The frequency of high floods is one of the most important factors shaping the riverbed and influencing other aspects, such as sediment transport and deposition, vegetation establishment and growth. The aim of this study is to assess the impact of climate change on the flood regime of the Neris River (eastern part of the Baltic Sea basin) and the related changes in river islands, morphometric indicators of the riverbed, and vegetation colonization. To identify changes in the hydrological regime of the river, water level measurement data from the Buivydžiai and Jonava hydrological stations were used. To assess vegetation coverage and the presence of islands in the Neris River, orthophotos at a scale of 1:10 000 from the years 2005–2006, 2012–2013, and 2018–2020 were analyzed. Using the ArcGIS ArcMap software package, river island area and island forest coverage were calculated. The results of the study show that during the observation period (2005–2020), in the lower course of the river, the area of the islands increased, and island forest coverage grew from 7% to 18%. Between 2005 and 2020, the water level in the lower course rose above 300 cm (above the station’s zero line) only twice. The absence of high floods creates favorable conditions for plants to colonize alluvial environments. Consequently, this may lead to extreme flood events in the future, caused by a restructured river channel following a prolonged period of low flood activity.
Baltakis, V., Beconis, M., Česnulevičius, A., Dicevičienė, L., Dvareckas, V., Juozapavičius, G. et al. 1982. Neries slėnio geodinaminiai procesai (Geodynamic processes of the Neris valley). Geografijos metraštis, XX, 5–64.
Barry, R. G. 1985. The cryosphere and climate charmes. In Detecting the Climatic Effects of Increasing Carbon Dioxide (MacCracken, M. C. and Luther, M. F., eds). Department of Energy, Washington DC, 109–149.
Baubinienė, A., Satkūnas, J. and Taminskas, J. 2015. Formation of fluvial islands and its determining factors, case study of the River Neris, the Baltic Sea basin. Geomorphology, 231, 343–352.
https://doi.org/10.1016/j.geomorph.2014.12.025
Bertoldi, W., Gurnell, A., Surian, N., Tockner, K., Zanoni, L., Ziliani, L. et al. 2009. Understanding reference processes: linkages between river flows, sediment dynamics and vegetated landforms along the Tagliamento River, Italy. River Research and Applications, 25(5), 501–516.
https://doi.org/10.1002/rra.1233
Blöschl, G. 2023. Three hypotheses on changing river flood hazards. Hydrology and Earth System Sciences, 26(19), 5015–5033.
https://doi.org/10.5194/hess-26-5015-2022
Blöschl, G., Hall, J., Viglione, A., Perdigão, R. A. P., Parajka, J., Merz, B. et al. 2019. Changing climate both increases and decreases European river floods. Nature, 573, 108–111.
https://doi.org/10.1038/s41586-019-1495-6
Braudrick, C. A., Dietrich, W. E., Lieverich, G. T. and Sklar, L. S. 2009. Experimental evidence for the conditions necessary to sustain meandering in coarse-bedded rivers. Proceedings of the National Academy of Sciences, 106(40), 16936–16941.
https://doi.org/10.1073/pnas.0909417106
Bravard, J.-P. 1990. La métamorphose des rivières des Alpes françaises à la fin du Moyen-Âge et à l’époque contemporaine (The Metamorphosis of the Rivers of the French Alps in the Late Middle Ages and Contemporary Periods). Bulletin de la Société Géographique de Liège, 25, 145–157.
http://popups.ulg.ac.be/0770-7576/index.php?id=3799
Brummer, T. J., Byrom, A. E., Sullivan, J. J. and Hulme, P. E. 2016. Alien and native plant richness and abundance respond to different environmental drivers across multiple gravel floodplain ecosystems. Diversity and Distributions, 22(7), 823–835.
https://doi.org/10.1111/ddi.12448
Česnulevičius, A. and Baubinienė, A. 1997. Mažųjų Neries intakų išilginių profilių sąsaja su jų baseinų reljefo geneze (The relation of longitudinal profiles of river-beds of small Neris tributaries with the relief genesis of basins). Geografijos metraštis, 30, 170–178.
Comiti, F. 2012. How natural are Alpine mountain rivers? Evidence from the Italian Alps. Earth Surface Processes and Landforms, 37(7), 693–707. https://doi.org/10.1002/esp.2267
Fallot, J.-M., Barry, R. G. and Hoogstrate, D. 1997. Variations of mean cold season temperature, precipitation and snow depths during the last 100 years in the former Soviet Union (FSU). Hydrological Sciences Journal, 42(3), 301–327.
http://dx.doi.org/10.1080/02626669709492031
Geoportal of Lithuania.
https://www.geoportal.lt/geoportal (accessed 2023-05-12).
