Background The aquatic warbler (Acrocephalus paludicola) is Europe’s rarest migratory songbird and a globally threatened species (its IUCN status is ‘vulnerable’). Some 99% of its population is confined to Europe, with Poland accounting for around 25%. The aquatic warbler is listed in Annex I of the Birds Directive and has been identified as a priority species for LIFE+ Nature funding. Once widespread and numerous on fen mires and wet meadows, the aquatic warbler has suffered from habitat loss and degradation. With its habitats now dependant on human land-use and being extremely susceptible to land-use changes, it is now effectively a conservation-dependent species. An earlier LIFE Nature project (LIFE05 NAT/PL/000101, Aquatic Warbler project) concentrated on the protection of a remnant Pomeranian population of the species, along the German-Polish border. It also tested and developed conservation methods at the Biebrza Marshes in northeast Poland, the principal site of the species in Poland. This project will build on this experience, focusing on six sites in eastern Poland, which jointly hold 80% of the Polish and 21% of the world population of the aquatic warbler. At these sites, the key threat to the species is the slow deterioration of the open fen habitat through overgrowth with reeds, scrub and trees after the abandonment of traditional low-intensity manual mowing several decades ago. Objectives The objective of the Biomass use for Aquatic W project was to link the production of biomass as a renewable energy source with the large-scale mechanised management of aquatic warbler habitat. The aim was to demonstrate that conservation management of this habitat can also be economically viable. The project would be implemented in six project sites, all special protection areas (SPAs) according to the Birds Directive. Specific objectives were to: Test and improve innovative systems for the use of biomass; Increase the area of suitable habitat for the aquatic warbler in eastern Poland; Implement regular, ongoing management of major parts of the project sites secured through income from the use of biomass; and Raise awareness among conservation and business managers, site administrators and the general public. Results The project succeeded in enlarging the area covered by recurring land management favourable to the target species from 1 551 ha to 6 344 ha. This habitat restoration was mostly achieved by tree and bush removal and first time mowing. As a result, the area now occupied by aquatic warblers has increased from 3 602 ha to 3 879 ha – a 7.71% increase. The number of individuals in the project priority areas between 2009 and 2014 has risen by 26%, that is by 575 individuals, significantly more than the hundred foreseen. As planned, the biomass at the project sites was utilised. This involved transporting it by caterpillar tracked vehicles used for mowing fen mires. It was then converted into pellets, specifically the OTOPellet, which proved to be a good fuel that carries 16 GJ per pellet. This is more than a pellet made of straw and only slightly less than wooden pellets. The OTOPellet is very price competitive and thus has already gained recognition among the local population. The setting up of the pelleting facility at Biebrza Valley, established under the project, had a positive socio-economic impact, creating four jobs. Moreover, a feasibility study was carried out of an electric power plant fuelled by at the power plant, in Mońki County. The plant could be modernised as a result, bringing more new jobs to the region and benefitting the environment. The project also resulted in indirect social-economic benefits by raising awareness of the value of the habitat. It helped to shape the Rural Development Programme for 2014-2020 in Poland, which included conservation measures for the aquatic warbler. The long-term management of the sites will be assured by agri-environment scheme subsidies for mowing and other conservation measures. The approach taken by the project was very flexible and can be adjusted to various habitat types used by the aquatic warbler – from mesotrophic mires, through Cladium rushes to river floodplains. Furthermore, land was purchased under the project by the co-ordinating to ensure the sustainability of the project results. The land managed by the associated beneficiaries (FUT Zelent and Eko-Różanka), as well as other land restored in the project, will also be supported by agri-environmental scheme payments. Additionally, the aquatic warbler population was included in the environmental monitoring carried out by the general inspectorate for the environmental protection (GIOŚ). Further information on the project can be found in the project's layman report and After-LIFE Conservation Plan (see "Read more" section).