Developing macrophytes-based methods for assessing the ecological status in rivers needs to deal with different analyze scales: floristic data are recorded at the site scale while the anthropic pressures are defined at large scale of catchment area. Thus, the response of the macrophytes communities cannot be directly explained by the catchment features. To focus on the hydromorphology highlights the needs of multi-scales approach. Indeed these environmental parameters cover functioning (hydrology) and characteristics (substrate, river shape) at nested scales. The search for sensitive macrophytes metrics assessing the impact of environmental parameters, especially for the hydromorphological aspects, were tackled by 1/ determinate the relationship between population and habitat at the site scale, 2/ understand the links between large-scale pressure and local morphological feature, 3/ analyzing the correlations between both scales and biocenosis characteristics. This approach was undertaken using the French WFD biological monitoring (over 4000 surveys). A set of biological (IBMR, growth forms, vegetal cover) and environmental metrics was defined and tested as integrating meta-data. A PLS modeling distinguishing pressures at catchment, reach and site scales was used in order to respect the hierarchical spatial organization. This multi-scalar method was developed to identify and quantify the biotic response through these different scales.