Initial stages of formation of floodplain forests of the bottom of the Kakhovка reservoir and forecast of their development

After the destruction of the Kakhovka Reservoir Dam on June 6, 2023, four trips were made (June 30 and October 19, 2023, April 25 and October 20, 2024), during which the initial stages of floodplain willowpoplar forests were studied. These forests occupied about 30% of the drained reservoir bottom. Investigations of the drained bottom of the Kakhovka Reservoir in 2024 showed rapid growth of Salix×rubens, and in 2024, Populus alba and P. nigra. It was established that the average number of willow shoots after three weeks was about 90 pcs/m2; at the end of the 2023 season it was 23 pcs/m2, in 2024 – 10.3 pcs/m2, and the average height increased from 190 to 350 cm. The phytomass ratio of trunks, branches, leaves and roots in the first year of development was 0.45:0.16:0.18:0.2. The calculated indicators of the increase in phytomass of trees after 10, 20, and 50 years show, that their energy reserves of biomass, costs for transpiration, photosynthesis, respiration, support of trophic chains, and waste, which characterize functional (supporting and regulating) ecosystem services, are, in monetary equivalent, 825, 1338, and 1523 c.u., respectively, with a forest area of 30% of the reservoir bottom. Based on the calculations, it was established that the natural state of floodplain forest ecosystems will form after 20 years. The ecological role of floodplain poplarwillow biotopes, which are included in Resolution No. 4 of the Bern Convention as G1.11 Riverine Salix woodland and are represented by the groups of the cl. Salicetea purpureae Moor 1958, all. Salicion albae Soȯ 1951 (Mucina et al. 2016) as. Salicetum albae Issler 1926, Myosotido palustris-Salicetum albae Shevchyk et Solomakha 1996, Salici-Populetum (Tx.1931) Meijer-Drees 1936, is highlighted. Floodplain forests of the gallery type have high water-regulating, soil-forming, and remedial value. They provide habitats for numerous avifaunal and entomofaunal species, which are protected at the European level. Floodplain forests in Ukraine occupy only 0.1% of the total forest area. The expediency of restoring the Kakhovka Reservoir is questioned, calling for a balanced decision that considers the economic importance alongside the ecological, historical, and cultural value of the territory.