Black Alder (Alnus glutinosa) - forest stands on the lower stretch of the Danube Delta Sf. Gheorghe branch, Romania

A single small enclave of natural black alder (Alnus glutinosa) forest is known from the Danube Delta, located in the Erenciuc area of the Danube River - Sfântu Gheorghe branch. Recognized for its uniqueness, it has been designated as a protected area. In 2022, our research focused on an until now undocumented black alder forest stand near the lowest stretch of the Sf. Gheorghe branch, close to its mouth at the Black Sea. In the Danube Delta, small, protected black alder forests, like the one at Erenciuc Lake, are unique and ecologically significant. These forests have dense canopies that limit ground vegetation, but species like stiff sedge (Carex elata) and whorled milfoil (Myriophyllum verticillatum) thrive in low light and fluctuating water levels. A common liana plant in this alder forest is silkvine Periploca graeca. Black alder dominated floodplain are also found near the Danube's mouth, with reed-beds and water nut indicating slow-moving waters. These stands are rare and vital to the region's biodiversity, thriving under conditions of shallow banks, low flow velocity, and stable water levels. The alder forest stands are not only unique but also hold significant biogeographical importance for the entire Danube Delta and the Danube River as a whole. ... mehrBeyond their coenological importance in natural floodplains, black alder riparian forests, with their substantial aboveground biomass, may have significant potential as carbon sinks, helping to mitigate rising atmospheric CO₂ levels driven by recent human activities.