Vegetation, hydrological, and morphological dynamics of natural islands in the Danube Delta

Simona Dumitrița Chirilă; Alexandru Bănescu; Cristian Trifanov; Mihai Doroftei; Silviu Covaliov

doi:10.3986/hacq-2025-0019

Authors

Simona Dumitrița Chirilă Danube Delta National Institute for Research and Development https://orcid.org/0000-0003-3397-1834
Alexandru Bănescu Danube Delta National Institute for Research and Development https://orcid.org/0000-0001-5868-671X
Cristian Trifanov Danube Delta National Institute for Research and Development https://orcid.org/0000-0002-6373-6977
Mihai Doroftei Danube Delta National Institute for Research and Development https://orcid.org/0000-0002-8388-087X
Silviu Covaliov Danube Delta National Institute for Research and Development https://orcid.org/0000-0002-0412-4102

DOI:

https://doi.org/10.3986/hacq-2025-0019

Keywords:

Danube Delta, Island, hydrological dynamics, riparian vegetation, wetlands

Abstract

The Danube Delta is a unique ecosystem located in southeastern Romania. Within this ecosystem, hydrological and morphological dynamics have an important role in maintaining biodiversity. The study aimed to analyze the vegetation, hydrological factors, and morphological dynamics of seven islands in the Danube Delta. The study was carried out during 2023–2024 at Isaccea (three islands), Dunavăț (three islands) and Dranov (one island) in all four seasons. Phytocoenological relevés were carried out for the vegetation analysis, and the SonTek RiverSurveyor M9 equipment was used for the hydrological analysis. The analysis of island dynamics was carried out through morphometric methods, using ANCPI orthophotos (2004 and 2021) and Landsat satellite images (2010). In the seven islands, six associations from the Artemisietea vulgaris, Lemnetea, Phragmito-Magnocaricetea, and Salicetea purpureae classes were found. The hydrological analysis indicated seasonal fluctuations in water level, flow, and velocity, with significant increases in the autumn and winter, especially at Isaccea. The hydrological regime has an important role in the morphodynamic modelling of the Danube Delta islands, indicating the river's ability to induce rapid transformations through sedimentation and erosion processes. The morphodynamic analysis of the islands indicated a complex interaction of erosion and accumulation. The island's location influences this interaction, the river flow dynamics and human interventions such as the rectification of meanders.

Downloads

Download data is not yet available.

References

Avramidou, E. V., Korakaki, E., Malliarou, E., Solomou, A. D., Mantakas, G., & Karetsos, G. (2023). First report and genetic analysis of the invasive species A. fruticosa L. in Greece: a combined genetic and regeneration study. Ecologies, 4(3), 627–635. https://doi.org/10.3390/ecologies4030041

Bănescu, A., Arseni, M., Georgescu, L. P., Rusu, E., & Iticescu, C. (2020). Evaluation of different simulation methods for analyzing flood scenarios in the Danube Delta. Applied Sciences, 10(23), 8327. https://doi.org/10.3390/app10238327

Bondar, C. (1992). Hidrologia Deltei Dunării. Editura Academiei Române.

Bondar, C., State, I., Cernea, D., Harabagiu, E. (1992). Scurgerea de apa si aluviuni a Dunarii la gurile bratelor Deltei Dunarii in anii 1858-1988. Studii de Hidraulica, București, Vol. XXXIII, 119–129 pp.

Bouxin, G. (2005). Ginkgo, a multivariate analysis package. Journal of Vegetation Science, 16, 355–359. https://doi.org/10.1111/j.1654-1103.2005.tb02374.x

Braun-Blanquet, J. (1964). Pflanzensoziologie. Grundzüge der Vegetationskunde. Springer, Wien.