Gurnell, A. M. and Bertoldi, W. 2022. Extending the conceptual model of river island development to incorporate different tree species and environmental conditions. River Research and Applications, 36(8), 1730–1747.
https://doi.org/10.1002/rra.3691
Gurnell, A. M. and Petts, G. E. 2002. Island-dominated landscapes of large floodplain rivers, a European perspective. Freshwater Biology, 47(4), 581–600.
http://dx.doi.org/10.1046/j.1365-2427.2002.00923.x
Gurnell, A. M., Petts, G. E., Hannah, D. M., Smith, B. P. G., Edwards, P. J., Kollmann J. et al. 2001. Riparian vegetation and island formation along the gravel-bed Fiume Tagliamento, Italy. Earth Surface Processes and Landforms, 26(1), 31–62.
http://dx.doi.org/10.1002/1096-9837(200101)26:1%3C31::AID-ESP155%3E3.0.CO;2-Y
Gurnell, A. M., Surian, N. and Zanoni, L. 2009. Multi-thread river channels: a perspective on changing European Alpine river systems. Aquatic Sciences, 71, 253–265.
http://dx.doi.org/10.1007/s00027-009-9186-2
Gurnell, A. M., Rinaldi, M., Buijse, A. D, Brierley, G. and Piégay, H. 2015. Hydromorphological frameworks: emerging trajectories. Aquatic Sciences, 78, 135–138.
http://dx.doi.org/10.1007/s00027-015-0436-1
Gurnell, A. M., Bertoldi, W., Francis, R. A., Gurnell, J. and Mardhiah, U. 2018. Understanding processes of island development on an island braided river over timescales from days to decades. Earth Surface Processes and Landforms, 44(2), 624–640.
http://dx.doi.org/10.1002/esp.4494
Hansen, J., Ruedy, R., Sato, M. and Lo, K. 2010. Global surface temperature change. Reviews of Geophysics, 48(4), 1–29.
https://doi.org/10.1029/2010RG000345
Hickin, E. J. (ed.) 1995. River Geomorphology. Wiley, Chichester.
Hooke, J. and Chen, H. 2015. Evidence of increase in woody vegetation in a river corridor, northwest England, 1984–2007. Journal of Maps, 12(3), 484–491.
https://doi.org/10.1080/17445647.2015.1044039
Hooke, J. M. and Yorke, L. 2011. Channel bar dynamics on multi-decadal timescales in an active meandering river. Earth Surface Processes and Landforms, 36(14), 1910–1928.
http://dx.doi.org/10.1002/esp.2214
Jones, P. D. and Hulme, M. 1996. Calculating regional climate time series for temperature and precipitation: methods and illustrations. International Journal of Climatology, 16(4), 361–377.
https://doi.org/10.1002/(SICI)1097-0088(199604)16:4%3C361::AID-JOC53%3E3.0.CO;2-F
Keesstra, S. D., van Huissteden, J., Vandenberghe, J., Van Dam, O., de Gier, J. and Pleizier, I. D. 2005. Evolution of the morphology of the river Dragonja (SW Slovenia) due to land-use changes. Geomorphology, 69(1–4), 191–207.
http://dx.doi.org/10.1016/j.geomorph.2005.01.004
Knighton, D. 1998. Fluvial Forms and Processes. Routledge, London.
https://doi.org/10.4324/9780203784662
Kollmann, J., Vieli, M., Edwards, P. J., Tockner, K. and Ward J. V. 1999. Interactions between vegetation development and island formation in the Alpine river Tagliamento. Applied Vegetation Science, 2(1), 25–36.
https://doi.org/10.2307/1478878
Kondolf, G. M. 1997. Application of the pebble count notes on purpose, method, and variants. Journal of the American Water Resources Association, 33(1), 79–87.
https://doi.org/10.1111/j.1752-1688.1997.tb04084.x
Kondolf, G. M., Piégay, H. and Landon, N. 2007. Changes in the riparian zone of the lower Eygues River, France, since 1830. Landscape Ecology, 22, 367–384.
https://doi.org/10.1007/s10980-006-9033-y
https://link.springer.com/article/10.1007/s10980-006-9033-y
Liébault, F. and Piégay, H. 2002. Causes of 20th century channel narrowing in mountain and piedmont rivers of southeastern France. Earth Surface Processes and Landforms, 27(4), 425–444.
https://doi.org/10.1002/esp.328
Lobera, G., Besné, P., Vericat, D., López-Tarazón, J. A., Tena, A., Aristi, I. et al. 2015. Geomorphic status of regulated rivers in the Iberian Peninsula. Science of The Total Environment, 508, 101–114.
https://doi.org/10.1016/j.scitotenv.2014.10.058
Mangini, W., Viglione, A., Hall, J., Hundecha, Y., Ceola, S., Montanari, A. et al. 2018. Detection of trends in magnitude and frequency of flood peaks across Europe. Hydrological Sciences Journal, 63(4), 493–512.
https://doi.org/10.1080/02626667.2018.1444766
Murray, A. B. and Paola, C. 2003. Modelling the effect of vegetation on channel pattern in bedload rivers. Earth Surface Processes and Landforms, 28(2), 131–143.
https://doi.org/10.1002/esp.428
National Land Services and Vilnius University. 2014. The National Atlas of Lithuania, Vol. 1. Vilnius.
