Fire shifts the structure and dynamics of woody plant communities in a mediterranean coastal dune ecosystem

Coastal dune ecosystems are dynamic and fragile environments shaped by complex interactions between vegetation and its characteristic abiotic factors. This study investigates the effects of the wildfire that affected the Donana Nacional Park (SW Spain) in 2017 on the composition and structure of woody plant communities in two adjacent Mediterranean coastal dune areas: one affected by fire (Cuesta Maneli) and one unburned (Laguna del Jaral). Using a combination of several analyses (such as non-metric multidimensional scaling (NMDS); Mantel tests; and co-occurrence analyses), we examined how fire influences species distribution, abundance, and their interactions along a coastal-inland gradient. Our results reveal that fire homogenizes woody plant community composition across the coastal-inland gradient, reducing spatial differentiation and increasing overall species abundance in the burned area. Soil characteristics influenced species composition significantly only in the unburned site, suggesting that fire disrupted abiotic filtering processes. Co-occurrence patterns indicate more neutral interactions in the burned area, consistent with reduced competition and increased resource availability post-disturbance. In contrast, the unburned site displayed structured communities with stronger negative co-occurrence at the smaller scales and spatial clustering of species. Spatial pattern analyses showed that positive co-occurrence was more prevalent in the burned area, particularly at smaller spatial scales, indicating potential facilitation effects during early post-fire recovery. These findings highlight how fire reshapes community structure and dynamics after succession. Understanding these processes is critical for effective conservation and management of Mediterranean coastal dune ecosystems facing increasing anthropogenic pressures and climate change-related disturbances.