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| 2. |
- Cockerill, Christopher Alan, 1994-, et al.
(författare)
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Genomic Consequences of Fragmentation in the Endangered Fennoscandian Arctic Fox (Vulpes lagopus)
- 2022
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Ingår i: Genes. - : MDPI AG. - 2073-4425. ; 13:11
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Tidskriftsartikel (refereegranskat)abstract
- Accelerating climate change is causing severe habitat fragmentation in the Arctic, threatening the persistence of many cold-adapted species. The Scandinavian arctic fox (Vulpes lagopus) is highly fragmented, with a once continuous, circumpolar distribution, it struggled to recover from a demographic bottleneck in the late 19th century. The future persistence of the entire Scandinavian population is highly dependent on the northernmost Fennoscandian subpopulations (Scandinavia and the Kola Peninsula), to provide a link to the viable Siberian population. By analyzing 43 arctic fox genomes, we quantified genomic variation and inbreeding in these populations. Signatures of genome erosion increased from Siberia to northern Sweden indicating a stepping-stone model of connectivity. In northern Fennoscandia, runs of homozygosity (ROH) were on average ~1.47-fold longer than ROH found in Siberia, stretching almost entire scaffolds. Moreover, consistent with recent inbreeding, northern Fennoscandia harbored more homozygous deleterious mutations, whereas Siberia had more in heterozygous state. This study underlines the value of documenting genome erosion following population fragmentation to identify areas requiring conservation priority. With the increasing fragmentation and isolation of Arctic habitats due to global warming, understanding the genomic and demographic consequences is vital for maintaining evolutionary potential and preventing local extinctions.
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| 5. |
- Flagstad, Øystein, 1967-
(författare)
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Population History and Non-invasive Monitoring : Use of low copy number DNA in Conservation Genetics
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Conservation genetics research is increasingly becoming an integrated part of the management of small and endangered populations. In this thesis I developed tools for genetic analysis of low copy number sources of DNA, such as old teeth from museum specimens as well as field-collected faeces and urine. The newly developed techniques were experimentally tested and were subsequently used in studies of small and vulnerable populations of three taxa.Swayne’s hartebeest, a critically endangered antelope of Ethiopia, has undergone a dramatic population decline during the 20th century. The decline was accompanied by loss of genetic variability, although only evident for the mtDNA genome. Two examined populations were significantly differentiated (p<0.001) and genetic variability was significantly lower (p<0.05) for the smaller population. The data demonstrated that a translocation of 120 animals in 1974 from the larger to the smaller population failed.The wolverine population in southern Norway is the smallest of three populations in Scandinavia. Individual identification of wolverines, based on genetic tagging of 147 faeces samples, provided an estimated population size of 92 ± 9 individuals. The data suggested that Swedish immigrants have contributed and still contribute to the gene pool in Southern Norway, counteracting genetic erosion and reducing the risk of inbreeding depression.The Scandinavian wolf was considered functionally extinct in the 1960s after a dramatic decline for more than a century. Genetic variability was lost during the 1800s and the first decades of the 1900s. Immigration from eastern populations appeared to be low during this period. After 1940, however, several immigrants were detected in the population, which could be related to population expansion events in Russian Karelia. A combined data set of historical and contemporary samples showed that two eastern immigrants founded the contemporary population in 1983. During the 1980s, severe inbreeding took place and genetic variability was again lost. However, with the arrival of a single male immigrant in 1991, there is evidence of increased heterozygosity, a rapid spread of new alleles, and exponential population growth, implying that rare immigration can lead to the rescue and recovery of isolated and endangered populations.
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| 6. |
- Hasselgren, Malin, et al.