Osterkamp, W. R. 1998. Processes of fluvial island formation, with examples from Plum Creek, Colorado and Snake River, Idaho. Wetlands, 18, 530–545.
https://doi.org/10.1007/BF03161670
Picco, L., Mao, L., Rainato, R. and Lenzi, M. A. 2014. Medium‐term fluvial island evolution in a disturbed gravel‐bed river (Piave River, northeastern Italian Alps). Geografiska Annaler: Series A, Physical Geography, 96, 83–97.
https://doi.org/10.1111/geoa.12034
Picco, L., Pellegrini, G., Iroumé, A., Lenzi, M. A. and Rainato, R. 2023. The role of in-channel vegetation in driving and controlling the geomorphic changes along a gravel-bed river. Geomorphology, 437, 108803.
http://dx.doi.org/10.1016/j.geomorph.2023.108803
van Rijn, L. C. 1993. Principles of Sediment Transport in Rivers, Estuaries and Coastal Areas. Aqua Publications, Amsterdam.
Rimkus, E., Kažys, J., Junevičiūtė, J. and Stonevičius, E. 2007. Lietuvos klimato pokyčių XXI amžiuje prognozė (Climate change predictions for the 21st century in Lithuania). Geografija, 43(2), 37–47.
Rinaldi, M. 2003. Recent channel adjustments in alluvial rivers of Tuscany, central Italy. Earth Surface Processes and Landforms, 28(6), 587–608.
http://dx.doi.org/10.1002/esp.464
Robins, P. E., Skov, M. W., Lewis, M. J., Giménez, L., Davies, A. G., Malham, S. K. et al. 2016. Impact of climate change on UK estuaries: a review of past trends and potential projections. Estuarine, Coastal and Shelf Science, 169, 119–135.
https://doi.org/10.1016/j.ecss.2015.12.016
Rovira, A., Batalla, R. J. and Sala, M. 2005. Response of a river sediment budget after historical gravel mining (the lower Tordera, NE Spain). River Research and Applications, 21(7), 829–847.
http://dx.doi.org/10.1002/rra.885
Schneider, C., Laizé, C. L. R., Acreman, M. C. and Flörke, M. 2013. How will climate change modify river flow regimes in Europe? Hydrology and Earth System Sciences, 17(1), 325–339.
https://doi.org/10.5194/hess-17-325-2013
Schumm, S. A. (ed.) 1972. River Morphology. Dowden, Hutchinson & Ross, Stroudsburg.
Simon, A. and Collison, A. J. C. 2002. Quantifying the mechanical and hydrologic effects of riparian vegetation on streambank stability. Earth Surface Processes and Landforms, 27(5), 527–546.
https://doi.org/10.1002/esp.325
Surian, N. and Rinaldi, M. 2003. Morphological response to river engineering and management in alluvial channels in Italy. Geomorphology, 50(4), 307–326.
https://doi.org/10.1016/S0169-555X(02)00219-2
Surian, N., Rinaldi, M., Pellegrini, L., Audisio, C., Maraga, F., Teruggi, L. et al. 2009. Channel adjustments in northern and central Italy over the last 200 years. In Management and Restoration of Fluvial Systems with Broad Historical Changes and Human Impacts (James, L. A., Rathburn, S. L. and Whittecar, G. R., eds). The Geological Society of America, Boulder, 83–95.
http://dx.doi.org/10.1130/2009.2451(05)
Surian, N., Barban, M., Ziliani, L., Monegato, G., Bertoldi, W. and Comiti, F. 2014. Vegetation turnover in a braided river: frequency and effectiveness of floods of different magnitude. Earth Surface Processes and Landforms, 40(4), 542–558.
https://doi.org/10.1002/esp.3660
Tal, M. and Paola, C. 2010. Effects of vegetation on channel morphodynamics: results and insights from laboratory experiments. Earth Surface Processes and Landforms, 35(9), 1014–1028.
https://doi.org/10.1002/esp.1908
Termini, D. 2021. Investigation of a gravel-bed river’s pattern changes: insights from satellite images. Applied Sciences, 11(5), 2103.
http://dx.doi.org/10.3390/app11052103
Tockner, K., Ward, J. V., Arscott, D. B., Edwards, P. J., Kollmann, J., Gurnell, A. M. et al. 2003. The Tagliamento River: a model ecosystem of European importance. Aquatic Sciences, 65, 239–253.
https://doi.org/10.1007/s00027-003-0699-9
Wyrick, J. and Klingeman, P. C. 2011. Proposed fluvial island classification scheme and its use for river restoration. River Research and Applications, 27(7), 814–825.
http://dx.doi.org/10.1002/rra.1395
Wyzga, B. 1993. River response to channel regulation: case study of the Raba River, Carpathians, Poland. Earth Surface Processes and Landforms, 18(6), 541–556.
http://dx.doi.org/10.1002/esp.3290180607
Wyzga, B. 2007. A review on channel incision in the Polish Carpathian rivers during the 20th century. Developments in Earth Surface Processes, 11, 525–553.
http://dx.doi.org/10.1016/S0928-2025(07)11142-1
