The cumulative effects of environmental and anthropogenic pressures on marine environments are endangering the biocoenosis that inhabit them. Identifying and understanding the impacts of global changes are key challenges for maintaining the habitats in good working state and require the use of standardized monitoring and reliable indicators.Between 2014 and 2023, as part of various research programs, macrofaunal communities were inventoried in the boulder fields in the Southeastern Bay of Biscay, in an area devoid of fishing pressure. Following a stratified random sampling design, the mobile and sessile macrofaunal of the upper and lower medio littoral zones were identified annually between March and July. The results reveal significant changes over the study period, with a transitional year in 2020. Changes in biodiversity, functionality and indicator species of the habitat are observed, with the decline or even disappearance of species. In functional aspects, the abundance of grazers declines in favour of scavengers. The transition to a new state coincides with changes in environmental parameters (water temperature, salinity, etc.) and confirms the ability of this monitoring method to characterize changes and emerging pressures. The effect of the change and the transition to a new state on ecosystem functioning are discussed.These results underscored the importance of ongoing monitoring for the management and conservation of coastal ecosystems in the Southeastern Bay of Biscay.