(författare)
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Genetic rescue in an inbred Arctic fox (Vulpes lagopus) population
- 2018
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 285:1875
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Tidskriftsartikel (refereegranskat)abstract
- Isolation of small populations can reduce fitness through inbreeding depression and impede population growth. Outcrossing with only a few unrelated individuals can increase demographic and genetic viability substantially, but few studies have documented such genetic rescue in natural mammal populations. We investigate the effects of immigration in a subpopulation of the endangered Scandinavian arctic fox (Vulpes lagopus), founded by six individuals and isolated for 9 years at an extremely small population size. Based on a long-term pedigree (105 litters, 543 individuals) combined with individual fitness traits, we found evidence for genetic rescue. Natural immigration and gene flow of three outbred males in 2010 resulted in a reduction in population average inbreeding coefficient (f), from 0.14 to 0.08 within 5 years. Genetic rescue was further supported by 1.9 times higher juvenile survival and 1.3 times higher breeding success in immigrant first-generation offspring compared with inbred offspring. Five years after immigration, the population had more than doubled in size and allelic richness increased by 41%. This is one of few studies that has documented genetic rescue in a natural mammal population suffering from inbreeding depression and contributes to a growing body of data demonstrating the vital connection between genetics and individual fitness.
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| 7. |
- Hemphill, Elisa June Keeling, et al.
(författare)
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Genetic consequences of conservation action: Restoring the arctic fox (Vulpes lagopus) population in Scandinavia
- 2020
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 248
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Tidskriftsartikel (refereegranskat)abstract
- The Arctic fox (Vulpes lagopus) population in Fennoscandia experienced a drastic bottleneck in the late 19th century as a result of high hunting pressure. In the 1990s, despite nearly 70 years of protection, the population showed no signs of recovery. In order to mitigate the population decline and facilitate re-establishment, conservation actions including supplementary feeding and red fox culling were implemented in 1998, followed by the reintroduction of foxes from a captive breeding programme, starting in 2006. A positive demographic impact of these actions is evident from a doubling of the population size over the past decade. We used genetic data collected in eight subpopulations between 2008 and 2015 to address whether the recent demographic recovery has been complemented by changes in genetic variation and connectivity between subpopulations. Our results show that genetic variation within subpopulations has increased considerably during the last decade, while genetic differentiation among subpopulations has decreased. A marked shift in metapopulation dynamics is evident during the study period, suggesting substantially increased migration across the metapopulation. This shift followed the recolonization of an extinct subpopulation through the release of foxes from the captive breeding programme and was synchronized in time with the implementation of supplementary feeding and red fox culling in stepping stone patches between core subpopulations in mid-Scandinavia. Indeed, the increase in genetic variation and connectivity in the Scandinavian arctic fox population suggests that metapopulation dynamics have been restored, which may indicate an increase in the long-term viability of the population.
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| 8. |
- Laporte-Devylder, Lucie, et al.
(författare)
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A camera trap-based assessment of climate-driven phenotypic plasticity of seasonal moulting in an endangered carnivore
- 2023
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Ingår i: Remote Sensing in Ecology and Conservation. - : Wiley. - 2056-3485. ; 9:2, s. 210-221
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Tidskriftsartikel (refereegranskat)abstract
- For many species, the ability to rapidly adapt to changes in seasonality is essential for long-term survival. In the Arctic, seasonal moulting is a key life-history event that provides year-round camouflage and thermal protection. However, increased climatic variability of seasonal events can lead to phenological mismatch. In this study, we investigated whether winter-white (white morph) and winter-brown (blue morph) Arctic foxes (Vulpes lagopus) could adjust their winter-to-summer moult to match local environmental conditions. We used camera trap images spanning an eight-year period to quantify the timing and rate of fur change in a polymorphic subpopulation in south-central Norway. Seasonal snow cover duration and temperature governed the phenology of the spring moult. We observed a later onset and longer moulting duration with decreasing temperature and longer snow season. Additionally, white foxes moulted earlier than blue in years with shorter periods of snow cover and warmer temperatures. These results suggest that phenotypic plasticity allows Arctic foxes to modulate the timing and rate of their spring moult as snow conditions and temperatures fluctuate. With the Arctic warming at an unprecedented rate, understanding the capacity of polar species to physiologically adapt to a changing environment is urgently needed in order to develop adaptive conservation efforts. Moreover, we provide the first evidence for variations in the moulting phenology of blue and white Arctic foxes. Our study underlines the different intraspecific selective pressures that can exist in populations where several morphs co-occur, and illustrates the importance of integrating morph-based differences in future management strategies of such polymorphic species.
