This paper presents the 2024 research results from the Danube Delta Biosphere Reserve (DDBR), including reed bed mapping and typology for fire management, assessment of sustainable use of vegetal resources, conservation status of invertebrates, fish, reptiles, amphibians, colonial waterbirds, and mammals of Community interest, evaluation of species invasiveness under climate change, and studies on human well-being and ecotourism within a sustainable development framework.

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.

This paper presents the 2024 research results from the Danube Delta Biosphere Reserve (DDBR), including reed bed mapping and typology for fire management, assessment of sustainable vegetal resource use, conservation status of invertebrates, fish, reptiles, amphibians, colonial waterbirds, and mammals of Community interest, evaluation of species invasiveness under climate change, and studies on human well-being and ecotourism within a sustainable development framework.