Impact of unpaved roads on the fluvial ecosystems in the XXI century: a review

Abstract Aim Considering the strategic role of water resources for ecosystem sustainability and the increasing anthropogenic pressure, particularly from roads, this study aimed to analyze the impacts of unpaved roads on fluvial ecosystems, with emphasis on erosion processes and related mechanisms. Methods A systematic literature review was conducted using the Methodi Ordinatio, with searches in the Scopus and Web of Science databases. After applying the selection criteria, 29 articles published between 2001 and the present were analyzed. Initially, a scientometric analysis was carried out, followed by a knowledge synthesis and suggestions for future research directions. Results The findings indicate a growing interest in the topic, with a geographic concentration of studies in countries such as the USA, China, and Australia, predominantly focused on forest roads in mountainous regions and streams. Most investigations addressed hydro-sedimentological dynamics and the effectiveness of best management practices (BMPs), while fewer studies examined direct impacts on water quality and aquatic biota. The studies showed that unpaved roads reduce infiltration, increase surface runoff, and intensify the production and delivery of fine sediments, with strong hydrological connectivity, especially at stream crossings and roadside ditches. BMPs such as road decommissioning, gravel surfacing, revegetation, and the establishment of riparian zones were effective in mitigating these impacts, particularly when well-implemented and adapted to local conditions. Conclusions Although the reviewed studies provide evidence of the impacts of roads on fluvial systems, gaps remain in the literature. It is necessary to expand the geographical scope of investigations, deepen the evaluation of direct impacts on water quality and biodiversity, especially at a longitudinal scale, and test the effectiveness of BMPs under different environmental conditions to support the conservation of fluvial ecosystems in rural areas.