Catianis, I., Pojar, I., Scrieciu, A., Grosu, D., & Pavel, A. B. (2016). A preliminary assessment of the physical-chemical features of water and sediments from different deltaic aquatic systems. Case study: Fortuna lake, Matita lake and Musura bay Danube Delta, Romania. https://doi.org/10.21698/simi.2016.0047

Chifu, T., Irimia I. (2014). Diversitatea fitosociologică a vegetaţiei României. III. Vegetația pădurilor și tufișurilor. Institutul European.

Chifu, T., Irimia I., Zamfirescu O. (2014a). Diversitatea fitosociologică a vegetaţiei României. II. Vegetația erbacee antropizată. A. Vegetația pajiștilor. Institutul European.

Chifu, T., Irimia I., Zamfirescu O. (2014b). Diversitatea fitosociologică a vegetaţiei României. I. Vegetația erbacee naturală. Institutul European.

Church, M., & Ferguson, R. (2015). Morphodynamics: Rivers beyond steady state. Water Resources Research, 51(4), 1883–1897, https://doi.org/10.1002/2014wr016862

Chytrý, M., Tichý, L., Hennekens, S.M., …. & Schaminée J.H.J. (2020). EUNIS Habitat Classification: expert system, characteristic species combinations and distribution maps of European habitats. Applied Vegetation Science, 23, 648–675. https://doi.org/10.1111/avsc.12519

Chytrý, M., Tichý, L., Holt, J., Botta‐Dukát, Z. (2002). Determination of diagnostic species with statistical fidelity measures. Journal of Vegetation Science, 13(1), 79–90. https://doi.org/10.1111/j.1654-1103.2002.tb02025.x

Claudino-Sales, V. (2019). Danube Delta, Romania. In: Coastal World Heritage Sites. Coastal Research Library, vol 28. Springer, Dordrecht.

Covaliov, S., Doroftei, M., Chirilă, S.D., & Hanganu J. (2023). Stufărișurile din Delta Dunării. Ghidul de bune practici în managementul stufărișurilor. Centrul de Informare Tehnologică Delta Dunării, Tulcea. https://doi.org/10.5281/zenodo.10570838

Crețescu, I., Kovacs, Z., Lazar, L., Burada, A., Sbarcea, M., Teodorof, L., ... & Soreanu, G. (2021). Danube Delta: Water Management on the Sulina Channel in the frame of environmental sustainability. In River Deltas Research-Recent Advances. IntechOpen. https://doi.org/10.5772/intechopen.97877

Cristea, V., Gafta D., & Pedrotti, F. (2004). Fitosociologie. Presa Universitară Clujeană.

Day Jr, J. W., Boesch, D.F., Clairain, E.J., Kemp, G.P., Laska, S. B., Mitsch, W.J., ... & Whigham, D.F. (2007). Restoration of the Mississippi Delta: lessons from hurricanes Katrina and Rita. science, 315(5819), 1679-1684.

Dijk, W., Teske, R., Lageweg, W., & Kleinhans, M. (2013). Effects of vegetation distribution on experimental river channel dynamics. Water Resources Research, 49(11), 7558–7574. https://doi.org/10.1002/2013wr013574

Euro+Med (2024). Euro+Med PlantBase – the information resource for Euro-Mediterranean plant diversity. Data from: http://ww2.bgbm.org/EuroPlusMed. [accessed 2024 October 20].

Frihy, O.E. (2003). The Nile delta-Alexandria coast: vulnerability to sea-level rise, consequences and adaptation. Mitigation and Adaptation Strategies for Global Change, 8, 115-138.

Gâştescu, P., & Ştiucă, R. (2006). Delta Dunării - Rezervație a biosferei. Editura Dobrogea.

Gómez-Baggethun, E., Tudor, M., Doroftei, M., Covaliov, S., Năstase, A., Onără, D.F., Mierlă, M., Marinov, M., Doroșencu, A.C., Lupu, G., Teodorof, L., Tudor, I.M., Köhler, B., Museth, J., Aronsen, E., Johnsen, S.I., Ibram, O., Marin, E., Crăciun, A., Cioacă, E. (2019). Changes in ecosystem services from wetland loss and restoration: An ecosystem assessment of the Danube Delta (1960–2010). Ecosystem Services, 39. https://doi.org/10.1016/j.ecoser.2019.100965

Gordon, N.D., McMahon, T.A., & Finlayson, B.L. (2004). Stream hydrology: an introduction for ecologists. John Wiley & Sons.

