| 1. |
- Elmberg, Johan, et al.
(författare)
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Farmed European mallards are genetically different and cause introgression in the wild population following releases
- 2016
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Konferensbidrag (refereegranskat)abstract
- The practice of restocking already viable populations to increase harvest potential has since long been common in forestry, fisheries and wildlife management. The potential risks of restocking native species have long been overshadowed by the related issue of invasive alien species. However, during the last decade releases of native species with potentially non-native genome have received more attention. A suitable model to study genetic effects of large-scale releases of native species is the Mallard Anas platyrhynchos, being the most widespread duck in the world, largely migratory, and an important quarry species. More than 3 million unfledged hatchlings are released each year around Europe to increase local harvest. The aims of this study were to determine if wild and released farmed Mallards differ genetically, if there are signs of previous or ongoing introgression between wild and farmed birds, and if the genetic structure of the wild Mallard population has changed since large-scale releases started in Europe in the 1970s. Using 360 Single Nucleotide Polymorphisms (SNPs) we found that the genetic structure differed among historical wild, present-day wild, and farmed Mallards in Europe. We also found signs of introgression in the wild Mallard population, that is, individuals with a genetic background of farmed stock are part of the present free-living population. Although only a small proportion of the released Mallards appears to survive to merge with the free-living breeding population, their numbers are still so large that the genetic impact may have significance for the wild population in terms of individual survival and longterm fitness.
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| 2. |
- Elmberg, Johan, et al.
(författare)
-
Farmed European mallards are genetically different and cause introgression in the wild population following releases
- 2016
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The practice of restocking already viable populations to increase harvest potential has since long been common in forestry, fisheries and wildlife management. The potential risks of restocking native species have long been overshadowed by the related issue of invasive alien species. However, during the last decade releases of native species with potentially non-native genome have received more attention. A suitable model to study genetic effects of large-scale releases of native species is the Mallard Anas platyrhynchos, being the most widespread duck in the world, largely migratory, and an important quarry species. More than 3 million unfledged hatchlings are released each year around Europe to increase local harvest. The aims of this study were to determine if wild and released farmed Mallards differ genetically, if there are signs of previous or ongoing introgression between wild and farmed birds, and if the genetic structure of the wild Mallard population has changed since large-scale releases started in Europe in the 1970s. Using 360 Single Nucleotide Polymorphisms (SNPs) we found that the genetic structure differed among historical wild, present-day wild, and farmed Mallards in Europe. We also found signs of introgression in the wild Mallard population, that is, individuals with a genetic background of farmed stock are part of the present free-living population. Although only a small proportion of the released Mallards appears to survive to merge with the free-living breeding population, their numbers are still so large that the genetic impact may have significance for the wild population in terms of individual survival and longterm fitness.
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| 3. |
- Guillemain, Matthieu, et al.
(författare)
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Combined effects of climate change and fluctuating habitat quality on the distribution of ducks in southern Europe
- 2016
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Ingår i: 7th North American Duck Symposium.
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Konferensbidrag (refereegranskat)abstract
- Changes in waterfowl ranges over the last decades are increasingly reported, both in North America and in Europe. The relative importance of different winter quarters may fluctuate under the influence of changing local habitat conditions, as well as according to general trends caused by global climate change. Several European duck species have shifted their winter range to the North-East, i.e. the distance between breeding and wintering grounds was reduced, in a pattern consistent with a global temperature increase. In northern countries, this could also indicate an increasing proportion of sedentary birds. We compared the geographic distribution of recoveries of bands fitted to Mallard (Anas platyrhynchos) and Common Teal (A. crecca) in Camargue, southern France, over the last 60 years. Close to 75,000 ducks were banded since the early 1950s. Band recoveries occurred to a much greater extent in the Camargue area than in other parts of the flyways during the last decade compared to earlier years: as opposed to earlier studies, recoveries of Camargue-ringed ducks are increasingly made to the South-West. For migratory Teal, this indicates an increased faithfulness to the Camargue winter quarter. For Mallard, though, some birds may have become around-the-year residents: while the distance from banding site to recovery location was >400 km between the 1950s and 1970s, it is <75 km nowadays. Several hypotheses are proposed to explain these changes in European duck distributions. Survival analyses are also carried out, which help assessing whether changes in geographic distribution have also translated into altered demographic rates. Besides the overriding effects of climate change in the long-term, the present results suggest that local habitat management practices still have the potential to greatly affect the distribution of waterfowl.
