1. Limitation of the habitat
The wetlands disappearance has been a constant in the European geography all along its history, so that it is now a priority to recover them, totally or partly. In the wetland of La Nava , 59 of the present bird species are included in the Annex 1 of the Birds Directive 79/409/EEC (relative to the conservation of wild birds), among which ones we find the aquatic warbler. Is also present one type of habitat included in the Annex 1 of the Habitat Directive : "hard oligomesotrophic waters with benthic vegetation of Chara spp." (type 3140), considered of community interest.
The wetland extension to the grasslands of La Güera and El Hoyo, and the flooding improvement in Cantarranas, tend to provide favourable conditions for the conservation of all these species and environments.
2. Quality of water
The origin of the water pollution comes from four sources : leaching of the old rubbish dump of Fuentes de Nava, overflowing of the sewage farm emissary of Fuentes de Nava, sewage of the locality of Paredes de Nava and diffused contamination of farming products.
The project seeks to limit this pollution, at least partly, through various performances as the burial of the sewage farm emissary of Fuentes de Nava and the adaptation of a "by-pass" in the stream of La Culebra.
3. Accumulation of vegetal remains and extension of the ciperaceae meadows
La Nava is a tremendously productive wetland, with a annual production (in wet weight) which exceeds twenty tons/ha. of carex and reed and which reachs fifty tons/ha. in the case of Scirpus maritimus or for the Drepanocladus aduncus moss.
This evolution undoubtfully affects the quality of the habitat as breeding, wintering and stop-over area of a lot of water fowl species, especially for those which are included in the appendix 1 of the Birds Directive 79/409/EEC, as the aquatic warbler, purple heron, whiskered tern, black tern, black-winged stilt and spoonbill. Moreover, the accumulation of vegetal remains reduces the extension of the habitat (type 3140 of the appendix 1 of the Directive 92/43/CEE).
The efficiency of different management methods, as controled grazing, harvesting, decapping and controled fires, is being evaluated.
4. Management of the public use.
The human pressure is more and more important upon a wetland whose national and international fame grows from year to year, and the visits of the tourists make particularly necessary to take measures to avoid nuisances.
The service of a watchman has been contracted, besides adapting some spots and roads for public use.
5. Lack of knowledge about the aquatic warbler's biology
That's why studies about these species situation and biology are carried out, based on the scientific ringing, the census itineraries and the radiotracking. Moreover the organization of congresses and meetings of experts of the aquatic warbler is planed.
6. Lack of knowledge by the society about the conservation problems of the aquatic warbler.
Several materials to disseminate these problems are regularly edited : web pages, videos, leaflets, .