| 1. |
- Jiguet, Frédéric, et al.
(författare)
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An update of the European breeding population sizes and trends of the Ortolan Bunting (Emberiza hortulana)
- 2016
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Ingår i: Ornis Fennica. - : University of Helsinki. - 0030-5685. ; 93:3, s. 186-196
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Forskningsöversikt (refereegranskat)abstract
- Following recent updates proposed by BirdLife International and further updates across Europe gathered in the context of a continent-wide study of the migration strategy of the species, we propose here an update of national population sizes and associated recent trends of the Ortolan Bunting (Emberiza hortulana). Previous estimates for the period 1999-2002 reported 5,200,000 to 16,000,000 breeding pairs, for an area extending east to European Russia, and south to the Caucasus and Turkey. The countries holding the largest populations were Turkey (3-10 million pairs) and Russia (1.5-5.0 million pairs). The updated results give approximately 3,319,000 to 7,057,000 pairs in Europe (for the period 2012-2014), representing a c. 50% decrease in numbers over the last decade. This decrease is partly due to overestimates proposed in previous reports for the key country, Turkey, which is now considered to support only 500,000 to 1,000,000 pairs. Russia still holds 2.0-4.3 million pairs, although with an estimated decline of c.15-30% since 2000. Overall, within the 39 European countries assessed here, recent decadal trends (on average 2000-2012) in population size are reported as unknown in 15 countries, increasing in 2 countries (Germany and Serbia), stable or fluctuating in 6 countries, and decreasing in 16 countries including recent extinctions in Belgium, Hungary, Slovakia and the Netherlands. Overall, declining populations are mostly located in northern Europe, and fourteen of the 15 northern European countries with a known national trend have declining breeding populations, suggesting that northern breeders are of particular conservation concern.
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| 2. |
- Jiguet, Frederic, et al.
(författare)
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Desert crossing strategies of migrant songbirds vary between and within species
- 2019
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Each year, billions of songbirds cross large ecological barriers during their migration. Understanding how they perform this incredible task is crucial to predict how global change may threaten the safety of such journeys. Earlier studies based on radar suggested that most songbirds cross deserts in intermittent flights at high altitude, stopping in the desert during the day, while recent tracking with light loggers suggested diurnal prolongation of nocturnal flights and common non-stop flights for some species. We analyzed light intensity and temperature data obtained from geolocation loggers deployed on 130 individuals of ten migratory songbird species, and show that a large variety of strategies for crossing deserts exists between, but also sometimes within species. Diurnal stopover in the desert is a common strategy in autumn, while most species prolonged some nocturnal flights into the day. Nonstop flights over the desert occurred more frequently in spring than in autumn, and more frequently in foliage gleaners. Temperature recordings suggest that songbirds crossed deserts with flight bouts performed at various altitudes according to species and season, along a gradient ranging from low above ground in autumn to probably >2000 m above ground level, and possibly at higher altitude in spring. High-altitude flights are therefore not the general rule for crossing deserts in migrant songbirds. We conclude that a diversity of migration strategies exists for desert crossing among songbirds, with variations between but also within species.
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| 3. |
- Jiguet, Frédéric, et al.
(författare)
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Unravelling migration connectivity reveals unsustainable hunting of the declining ortolan bunting
- 2019
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 5:5
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Tidskriftsartikel (refereegranskat)abstract
- In France, illegal hunting of the endangered ortolan bunting Emberiza hortulana has been defended for the sake of tradition and gastronomy. Hunters argued that ortolan buntings trapped in southwest France originate from large and stable populations across the whole of Europe. Yet, the European Commission referred France to the Court of Justice of the European Union (EU) in December 2016 for infringements to legislation (IP/16/4213). To better assess the impact of hunting in France, we combined Pan-European data from archival light loggers, stable isotopes, and genetics to determine the migration strategy of the species across continents. Ortolan buntings migrating through France come from northern and western populations, which are small, fragmented and declining. Population viability modeling further revealed that harvesting in southwest France is far from sustainable and increases extinction risk. These results provide the sufficient scientific evidence for justifying the ban on ortolan harvesting in France.
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| 4. |
- Moussy, Caroline, et al.
