| 1. |
- Ronka, N., et al.
(författare)
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Near panmixia at the distribution-wide scale but evidence of genetic differentiation in a geographically isolated population of the Terek Sandpiper Xenus cinereus
- 2019
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Ingår i: Ibis. - : Wiley. - 0019-1019. ; 161:3, s. 632-647
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Tidskriftsartikel (refereegranskat)abstract
- Populations from different parts of a species range may vary in their genetic structure, variation and dynamics. Geographically isolated populations or those located at the periphery of the range may differ from those located in the core of the range. Such peripheral populations may harbour genetic variation important for the adaptive potential of the species. We studied the distribution-wide population genetic structure of the Terek Sandpiper Xenus cinereus using 13 microsatellite loci and the mitochondrial DNA (mtDNA) control region. In addition, we estimated whether genetic variation changes from the core towards the edge of the breeding range. We used the results to evaluate the management needs of the sampled populations. Distribution-wide genetic structure was negligible; the only population that showed significant genetic differentiation was the geographically isolated Dnieper River basin population in Eastern Europe. The genetic variation of microsatellites decreased towards the edge of the distribution, supporting the abundant-centre hypotheses in which the core area of the distribution preserves the most genetic variation; however, no such trend could be seen with mtDNA. Overall genetic variation was low and there were signs of past population contractions followed by expansion; this pattern is found in most northern waders. The current effective population size (N-e) is large, and therefore global conservation measures are not necessary. However, the marginal Dnieper River population needs to be considered its own management unit. In addition, the Finnish population warrants conservation actions due to its extremely small size and degree of isolation from the main range, which makes it vulnerable to genetic depletion.
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| 2. |
- Rönkä, N., et al.
(författare)
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Panmixia at a distribution-wide scale but indications of genetic differentiation in isolated populations of the Terek Sandpiper (Xenus cinereus)
- 2016
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Ingår i: International Wader Study Group Conference 2016, 9-12 September 2016, Trabolgan, Cork, Ireland.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Populations at different parts of the species range may vary in their population dynamics and in their genetic structure and variation. Geographically separated populations or those located at the edge of the range may differ from the populations located at the core, or even be independent of them. The peripheral populations may hold genetic variation that is important for the adaptive potential of the species and therefore be of special conservation value. We studied the distribution-wide population genetic structure of the Terek Sandpiper (Xenus cinereus) using 13 microsatellite loci and two mitochondrial DNA markers: the control region and cytochrome oxidase I (COI). We evaluated the difference in genetic variation between the peripheral and core populations. Specifically, we sought signs of changes in population sizes and evaluated the management need of the populations. Distribution-wide differentiation was negligible, but geographically isolated populations in Finland and Dnieper River basin in Eastern Europe were differentiated from the main range. Edge populations had lower genetic variation than populations at the core when estimated with microsatellites and the COI, supporting the hypotheses where the core area of the distribution preserves the most variation. However, no such trend was observed with the control region data, which follows the model of no change throughout the distribution. The differences between the markers may reflect their different mutation rates, or be linked to the species’ dispersal behaviour. Our results revealed low overall nucleotide diversity and signs of past population contractions followed by expansion. Although the estimated current effective population size is large and therefore global conservation measures are not needed, the Finnish and Dnieper River basin populations nevertheless warrant management actions – not only because they may possess variation not present anywhere else, but also due to their smallness and large distances to the main range.
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| 3. |
- Thies, L., et al.
(författare)
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Population and subspecies differentiation in a high latitude breeding wader, the Common Ringed Plover Charadrius hiaticula
- 2018
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Ingår i: Ardea. - : Netherlands Ornithologists' Union. - 0373-2266. ; 106:2
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Tidskriftsartikel (refereegranskat)abstract
- Exploring the patterns of genetic structure in the context of geographical and phenotypic variation is important to understand the evolutionary processes involved in speciation. We investigated population and subspecies differentiation in the Common Ringed Plover Charadrius hiaticula, a high latitude wader that breeds in arctic and temperate zones from northeast Canada across Eurasia to the Russian Far East. Three subspecies, hiaticula, tundrae and psammodromus, are currently widely recognised, whereas a fourth subspecies, kolymensis, has been proposed based on geographic isolation and phenotypic differences. We genotyped 173 samples from eleven Common Ringed Plover breeding sites, representing all four putative subspecies, at eight polymorphic microsatellite loci to examine the patterns of population and subspecies differentiation. Bayesian clustering identified three genetic clusters among samples, corresponding to the breeding sites of the three currently recognised subspecies. The existence of the subspecies kolymensis was not supported. We also detected the presence of a previously unknown hybridisation zone extending from Northern Scandinavia to Belarus. Differentiation of the subspecies tundrae and hiaticula most likely occurred in allopatry on the Eurasian continent during past glaciation events, followed by population expansion leading to colonisation of Iceland and Greenland. The lack of genetic differentiation within the tundrae subspecies is consistent with ongoing range expansion and high gene flow maintained through migratory behaviour. We discuss the importance of historic climate changes, migratory behaviour and mating system on shaping the observed pattern of genetic differentiation.
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| 4. |
- Pakanen, V. M., et al.
(författare)
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Low frequencies of supernormal clutches in the Southern Dunlin and the Temminck's Stint
- 2019
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Ingår i: Ardea. - : Netherlands Ornithologists' Union. - 0373-2266. ; 107:1, s. 61-74
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Tidskriftsartikel (refereegranskat)abstract
- Supernormal clutches are found across bird species. Such clutches often result from more than one female laying eggs in the same nest and can reflect different behaviours from parasitism to laying mistakes. Enlarged clutches are readily visible among waders due to a maximum maternal clutch size of four eggs, yet surprisingly little is known about this phenomenon. Since supernormal clutches are rare, large sample sizes are required to reliably quantify their natural frequencies. We used a large dataset to estimate the frequency of supernormal clutches in the polygamous Temminck's Stint Calidris temminckii and the monogamous Southern Dunlin C. alpina schinzii, and examine the timing of supernormal clutches in relation to the general distribution of nest initiation dates. While supernormal clutches were very rare, they were over four times more common in the Temminck's Stint (0.50%, n = 1594) than in the Southern Dunlin (0.11%, n = 2766). Dunlin show among the lowest frequency of supernormal clutches reported for waders. In the Temminck's Stint, supernormal clutches were found in the middle of the season, while in the Southern Dunlin such clutches occurred in late season replacement nests. The higher rate and timing of enlarged clutches in Temminck's Stints probably relates to the species' breeding system, which can include simultaneous courtship of multiple partners, but more work is needed to assess the relative influence of different factors. We argue that intraspecific nest parasitism is unlikely to be a primary reproductive tactic in small sandpipers.
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