| 1. |
- Bengtson, Sven-Axel, et al.
(författare)
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Man-dependence of House Sparrows (Passer domesticus) in the Faroe Islands: habitat patch characteristics as determinants of presence and numbers
- 2010
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Ingår i: Dorete - her book, Annales Societatis Scientiarum Færoensis, Suppl. 52. ; , s. 227-243
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The House Sparrow (Passer domesticus) began to colonize the Faroe Islands in the mid-1940s and occurs in most built-up areas. Breeding is confined to the discrete human habitations (settlements) that form a pattern of patches (”habitat-islands”). In 2002 all settlements were surveyed and the number of pairs of sparrows (total number ca. 2,700 pairs) and amount of vegetation (”green space”) were estimated. The settlements ranged in size from 0.01 km2 (a single farmstead) to 8.72 km2 (the capital) and 68% of them (n=118) were occupied by sparrows. Patch occupancy was positively correlated with both area and amount of vegetation (p < 0.001) but not quite with the degree of isolation (p = 0.15). The latter was crudely scored as a function of distance to nearest settlement with > 10 pairs (a possible source area) and topography (mainly mountains and open sea). The patch variables area, human population, number of houses and houses were strongly intercorrelated. Abundance (number of pairs) of sparrows was positively correlated with the number of houses (r = 0.84, p < 0.001). In all but one of the settlements with < 10 houses sparrows were absent, and also in many of those with 10-60 houses where the scatter swas wide (no significant correlation p = 0.25). All but one of the settlements with > 60 houses supported sparrows and the correlation with abundance was highly significant (p < 0.001). The absence of sparrows in small settlements is discussed in terms of risks of associated with small populations such as stochastic extinctions, Allee effects, competition, and predation (incl. persecution by Man). Various anthropogenic effects on abundance of sparrows are discussed; e.g. age, type and conditions of buildings and the presence of gardens, cultivations, and plantations all contributing to shelter and food resources. The Faroese House Sparrow as a metapopulation is briefly discussed.
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| 2. |
- Ferraguti, Martina, et al.
(författare)
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Environmental, geographical and time-related impacts on avian malaria infections in native and introduced populations of house sparrows (Passer domesticus), a globally invasive species
- 2023
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 32:5, s. 809-823
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Tidskriftsartikel (refereegranskat)abstract
- Aim: The increasing spread of vector-borne diseases has resulted in severe health concerns for humans, domestic animals and wildlife, with changes in land use and the introduction of invasive species being among the main possible causes for this increase. We explored several ecological drivers potentially affecting the local prevalence and richness of avian malaria parasite lineages in native and introduced house sparrows (Passer domesticus) populations. Location: Global. Time period: 2002–2019. Major taxa studied: Avian Plasmodium parasites in house sparrows. Methods: We analysed data from 2,220 samples from 69 localities across all continents, except Antarctica. The influence of environment (urbanization index and human density), geography (altitude, latitude, hemisphere) and time (bird breeding season and years since introduction) were analysed using generalized additive mixed models (GAMMs) and random forests. Results: Overall, 670 sparrows (30.2%) were infected with 22 Plasmodium lineages. In native populations, parasite prevalence was positively related to urbanization index, with the highest prevalence values in areas with intermediate urbanization levels. Likewise, in introduced populations, prevalence was positively associated with urbanization index; however, higher infection occurred in areas with either extreme high or low levels of urbanization. In introduced populations, the number of parasite lineages increased with altitude and with the years elapsed since the establishment of sparrows in a new locality. Here, after a decline in the number of parasite lineages in the first 30 years, an increase from 40 years onwards was detected. Main conclusions: Urbanization was related to parasite prevalence in both native and introduced bird populations. In invaded areas, altitude and time since bird introduction were related to the number of Plasmodium lineages found to be infecting sparrows.
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| 3. |
- Giska, Iwona, et al.
(författare)
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Introgression drives repeated evolution of winter coat color polymorphism in hares
- 2019
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 116:48, s. 24150-24156
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Tidskriftsartikel (refereegranskat)abstract
- Changing from summer-brown to winter-white pelage or plumage is a crucial adaptation to seasonal snow in more than 20 mammal and bird species. Many of these species maintain nonwhite winter morphs, locally adapted to less snowy conditions, which may have evolved independently. Mountain hares (Lepus timidus) from Fennoscandia were introduced into the Faroe Islands in 1855. While they were initially winter-white, within ∼65 y all Faroese hares became winter-gray, a morph that occurs in the source population at low frequency. The documented population history makes this a valuable model for understanding the genetic basis and evolution of the seasonal trait polymorphism. Through whole-genome scans of differentiation and single-nucleotide polymorphism (SNP) genotyping, we associated winter coat color polymorphism to the genomic region of the pigmentation gene Agouti, previously linked to introgression-driven winter coat color variation in the snowshoe hare (Lepus americanus). Lower Agouti expression in the skin of winter-gray individuals during the autumn molt suggests that regulatory changes may underlie the color polymorphism. Variation in the associated genomic region shows signatures of a selective sweep in the Faroese population, suggesting that positive selection drove the fixation of the variant after the introduction. Whole-genome analyses of several hare species revealed that the winter-gray variant originated through introgression from a noncolor changing species, in keeping with the history of ancient hybridization between the species. Our findings show the recurrent role of introgression in generating winter coat color variation by repeatedly recruiting the regulatory region of Agouti to modulate seasonal coat color change.