Gudžinskas, Z., & Žalneravičius, E. (2015). Notes on alien plant species Amorpha fruticosa new to Lithuania. Botanica Lithuanica (1392-1665), 21(2). https://doi.org/10.1515/botlit-2015-0020

Hanganu, J., Constantinescu, A., Doroftei, M., & Tošić, K. (2017). Investigation of the effects of multiple pressures in the lower danube basin. Water and Environment Journal, 32(2), 217–228. https://doi.org/10.1111/wej.12317

Heath, M.F., & Evans, M.I. (2000). Important Bird Areas in Europe: Priority sites for conservation. 2 vols. Cambridge, UK: BirdLife International (BirdLife Conservation Series No. 8).

Hrynkiewicz, K., Szymańska, S., Piernik, A., & Thiem, D. (2015). Ectomycorrhizal community structure of Salix and Betula spp. at a saline site in central Poland in relation to the seasons and soil parameters. Water, Air, & Soil Pollution, 226, 1–15. https://doi.org/10.1007/s11270-015-2308-7

Hwang, T., Band, L., Vose, J., & Tague, C. (2012). Ecosystem processes at the watershed scale: hydrologic vegetation gradient as an indicator for lateral hydrologic connectivity of headwater catchments. Water Resources Research, 48(6), W06514. https://doi.org/10.1029/2011wr011301

James, C., Mackay, S., Arthington, A., Capon, S., Barnes, A., & Pearson, B. (2016). Does stream flow structure woody riparian vegetation in subtropical catchments? Ecology and Evolution, 6(16), 5950–5963. https://doi.org/10.1002/ece3.2249

Jencso, K., & McGlynn, B. (2011). Hierarchical controls on runoff generation: topographically driven hydrologic connectivity, geology, and vegetation. Water Resources Research, 47(11), W11527. https://doi.org/10.1029/2011wr010666

Knighton, D. (1998). Fluvial forms and processes. Arnold.

Le, T.V.H., Nguyen, H.N., Wolanski, E., Tran, T.C., & Haruyama, S. (2007). The combined impact on the flooding in Vietnam's Mekong River delta of local man-made structures, sea level rise, and dams upstream in the river catchment. Estuarine, Coastal and Shelf Science, 71(1-2), 110-116.

Leopold, L.B., & Maddock, T. (1953). The hydraulic geometry of stream channels and some physiographic implications. U.S. Geological Survey Professional Paper 252.

Leopold, L.B., & Wolman, M.G. (1957). River channel patterns: braided, meandering, and straight. U.S. Geological Survey Professional Paper 282-B.

Mucina, L., Bültmann, H., Dierßen, K. ... Tichý, L. (2016). Vegetation of Europe: hierarchical floristic classification system of vascular plant, bryophyte, lichen and algal communities. Applied Vegetation Science, 19, 3–264. https://doi.org/10.1111/avsc.12257

Nagy, J., Kiss, T., Fehérváry, I., & Vaszkó, C. (2018). Changes in floodplain vegetation density and the impact of invasive Amorpha fruticosa on flood conveyance. Journal of Environmental Geography, 11(3-4), 3–12. https://doi.org/10.2478/jengeo-2018-0008

Panin, N. (1996). Danube Delta: geology and sedimentology. Geo-Eco-Marina, 1, 5–21.

Pekarova, P., Gorbachova, L., Mitkova, V. B., Pekar, J., & Miklanek, P. (2019). Statistical analysis of hydrological regime of the Danube River at Ceatal Izmail Station. In IOP Conference Series: Earth and Environmental Science, 221(1), 012035. IOP Publishing.

R Core Team (2024). R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria. <https://www.R-project.org/>.

