on long-term circulation of pathogens in wildlife populations are seldom collected, and hence understanding of spatial-temporal variation in prevalence and genotypes is limited. Here, we analysed a long-term surveillance series on influenza A virus (IAV) in mallards collected at an important migratory stopover site from 2002 to 2010, and characterized seasonal dynamics in virus prevalence and subtype diversity. Prevalence dynamics were influenced by year, but retained a common pattern for all years whereby prevalence was low in spring and summer, but increased in early autumn with a first peak in August, and a second more pronounced peak during October-November. A total of 74 haemagglutinin (HA)/neuraminidase (NA) combinations were isolated, including all NA and most HA (H1-H12) subtypes. The most common subtype combinations were H4N6, H1N1, H2N3, H5N2, H6N2 and H11N9, and showed a clear linkage between specific HA and NA subtypes. Furthermore, there was a temporal structuring of subtypes within seasons based on HA phylogenetic relatedness. Dissimilar HA subtypes tended to have different temporal occurrence within seasons, where the subtypes that dominated in early autumn were rare in late autumn, and vice versa. This suggests that build-up of herd immunity affected IAV dynamics in this system.
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