Integrating Satellite Data Into Meso-Scale Habitat Modeling for Non-Perennial Rivers and Streams

Non-perennial rivers and streams (NPRs) are widespread and projected to become more common, yet effective tools for their characterization and management remain limited. This study introduces a novel approach to assess aquatic habitat availability in NPRs, applied to a regulated reach of the Sangone River (Northern Italy). Using the NPRs-module of the MesoHABitat Simulation Model (MesoHABSIM), we evaluated habitat dynamics for two native fish species (Telestes muticellus and Padogobius bonelli) and the macroinvertebrate community (Flow-T index), in relation to streamflow and the time elapsed since discharge cessation. Habitat characterization was supported by high-resolution geospatial and field data collected in July 2021. To analyze flow intermittency, over 1700 multisource satellite images (monitoring period: 2017-2023) were classified in flowing, ponding, and dry conditions. This information, combined with local hydrological data, enabled the estimation of ponding durations (median = 8 days), a key factor for evaluating aquatic habitat persistence during non-flowing phases, and identification of the driest period (i.e., summer 2022), warranting focused habitat analysis. Habitat availability varied across ecological targets: adult T. muticellus preferred higher flows (>1 m(3)/s) and suffered rapid habitat loss during ponding, making it highly vulnerable to intermittency. In contrast, juveniles and P. bonelli favored lower flows (similar to 0.15 m(3)/s) and declined more gradually after flow interruption. For macroinvertebrates, suitable habitat increased monotonically with flow and showed the highest persistence during the ponding condition. This study provides an effective methodology for NPR characterization and aquatic habitat analysis, offering insights to guide ecological flow strategies to support NPRs ecosystem conservation.