Urbanization reduces biodiversity and affects plant–insect interactions, creating a need for more functional green spaces. Urban meadows with native species are a promising option, but their use is still limited due to a variety of reasons concerning the utilization framework of suitable plant species. The present study aimed to develop seed germination protocols for 26 native Mediterranean herbaceous species originating from northeastern Greece selected to support the establishment of species-rich and self-sustaining urban meadows. To the above end, seed germination experiments were conducted ex situ under controlled environment conditions using seeds collected from the wild for each species. Seed viability was assessed using the tetrazolium (TTZ) test to determine the maximum germination potential in each case. Freshly collected seeds were stored under ambient conditions for approximately 3 months (after-ripening) prior to germination testing, which was followed by cold stratification as a pretreatment for dormancy release. The results showed high embryo viability in all species and indicated that most taxa exhibited either no dormancy or relatively shallow physiological dormancy. Germination tests revealed that 14 of the 26 species presented high germination percentages in the control treatment, which suggests that after-ripening contributed to dormancy release in a significant portion of the seed lot. However, it remains unclear whether freshly collected seeds require an initial after-ripening period before responding to cold stratification. Furthermore, cold stratification significantly enhanced germination in 12 species confirming its effectiveness as a simple and practical method for dormancy release. In addition to the seed germination results, the selected species present a wide range of functional and esthetic characteristics, including variation in plant height, flowering phenology and flower and leaf color. These traits are important for both ecological performance and visual quality in urban environments. The combination of extended flowering periods and color diversity suggests the potential for continuous floral resource availability, which can support diverse pollinator communities and, indirectly, urban fauna such as insectivorous birds. The results indicate that the studied species are suitable for biodiversity-oriented urban plantings. Their relatively shallow dormancy and ease of propagation, coupled with their functional and aesthetic traits, support their use in the development of resilient and self-sustaining urban meadows.

Deltas are highly susceptible to biological invasions because of strong hydrological connectivity, frequent disturbance, and intense human use. Here, we synthesise coordinated monitoring observations and literature evidence on invasive alien plant species (IAS) recorded in four Black Sea riparian protected areas located across five countries, surveyed under the IASON/IASON+ initiatives (Danube Delta, Nestos Delta and Lake Vistonida, Kızılırmak Delta, Chorokhi Delta and Kolkheti National Park). Across the study sites, 17 IAS were documented, mainly represented by taxa native to North America and characterised by high propagule production and/or strong vegetative regeneration. Woody riparian invaders (e.g., Amorpha fruticosa, Robinia pseudoacacia, Acer negundo, Gleditsia triacanthos and Ailanthus altissima) exploited nutrient-rich floodplain soils and disturbances. In contrast, annual weeds (e.g., Ambrosia artemisiifolia, Sicyos angulatus and Xanthium orientale) remained associated with disturbed habitat edges. Aquatic dominance was confined to the Danube Delta, where Elodea nuttallii and Elodea canadensis formed dense submerged stands. Species were assigned to broad range expansion categories (slowly, moderately and rapidly spreading species) based on project observations and supporting records. We discuss shared invasion syndromes linked to reproductive and dispersal traits and outline management implications for Black Sea deltas, emphasising pathway prevention, early detection and rapid response for localised taxa, and sustained control combined with restoration for dominant invaders.