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| 4. |
- Guillemain, Matthieu, et al.
(författare)
-
Combined effects of climate change and fluctuating habitat quality on the distribution of ducks in southern Europe
- 2016
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Changes in waterfowl ranges over the last decades are increasingly reported, both in North America and in Europe. The relative importance of different winter quarters may fluctuate under the influence of changing local habitat conditions, as well as according to general trends caused by global climate change. Several European duck species have shifted their winter range to the North-East, i.e. the distance between breeding and wintering grounds was reduced, in a pattern consistent with a global temperature increase. In northern countries, this could also indicate an increasing proportion of sedentary birds. We compared the geographic distribution of recoveries of bands fitted to Mallard (Anas platyrhynchos) and Common Teal (A. crecca) in Camargue, southern France, over the last 60 years. Close to 75,000 ducks were banded since the early 1950s. Band recoveries occurred to a much greater extent in the Camargue area than in other parts of the flyways during the last decade compared to earlier years: as opposed to earlier studies, recoveries of Camargue-ringed ducks are increasingly made to the South-West. For migratory Teal, this indicates an increased faithfulness to the Camargue winter quarter. For Mallard, though, some birds may have become around-the-year residents: while the distance from banding site to recovery location was >400 km between the 1950s and 1970s, it is <75 km nowadays. Several hypotheses are proposed to explain these changes in European duck distributions. Survival analyses are also carried out, which help assessing whether changes in geographic distribution have also translated into altered demographic rates. Besides the overriding effects of climate change in the long-term, the present results suggest that local habitat management practices still have the potential to greatly affect the distribution of waterfowl.
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| 5. |
- Guillemain, Matthieu, et al.
(författare)
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Still worth the travel? : changes in Camargue teal migration patterns, body condition and demographic parameters over 60 years
- 2015
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Ingår i: 4th Pan-European Duck Symposium, Hangö, Finland, 8-11/4 2015. ; , s. 28-
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Konferensbidrag (refereegranskat)abstract
- Climate and habitat changes linked with human activities have profoundly modified the road maps of waterfowl across their geographic ranges. If new breeding grounds open to the North, traditional wintering sites may gradually get deserted by birds short-stopping during the autumn and shifting their nonbreeding distribution. More than 60,000 ringing data were collected from wintering Teal (Anas crecca) in the area from the early 1950s to the beginning of the 2010s. Migration patterns have changed with birds now arriving much earlier, and overall population movements being much reduced during winter. The body condition of Camargue-wintering Teal has improved dramatically compared to the pre-1970 era, which could be a cause and/or a consequence of such changes in migration processes: Teal may arrive increasingly early in the year because artificial summer flooding of wetlands and baiting now provide suitable habitat and abundant accessible food. In turn, reduced movements linked with greater residency in the Camargue would impose smaller use of the body reserves. The comparison of Teal turnover and survival rates during historical (1950s- 1970s) and modern (post-2002) years provides some insight as to whether the situation has gradually improved for these birds. Conversely, the sustained use of the Camargue could simply reflect these birds being lured by artificially increased availability of food, which they would use at the expense of their survival rate, hence with no positive consequences in terms of population dynamics.
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| 6. |
- Guillemain, Matthieu, et al.