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| 9. |
- Larsson, Petter, et al.
(författare)
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Consequences of past climate change and recent human persecution on mitogenomic diversity in the arctic fox
- 2019
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Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 374:1788
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Tidskriftsartikel (refereegranskat)abstract
- Ancient DNA provides a powerful means to investigate the timing, rate and extent of population declines caused by extrinsic factors, such as past climate change and human activities. One species probably affected by both these factors is the arctic fox, which had a large distribution during the last glaciation that subsequently contracted at the start of the Holocene. More recently, the arctic fox population in Scandinavia went through a demographic bottleneck owing to human persecution. To investigate the consequences of these processes, we generated mitogenome sequences from a temporal dataset comprising Pleistocene, historical and modern arctic fox samples. We found no evidence that Pleistocene populations in mid-latitude Europe or Russia contributed to the present-day gene pool of the Scandinavian population, suggesting that postglacial climate warming led to local population extinctions. Furthermore, during the twentieth-century bottleneck in Scandinavia, at least half of the mitogenome haplotypes were lost, consistent with a 20-fold reduction in female effective population size. In conclusion, these results suggest that the arctic fox in mainland Western Europe has lost genetic diversity as a result of both past climate change and human persecution. Consequently, it might be particularly vulnerable to the future challenges posed by climate change. This article is part of a discussion meeting issue 'The past is a foreign country: how much can the fossil record actually inform conservation?'
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| 10. |
- Norén, Karin, et al.
(författare)
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Evolution, ecology and conservation—revisiting three decades of Arctic fox population genetic research
- 2017
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Ingår i: Polar Research. - : Norwegian Polar Institute. - 0800-0395 .- 1751-8369. ; 36
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Forskningsöversikt (refereegranskat)abstract
- Three decades have passed since the Arctic fox (Vulpes lagopus) was first put into a population genetic perspective. With the aim of addressing how microevolution operates on different biological levels, we here review genetic processes in the Arctic fox at the level of species, populations and individuals. Historical and present dispersal patterns, especially in the presence of sea ice, are the most powerful factors that create a highly homogeneous genetic structure across the circumpolar distribution, with low detectable divergence between the coastal and lemming ecotypes. With dispersal less pronounced or absent, other processes emerge; populations that are currently isolated, for example, because of the lack of sea ice, are genetically divergent. Moreover, small populations generally display signatures of genetic drift, inbreeding, inbreeding depression and, under specific situations, hybridization with domestic fox breeds. Mating system and social organization in the Arctic fox appear to be determined by the ecological context, with complex mating patterns and social groups being more common under resource-rich conditions. In isolated populations, complex social groups and inbreeding avoidance have been documented. We emphasize the value of genetic data to decipher many previously unknown aspects of Arctic fox biology, while these data also raise numerous questions that remain unanswered. Pronounced intra-specific ecological variation makes the Arctic fox an ideal study organism for population genetic processes and the emergence of functional genomics will generate an even deeper understanding of evolution, ecology and conservation issues for several species.
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| 11. |
- Norén, Karin, et al.
(författare)
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Genetic footprints reveal geographic patterns of expansion in Fennoscandian red foxes
- 2015
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 21:9, s. 3299-3312
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Tidskriftsartikel (refereegranskat)abstract
- Population expansions of boreal species are among the most substantial ecological consequences of climate change, potentially transforming both structure and processes of northern ecosystems. Despite their importance, little is known about expansion dynamics of boreal species. Red foxes (Vulpes vulpes) are forecasted to become a keystone species in northern Europe, a process stemming from population expansions that began in the 19th century. To identify the relative roles of geographic and demographic factors and the sources of northern European red fox population expansion, we genotyped 21 microsatellite loci in modern and historical (1835–1941) Fennoscandian red foxes. Using Bayesian clustering and Bayesian inference of migration rates, we identified high connectivity and asymmetric migration rates across the region, consistent with source-sink dynamics, whereby more recently colonized sampling regions received immigrants from multiple sources. There were no clear clines in allele frequency or genetic diversity as would be expected from a unidirectional range expansion from south to north. Instead, migration inferences, demographic models and comparison to historical red fox genotypes suggested that the population expansion of the red fox is a consequence of dispersal from multiple sources, as well as in situ demographic growth. Together, these findings provide a rare glimpse into the anatomy of a boreal range expansion and enable informed predictions about future changes in boreal communities.
