Aquatic Vegetation in a Historically Reclaimed Coastal Wetland: A Phytosociological Survey of the Ariscianne Channels (Apulia, Southern Italy)

Wetlands are among the most threatened ecosystems worldwide, particularly in the Mediterranean Basin, where historical land reclamation and agricultural intensification have profoundly altered natural landscapes and biodiversity. The Ariscianne area (Apulia, southern Italy) represents a highly transformed coastal wetland in which remnants of aquatic vegetation persist mainly within artificial irrigation channels. This study provides the first phytosociological assessment of the aquatic vegetation currently occurring within these channels, with the aim of documenting plant community composition and identifying habitats of conservation interest. Vegetation surveys based on the phytosociological approach were conducted, and plant communities were classified through multivariate cluster analysis supported by expert validation. Five plant associations were identified, belonging to three vegetation classes: Lemnetea (Lemnetum minoris), Potamogetonetea (Zannichellietum palustris, Potamogetonetum trichoidis), and Phragmito-Magnocaricetea (Nasturtietum officinalis, Helosciadetum nodiflori). The distribution of these communities was consistent with subtle hydrological and environmental differentiation within the channel network, although measured differences in water depth were not statistically significant. The Annex I habitat 3150 (“Natural eutrophic lakes with Magnopotamion or Hydrocharition-type vegetation”) was recorded for the first time in this locality, and Potamogeton trichoides was rediscovered after several decades, highlighting the ecological relevance of these relict channel systems. The results demonstrate that artificial irrigation channels, despite their anthropogenic origin, can retain habitat types of conservation interest and function as secondary refugia for wetland vegetation within reclaimed Mediterranean landscapes. This study provides a baseline framework to support future ecological investigations, monitoring activities, and site-specific conservation strategies.