(författare)
-
Still worth the travel? : changes in Camargue teal migration patterns, body condition and demographic parameters over 60 years
- 2015
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Climate and habitat changes linked with human activities have profoundly modified the road maps of waterfowl across their geographic ranges. If new breeding grounds open to the North, traditional wintering sites may gradually get deserted by birds short-stopping during the autumn and shifting their nonbreeding distribution. More than 60,000 ringing data were collected from wintering Teal (Anas crecca) in the area from the early 1950s to the beginning of the 2010s. Migration patterns have changed with birds now arriving much earlier, and overall population movements being much reduced during winter. The body condition of Camargue-wintering Teal has improved dramatically compared to the pre-1970 era, which could be a cause and/or a consequence of such changes in migration processes: Teal may arrive increasingly early in the year because artificial summer flooding of wetlands and baiting now provide suitable habitat and abundant accessible food. In turn, reduced movements linked with greater residency in the Camargue would impose smaller use of the body reserves. The comparison of Teal turnover and survival rates during historical (1950s- 1970s) and modern (post-2002) years provides some insight as to whether the situation has gradually improved for these birds. Conversely, the sustained use of the Camargue could simply reflect these birds being lured by artificially increased availability of food, which they would use at the expense of their survival rate, hence with no positive consequences in terms of population dynamics.
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| 7. |
- Kraus, R.H.S., et al.
(författare)
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Freigelassenes Federwild führt zu kontinent-weiter genetischer Introgression : die sich ändernde genetische Landschaft der Stockente Anas platyrhynchos in Europa
- 2015
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Konferensbidrag (refereegranskat)abstract
- Es ist eine seit langem übliche Praxis in Forstwirtschaft, Fischerei und allgemeinem Wildtiermanagement, Wildtierbestände gezielt aufzustocken. In den letzten ca. zehn Jahren haben aber solche Programme Aufmerksamkeit erregt, in denen lokale Bestände von Tierarten mit Individuen der gleichen Art, aber aus anderen Regionen und damit potentiell nicht-nativen Genomen aufgestockt wurden. Die Stockente Anas platyrhynchos ist ein geeignetes Modell um die genetischen Effekte solcher großskaligen Freisetzungen auf den einheimischen Genpool zu untersuchen, weil sie die am weitesten verbreitete und zahlreichste Entenart der Welt ist, über weite Strecken migrieren kann und gleichzeitig global das wichtigste Federwild darstellt. In vielen europäischen Ländern wird die Stockente seit etwa den frühen 1970er Jahren auch auf speziellen Farmen gezüchtet und zu Jagdzwecken ausgesetzt. So gehen aktuelle Schätzungen davon aus, dass jährlich etwa drei Millionen junge Enten nur zum Zweck der Aufstockung zur Jagd an europäischen Gewässern ausgesetzt werden. Die Ziele unserer Studie waren herauszufinden, ob sich Enten von Farmpopulationen genetisch von wilden Enten unterscheiden lassen, ob es Anzeichen früherer oder anhaltender genetischer Introgression zwischen diesen beiden Gruppen gibt und ob sich die genetische Struktur der wilden Entenpopulationen seit der großskaligen Entenaufstockung verändert hat. Dazu verwendeten wir 360 SNP Marker (Single Nucleotide Polymorhpism) um die genetische Struktur von historischen wilden Stockenten (Museumsproben), zeitgenössischen wilden Stockenten und Farm-Enten zu vergleichen (N = 591). Wir fanden klare genetische Unterschiede zwischen wilden Stockenten und Farm-Enten in mehreren Ländern Europas. Ebenfalls konnten wir genetische Introgression von Genen der Farm-Enten in die wilde Stockentenpopulation zeigen. Die Vermischung scheint bisher zwar messbar aber noch gering zu sein, da auf Farmen gezüchtete Stockenten in der Wildnis geringe Überlebensraten aufweisen. Dennoch sollte die weitere Einkreuzung von Farm-Enten in die wilden Stockentenpopulationen so gering wie möglich gehalten werden, da durch anhaltende genetische Introgression möglicherweise in Zukunft lokale Anpassungen der wilden Stockenten geschwächt werden, was eine Bedrohung dieser Bestände darstellen könnte.
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