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| 12. |
- Tietgen, Lukas, et al.
(författare)
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Fur colour in the Arctic fox : genetic architecture and consequences for fitness
- 2021
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 288:1959
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies provide good opportunities for studying the genetic basis of adaptive traits in wild populations. Yet, previous studies often failed to identify major effect genes. In this study, we used high-density single nucleotide polymorphism and individual fitness data from a wild non-model species. Using a whole-genome approach, we identified the MC1R gene as the sole causal gene underlying Arctic fox Vulpes lagopus fur colour. Further, we showed the adaptive importance of fur colour genotypes through measures of fitness that link ecological and evolutionary processes. We found a tendency for blue foxes that are heterozygous at the fur colour locus to have higher fitness than homozygous white foxes. The effect of genotype on fitness was independent of winter duration but varied with prey availability, with the strongest effect in years of increasing rodent populations. MC1R is located in a genomic region with high gene density, and we discuss the potential for indirect selection through linkage and pleiotropy. Our study shows that whole-genome analyses can be successfully applied to wild species and identify major effect genes underlying adaptive traits. Furthermore, we show how this approach can be used to identify knowledge gaps in our understanding of interactions between ecology and evolution.
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| 13. |
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| 14. |
- Wallén, Johan, et al.
(författare)
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Multiple recolonization routes towards the north : population history of the Fennoscandian red fox (Vulpes vulpes)
- 2018
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Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 124:4, s. 621-632
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the response of boreal species to past climate warming can help to predict future responses to climate change. In the Northern Hemisphere, the distribution and abundance of northern populations have been influenced by previous glaciations. In this study, we investigated the population history of the Fennoscandian red fox (Vulpes vulpes), which is a generalist carnivore currently undergoing range expansion in the tundra ecosystem. By analysing a 696 bp sequence of the mitochondrial DNA (N = 259) and two Y chromosome-specific microsatellite loci (N = 120), we specifically investigated where the red fox survived the Last Glacial Maximum and how Fennoscandia was recolonized. There was high genetic continuity across most of Fennoscandia, and we identified at least two recolonization pathways: one from continental Europe and one from the northeast (Siberia). Mitochondrial haplotype diversity displayed a significant decline with increasing latitude, consistent with expectations of unidirectional colonization. Each region displayed signatures of recent demographic and/or range expansions. For Finland, an additional recolonization route was suggested from the mismatch distribution analysis and identification of novel haplotypes. We concluded that, as with many boreal generalist species, the Fennoscandian red fox originates from multiple refugia, suggesting that it has benefited from diverse evolutionary histories, potentially enhancing its tolerance to different habitat conditions.
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| 15. |
- Åkesson, Mikael, et al.
(författare)
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Genetic rescue in a severely inbred wolf population
- 2016
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 25:19, s. 4745-4756
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Tidskriftsartikel (refereegranskat)abstract
- Natural populations are becoming increasingly fragmented which is expected to affect their viability due to inbreeding depression, reduced genetic diversity and increased sensitivity to demographic and environmental stochasticity. In small and highly inbred populations, the introduction of only a few immigrants may increase vital rates significantly. However, very few studies have quantified the long-term success of immigrants and inbred individuals in natural populations. Following an episode of natural immigration to the isolated, severely inbred Scandinavian wolf (Canis lupus) population, we demonstrate significantly higher pairing and breeding success for offspring to immigrants compared to offspring from native, inbred pairs. We argue that inbreeding depression is the underlying mechanism for the profound difference in breeding success. Highly inbred wolves may have lower survival during natal dispersal as well as competitive disadvantage to find a partner. Our study is one of the first to quantify and compare the reproductive success of first-generation offspring from migrants vs. native, inbred individuals in a natural population. Indeed, our data demonstrate the profound impact single immigrants can have in small, inbred populations, and represent one of very few documented cases of genetic rescue in a population of large carnivores.
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