The importance of non-native prey, the Zebra Mussel Dreissena polymorpha, for the declining greater Scaup Aythya marila : a case study at a key European Staging and wintering site?

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The European population of Greater Scaup Aythya marila has experienced an alarming, ~60% decline in numbers over the last two decades. The brackish lagoons of the Odra River Estuary (ORE) in the south-western Baltic Sea, represent an important area for the species during the non-breeding season in Europe. The lagoons regularly support over 20 000 Scaup, with peaks exceeding 100 000 (38%–70% of the population wintering in NW Europe and the highest number recorded in April 2011–105 700). In the ORE, Scaup feed almost exclusively on the non-native Zebra Mussel Dreissena polymorpha. This mussel was present in the ORE already in the 19th century and continues to be superabundant. Using the results of 22 Scaup censuses (November to April 2002/2003 to 2013/2014) from the whole ORE (523 km2 of water), we show that Scaup flocks follow areas with the greatest area of occurrence and biomass of the Zebra Mussel, while areas with low mussel densities are ignored. The numbers of Scaup in the ORE are primarily related to the area of Zebra Mussel occurrence on the lagoon’s bottom (km2) in a non-linear fashion. Zebra Mussels were absolutely prevalent (97% of biomass) in the digestive tracts of birds unintentionally by-caught in fishing nets (n = 32). We estimate that Scaup alone consume an average of 5 400 tons of Zebra Mussels annually, which represents 5.6% of the total resources of the mussel in the ORE. Our results provide a clear picture of the strong dependence of the declining, migratory duck species on the non-native mussel, its primary food in the ORE. Our findings are particularly important as they can form the basis for the conservation action plan aimed at saving the north-western European populations of Scaup.

Tytuł
The importance of non-native prey, the Zebra Mussel Dreissena polymorpha, for the declining greater Scaup Aythya marila : a case study at a key European Staging and wintering site?
Twórca
Marchowski Dominik
Słowa kluczowe
Zebra Mussel; Dreissena polymorpha; Greater Scaup; Aythya marila; feeding sites
Słowa kluczowe
ogorzałka zwyczajna; miejsca żerowania
Współtwórca
Neubauer Grzegorz
Ławicki Łukasz
Woźniczka Adam
Wysocki Dariusz ORCID 0000-0001-6449-1126
Guenzel Sebastian
Jarzemski Maciej
Data
2015
Typ zasobu
artykuł
Identyfikator zasobu
DOI 10.1371/journal.pone.0145496
Źródło
PLoS ONE, 2015, vol. 10 iss. 12, [br. s.], 0145496
Język
angielski
Prawa autorskie
CC BY CC BY
Kategorie
Publikacje pracowników US
Data udostępnienia6 paź 2022, 15:27:16
Data mod.6 paź 2022, 15:27:16
DostępPubliczny
Aktywnych wyświetleń0