(författare)
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The genetic structure of the European breeding populations of a declining farmland bird, the ortolan bunting (Emberiza hortulana), reveals conservation priorities
- 2018
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Ingår i: Conservation Genetics. - : Springer. - 1566-0621 .- 1572-9737. ; 19:4, s. 909-922
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic activities, such as agricultural intensification, caused large declines in biodiversity, including farmland birds. In addition to demographic consequences, anthropogenic activities can result in loss of genetic diversity, reduction of gene flow and altered genetic structure. We investigated the distribution of the genetic variation of a declining farmland and long-distance migratory bird, the ortolan bunting Emberiza hortulana, across its European breeding range to assess the impact of human-driven population declines on genetic diversity and structure in order to advise conservation priorities. The large population declines observed have not resulted in dramatic loss of genetic diversity, which is moderate to high and constant across all sampled breeding sites. Extensive gene flow occurs across the breeding range, even across a migratory divide, which contributes little to genetic structuring. However, gene flow is asymmetric, with the large eastern populations acting as source populations for the smaller western ones. Furthermore, breeding populations that underwent the largest declines, in Fennoscandia and Baltic countries, appear to be recently isolated, with no gene exchange occurring with the eastern or the western populations. These are signs for concern as declines in the eastern populations could affect the strength of gene flow and in turn affect the western populations. The genetic, and demographic, isolation of the northern populations make them particularly sensitive to loss of genetic diversity and to extinction as no immigration is occurring to counter-act the drastic declines. In such a situation, conservation efforts are needed across the whole breeding range: in particular, protecting the eastern populations due to their key role in maintaining gene flow across the range, and focussing on the northern populations due to their recent isolation and endangered status.
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| 5. |
- Väli, Ulo, et al.
(författare)
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Microsatellites and single nucleotide polymorphisms in avian hybrid identification : a comparative case study
- 2010
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Ingår i: Journal of Avian Biology. - 0908-8857 .- 1600-048X. ; 41:1, s. 34-49
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Tidskriftsartikel (refereegranskat)abstract
- The correct identification of hybrids is essential in avian hybridisation studies, but selection of the appropriate set of genetic markers for this purpose is at times complicated. Microsatellites and single nucleotide polymorphisms (SNPs) are currently the most commonly used markers in this field. We compare the efficiency of these two marker types, and their combination, in the identification of the threatened avian species, the greater spotted eagle and the lesser spotted eagle, as well as hybrids between the two species. We developed novel SNP markers from genome-wide distributed 122 candidate introns using only sympatric samples, and tested these markers successfully in 60 sympatric and allopatric spotted eagles using Bayesian model-based approaches. Comparatively, only one out of twelve previously described avian nuclear intron markers showed significant species-specific allele frequency difference, thus stressing the importance of selecting the proper markers. Twenty microsatellites outperformed selected nine SNPs in species identification, but were poorer in hybrid detection, whereas the resolution power of ten microsatellites remained too low for correct assignment. A combination of SNPs and microsatellites resulted in the most efficient and accurate identification of all individuals. Our study shows that the use of various sets of markers could lead to strikingly different assignment results, hybridisation studies may have been affected by too low a resolution power of used markers, and that an appropriate set of markers is essential for successful hybrid identification.
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| 6. |
- Väli, Ülo, et al.
(författare)
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Widespread hybridization between the Greater Spotted Eagle Aquila clanga and the Lesser Spotted Eagle Aquila pomarina (Aves: Accipitriformes) in Europe
- 2010
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Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 100:3, s. 725-736
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Tidskriftsartikel (refereegranskat)abstract
- Hybridization is a significant threat for endangered species and could potentially even lead to their extinction. This concern applies to the globally vulnerable Greater Spotted Eagle Aquila clanga, a species that co-occurs, and potentially interbreeds, with the more common Lesser Spotted Eagle Aquila pomarina in a vast area of Eastern Europe. We applied single nucleotide polymorphism (SNP) and microsatellite markers in order to study hybridization and introgression in 14 European spotted eagle populations. We detected hybridization and/or introgression in all studied sympatric populations. In most regions, hybridization took place prevalently between A. pomarina males and A. clanga females, with introgression to the more common A. pomarina. However, such a pattern was not as obvious in regions where A. clanga is still numerous. In the course of 16 years of genetic monitoring of a mixed population in Estonia, we observed the abandonment of A. clanga breeding territories and the replacement of A. clanga pairs by A. pomarina, whereby on several occasions hybridization was an intermediate step before the disappearance of A. clanga. Although the total number of Estonian A. clanga × A. pomarina pairs was twice as high as that of A. clanga pairs, the number of pairs recorded yearly were approximately equal, which suggests a higher turnover rate in interbreeding pairs. This study shows that interspecific introgressive hybridization occurs rather frequently in a hybrid zone at least 1700-km wide: it poses an additional threat for the vulnerable A. clanga, and may contribute to the extinction of its populations.
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