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Abstract. Dragonfly exuviae were collected between 2010 and 2013 in the following sections of River Tisza: Vilok (Вилок, Tiszaújlak), Nove Szelo (Нове Cело, Tiszaújhely), Tiszobikeny (Тисабікень, Tiszabökény), Vinohragyiv (Виноградiв, Nagyszőlős) and Huszt (Хуст, Huszt). Based on the examination of the 1965 exuviae, collected from 13 main channel sections, 6 dragonfly species were identified [Gomphus vulgatissimus (Linnaeus, 1758), Gomphus flavipes (Charpentier, 1825), Onychogomphus forcipatus (Linnaeus, 1758), Ophiogomphus cecilia (Fourcroy, 1785), Calopteryx splendens (Harris, 1782), Platycnemis pennipes (Pallas, 1771)]. Summing up the collected exuviae, the two most frequent species were G. vulgatissimus (57.3%) and O. forcipatus (39.08%), however significant assemblages of O. cecilia (1.93%), G. flavipes (1.17%), C. splendens (0.36%) and P. pennipes (0.15%) could be found as well. In compliance with the Mantel test the channel and riverbank characteristics show a significant correlation with the composition of dragonfly assemblages (R=0.309, p=0 024). According to the canonical correspondence analysis (15 habitat characteristics) the exuviae data of G. vulgatissimus are connected with the extent of plant coverage, the closure of foliage and the characteristics of riverbanks; the exuviae data of O. forcipatus are associated with water depth, channel deepening tendency, water temperature and type of plant coverage on the river bank.

In the section above Tiszaújlak, despite the presence of embankments, the River Tisza shows active meandering tendency and it splits into branches resulting in side channels, dead channels and backwaters that follow the main channel. In our work we examined the right-and the left-side riverbank sections of the River Tisza, between Tiszaújlak (Вилок) and Tiszasásvár (Тросник), as well as between Tiszaújlak and Tiszapéterfalva (Пийтерфолво), to reveal the extent of bar depositions between 2006 and 2015, and to what extent the intensity and direction of the riverbank formation processes were influenced by the material of the bank and the plant coverage, its rate and characteristics. We tried to reveal which sections were eroded by the river and what security risks they have for the safety of the settlements along the Tisza River. On the right side of the Tisza River riverbank 51, and on the left side 62 main measuring points were recorded by GPS positioning satellite in 2009, 2010 and 2015. Our results were compared to the satellite images of Google Earth taken in 2006, too. According to our experience, in several bends of the examined sections of the river, active bar deposition can be observed; in some cases more than 100 m of bar depositions were detected.

We studied dragonfly assemblages in the Ukrainian section of the River Tisza, which still shows several natural (unregulated) properties. In 2010 and 2011 larvae and exuviae were collected in the vicinity of the villages Vilok (Вилок, Tiszaújlak), Nove Szelo (Нове Cело, Tiszaújhely), Tiszobikeny (Тисабикень, