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Genetic and morphological variation in Dunlin Calidris alpina breeding in the Palearctic tundra
Abstract
The extensive overlap in morphological characters between populations of Dunlin Calidris alpina imposes problems of determining the origin of migrating and wintering birds. The morphology of the birds also varies between the sexes, and the sex of a Dunlin may often be difficult to determine. To clarify if mitochondrial DNA can be used to identify which breeding areas migrating Dunlin come from, we investigated the occurrence of different mtDNA haplotypes in Dunlin from eight breeding areas on the Russian and Siberian tundra. Four haplotypes were found and at most sites more than one haplotype occurred. The European haplotype predominated in the area west of the Taymyr Peninsula, the Siberian haplotype in central Siberia (from the Taymyr Peninsula to the Lopatka Peninsula) and the Beringian haplotype in eastern Siberia. One individual of an Alaskan haplotype, not detected previously among breeding birds outside North America, was found on Wrangel Island. The sex of each bird was identified genetically and the morphology of males and females was analysed separately. Birds with the European haplotype were generally smaller than birds with the Beringian or Alaskan haplotypes. Birds possessing the Siberian haplotype showed intermediate values in most cases. After compensating for differences between sites, males with the Siberian haplotype had significantly longer bills than males having the European haplotype. Multiple regressions indicate that mitochondrial DNA analysis improves models estimating the breeding origin of migrating Dunlin.
... Up to 11 subspecies have been described worldwide based on plumage characters, morphometrics, moulting pattern, and migratory behaviour (Cramp & Simmons, 1983;Greenwood, 1986;Hayman, Marchant & Prater, 1986;del Hoyo, Elliott & Sargatal, 1996;Engelmoer & Roselaar, 1998). Sequencing of the control region of mitochondrial DNA (mtDNA) in dunlins revealed five phylogenetic clades in the world (Wenink, Baker & Tilanus, 1993;, and later studies have confirmed these when investigating the haplotype frequencies at smaller scales (Wennerberg et al., 1999;Wennerberg, 2001). There are thus more recognized subspecies than mtDNA lineages. ...
... One region where there is low mtDNA resolution compared to the number of recognized subspecies is the western Palearctic; from East Greenland to central Siberia. In that region, there are only two mtDNA lineages (EUR and SIB; Wenink et al., 1993;Wennerberg et al., 1999;Wennerberg, 2001;Lopes, Marques & Wennerberg, 2006) (Fig. 1), but at least three recognized Wenink et al. (1993), , Wennerberg et al. (1999), Wennerberg (2001) and L. Wennerberg (unpubl. data). ...
... One region where there is low mtDNA resolution compared to the number of recognized subspecies is the western Palearctic; from East Greenland to central Siberia. In that region, there are only two mtDNA lineages (EUR and SIB; Wenink et al., 1993;Wennerberg et al., 1999;Wennerberg, 2001;Lopes, Marques & Wennerberg, 2006) (Fig. 1), but at least three recognized Wenink et al. (1993), , Wennerberg et al. (1999), Wennerberg (2001) and L. Wennerberg (unpubl. data). ...
In a circumpolar wader, the dunlin (Calidris alpina), there are 11 named subspecies, but only five mitochondrial DNA (mtDNA) lineages have been found. In the present study, we investigated the genetic structure of dunlins in western Palearctic (from East Greenland to Taimyr peninsula) using DNA microsatellites and amplified fragment length polymorphism (AFLP) markers that may detect more recent differentiation than mtDNA. In this region, we consider four described subspecies; alpina, schinzii, arctica and centralis, together comprising two mtDNA lineages. We analyse seven polymorphic microsatellite loci and 91 AFLP markers in 287 and 152 unrelated individuals, respectively, originating from 17 populations. Neither microsatellites nor AFLPs reveal distinct groups that correspond to currently recognized subspecies. There is a clear pattern of isolation by distance in microsatellites. Our results do not contradict the former mtDNA results that there are two phylogenetic lineages (approximately corresponding to schinzii and centralis) that have met and formed a cline (alpina). We find no difference between schinzii and arctica (East Greenland). We conclude that, given the lack of distinct groups and the gradual changes in microsatellite allele frequencies, these markers provide little genetic support for the dunlin subspecies taxonomy in the western Palearctic. (c) 2007 The Linnean Society of London.
... Although all Dunlin subspecies show some phenotypic variation (Tomkovich 1986;Nechaev and Tomkovich 1987;Browning 1991), it is difficult to separate them outside of the breeding grounds using commonly employed morphological characters such as plumage or culmen, head, wing, and tarsus measurements (Warnock and Gill 1996;Wennerberg et al. 1999; but see Gates et al. 2013). This is particularly true in eastern Asia where four subspecies are thought to intermix during the non-breeding season (Lanctot et al. 2009;Gates et al. 2013). ...
... provide evidence for differentiation among Dunlin subspecies and breeding populations from the region? While prior work has examined phylogeographic patterns in the Northern Hemisphere, most studies were based on small sample sizes and had limited (or no) sampling within Beringiaassociated subspecies (e.g., Wennerberg et al. 1999;Marthinsen et al. 2007). 2) Does genetic differentiation among subspecies provide a basis for the probabilistic identification of subspecies where they co-occur (sensu Patten and Unitt 2002)? ...
... In contrast to past genetic studies of Dunlin that included limited sampling of Beringiaassociated subspecies (e.g., Wenink et al. 1993;Wennerberg et al. 1999;Wennerberg et al. 2008), genetic analyses from our investigation revealed marked genetic differentiation among some Dunlin subspecies based on mtDNA analyses. Phylogenetic analysis revealed four separate phylogroups with high levels of statistical support (Fig. 2). ...
Waterfowl (Anseriformes) and shorebirds (Charadriiformes) are the most common wild vectors of influenza A viruses. Due to their migratory behavior, some may transmit disease over long distances. Migratory connectivity studies can link breeding and nonbreeding grounds while illustrating potential interactions among populations that may spread diseases. We investigated Dunlin (Calidris alpina), a shorebird with a subspecies (C. a. arcticola) that migrates from nonbreeding areas endemic to avian influenza in eastern Asia to breeding grounds in northern Alaska. Using microsatellites and mitochondrial DNA, we illustrate genetic structure among six subspecies: C. a. arcticola, C. a. pacifica, C. a. hudsonia, C. a. sakhalina, C. a. kistchinski, and C. a. actites. We demonstrate that mitochondrial DNA can help distinguish C. a. arcticola on the Asian nonbreeding grounds with >70% accuracy depending on their relative abundance, indicating that genetics can help determine if C. a. arcticola occurs where they may be exposed to highly pathogenic avian influenza (HPAI) during outbreaks. Our data reveal asymmetric intercontinental gene flow, with some C. a. arcticola short-stopping migration to breed with C. a. pacifica in western Alaska. Because C. a. pacifica migrates along the Pacific Coast of North America, interactions between these subspecies and other taxa provides route for transmission of HPAI into other parts of North America.This article is protected by copyright. All rights reserved.
... Up to 11 subspecies have been described worldwide based on plumage characters, morphometrics, moulting pattern, and migratory behaviour (Cramp & Simmons, 1983;Greenwood, 1986;Hayman, Marchant & Prater, 1986;del Hoyo, Elliott & Sargatal, 1996;Engelmoer & Roselaar, 1998). Sequencing of the control region of mitochondrial DNA (mtDNA) in dunlins revealed five phylogenetic clades in the world (Wenink, Baker & Tilanus, 1993;, and later studies have confirmed these when investigating the haplotype frequencies at smaller scales (Wennerberg et al., 1999;Wennerberg, 2001). There are thus more recognized subspecies than mtDNA lineages. ...
... One region where there is low mtDNA resolution compared to the number of recognized subspecies is the western Palearctic; from East Greenland to central Siberia. In that region, there are only two mtDNA lineages (EUR and SIB;Wenink et al., 1993;Wennerberg et al., 1999;Wennerberg, 2001;Lopes, Marques & Wennerberg, 2006) ( Fig. 1), but at least three recognized . Sampling localities and geographical distributions of dunlin Calidris alpina subspecies in western Palearctic and East Greenland as referred to in the present study. ...
... Sample sizes are shown within the pies. Data on mitochondrial DNA are from Wenink et al. (1993), , Wennerberg et al. (1999), Wennerberg (2001) and L. Wennerberg (unpubl. data). ...
In a circumpolar wader, the dunlin (Calidris alpina), there are 11 named subspecies, but only five mitochondrial DNA (mtDNA) lineages have been found. In the present study, we investigated the genetic structure of dunlins in western Palearctic (from East Greenland to Taimyr peninsula) using DNA microsatellites and amplified fragment length polymorphism (AFLP) markers that may detect more recent differentiation than mtDNA. In this region, we consider four described subspecies; alpina, schinzii, arctica and centralis, together comprising two mtDNA lineages. We analyse seven polymorphic microsatellite loci and 91 AFLP markers in 287 and 152 unrelated individuals, respectively, originating from 17 populations. Neither microsatellites nor AFLPs reveal distinct groups that correspond to currently recognized subspecies. There is a clear pattern of isolation by distance in microsatellites. Our results do not contradict the former mtDNA results that there are two phylogenetic lineages (approximately corresponding to schinzii and centralis) that have met and formed a cline (alpina). We find no difference between schinzii and arctica (East Greenland). We conclude that, given the lack of distinct groups and the gradual changes in microsatellite allele frequencies, these markers provide little genetic support for the dunlin subspecies taxonomy in the western Palearctic. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 92, 713–726.
... tions of dunlin. Using a more specific method, a larger sample was analysed by Wenink et al . (1993, who sequenced DNA from the mitochondrial control region and found five major mitochondrial DNA (mtDNA) lineages in dunlin from all over the world. These different phylogenetic groups of dunlin can now be identified easily using restriction analysis Wennerberg et al . 1999), and have also been identified in samples from migrating dunlin Tiedemann 1999). Further data have accumulated since the study of , showing the mitochondrial haplotype distribution of the dunlin on the Palaearctic breeding grounds in some geographical detail (Wennerberg et al . 1999;this study). The frequency of mtDNA haplotypes varies ...
... of dunlin can now be identified easily using restriction analysis Wennerberg et al . 1999), and have also been identified in samples from migrating dunlin Tiedemann 1999). Further data have accumulated since the study of , showing the mitochondrial haplotype distribution of the dunlin on the Palaearctic breeding grounds in some geographical detail (Wennerberg et al . 1999;this study). The frequency of mtDNA haplotypes varies according to a consistent geographical pattern within the breeding range. This makes it possible to use genetic markers to estimate the possible breeding origins of dunlin on stopover sites during migration or at winter sites. ...
... In this paper, a map is presented with the distribution of each mtDNA haplotype of dunlin in the breeding grounds, in which all the available results from the breeding areas are summarized and new data are included (Wenink et al . 1993Wennerberg et al . 1999). ...
The large-scale migration of birds has been studied extensively by recoveries of ringed birds. However, there is very little ringing data from the arctic breeding grounds of waders. Here, the migration pattern of the dunlin, Calidris alpina, is studied with population genetic markers, using haplotype frequencies to estimate the breeding origin of migrating and wintering populations. Polymerase chain reaction (PCR) and restriction analysis of DNA from the mitochondrial control region was used to study the breeding origins of morphologically similar winter populations in the western Palaearctic, and to describe the population structure of the dunlin during winter. Also migrating dunlin from various stopover sites in Europe, Africa and Asia, were analysed with respect to their mitochondrial DNA (mtDNA) haplotypes. The genetic markers clearly show that the dunlin has a parallel migration system, with populations breeding in the western Palaearctic wintering mainly in the western part of the wintering range, and dunlin populations breeding further east wintering further east. The results also show that the distance between breeding and wintering area increases eastwards in this region.
... The sequences were first used to make inferences about the historical demography of the two species. We then examined the relative importance of nonequilibrium conditions (or shared ancestral polymorphisms) among populations versus gene flow on the FIGURE 1. Arctic breeding grounds for a) Red Knot subspecies (Piersma and Davidson 1992) and b) Dunlin mtDNA lineages (Wennerberg et al. 1999). Land masses are shaded light grey and breeding areas are shaded in translucent dark grey. ...
... Because Dunlin lineages are in genetic equilibrium, the small amount of mixing found in their haplotype network should be interpreted as a small number of contemporary migrants, and not as shared ancestral polymorphism. The mixing between the European and Siberian phylogroups is probably caused by occasional migrants and interbreeding in the geographically restricted zones of overlap between these groups , Wennerberg et al. 1999, Wennerberg 2001. ...
We employed Bayesian coalescent modeling of samples of mitochondrial control region sequences in two species of shorebird, Red Knots (Calidris canutus) and Dunlins (Calidris alpina) to estimate evolutionary effective population size, population divergence times, and time to most recent common ancestor of genes in the samples. The gene trees for the two species contrast sharply: knot haplotypes were connected in a shallow, star phylogeny whereas Dunlin haplotypes were related in a deeper bifurcating genealogy. Divergence times of populations representing all six subspecies of knots are estimated to have occurred within the last 20 000 (95% CI: 5600–58 000) years, and evolutionary effective population sizes of females are small (Nef = 2000–14 000). We hypothesized that breeding knots were restricted to unglaciated regions of Eurasia during the last glacial maximum, and gradually expanded eastwards into Alaska, the high Canadian Arctic and Greenland as the ice melted. Population divergence times in Dunlins are much older (58 000–194 000 ybp) and effective population size has historically been higher in major lineages (Nef = 12 000–44 000). We conclude that Dunlin populations were not severely reduced in size in the last 200 000 years, and major lineages have differentiated under restricted gene flow for a much longer time than knots. Knots present a snapshot of genetic evolution in the last 20 000 years, whereas Dunlins display patterns of genetic evolution over an order of magnitude longer time frame.
Tiempos de Divergencia Poblacional e Historia Demográfica en Calidris canutus y C. alpina
Resumen. Aplicamos modelos Bayesianos de coalescencia en una muestra de secuencias de la región de control mitocondrial de dos especies de playeros, Calidris canutus y C. alpina, para estimar el tamaño efectivo de la población, los tiempos de divergencia entre poblaciones y la distancia cronológica al antepasado común más reciente de los genes muestreados. Los árboles genealógicos de las dos especies contrastan fuertemente: los haplotipos de C. canutus están conectados superficialmente siguiendo un patrón filogenético en forma de estrella, mientras que los haplotipos de C. alpina se relacionan de manera más profunda, mostrando patrones de genealogía bifurcados. Se estima que la divergencia poblacional de las seis subespecies de C. canutus tuvo lugar durante los últimos 20 000 años aproximadamente, y los tamaños efectivos de la población de hembras son pequeños (Nef = 2000–14 000). Presumimos que la reproducción de C. canutus estuvo restringida sólo a regiones de Eurasia que estuvieron libres de hielo durante el último máximo glacial y se expandieron gradualmente hacia el este de Alaska, el Ártico canadiense y Groenlandia cuando el hielo se derritió. Los tiempos de divergencia poblacional en C. alpina son más antiguos (58 000–194 000), y el tamaño efectivo de la población ha sido históricamente más alto en los linajes principales (Nef = 12 000–44 000). Concluimos que las poblaciones de C. alpina no mostraron reducciones serias en los últimos 200 000 años, y que sus linajes se han diferenciado por un período de tiempo mucho más prolongado que los de C. canutus. Los patrones encontrados para C. canutus representan una imagen de evolución genética ocurrida durante los últimos 20 000 años, mientras que los patrones de C. alpina indican la ocurrencia de evolución genética durante un período de tiempo diez veces más largo.
... Dunlin subspecies overlap in morphological characters, which makes it difficult to determine the origin of migrant birds observed at stopover sites and wintering grounds [34,75]. There are only a few ringing recoveries between the Vistula Mouth stopover site and the breeding grounds, indicating that dunlins migrating through the Baltic region originate from the Eurasian Arctic, including Siberia [76,77]. ...
... The western limit of Siberian subspecies centralis breeding range remains unclear [78,79] and genetic studies suggest the persistence of alpina/centralis contact zone [80], but still, the occurrence of westernmost centralis at the southern Baltic during southward migration is likely [33,34,35]. Mitochondrial DNA analyses confirm both Siberian and European dunlin haplotypes were found at the Vistula Mouth stopover site [34,75,81]. Therefore, our conclusions cannot be directly applied to any given population or area, apart from the rather rough distinction based on plumage ('western' vs 'eastern' birds) we have made. ...
Weather and predation constitute the two main factors affecting the breeding success of those Arctic waders whose productivity is highly variable over the years. We tested whether reproductive success is associated with the post-breeding condition of adults, in which in ‘good’ years (with warm weather, plentiful food and low predation pressure) the condition of breeders and their productivity is high. To verify this hypothesis, we used a 10-year dataset comprising 20,792 dunlins Calidris alpina, trapped during migration at a stopover site on the southern Baltic Sea shore. Males were consistently in a slightly worse condition than females, likely due to male-biased parental investment in brood rearing. Annual productivity indices were positively correlated with the respective condition indices of breeders from the Eurasian Arctic, indicating that in ‘good’ years, despite great effort spent on reproduction, breeders leave the breeding grounds in better condition. The pattern did not hold for 1992: productivity was low, but the average condition of adults during migration was the highest noted over the decade. We suggest that the delayed effect of the Mount Pinatubo eruption in the Philippines in 1991, could be responsible for the unexpected high condition of Arctic breeders in 1992. High population-level average condition, coupled with the low productivity could stem from severe weather caused by the volcano eruption a year before and strong predation pressure, which in turn lead to a reduced investment in reproduction. The importance of large-scale episodic phenomena, like this volcano eruption, may blur the statistical associations of wildlife with local environmental drivers.
... In general, C. a. arcticola are slightly larger, darker and with less distinct black streaks on the flanks than C. a. sakhalina (Pyle 2008) and slightly shorter billed, smaller, and whiter on the breast than C. a. pacifica (MacLean and Holmes 1971;O'Brien et al. 2006). However, the extensive overlap in morphological characteristics between different populations often imposes problems of determining the origin of migrating and wintering birds (Wennerberg et al. 1999). ...
... Furthermore, recent genetic studies have suggested the existence of only five phylogenetic clades (Wenink et al. 1996;Wennerberg et al. 1999;Wennerberg 2001). In light of these recent genetic studies, C. a. arcticola and C. a. pacifica, which both breed in Alaska, may be considered a single group with genetic similarity (Wenink et al. 1996 Wenink et al. 1996;Pyle 2008), and migration strategy (MacLean and Holmes 1971; Warnock and Gill 1996). ...
In the Republic of Korea, two subspecies of the Dunlin Calidris alpina have been recognized: the abundant and common C. a. sakhalina and the vagrant C. a. pacifica. As a result of color-marked bird resightings on the west coast of Korea from 2007 to 2009, three C. a. arcticola, which bred in Barrow, northern Alaska, were observed in the Saemangeum reclamation project area. Given skipping migration strategies and high site fidelity of many shorebird species in Korea, this result strongly suggests, at least during their southward autumn migration, that the tidal wetlands of the Saemangeum area play an important role as a key staging site for the newly recorded C. a. arcticola in Korea. Further studies on the current status of the three Dunlin subspecies in Korea and the implementation of effective mitigation measures at Saemangeum are strongly recommended. key word: Calidris alpina arcticola, Dunlin, Saemangeum reclamation project, newly recorded subspecies, color-marked birds
... They most likely differentiated in allopatry in Pleistocene refugia (Wenink et al. 1996), but have since then met and mixed to some extent. There is now a gradual change of mtDNA control region haplotype frequencies from pure EUR populations in E Greenland, Iceland, the British Isles, southern Scandinavia and around the Baltic Sea, through populations constituting mixes of EUR and SIB in middle and northern Scandinavia and western Russia, to pure SIB populations in central Siberia (Wenink et al. 1993, Wenink et al. 1996, Wennerberg et al. 1999, Wennerberg 2001, Lopes et al. 2006, this study). This mtDNA pattern is inconsistent with the current designation of four subspecies in the area; arctica, schinzii, alpina and centralis. ...
... Cramp and Simmons 1983, del Hoyo et al. 1996). If mtDNA haplotypes should be translated into the current subspecies taxonomy, schinzii and arctica would correspond to the EUR clade, centralis would correspond to the SIB clade and alpina would constitute a hybrid zone between the two clades (Wenink et al. 1996, Wennerberg et al. 1999, Wennerberg 2001). Our analyses of the nuclear VLDLR-9 intron did not reveal any reciprocal monophyletic groups, and no pattern of isolation by distance. ...
Breeding populations of southern dunlin Calidris alpina schinzii in South Fennoscandia and the Baltic are severely fragmented and declining dramatically. Information on the genetic structure and diversity is therefore of importance for the conservation and management of these populations. Here we present the results of comparative genetic analyses of these populations with other populations of the schinzii, alpina and arctica subspecies in northern Europe. We sequenced the mitochondrial DNA control region and the Z-chromosome intron VLDLR-9, and analyzed microsatellites and AFLPs, for analyses of within-population genetic diversity. We also extended previous analyses of the phylogeographic structure of dunlins in northern Europe with a larger sample of individuals and populations. Our results revealed no evidence of reduced genetic diversity or increased levels of inbreeding in the small and fragmented populations around the Baltic Sea as compared to the more vital and larger populations elsewhere. Nevertheless, their small population sizes and presumably high degree of isolation may lead to local extinctions, indicating that demographic and ecological factors may pose a greater threat to the survival of these populations than purely genetic factors. Phylogeographically, the schinzii populations in Scandinavia and the Baltic do not form a separate genetic clade, but are part of larger cline of genetic variation encompassing several recognized subspecies of dunlins in the western Palearctic region. Only the Icelandic population showed some distinctiveness in genetic structure and might therefore be considered a separate management unit. Our study highlights the general problem of lack of genetic support for subspecies in avian taxonomy and conservation genetics.
... The sample sizes are also presented next to each pie in brackets. Breeding data were assembled from Wenink et al. (1993), Wennerberg et al. (1999), Wennerberg (2001a) and updated with unpublished data (L.W., unpublished data). The East Atlantic Flyway indicative limits are shown in migration panels while the winter range (dark grey) is shown in the winter panel. ...
... analysis only for comparison purposes, since this site may be considered to belong to another flyway, the Mediterranean flyway. For comparison with data from the breeding grounds, we also compiled an updated overview of all published results from mtDNA analysis of 280 breeding birds from 22 breeding populations (Fig. 1) from Wenink et al . (1993), Wennerberg et al . (1999), Wennerberg (2001a), and included unpublished additional data (L.W., unpublished data). ...
Dunlin Calidris alpina is one of the most abundant shorebirds using coastal habitats in the East Atlantic migratory flyway, that links arctic breeding locations (Greenland to Siberia) with wintering grounds (West Europe to West Africa). Differential migration and winter segregation between populations have been indicated by morphometrics and ringing recoveries. Here, we analyse the potential of genetic markers (mitochondrial DNA – mtDNA) to validate and enhance such findings. We compared mtDNA haplotypes frequencies at different wintering sites (from north-west Europe to West Africa). All birds from West Africa had western (European) haplotypes, while the eastern (Siberian) haplotypes were only present in European winter samples, reaching higher frequencies further north in Europe. Compilation of published results from migrating birds also confirmed these differences, with the sole presence of European haplotypes in Iberia and West Africa and increasingly higher frequencies of Siberian haplotypes from south-west to north-west Europe. Comparison with published haplotype frequencies of breeding populations shows that birds from Greenland, Iceland, and North Europe were predominant in wintering grounds in West Africa, while populations wintering in West Europe originated from more eastern breeding grounds (e.g. North Russia). These results show that genetic markers can be used to enhance the integrative monitoring of wintering and breeding populations, by providing biogeographical evidence that validate the winter segregation of breeding populations.
... The relatively low level of genetic variation found in the White-rumped Sandpiper is not uncommon among waders. Similar results are, for example, found in the Knot Calidris canutus , the Turnstone Arenaria interpres (Wenink et al. 1994), and the Curlew Sandpiper Calidris ferruginea (Wennerberg 2001b). Studies of allozymes show that the White-rumped Sandpiper and other wader species have lower intraspecific genetic variation than the average found for other bird taxa (Baker and Strauch 1988). ...
... Studies of allozymes show that the White-rumped Sandpiper and other wader species have lower intraspecific genetic variation than the average found for other bird taxa (Baker and Strauch 1988). The Knot, the Turnstone and the Curlew Sandpiper also have low levels of population differentiation Wenink et al. 1994;Wennerberg 2001b). They are all extreme longdistance migrants breeding on the high arctic tundra. ...
We studied the population structure of a high arctic breeding wader bird species, the White-rumped Sandpiper Calidris fuscicollis. Breeding adults, chicks and juveniles were sampled at seven localities throughout the species' breeding range in arctic Canada in 1999. The mitochondrial control region was analysed by DNA sequencing, feathers were analysed for carbon isotope ratios (C13/C12) by isotope ratio mass spectrometry, and morphological measurements were analysed using principal component analyses, taking the effect of sex into account (identified by molecular genetic methods). In general, our results support the notion that the White-rumped Sandpiper is a monotypic species with no subspecies, and most of the morphological and genetic variation occurs within sites. Nevertheless, some differences between sites were found. Birds from the two northernmost sites (Ellesmere and Devon Islands) had relatively longer bill and wing and shorter tarsus than birds sampled further south, possibly reflecting genetic differences between populations. The carbon isotope ratios were higher at the easternmost site (Baffin Island), revealing differences in the isotope content of the food. The mtDNA sequences showed no significant differentiation between sites and no pattern of isolation-by-distance was found. Based on the mtDNA variation, the species was estimated to have a long-term effective population size of approximately 9,000 females. The species shows no clear evidence of any population expansion or decline. Our results indicate that carbon isotope ratios, and possibly also certain mtDNA haplotypes, may be useful as tools for identifying the breeding origin of White-rumped Sandpipers on migration and wintering sites.
... (1) There is co-variation between breeding latitude and non-breeding habitat, with more northerly-breeding species relying to a greater extent on coastal and saline habitats during the non-breeding season than those breeding farther south (Piersma 1997Piersma , 2003); such habitats will be especially liable to climate-induced changes in sea level. (2) Most Arctic-breeding shorebird species are genetically less diverse than other birds (Baker and Strauch 1988, Baker 1992, Baker et al. 1994, Wennerberg et al. 1999, Avise 2000, Wennerberg 2001a, Wennerberg 2001b). This loss of genetic variation may reflect (repeated) population bottlenecks, perhaps caused by earlier climatic changes and extremes, selective sweeps perhaps caused by stringent selection events such as disease episodes, or a combination of these (Baker et al. 1994, Kraaijeveld and Nieboer 2000, Wennerberg 2001a). ...
... allozyme electrophoresis (Baker and Strauch 1988 ), mitochondrial DNA (mtDNA) sequencing (Baker et al. 1994, Wennerberg and Burke 2001, Ottvall et al. 2004, Buehler and Baker 2005) and microsatellite (nuclear DNA) analysis (van Treuren et al. 1999, Wennerberg and Bensch 2001). High Arctic species like red knot (Buehler and Baker 2005) and curlew sandpiper (Wennerberg and Burke 2001) all have very low genetic variability, whereas e.g. the dunlin, which breeds in Low Arctic and temperate areas, shows more variation in mitochondrial DNA than any other shorebird studied so far (Wenink et al. 1993, Wenink et al. 1996, Wennerberg et al. 1999, Wennerberg 2001b). Microsatellites are less frequent in birds than in mammals (Primmer et al. 1997) and highly variable microsatellite loci have been difficult to identify in shorebirds. ...
About 50 species of shorebirds breed in the Arctic, where they constitute the most characteristic component of the tundra avifauna. Here, we review the impact of weather and climate on the breeding cycle of shorebirds based on extensive studies conducted across the Arctic. Conditions for breeding shorebirds are highly variable among species, sites and regions, both within and between continents. Weather effects on breeding are most moderate in the Low Arctic of northern Europe and most extreme in the Siberian High Arctic. The decision of whether or not to breed upon arrival on the breeding grounds, the timing of egg-laying and the chick-growth period are most affected by annual variation in weather. In large parts of the Arctic, clutch initiation dates are highly correlated with snowmelt dates and in regions and years where extensive snowmelt occurs before or soon after the arrival of shorebirds, the decision to breed and clutch initiation dates appear to be a function of food availability for laying females. Once incubation is initiated, adult shorebirds appear fairly resilient to variations in temperature with nest abandonment primarily occurring in case of severe weather with new snow covering the ground. Feeding conditions for chicks, a factor highly influenced by weather, affects juvenile production in most regions. Predation has a very strong impact on breeding productivity throughout the Arctic and subarctic, with lemming Dicrostonyx spp. and Lemmus spp. fluctuations strongly influencing predation rates, particularly in the Siberian Arctic. The fate of Arctic shorebirds under projected future climate scenarios is uncertain, but High Arctic species and populations appear particularly at risk. Climatic amelioration may benefit Arctic shorebirds in the short term by increasing both survival and productivity, whereas in the long term habitat changes both on the breeding grounds and in the temperate and tropical non-breeding areas may put them under considerable pressure and may bring some of them near to extinction. Their relatively low genetic diversity, which is thought to be a consequence of survival through past climatically-driven population bottlenecks, may also put them more at risk to anthropogenic-induced climate variation than other avian taxa.
... Ring recoveries, recaptures, and resightings are valuable in providing accurate records of the links between breeding, stopover, and wintering sites for dunlin (Evans 1984, Gill et al. 2013, Lagassé et al. 2020. Studies of genetic and morphological variation also provide an outline of the phylogeography and migratory patterns (Greenwood 1984, Wennerberg et al. 1999, Popovic et al. 2019. Morphological characters, especially bill, wing, and tarsus lengths, have also been used to identify the origins of dunlins from Alaska and the Russian Far East region (Greenwood 1986), but sexual dimorphism in size requires that birds be sexed for accurate analysis of morphological data. ...
Dunlin (Calidris alpina) is a polymorphic species with a complex of subspecies. A migration stopover site on the intertidal mudflats of Jiangsu Province, China, has a pivotal role in the migratory connectivity of dunlin along the East Asian–Australasian Flyway (EAAF). However, to date, the dunlin subspecies that visit the coast of China during migration remains uncertain. To determine the subspecies, an integrated approach based on mitochondrial DNA, ring recoveries, and morphological traits was used to analyze dunlins sampled at the Jiangsu stopover site. Alaskan and Beringian lineages were the two dominant lineages that migrated through Jiangsu, and the number of dunlins from the Alaskan lineage greatly exceeded that from other lineages. According to genetic analysis, the proportion of identified lineages was greater than 70%. At least four subspecies were detected in eastern Jiangsu Province, including C. a. actites, C. a. kistchinski, C. a. sakhalina, and C. a. arcticola. There were significant differences in morphological characters between years, suggesting that proportions of subspecies at the stopover varied over time and that different subspecies adopted different migratory strategies and timings. The findings of this study highlight the need to further consider how subspecies contribute to the composition of populations and migratory connectivity of dunlin.
... On the other hand, traditional genetic markers (i.e. mitochondrial and microsatellite markers) have provided little phylogenetic resolution for distinguishing between some morphologically defined Dunlin subspecies (e.g., Wenink et al. 1993, Wennerberg et al. 1999, Miller et al. 2015 and finer-scale genetic structure has not been evidenced within subspecies (e.g., Wennerberg et al. 2008). Failure to differentiate adequately between populations constrained by narrow migratory pathways may lead to underestimations of the impacts of wintering habitat loss on genetically distinct populations (Runge et al. 2014). ...
Information on how migratory populations are genetically structured during the overwintering season of the annual cycle can improve our understanding of the strength of migratory connectivity and help identify populations as units for management. Here, we use a genotype-by-sequencing approach to investigate whether population genetic structure exists among overwintering aggregations of the Pacific Dunlin subspecies (Calidris alpina pacifica) sampled at 2 spatial scales (within and among overwintering sites) in the eastern Pacific Flyway. Genome-wide analyses of 874 single nucleotide polymorphisms across 80 sampled individuals revealed no evidence for genetic differentiation among aggregations overwintering at 3 locations within the Fraser River Estuary (FRE) of British Columbia. Similarly, comparisons of aggregations in the FRE and those overwintering in southern sites in California and Mexico indicated no genetic segregation between northern and southern overwintering areas. These results suggest that Pacific Dunlin within the FRE, Sacramento Valley (California), and Guerrero Negro (Mexico) are genetically homogeneous, with no evident genetic structure between sampled sites or regions across the overwintering range. Despite no evidence for differentiation among aggregations, we identified a significant effect of geographical distance between sites on the distribution of individual genotypes in a redundancy analysis. A small proportion of the total genotypic variance (R 2 = 0.036, P = 0.011) was explained by the combined effect of latitude and longitude, suggesting weak genomic patterns of isolation-by-distance that are consistent with chain-like migratory connectivity between breeding and overwintering areas. Our study represents the first genome-scale investigation of population structure for a Dunlin subspecies and provides essential baseline estimates of genomic diversity and differentiation within the Pacific Dunlin.
... DFA has been used to determine sex within other Dunlin subspecies (Brennan et al. 1984;Meissner and Pilacka 2008;Gates et al. 2013), but no such equation has yet been calculated for C. a. hudsonia, which is suspected of declining and faces considerable risks from climate change and disturbances on breeding and non-breeding grounds (Fernández et al. 2010;Galbraith et al. 2014). Based on the extent of morphological variability among Dunlin subspecies (Wennerberg et al. 1999), we expected that a discriminant function (DF) specific to this subspecies would have the greatest discriminatory power as compared to all other DFs developed to differentiate between sexes in Dunlin. Our objective was to apply a DFA to morphological data from Dunlin breeding near Churchill, Manitoba, Canada, to determine which external measurements might allow for differentiation between sexes in the C. a. hudsonia subspecies. ...
Male and female Dunlin (Calidris alpina) exhibit slight plumage and structural differences. Discriminant function analysis based on morphological characteristics can effectively differentiate between sexes in several subspecies of Dunlin. We assessed the level of sexual size dimorphism in a subspecies that breeds in sub-Arctic Canada (C. a. hudsonia), and used discriminant function analysis to create equations to classify individuals to sex using five body measurements (body mass, head length, culmen length, tarsus length, and flattened wing chord). Females were significantly larger than males for all body measurements. Discriminant function analysis using tarsus length, head length, and body mass correctly classified 87.1% of molecularly sexed females (n = 31) and 92.6% of males (n = 27). The classification of an independent sample (n = 12) resulted in 100.0% correct assignment of sex with 33.3% of individuals falling within the undetermined range. A discriminant function analysis equation is provided for use with non-breeding populations using only structural characteristics with classification accuracies of 83.9% for females and 81.5% for males. The resulting equations from this study have classification accuracies comparable to those equations developed for other Dunlin subspecies and can be used to reliably differentiate sexes of C. a. hudsonia using body measurements collected in the field.
... Variation in a few morphological traits -wing length, amount of grey plumage on flanks and leg coloration -was descri-bed from wintering grounds and on migration routes by Lövei et al. (1986) and Pettersson et al. (1990); the latter authors assuming that analogous differences occurred across the breeding range. Studies of Wennerberg et al. (1999) and Wennerberg (2001) on the Dunlin Calidris alpina also revealed genetic variation among populations from adjacent winter quarters corresponding to differences in their morphology, migration routes and timing, and in the areas of breeding origin. In the studies on the Willow Warbler (Bensch et al. 1999;Chamberlain et al. 2000), morphological differences in two adjacent breeding populations were also associated with different migratory behaviour. ...
The pattern of the present migration routes and winter distribution of a species is the consequence of historical factors (re-colonisation from Ice-Age refugia), and of more recent evolutionary mechanisms superimposed upon this base. The present study discusses the balance between these factors as exemplified in the Robin Erithacus rubecula. The two hypotheses on the course of the species' autumn migration through the Baltic coastal area which were tested considered: (1) sequential passage of different populations, with early migrants migrating SW and later ones heading gradually more to the SE; (2) alternate passage of populations heading to the SW, SSW and SE during the season. Analysis of 1082 recoveries of Robins ringed in the autumn on the Baltic coast allowed to distinguish four main routes of passage across Europe, as used by allohiemic populations differing in timing of migration, and partly separated by migratory divides. The temporal sequence in which the routes are used by populations crossing the Baltic coastal area is in agreement with the second hypothesis. The revealed spatio-temporal segregation of Robins over the non-breeding range can provide a basis for further studies on the origin of this pattern within the species, and the mechanisms by which it is maintained.
... Data on mtDNA sequences were available for three species: Dunlin (Calidris alpina) (Wenink: et al. 1993;Wenink: et al. 1994;Wennerberg et al. 1999), Red Knot (Calidris canutus) and Ruddy Turnstone (Arenaria interpres) (Wenink: et al. 1994). These studies used direct sequencing of the hypervariable control region segments I and n. ...
This review links published data on mitochondrial DNA phylogeography of three wader species breeding in the Arctic to the availability of suitable breeding habitat during the past 250 000 years. We argue that the breeding ranges of arctic waders were most restricted in size during warm phases in the earth's climate (interglacials), resulting in population bottlenecks in species breeding in the high arctic zone, such as Red Knot Calidris canutus and Ruddy Turnstone Arenaria interpres, and population contraction and the initiation of genetic divergence in low arctic species, such as Dunlin Calidris alpina. When the climate cooled, all species could spread over larger areas. However, large ice-sheets fragmented tundra habitat, which resulted in more differentiation. Subspecies of Dunlin that became isolated during or before the last glacial period are genetically distinct, while those that originated after the glacial cannot be distinguished using mitochondrial DNA. The sensitivity of waders breeding in the high Arctic to increases in global temperature raises concerns over the effect of possible global warming due to anthropogenic factors on these species.
... Assessment: Rare spring and common autumn migrant. Taxonomy: Subspecific identity of birds at LB is unknown (see Gladkov 1951, Tomkovich 1986, Wenink et al. 1996, Engelmoer and Roselaar 1998, Lappo and Tomkovich 1998, Wennerberg et al. 1999, Stepanyan 2003. ...
Lake Baikal lies in eastern Siberia, Russia. Due to its huge size, its waterbird fauna is still insufficiently known in spite of a long history of relevant research and the efforts of local and visiting ornithologists and birdwatchers. Overall, 137 waterbird species have been recorded at Lake Baikal since 1800, with records of five further species considered not acceptable, and one species recorded only prior to 1800. Only 50 species currently breed at Lake Baikal, while another 11 species bred there in the past or were recorded as occasional breeders. Only three species of conservation importance (all Near Threatened) currently breed or regularly migrate at Lake Baikal : Asian Dowitcher Limnodromus semipalmatus, Black-tailed Godwit Limosa limosa and Eurasian Curlew Numenius arquata.
... A combination of molecular sexing techniques (e.g. Remisiewicz & Wennerberg 2006, Wennerberg et al. 1999overview in Dos Remedios et al. 2010) and the recently developed statistical tools for analysing moult now allow researchers to link the mating systems of migrant waders and their parental care strategy with variation in primary moult patterns or those of other feather tracts (Meissner et al. in press). ...
This paper presents an overview of patterns in the primary moult of waders using the Eurasian–African migration
system and updates earlier summaries with results obtained from the Underhill–Zucchini moult models (1988,
1990). Recent applications of these models allow researchers to examine moult timing down to the progress
of an individual feather in a tract and to determine the effects of environmental factors on moult. Waders
present a wide variety of inter- and intra-specific strategies for their primary moult, an energy-costly activity
they must fit in with breeding and migration, the other main energy-demanding events in their life cycle. Here
I present the moult strategies of waders in the context of their age, size, sex and annual variation in breeding
success, seasonal food abundance, the latitude where they moult, the distance they migrate, the habitats they
use, and the rainfall patterns and temperatures at their moulting grounds. I also discuss how moult is adjusted
to these factors. This overview emphasises the flexibility of many waders’ moult strategies as an adaptation
to the unpredictable food supply provided by ephemeral inland wetlands and compares these strategies with
those of populations that use predictable coastal habitats. Discovering the mechanisms that allow waders to
adjust their genetically controlled and hormonally regulated moult to proximate factors is suggested as one of
the challenges in further studies of moult.
... The split between the European lineage and the more closely related Taymyr/Alaska lineages was estimated to have occurred 350,000 years ago (Wenink & al., 1993). This species was also studied in detail using various molecular markers by Wennerberg & al. (1999) and Wennerberg (2001a, b), but these studies concentrated on the Palearctic populations. Terrestrial mammals. ...
Up to the 1960s, there was nearly complete consensus that disjunctions and endemism in the North Atlantic cannot be explained without �in situ� survival during the glaciations (the nunatak hypothesis). The alternative �tabula rasa� hypothesis of postglacial immigration was regarded to be of merely historical interest. Herein we review recent geological, molecular, taxonomic, and biogeographic data to re-examine this view. There is now strong geological evidence for some ice-free North Atlantic areas within the maximum limits of the Late Weichselian/Wisconsian ice sheets, but no fossils have been found to prove continuous �in situ� existence of life in these areas. Molecular data suggest that many plants and animals have migrated recently across the Atlantic, even if they lack mechanisms promoting long-distance dispersal. In other species, there are deep trans-oceanic phylogeographic splits suggesting survival in two or more refugia, but these refugia may have been located outside the ice sheets. Fo
... Similar patterns of high genetic structure that most likely is the result of isolation in different refugia have been found in e.g. dunlin Calidris alpina (Wenink et al. 1993, Wennerberg et al. 1999, Wennerberg 2001, arctic charr Salvelinus alpinus (Brunner et al. 2001), root vole Microtus oeconomus (Brunhoff et al. 2003) and reindeer Rangifer tarandus (Flagstad and Røed 2003). This study has focused mainly on sampling in western Palearctic and Nearctic regions. ...
The ancestors of rock ptarmigan Lagopus muta originated in the Beringia area well before the disruption of the Beringian land bridge. They spread westwards to Siberia and eastwards to the North American arctic and Greenland. The distribution of rock ptarmigan has been affected by glaciations restricting it to geographically limited refugia. Today the species has a circumpolar distribution in arctic tundra and alpine habitats, with up to 30 subspecies recognised based on morphological characters. We sequenced the mitochondrial control region for 72 individuals and genotyped 69 individuals for 12 microsatellite loci to investigate neutral genetic variation within and among five rock ptarmigan populations, Greenland, Iceland, Scandinavia, Svalbard and Taimyr. Genetic structure among the studied samples was high, overall FST estimated from microsatellite loci was 0.18 and only one out of 16 mtDNA haplotypes was found in more than one population. Genetic variation (h, π, He, allelic richness) was slightly lower in the Svalbard population than in other populations, suggesting a low effective population size, possibly due to isolation following colonisation. An unrooted network and a phylogenetic tree showed that the Scandinavian population has diverged from the other populations by at least ten mutational steps, probably due to independent colonisation of Europe and subsequent long-term isolation, and rules out Scandinavia as a source for colonisation of Svalbard. Alignment with partial control region sequences from other studies showed that the haplotype that was central in our network and found on Svalbard and in Taimyr, most likely corresponds to a haplotype found in Siberia, Alaska and the Canadian Arctic, but not in Greenland, Scandinavia and Iceland. This suggests an eastern origin of rock ptarmigan in Svalbard, although this question cannot be settled conclusively.
... R. Krupa, Department of Zoology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 5, PL-10-975 Olsztyn, Poland, E-mail: krupi.r@gmail.com von Blotzheim et al. 1975, Greenwood 1984, Tomkovich 1986, Browning 1991, Wennerberg et al. 1999 ). It is known that at least two subspecies migrate through the Baltic area: C. a. shinzii from local breeding population and C. a. alpina inhabiting vast area between Scandinavia and North Central Siberia (Glutz von Blotzheim et al. 1975 ). ...
Biometrics of the Dunlin ( Calidris alpina ) Migrating in Autumn Along the Polish Baltic Coast
The aim of this study is to present the general biometrical characteristics of Dunlins passing the Polish Baltic coast during autumn migration. Data were collected between the first week of July and the end of September in 1991-2002. Comparison of the mean wing lengths of Dunlins from different regions revealed that birds migrating through the Puck Bay had on average shorter wings than those trapped in areas located more south-easterly and clearly longer than those from Mauritania. In adults, seasonal variation of mean bill and wing lengths showed sigmoid pattern with larger birds in July at the beginning of migration and in mid-September. Such pattern is typical for this species, because females, which are larger than males, migrate earlier. Similar pattern of seasonal changes of mean bill and wing lengths might be noted in second-year birds. Juveniles caught in July must have belonged to local population of C. a. shinzii , which is smaller than the nominative subspecies. The sample of juvenile birds trapped in the beginning of August probably consisted of individuals from both subspecies, which resulted in the lower mean values of wing and bill lengths. Changes in the size of juveniles from year to year might be caused by differences in food availability on the breeding grounds, e.g. due to weather conditions.
... Thanks to the development of laboratory techniques, sex determination in birds, including waders, based on DNA analysis has become possible (e.g. Fridolfsson & Ellegren 1999, Griffiths et al. 1998, Wennerberg et al. 1999, Nebel et al. 2004). In this study, we apply molecular sexing techniques to Wood Sandpiper samples, and thereby reveal differences in spring migration phenology between females and males. ...
Sex and age differences in spring migration phenology were studied in the Wood Sand-piper a monomorphic wader of inland wetlands. Birds were sexed by DNA analysis. During the rapid passage through NE Poland in 2003, the first males occurred 4 days be-fore the first females. Thereafter both sexes were represented. Median migration dates were significantly earlier for males than for females among the older age group (2+ birds). A similar tendency was shown for second-year birds (2K). The sex differences can be ex-plained by earlier arrival of males at the breeding grounds. Second-year birds migrated significantly later than older birds. Females were significantly larger than males in total head, tarsus plus toe, wing length and body mass. Total head length allowed for identifica-tion of a low proportion of 2+ males and females, but the other measurements did not al-low reliable sexing because of size range overlaps between the sexes. Principle Compo-nent Analysis (PCA), where the body size coefficient (PC1) combines three linear body measurements, slightly improved the accuracy of the sexing. Thus, genetic sexing of Wood Sandpipers is preferable. We recommend application of molecular sexing in stud-ies of the behaviour of sex, age and population groups in monomorphic species.
... ty & Nei 1976, Hartl & Clark 1989). Body size in birds has a genetic component (Boag & Van Noordwijk 1987), although environmental factors can also play an important part in determining its variation (James 1983). Many bird species exhibit geographical variation in morphology (Ball et al . 1988, Randi et al . 1989, Moen 1991, Friesen et al . 1996, Wennerberg et al . 1999), some of them with no obvious genetic explanation for this variation (Randi et al . 1989, Moen 1991). In Audouin's Gull Larus audouinii there are no data on possible morphological variation at geographical level, although Ruiz et al . (1998) found that environmental factors affected chick growth in a single colony of Audouin's Gull modi ...
We assessed the genetic and morphological differences between the two largest breeding colonies of Audouin's Gull Larus audouinii, an endemic seabird species of the Mediterranean region. The two colonies comprise c. 75% of the total world population and are 655 km apart. The Ebro Delta colony was formed recently and, after dramatic growth mainly due to high rates of both immigration and reproductive success, is now the largest in the world (more than 60% of the total population). The Chafarinas Islands support an ancient colony with relatively little fluctuation in breeding numbers. The two colonies also differ greatly in environmental conditions, with the Ebro Delta being a higher quality breeding site. Very little movement occurs between the two colonies. We collected morphological data and blood samples from both colonies. Polymorphic microsatellite markers were used to study the genetic differentiation. These showed no significant variation between colonies, nor evidence of a founder effect in the Ebro Delta. Individuals from the Ebro Delta were larger than those from Chafarinas, the difference being greater for males. This probably reflects a stronger male susceptibility to worse environmental conditions during chick growth at the Chafarinas Islands.
... eastern Siberia, Alaska and northwestern Canada), suggesting a history of glacial isolation within Beringia. The same phylogeographical pattern in Beringia has been observed in a variety of other species, including the lemming Lemmus trimucronatus (Fedorov et al. 1999b) and the avian wader Calidris alpina (Wenink et al. 1996;Wennerberg et al. 1999;Wennerberg 2001). ...
A species-wide phylogeographical study of the root vole (Microtus oeconomus) was performed using the whole 1140 base pair mitochondrial (mt) cytochrome b gene. We examined 83 specimens from 52 localities resulting in 65 unique haplotypes. Our results demonstrate that the root vole is divided into four main mtDNA phylogenetic lineages that seem to have largely allopatric distributions. Net divergence estimates (2.0-3.5%) between phylogroups, as well as relatively high nucleotide diversity estimates within phylogroups, indicate that the distinct phylogeographical structure was initiated by historical events that predated the latest glaciation. European root voles are divided into a Northern and a Central mtDNA phylogroup. The mtDNA data in concert with fossil records imply that root voles remained north of the classical refugial areas in southern Europe during the last glacial period. The currently fragmented populations in central Europe belong to a single mtDNA phylogroup. The Central Asian and the North European lineages are separated by the Ural Mountains, a phylogeographical split also found in collared lemmings (Dicrostonyx) and the common vole (M. arvalis). The Beringian lineage occurs from eastern Russia through Alaska to northwestern Canada. This distribution is congruent with the traditional boundaries of the Beringian refugium and with phylogeographical work on other organisms. In conclusion, similarities between the phylogeographical patterns in the root vole and other rodents, such as Arctic and subarctic lemmings, as well as more temperate vole species, indicate that late Quaternary geological and climatic events played a strong role in structuring northern biotic communities.
... A longitudinal cline with body size increasing from west to east has been found previously in, for example, the dunlin Calidris alpina (Wennerberg et al., 1999) and in the white-fronted goose A. albifrons (Ely et al., 2005) in addition to bean, Middendorff's and pink-footed goose (Cramp and Simmons, 1977; this study). We did not find patterns of isolation by distance in the genetic differentiation, suggesting that the cline is not formed by gene flow between neighboring areas. ...
The bean goose Anser fabalis and the pink-footed goose A. brachyrhynchus breed in the tundra and taiga zones of Eurasia and eastern Greenland, and the taxonomy of the group based on morphology has been controversial. We investigated the phylogenetic relationships within the bean goose-the pink-footed goose complex using mitochondrial control region sequences of 199 individuals collected from the breeding areas in the Palaearctic and Eastern Nearctic. We found three mitochondrial clades geographically distributed to (1) Greenland, Iceland and Svalbard (A. brachyrhynchus), (2) the eastern taiga zone (former subspecies A. fabalis middendorffii), and (3) the western taiga and the tundra zone (subspecies A. fabalisrossicus, serrirostris and fabalis). MtDNA phylogeny suggests that morphological affinities between the taxa, e.g. in the bill structure, result from convergent evolution due to adaptation to similar habitats. Although a latitudinal cline in morphology was observed, clear phylogenetic discontinuities exist in the taiga and tundra zones supporting a species status for brachyrhynchus and middendorffii.
We used resightings of banded adults and hatch year birds, molecular markers and stable isotopes to document the migratory connectivity of five subspecies of Dunlin (Calidris alpina) that breed in Beringia and migrate either along the East Asian-Australasian Flyway or the Pacific Flyway of North America. Of more than 4000 Dunlin banded in the past decade, roughly 230 (~6%) have been resighted away from their capture site. Most resightings were of arcticola Dunlin seen in Japan and Taiwan, although a smaller number of 2 kistchinski and sakhalina Dunlin have also been resighted along the East Asian-Australasian flyway. Few resightings have occurred in mainland China despite this being the major nonbreeding area for Dunlin. Due to potential biases associated with resighting marked Dunlin, we also employed molecular and stable isotope markers to indirectly assess migratory connectivity. In order to use molecular markers, which rely on the relatedness of individuals to establish linkages, it must be shown that individuals belonging to the five subspecies can be differentiated from one another. Preliminary results from variable microsatellite DNA markers indicated this was not possible among individuals of the sakhalina, pacifica and arcticola subspecies. However, we still need to test two more Russian-breeding subspecies and conduct mitochondrial DNA analysis on all five subspecies before we can determine the value of this technique. Should either the microsatellite or mitochondrial DNA reveal significant population structure, we can then use samples collected from birds on the nonbreeding grounds and try to link them to breeding areas. We also used stable isotope signatures of particular feathers grown by Dunlin on their breeding and nonbreeding grounds to determine if individuals from the five subspecies could be differentiated. Use of stable isotope markers to establish migration connectivity relies on the fact that feathers carry chemical markers that reflect the chemical composition of the resources used by birds as they grow the feathers, and that these chemical markers vary spatially across the surface of the earth. Preliminary results indicate that isotope markers from feathers acquired on the breeding grounds can distinguish among individuals from three subspecies (arcticola, pacifica, sakhalina) with some certainty. Additional analysis involving more individuals of all five subspecies is needed to fully evaluate this technique, although several classification procedures yielded low mis-classification rates. Like the molecular technique, we need to first determine whether this technique can differentiate the five Dunlin subspecies before attempting to connect individuals sampled on the staging and nonbreeding grounds to breeding areas. Dunlin exhibit a number of features that make them especially vulnerable to degradation or loss of habitats required during their migration and nonbreeding period. These features include a tendency to aggregate in a limited number of locations, a migration schedule timed to seasonally abundant food resources, and use of wetland habitats that are affected by a wide variety of human activities and developments. Because of this, it is essential that we understand how the various subspecies use the landscape so we can identify areas in need of recognition or protection, and promote their conservation.
Up to the 1960s, there was nearly complete consensus that disjunctions and endemism in the North Atlantic cannot be explained without in situ survival during the glaciations (the "nunatak hypothesis"). The alternative " tabula rasa hypothesis" of postglacial immigration was regarded to be of merely historical interest. Herein we review recent geological, molecular, taxonomic, and biogeographic data to re‐examine this view. There is now strong geological evidence for some ice‐free North Atlantic areas within the maximum limits of the Late Weichselian/Wisconsian ice sheets, but no fossils have been found to prove continuous in situ existence of life in these areas. Molecular data suggest that many plants and animals have migrated recently across the Atlantic, even if they lack mechanisms promoting long‐distance dispersal. In other species, there are deep trans‐oceanic phylogeographic splits suggesting survival in two or more refugia, but these refugia may have been located outside the ice sheets. For vascular plants, we provide an updated list of 77 north boreal, alpine, and arctic taxa accepted as North Atlantic endemics. The degree of endemism is very low (0.0‐1.9% single‐region endemism). Forty endemics occur in more than one of the isolated Atlantic regions, indicating extensive migration and complicating inferences on the location of refugia. Thirty‐four endemics are probably not hardy enough for nunatak survival and are explained by postglacial immigration (or in situ evolution). Among the 43 "hardy" endemics, there is not a single outcrossing diploid that could suggest long‐term evolution. Most of the hardy endemics are asexual or self‐fertilizing polyploids, some of postglacial hybrid origin. Others are preglacial polyploids which immigrated postglacially or survived in situ . Some ice‐free areas, such as the extensive Greenlandic ones, may have supported survival of some hardy organisms. The evidence accumulated since the 1960s suggests, however, that endemism and disjunctions in the North Atlantic can be explained without invoking in situ glacial survival.
The geographic pattern of mtDNA variation in lemmings from 13 localities throughout the Eurasian Arctic was studied by using eight restriction enzymes and sequencing of the cytochromebregion. These data are used to reveal the vicariant history ofLemmus, and to examine the effect of the last glaciation on mtDNA variation by comparing diversity in formerly glaciated areas to the diversity in non-glaciated areas. Phylogenetic congruence across different Arctic taxa and association between observed discontinuities, and probable Pleistocene barriers, suggest that glacial-interglacial periods were crucial in the vicariant history ofLemmus. Differences in amount of divergence (2.1–9.1%) across different historical barriers indicate chronologically separate vicariant events during the Quaternary. Populations from a formerly glaciated area are no less variable than those in the non-glaciated area. Regardless of glaciation history, no population structure and high haplotype diversity were found within geographic regions. The lack of population structure indicates that populations with high ancestral haplotype diversity shifted their distribution during the Holocene, and that lemmings tracked a changing environment during the Quaternary without reduction of effective population size.
The geographic pattern of mtDNA variation in lemmings from 13 localities throughout the Eurasian Arctic was studied by using eight restriction enzymes and sequencing of the cytochrome b region. These data are used to reveal the vicariant history of Lemmus, and to examine the effect of the last glaciation on mtDNA variation by comparing diversity in formerly glaciated areas to the diversity in non‐glaciated areas. Phylogenetic congruence across different Arctic taxa and association between observed discontinuities, and probable Pleistocene barriers, suggest that glacial‐interglacial periods were crucial in the vicariant history of Lemmus. Differences in amount of divergence (2.1–9.1%) across different historical barriers indicate chronologically separate vicariant events during the Quaternary. Populations from a formerly glaciated area are no less variable than those in the non‐glaciated area. Regardless of glaciation history, no population structure and high haplotype diversity were found within geographic regions. The lack of population structure indicates that populations with high ancestral haplotype diversity shifted their distribution during the Holocene, and that lemmings tracked a changing environment during the Quaternary without reduction of effective population size.
We employed Bayesian coalescent modeling of samples of mitochondrial control region sequences in two species of shorebird, Red Knots (Calidris canutus) and Dunlins (Calidris alpina) to estimate evolutionary effective population size, population divergence times, and time to most recent common ancestor of genes in the samples. The gene trees for the two species contrast sharply: knot haplotypes were connected in a shallow, star phylogeny whereas Dunlin haplotypes were related in a deeper bifurcating genealogy. Divergence times of populations representing all six subspecies of knots are estimated to have occurred within the last 20 000 (95% CI: 5600-58 000) years, and evolutionary effective population sizes of females are small (Nef = 2000-14 000). We hypothesized that breeding knots were restricted to unglaciated regions of Eurasia during the last glacial maximum, and gradually expanded eastwards into Alaska, the high Canadian Arctic and Greenland as the ice melted. Population divergence times in Dunlins are much older (58 000-194 000 ybp) and effective population size has historically been higher in major lineages (N ef = 12 000-44 000). We conclude that Dunlin populations were not severely reduced in size in the last 200 000 years, and major lineages have differentiated under restricted gene flow for a much longer time than knots. Knots present a snapshot of genetic evolution in the last 20 000 years, whereas Dunlins display patterns of genetic evolution over an order of magnitude longer time frame.
Migratory connectivity plays an important role in conservation of long-distance migrant birds. Here, we study migratory links of dunlin (Calidris alpina), focusing on a stopover and wintering region (Portugal) where it is known that migration routes of dunlin from a broad geographic range (three subspecies) converge, and populations occur simultaneously or separated in time. We combine three methods (ringing recoveries, morphometrics and molecular genetics) to assess breeding origins and extent of temporal segregation of dunlin
assemblages. Ringing recoveries show temporal separation of dunlin from different migration routes. Birds found in Portugal during August and September, migrating via Britain, reveal links to breeding areas in Iceland and Greenland. In October, a clear shift to more eastern migration routes occurs, with most Portuguese winter records from stopover sites along migration routes of populations from northern Scandinavia and Russia. Mitochondrial DNA (mtDNA) of Portuguese dunlin was compared with breeding populations. Spring and autumn migrants in Portugal corresponded to C. a. schinzii and C. a. arctica populations, while the Portuguese winter population clearly differs by including mtDNA haplotypes of C. a. alpina. For genetically sexed individuals, we found significant differences in morphology (bill and tarsus length) supporting the temporal separation of populations/subspecies revealed by recoveries and mtDNA. Our results give evidence for migratory connectivity of dunlin populations between geographic areas previously not considered connected. They confirm the existence of clear differences in breeding origin between birds in Portugal at different times of year. These results are important in the consideration of future long-term conservation plans.
Studies of how organisms are adapted to regional climatic conditions are valuable when predicting the effects of global climatic changes on biota. Here we report on the geographical variation in timing of breeding and moult of an Arctic breeding wader, the dunlin (Calidris alpina). The Palearctic study sites range latitudinally between 68 and 76N and longitudinally between 46 and 179E, and encompass a variety of local climates. The sites were visited in sequence from west to east within 1 year, and therefore the data are not affected by confounding interannual variations. The estimated breeding start ranged from 5 to 25 June across populations. Birds at more southern sites were found to breed earlier than those at more northern breeding sites. Within populations, the breeding start for first clutches spanned a period of 8 days and, when including replacement clutches, 3-4 weeks. No dunlin west of the Taimyr Peninsula were found moulting while incubating at the nest, whereas all dunlin on Taimyr Peninsula and eastwards were in active wing moult while incubating or rearing chicks. The onset of moult in these populations ranged from 23 to 27 June. The consequences of geographical variation of breeding conditions for variation in the annual cycle of this species are discussed.
The molecular methods that are presently being used for studying phylogenetics, phylogeography and population genetics can
also be applied to study bird migration. They are powerful and can supplement the information obtained from ringing, telemetry,
morphometrics, ringing, radar tracking and isotope analysis. This short review describes the principles, scopes and limitations
DNA methods and DNA markers that are relevant for migration research, such as DNA sequences, short tandem repeats (microsatellites),
single nucleotide polymorphisms, amplified fragment length polymorphism, inter simple sequence repeats and molecular sexing.
We investigated the genetic structure of the presumably small (10–100 pairs) and isolated dunlin (Calidris alpina) population breeding in Svalbard, and compared it with similar data recently published from several dunlin populations in
the western Palearctic and East Greenland. Using mitochondrial and nuclear DNA markers, as well as data on bill lengths, we
sought to infer the phylogeographic origin of Svalbard dunlins and assess their within-population level of genetic diversity.
Only dunlins with haplotypes of the European mtDNA clade (EUR) were found in Svalbard, indicating a close resemblance to dunlin
populations in East Greenland and Iceland. Microsatellite data for Svalbard dunlins, as well as their short bills, also supported
a western origin. The Svalbard population did not show signs of inbreeding or reduced levels of genetic diversity compared
to other investigated populations, which suggests that the population was recently founded or is currently subject to considerable
gene flow.
The lesser white-fronted goose is a sub-Arctic species with a currently fragmented breeding range, which extends from Fennoscandia to easternmost Siberia. The population started to decline at the beginning of the last century and, with a current world population estimate of 25,000 individuals, it is the most threatened of the Palearctic goose species. Of these, only 30–50 pairs breed in Fennoscandia. A fragment of the control region of mtDNA was sequenced from 110 individuals from four breeding, one staging and two wintering areas to study geographic subdivisions and gene flow. Sequences defined 15 mtDNA haplotypes that were assigned to two mtDNA lineages. Both the mtDNA lineages were found from all sampled localities indicating a common ancestry and/or some level of gene flow. Analyses of molecular variance showed significant structuring among populations (
ST 0.220, P < 0.001).="" the="" results="" presented="" here="" together="" with="" ecological="" data="" indicate="" that="" the="" lesser="" white-fronted="" goose="" is="" fragmented="" into="" three="" distinctive="" subpopulations,="" and="" thus,="" the="" conservation="" status="" of="" the="" species="" should="" be="">
The behaviour of a male bird towards a potential mate and her clutch may depend both on his expected paternity and on the
likelihood that she will produce a replacement clutch if he commits infanticide. In this study we evaluate the choices made
by replacement male European starlings Sturnus vulgaris. By removing males before and during laying, we induced other males, mainly neighbours, to mate with the reproductively active
females. When the original male was removed before laying, a new male adopted the subsequent clutch in 14 out of 15 cases.
When ten females were widowed during their laying period, replacement males never adopted their clutches. The paternity of
replacement males was a function of when they replaced the former male. When replacement occurred more than 3 days before
egglaying, the new male fathered nearly all offspring; when it occurred the day before laying, the new male still fathered
more than every second young. When the original male was removed during his mate’s laying period, in five out of ten cases
a replacement male committed infanticide by throwing out the eggs, but this only occurred in one out of 15 cases when removal
took place before laying. The evidence for infanticide actually being committed by the replacement male was circumstantial.
Four out of six of the females affected by apparent infanticide produced replacement clutches in which the male presumably
had higher paternity than in the original clutch. In all cases, the male adopted the replacement clutch. In five cases when
the original male was removed during laying, the neighbours neither adopted the brood nor committed infanticide, although
they sometimes were seen courting the widowed female and copulating with her. These cases occurred later during laying than
those were males comitted infanticide. The time from infanticide to the laying of the replacement clutch tended to increase
as infanticide was committed later in the laying sequence. We conclude that strategies of potential replacement males are
influenced by their expected paternity in the current brood and the probability that the female will produce an early replacement
clutch.
It is difficult to identify sex in many species of eukaryotic organism. This can considerably impede research into their biology. Fortunately, one sex often possesses a unique chromosome termed Y or W. When DNA markers are available for these chromosomes, then sex identification becomes straightforward. We describe a technique that facilitates the isolation of such markers. The procedure makes use of low-stringency PCR to screen randomly selected primers for their ability to amplify sex-specific loci.
Hypervariable segments of the control region of mtDNA as well as part of the cytochrome b gene of Dunlins were amplified with PCR and sequenced directly. The 910 base pairs (bp) obtained for each of 73 individuals complete another of the few sequencing studies that examine the global range of a vertebrate species. A total of 35 types of mtDNA were detected, 33 of which were defined by the hypervariable-control-region segments. Thirty of the latter were specific to populations of different geographic origin in the circumpolar breeding range of the species. The remaining three types indicate dispersal between populations in southern Norway and Siberia, but female-mediated flow of mtDNA apparently is too low to overcome the effects of high mutation rates of the control-region sequences, as well as population subdivision associated with historical range disjunctions. A genealogical tree relating the types grouped them into five populations: Alaska, West Coast of North America, Gulf of Mexico, western Europe, and the Taymyr Peninsula. The Dunlin is thus highly structured geographically, with measures of mutational divergence approaching 1.0 for fixation of alternative types in different populations. High diversity of types within populations as well as moderate long-term effective population sizes argue against severe population bottlenecks in promoting this differentiation. Instead, population fragmentation in Pleistocene refuges is the most plausible mechanism of mtDNA differentiation but at a much earlier time scale than suggested previously with morphometric data.
Comparison of mitochondrial DNA (mtDNA) control-region sequences of 155 dunlins from 15 breeding populations confirmed the existence of five major phylogeographic groups in the circumpolar breeding range of this migratory shorebird species. Time estimates of the origin of groups, based on sequence divergences and a molecular clock for birds, suggest a scenario of repeated fragmentation of populations in isolated tundra refugia during the late Pleistocene. The distribution of about three-quarters of all detected molecular variance between phylogeographic groups attests to the strongly subdivided genetic population structure in dunlins that is being maintained by natal philopatry. Each mtDNA phylogeographic group can be related to a morphometrically defined subspecies, but several other recognized subspecies are not supported by monophyletic mtDNA lineages within their purported ranges. More detailed analysis of several European populations reveals low amounts of gene flow and the partitioning of a substantial fraction of molecular variance between them. This ongoing evolution of population-genetic structuring within the European phylogeographic group most likely started with the last retreat of the ice sheets some 10,000 years ago. Dunlins thus provide one of the clearest examples of the linkage between historical and contemporary components of mtDNA phylogeographic structuring in birds.
Two main questions are discussed: (1) the eastern limit of Dunlin Calidris alpina populations migrating through the Baltic and (2) migration between the Baltic and the Mediterranean/Black Sea. Ringing and moult data show that some Dunlins migrating to the Baltic orignate from more easterly regions than previously presumed. Many Dunlins migrating in autumn through the Baltic are in active moult. Some of them probably start their moult while breeding and originate from areas east of the Urals. These birds show some easily recognized plumage patterns: their new median coverts (usually only some of them) are of "adult buff" type. This is characteristic of Central and Eastern Siberia populations which start moulting very early, while still on their breeding grounds. Ringing data show that these birds winter in western Europe as well as in the Mediterranean. Some Dunlins from the Baltic migrate in autumn in a SE direction - to the Mediterranean and the Black Sea regions. The origin of these birds is not known. The SE direction may be used also by Polish breeding schinzii. Some Dunlins of the sub-species alpina, ringed in the Baltic in autumn, are controlled in spring at the Black Sea; in autumn they seem to migrate along a more northern route - through the Baltic, while in spring they choose a more southern route - through the Black Sea (loop migration).
Mitochondrial DNA (mtDNA) control-region sequences of 52 migratory and wintering Dunlins (Calidris alpina) from around the world were determined with direct sequencing of PCR products. The genetic lineages detected in these birds are identical to those found previously in a much larger sample of 155 breeding Dunlins from their northern circumpolar range. Samples of nonbreeding Dunlins from both sides of the Pacific reveal a mixture of two lineages that breed separately in eastern Siberia and Alaska. The presence of Dunlins with an eastern Siberian haplotype along the west coast of North America indicates that the Bering Strait does not represent a biogeographic barrier to Dunlin migration. Dunlins wintering in eastern Asia most likely originated from the discrete breeding population in northern Alaska because they possess haplotypes that were found predominantly in birds from this region. Similarly, Dunlins front staging and wintering sites in Europe and western Asia reveal a mixture of two mtDNA lineages that were previously found confined largely to European and central Siberian breeding grounds. Limited gene flow between these breeding areas, however, precludes definitive allocation of individuals to their population of origin on the basis of mtDNA analysis alone. Body mass, time of migration, and molting pattern seem to be associated with the mtDNA types of migratory Dunlins in Europe, but data are too sparse to determine whether these characters are useful adjuncts in assigning nonbreeding birds to populations that correspond to the major genetic lineages. Overall, the genetic composition of nonbreeding populations indicates the confluence of breeding populations on southward migration. Because of strong phylogeographic population structure in Dunlins on their breeding grounds, mtDNA analysis can be extremely useful in defining broad migration corridors or flyways, and in determining staging and wintering areas used by the major breeding populations.
Comparison of mitochondrial DNA (mtDNA) control-region sequences of 155 dunlins from 15 breeding populations confirmed the existence of five major phylogeographic groups in the circumpolar breeding range of this migratory shorebird species. Time estimates of the origin of groups, based on sequence divergences and a molecular clock for birds, suggest a scenario of repeated fragmentation of populations in isolated tundra refugia during the late Pleistocene. The distribution of about three-quarters of all detected molecular variance between phylogeographic groups attests to the strongly subdivided genetic population structure in dunlins that is being maintained by natal philopatry. Each mtDNA phylogeographic group can be related to a morphometrically defined subspecies, but several other recognized subspecies are not supported by monophyletic mtDNA lineages within their purported ranges. More detailed analysis of several European populations reveals low amounts of gene flow and the partitioning of a substantial fraction of molecular variance between them. This ongoing evolution of population-genetic structuring within the European phylogeographic group most likely started with the last retreat of the ice sheets some 10,000 years ago. Dunlins thus provide one of the clearest examples of the linkage between historical and contemporary components of mtDNA phylogeographic structuring in birds.
Sur les races du Bécaseau cincle (ou variable) et du Tétras à bec noir
- Buturlin S.A.
A new subspecies of the Dunlin, Calidris alpina litoralis ssp. N. (Charadriidae, Aves), from the Sakhalin Island
- Nechaev V.A.
Primary moult of adult Dunlin Calidris alpina of different age during autumn migration.Vår FågelvärdSuppl
- J Gromadzka
A new name for Sakhalin Dunlin (Aves. Charadriidae)
- Nechaev V.A.
Genetic variability of the Dunlin in the far east
- Tomkovich P.S.