Disentangling the effects of sandy beach management on intertidal macrobenthic fauna: A path analysis approach

Sandy beaches are dynamic coastal ecosystems shaped by natural processes and human driven activities, hosting diverse macrobenthic communities that serve as key indicators of ecological health. This study examines the interplay between natural and anthropogenic drivers affecting these communities across five beaches along the Emilia Romagna coast, Italy. By employing path analysis, we quantified the direct and indirect effects of environmental variables, including sediment characteristics, physical processes, beach morphology, and management practices. Sampling was conducted at high and low tidal levels, analyzing 330 samples to assess community structure and diversity. Results reveal that both natural and human drivers significantly influence macrobenthic communities, with contrasting effects. Positive impacts were associated with beach nourishment, which increased habitat availability; while practices such as frequent mechanized cleaning and artificial dune construction negatively impacted diversity and abundance. Other drivers, including erosion and subsidence, exhibited complex relationships with species richness and community composition, highlighting the role of beach morphodynamics as a determinant of benthic diversity. Species-specific responses were observed, with the polychaete Scolelepis (scolelepis) squamata thriving in nourished environments, while Polydora sp. generally showed sensitivity to disturbance. The dominant bivalve Lentidium mediterraneum displayed neutral responses to management but was influenced by sediment properties. These findings emphasize the need for adaptive, ecologically sensitive beach management strategies that balance tourism demands with conservation goals. This study highlights the value of path analysis in unraveling complex ecological interactions, offering insights for the sustainable management of sandy beach ecosystems under increasing environmental and anthropogenic pressures. Future efforts should integrate these findings into broader frameworks addressing coastal resilience and biodiversity conservation.