RNLED is a high-important ornithological refuge, being a place of stay, nesting and passing thousands of birds, some of which are of priority conservation under the Community Bird Directive.

RNLED is part of the Vila Nova de Gaia Parks Network and the Municipal Master Plan itself provides for its integration into the National Ecological Reserve. Located around it, the São Paio Valley represents an important role of preservation of the RNLED itself, being also a nesting site of several birds and serving as a "buffer" to the reserve." São Paio Park will be a fake "Green Park", which "green" will have little. In the heart of the natural area full of biodiversity, it is incomprehensible a construction that is implying the morphological alteration of the land, as well as the chopping of all vegetation, namely ripícola, which is essential for local fauna.", warns Pedro Ribeiro de Castro, pan municipal deputy in Vila Nova de Gaia.The PAN already several times, and at several different times, proposed with the executive the integration of the São Paio Valley into RNLED, demonstrating his concern about the impacts that come from the construction of the São Paio Park and presenting alternatives to this space." We believe that the solution is not to build infrastructure such as those planned for the São Paio Valley, which will put in check the nature reserve, but rather take advantage of the existing environmental diversity, combining it with a strand of environmental literacy, educating for respect and promotion of biodiversity. An inclusive space, where people adapt to nature and not nature to people," says Pedro Ribeiro de Castro.The PAN also warns of the urban pressure that is already being created around the reserve, namely with the construction of new large complexes Housing. He argues that "the priority should be the creation of reserve protection measures and not the construction of new infrastructures that only increase human pressure on the site".