The Métropole Rouen Normandie has decided to improve its attractiveness at regional, national and international level. This attractiveness includes providing people and employees, as well as tourists, with favourable socio-economic conditions, but also a remarkable environment and quality of life. Quality natural areas contribute directly to this stated desire.For this, it is essential to associate the protection of natural habitats, in particular regulations (environmental code, SRCE, SCOT, PLU/PLU intercommunal to come, etc.), and the preservation or restoration of biodiversity reservoirs, as well as ecological corridors, which allow the maintenance of a good functional/ecological status of these reservoirs throughout the metropolis and in relation to the neighbouring territories.At the regional level, the SRCE recalls that the silica-growing environment, and in particular the siliciculture lawns, are very special open environments, home to rare, highly heritage flora and fauna. These environments are undeveloped and limited to the alluvial terraces of the Seine. Despite this rarity, Haute Normandie still presents the finest siliciculture ensembles in the northwest quarter of France. The SRCE therefore strongly encourages all regional actors, in particular local authorities and/or managers of natural areas or green areas, to protect and manage the last siliciculture lawns in the territory. In particular, the CNRS is proposed to strengthen the regulatory protection of these environments, and to the extent possible, their acquisition by a competent body.At the Metropole scale, drawing on the SRCE data refined at the margin for the SCOT project agreed in November 2014, and excluding CERS data from already urbanised sites (roads, habitats, area of activity...), siliciculture reservoirs represent an area of 147 ha and siliciculture corridors an area of 224 ha. So-called complementary silica-growing areas have also been identified, covering an area of 238 ha. These complementary areas, which are not currently retained as reservoirs or corridors, however, offer habitat characteristics conducive to the development of fauna and flora specific to the silica-growing environment. In total, it is a little less than 600 ha of silicon farming in the Métropole, of which more than 55 % are under public control. However, the analysis of urban planning documents (PLU) shows that more than 200 ha of these areas are currently classified as “AU” (A urbaniser), and more than 100 ha classified as “N other vocations” (including sites for the authorisation of extraction activities).The Métropole therefore proposes to undertake a wide-ranging study of the siliciculture media in its territory. It is also considering the restoration of a 200 ha siliciculture site in the municipalities of Bardouville and Anneville-Ambourville. Calcicultural habitats are also identified at regional level by the SRCE as being highly threatened. This is confirmed on the territory of the Metropolis. Just over 300 ha have been identified as part of a partnership initiated since 2012 with the Conservatoire d’Espaces Naturels in Haute-Normandie. Of these 300 ha, almost 40 % are unmanaged and are gradually getting worse. These 128 ha are 89 % private. This closure of the environment results in the decline of the heritage biodiversity of all remarkable calciculture habitats. The Métropole also proposes to intervene in favour of the restoration and preservation of these habitats typical of the Seine Valley.