Conservation genomics of the aquatic warbler, a specialist bird breeding in declining mire habitat
Dr. Justyna Kubacka is an evolutionary ecologist and ornithologist. She works in the Museum and Institute of Zoology, Polish Academy of Sciences, Warsaw. She belongs to the aquatic warbler genome team of the ERGA Pilot reference genome project.
This ERGA-BGE project, started in June 2024 and led by Dr. Justyna Kubacka, builds upon an ongoing study on the conservation genomics of the aquatic warbler, a threatened bird of highly fragmented central-European wetland. Under the ERGA-BGE umbrella, the project aims to whole-genome resequence around 20 individuals of the aquatic warbler from two populations. Samples were collected by Prof. Andrzej Dyrcz, Dr. Benedikt Giessing, Dr. Jarosław Krogulec, and Grzegorz Kiljan in the 1990s, and by Dr. Kubacka in the 2010s. The birds were sampled in one of the species’ strongholds, the Biebrza Valley in the northeast of Poland, which hosts about 25% of the global population, and in the currently extinct breeding site in Western Pomerania at the Polish-German border. The two regions are approx. 600 km apart with only scarce breeding habitat in between.
Handling and sampling small birds such as the aquatic warbler requires expertise and a lot of care.
Photo by Irene Arnaldos Giner.
The project will focus on two populations of aquatic warbler: a larger population from the well-preserved Biebrza Valley marshes and a population from Western Pomerania that is currently extinct. Photos by Justyna Kubacka and Knyva.
The ERGA-BGE project aims to complement the ongoing study with a more thorough evaluation of genomic inbreeding, effective population size, and genetic bottlenecks, as well as adaptive variation and population structure between the two distant populations. The results of the project will help us understand the extent of the loss of genetic diversity and its contribution to the decline of the aquatic warbler. They will inform translocation of the species, which is being carried out to restore the extinct population in Western Pomerania. Importantly, the ERGA-BGE project will use the recently finished chromosome-level reference genome of the aquatic warbler.
The research activities included fieldwork in remote mires to catch and blood-sample aquatic warblers. The samples collected in the 1990s were deposited in the Dresden Senckenberg Museum (Germany). Dr Kubacka extracted DNA from these samples on her visit to the Museum at the beginning of 2024. She is also curating a collection of aquatic warbler DNA samples, which will be used for the ERGA-BGE project. The project is expected to draw the attention of the scientific community as it will explore the past and present conservation genomics of a migratory bird that is a habitat specialist breeding in a vanishing wetland habitat.
Photo by Anna Dubiec.
The study is funded by the German Ornithological Society (DO-G) and through EU Life programme resources awarded to Förderverein Naturschutz im Peenetal e.v., Germany, and the Baltic Environmental Forum, Lithuania. It is being carried out in collaboration with Prof. Michael Wink, Dr. Volker Salewski, and Dr. Martin Paeckert. It would not be made possible without the collectors, who laboriously obtained samples from breeding sites covering the whole breeding range of the species, including those as distant and remote as Western Siberia. The whole-genome resequencing part of the project will be performed thanks to funding from the European Union under the European Union’s Horizon Europe research and innovation programme, co-funded by the Swiss Government and the British Government.
*Header image: Looking for the tiny aquatic warbler across the vast landscape of the Biebrza Valley. Photo by Szczepan Skibicki.
