The MoU covers 22 range states (Belarus, Belgium, Bulgaria, France, Germany, Hungary, Latvia, Lithuania, Luxembourg, Mali, Mauritania, Morocco, the Netherlands, Poland, Portugal, Russian Federation, Senegal, Slovakia, Spain, Switzerland, Ukraine and United Kingdom).

A meeting of the range states of the aquatic warbler was held in Minsk, Belarus, from 29 to 30 April 2003, to negotiate and adopt a MoU and action plan for the conservation of the species.

The signatories represented at the meeting were Belarus, Belgium, Bulgaria, Germany, Hungary, Latvia, Lithuania, Poland, Senegal, Ukraine and the United Kingdom.

Furthermore, the signatories decided to extend the geographical coverage of the MoU to include an additional seven new countries in Europe and Africa (Luxembourg, Mali, Mauritania, Morocco, Portugal, Slovakia and Switzerland), bringing the range state total to 22.

The main objective of the Action Plan is to maintain the aquatic warbler throughout its range and, in medium to long term, promote the expansion of the breeding population to other suitable areas.

Actions to be taken by the signatories can be summarized in four categories: In 2007, a BirdLife International team discovered a key site within the aquatic warbler's wintering grounds in West Africa, which was completely unknown until then.

The Polish BirdLife partner led a major project from 2005 to 2011, funded largely by the European Union's LIFE Nature programme, to restore 42,000 ha of the aquatic warbler's peatland habitat in Poland and Germany.

Measures to be implemented include hydrological management, removal of shrubs and overgrowth from wet meadows and mires and initiation of extensive grazing and considerate mowing of aquatic warbler habitats.

The latest monitoring results, conducted by The BirdLife International Aquatic Warbler Conservation Team (AWCT), showed decrease of approximately one-third in each of the countries where the species breed (Lithuania, Poland, Belarus and Ukraine).