At European level

In Europe, according to the Action Plan for the aquatic warbler, the following threats have been identified in the nesting areas :

• Loss of nesting habitat. Because of the wetlands desiccation, inadequate water management, and rivers canalization.
• Vegetal successions in the nesting habitat. Favoured by the disappearance of farming methods such as grazing and reaping of the helofitic vegetation, implying the wetlands invasion by other species as reeds or brushwoods.
• Loss or changes in the migration areas.
• Changes in the wintering ranges. Mainly justified by new projects of farming development (wetlands desiccation, abusive water extractions, excessive grazing, demographic increase, .) and by the cyclic droughts from which suffers western Africa.
• Nuisances caused by Man. They affect the nesting zones and are mainly caused by ornithologists or farmers.
• Eutrophication The low water level in some nesting areas favours the mineralization of the ground and implies changes in the vegetation.
• Uncontrolled fires. They are used as a tool to control the marsh vegetation when traditional works like reaping or grazing are not realized.

At national level

In Spain, the threats for this passerine have never been described, but they can be found in the following points :

• Wetlands destruction or alteration. This kind of habitat has suffered from a important decrease during the last years, more than 60% according to some authors, which has undoubtfully affected the places that could be traditionally or potentially used by the species.
• Changes in the habitat. The management performances in the wetlands tend to eliminate the helofitic vegetation zones to favour the spaces of open water, and could contribute in the elimination of the habitat available to such a selective species.

• Lack of information about the migrating phenology and stop-over sites of the species. The aquatic warbler is one of the most unknown species, about which we have the least informations in Spain. Despite the ringing campaigns, its presence has been so far practically unnoticed, possibly because of the particular habitat that it uses during the migration, zones which have not been properly prospected.
• Intensification of the farming works. The constant changes of crop type in the wetlands surroundings, and the more and more frequent use of phytosanitary products as weed-killers, insecticides or fungicides, could be responsible for the decrease of arthropods communities, which compose the diet of this and of other species of insectivorous birds.