Romanescu, G. (2014). The catchment area of the Milesian colony of Histria, within the Razim‐Sinoie lagoon complex (Romania): hydrogeomorphologic, economic and geopolitical implications. Area, 46(3), 320–327.

Rousseeuw, P.J. (1987). Silhouettes: a graphical aid to the interpretation and validation of cluster analysis. Computational and Applied Mathematics, 20, 53–65. https://doi.org/10.1016/0377-0427(87)90125-7

Rusu, M., Cara, I. G., Filip, M., Țopa, D., & Jităreanu, G. (2024b). Comparative analysis of digestion methods for quantifying heavy metals in plum orchards. Journal of Applied Life Sciences and Environment, 57(4): 701–721. https://doi.org/10.46909/alse-574159

Rusu, M., Cara, I. G., Stoica, F., Țopa, D., & Jităreanu, G. (2024a). Quality parameters of plum orchard subjected to conventional and ecological management systems in temperate production area. Horticulturae, 10(9), 907. https://doi.org/10.3390/horticulturae10090907

Rusu, M., Filip, M., Cara, I. G., Țopa, D., & Jităreanu, G. (2025). Soil nutrient dynamics and farming sustainability under different plum orchard management practices in the pedoclimatical conditions of Moldavian Plateau. Agriculture, 15(5), 509. https://doi.org/10.3390/agriculture15050509

Schneider, E. (2011). The Danube Delta - Biodiversity and Management. Danube Delta National Institute for Research and Development.

Sitzia, T., Barcaccia, G., & Lucchin, M. (2018). Genetic diversity and stand structure of neighboring white willow (Salix alba L.) populations along fragmented riparian corridors: A case study. Silvae Genetica, 67(1), 79–88. https://doi.org/10.2478/sg-2018-0011

Sočuvka, V., Okhravi, S., Velísková, Y., Schügerl, R., & Dulovičová, R. (2024). Evaluation of the Effect of Aquatic Vegetation on the Accuracy of ADCP Discharge Measurements in Lowland Streams. Proceedings CAUSummit, 184, 0189.

Temmerman, S., Meire, P., Bouma, T. J., Herman, P. M., Ysebaert, T., & De Vriend, H. J. (2013). Ecosystem-based coastal defence in the face of global change. Nature, 504(7478), 79-83.

Tichý, L. (2002). JUICE, software for vegetation classification. Journal of Vegetation Science, 13, 451–453. https://doi.org/10.1111/j.1654-1103.2002.tb02069.x

Tichý, L., Chytrý, M. (2006). Statistical determination of diagnostic species for site groups of unequal size. Journal of Vegetation Science, 17(6), 809–818. https://doi.org/10.1111/j.1654-1103.2006.tb02504.x

Tockner, K., & Stanford, J.A. (2002). Riverine flood plains: present state and future trends. Environmental conservation, 29(3), 308–330. https://doi.org/10.1017/S037689290200022X

Trifanov, C., Mihu-Pintilie, A., & Mierlă, M. (2019). Alteration of the morpho-hydrological conditions of the aquatic complexes adjacent to the Sf. Gheorghe branch (Danube Delta) as a result of the hydrotechnical works. Acta Geobalcanica, 5(2), 93-101. https://doi.org/10.18509/AGB.2019.11

Wickham, H. (2016). ggplot2: Elegant Graphics for Data Analysis. Springer.

Zhang, H.L., Sun, L.N., Tang, J.X., & Sun, T.H. (2013). Ecological protection techniques of riverbank in liaohe River, Northeast China. Advanced Materials Research, 726, 4053–4056. https://doi.org/10.4028/www.scientific.net/AMR.726-731.4053

Zhu, X., Yuan, G., Yi, X., & Du, T. (2017). Quantifying the impacts of river hydrology on riparian vegetation spatial structure: case study in the lower basin of the Tarim river, China. Ecohydrology, 10(7), e1887. https://doi.org/10.1002/eco.1887