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| 4. |
- Jones, Eleanor P., et al.
(författare)
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A molecular characterization of the charismatic Faroe house mouse
- 2011
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Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 102:3, s. 471-482
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Tidskriftsartikel (refereegranskat)abstract
- Faroe house mice are a 'classic' system of rapid and dramatic morphological divergence highlighted by J. S. Huxley during the development of the Modern Synthesis. In the present study, we characterize these charismatic mice using modern molecular techniques, examining specimens from all Faroe islands occupied by mice. The aims were to classify the mice within the modern house mouse taxonomy (i.e. as either Mus musculus domesticus or Mus musculus musculus) using four molecular markers and a morphological feature, and to examine the genetic diversity and possible routes of colonization using mitochondrial (mt) control region DNA sequences and microsatellite data (15 loci). Mice on the most remote islands were characterized as M. m. domesticus and exhibited exceptionally low genetic diversity, whereas those on better connected islands were more genetically diverse and had both M. m. musculus and M. m. domesticus genetic elements, including one population which was morphologically M. m. musculus-like. The mtDNA data indicate that the majority of the mice had their origins in south-western Norway (or possibly southern Denmark/northern Germany), and probably arrived with the Vikings, earlier than suggested by Huxley. The M. m. musculus genetic component appears to derive from recent mouse immigration from Denmark.
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| 5. |
- Marzal, Alfonso, et al.
(författare)
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Diversity, Loss, and Gain of Malaria Parasites in a Globally Invasive Bird.
- 2011
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:7
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Tidskriftsartikel (refereegranskat)abstract
- Invasive species can displace natives, and thus identifying the traits that make aliens successful is crucial for predicting and preventing biodiversity loss. Pathogens may play an important role in the invasive process, facilitating colonization of their hosts in new continents and islands. According to the Novel Weapon Hypothesis, colonizers may out-compete local native species by bringing with them novel pathogens to which native species are not adapted. In contrast, the Enemy Release Hypothesis suggests that flourishing colonizers are successful because they have left their pathogens behind. To assess the role of avian malaria and related haemosporidian parasites in the global spread of a common invasive bird, we examined the prevalence and genetic diversity of haemosporidian parasites (order Haemosporida, genera Plasmodium and Haemoproteus) infecting house sparrows (Passer domesticus). We sampled house sparrows (N = 1820) from 58 locations on 6 continents. All the samples were tested using PCR-based methods; blood films from the PCR-positive birds were examined microscopically to identify parasite species. The results show that haemosporidian parasites in the house sparrows' native range are replaced by species from local host-generalist parasite fauna in the alien environments of North and South America. Furthermore, sparrows in colonized regions displayed a lower diversity and prevalence of parasite infections. Because the house sparrow lost its native parasites when colonizing the American continents, the release from these natural enemies may have facilitated its invasion in the last two centuries. Our findings therefore reject the Novel Weapon Hypothesis and are concordant with the Enemy Release Hypothesis.
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| 6. |
- Puckett, Emily E., et al.
(författare)
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Genomic analyses reveal three independent introductions of the invasive brown rat (Rattus norvegicus) to the Faroe Islands
- 2020
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Ingår i: Heredity. - : NATURE PUBLISHING GROUP. - 0018-067X .- 1365-2540. ; 124:1, s. 15-27
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Tidskriftsartikel (refereegranskat)abstract
- Population genomics offers innovative approaches to test hypotheses related to the source and timing of introduction of invasive species. These approaches are particularly appropriate to study colonization of island ecosystems. The brown rat is a cold-hardy global invasive that has reached most of the world's island ecosystems, including even highly isolated archipelagoes such as the Faroe Islands in the North Atlantic Ocean. Historic records tell of rats rafting to the southern island of Suouroy in 1768 following a shipwreck off the coast of Scotland, then expanding across the archipelago. We investigated the demographic history of brown rats in the Faroes using 50,174 SNPs. We inferred three independent introductions of rats, including to Suouroy, the islands of Borooy and Viooy, and onto Streymoy from which they expanded to Eysturoy and Vagar. All Faroese populations showed signs of strong bottlenecks and declining effective population size. We inferred that these founder events removed low frequency alleles, the exact data needed to estimate recent demographic histories. Therefore, we were unable to accurately estimate the timing of each invasion. The difficulties with demographic inference may be applicable to other invasive species, particularly those with extreme and recent bottlenecks. We identified three invasions of brown rats to the Faroe Islands that resulted in highly differentiated populations that will be useful for future studies of life history variation and genomic adaptation.
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