Assessing the Distribution of Seagrass and Halophytic Habitats in the Nin Coastal Lagoon, Croatian Adriatic Sea, to Support Future Monitoring and Management

The coastal wetland in the Nin Lagoon, Croatia, represents a valuable and ecologically sensitive transitional ecosystem between land and sea. The aim of this study was to determine the presence and distribution of halophytic communities and seagrasses and to create a detailed vegetation habitat distribution map of the study area. Field research was conducted through visual census, photographic documentation, GPS mapping of vegetation, and the use of an unmanned aerial vehicle (DJI Mavic Air 2; SZ DJI Technology Co., Ltd., Shenzhen, China) to generate high-resolution orthophoto imagery. Spatial data were processed in GIS to identify habitat types, calculate polygon areas, and perform descriptive statistical analyses. Three halophytic habitat types were identified: glasswort and saltwort saltmarshes, Mediterranean tall rush communities, and reed and cattail beds. The confirmed seagrass were Cymodocea nodosa and Ruppia sp. The finding of Ruppia sp. is particularly significant, as this species was not previously recorded in the national map of coastal and benthic marine habitats. The two seagrass species mostly occurred in mixed stands, with some isolated populations. A total of 17.12 ha of saltmarsh area was mapped, including 11.89 ha of halophytic habitats and 5.23 ha of seagrass communities. These results confirm the ecological importance of the studied wetland and provide essential spatial data for future monitoring, conservation, and sustainable management of this sensitive coastal ecosystem.