Long-term Dynamics of Coastal Dune Landscapes and Floristic Diversity: Insights from a Quarter Century of Resurveys in Castelporziano Presidential Estate. Book of Abstracts – Conference of Young Botanists 2025. Conference of Young Botanists (CYBO)

Coastal dunes are transitional ecosystems situated along sandy shorelines, shaped by steep sea-to-inland environmental gradients. According to the 4th Habitat Report, over 85% of these habitats are classified as having poor conservation status, with a deteriorating trend driven by intense anthropogenic pressures. Monitoring temporal habitat changes is therefore critical to implement effective conservation measures. Traditional methods, such as field resurveys, remain a cornerstone for vegetation monitoring but are both time-consuming and costly. In contrast, in recent years Remote Sensing (RS) has emerged as a promising, cost-effective alternative, offering enhanced data availability and spatial resolution. This study investigates temporal changes in the coastal dune ecosystems of the Mediterranean Protected Area (PA) “Castelporziano Presidential Estate” (Natura2000 code: IT6030084), a strictly regulated zone with limited access. Specifically, we assess floristic and landscape dynamics over a 25-year period using data from 58 resurveyed vegetation plots within land cover classes: Herbaceous Dune Vegetation (HDV), Woody Dune Vegetation (WDV), and Broadleaf Mixed Forest (BMF). The main objective was to determine whether floristic diversity influences landscape dynamics by integrating field and RS data collected during two temporal snapshots (T0: 1998 and T1: 2023). Landscape changes were visualized using chord diagrams, while floristic shifts were evaluated with rank-abundance curves for T0 and T1. Shannon diversity indices were calculated to measure both floristic and landscape diversity within 25 m, 75 m, and 125 m circular buffers around the plots. To explore whether floristic diversity affects landscape dynamics and how these relationships evolve over time, we applied Linear Mixed Effects models. Our results revealed natural encroachment, vegetation succession and a reduction in artificial cover. Floristic analyses highlighted substantial differences between T0 and T1, particularly in WDV, where the dominance of Cistus sp. pl. significantly declined. Models assessing the influence of floristic diversity on landscape dynamics demonstrated strong explanatory power, particularly within larger buffers. Notably, relationships differed between T0 and T1 across all three vegetation units. Landscape diversity exhibited negative trends with increasing species dominance, whereas positive trends were associated with higher species evenness. This study underscores the utility of integrating field and RS data for monitoring temporal changes in Protected Areas. The approach offers valuable insights into the interplay between plant diversity and landscape dynamics and may serve as a foundation for accelerating resurvey efforts and implementing targeted conservation measures.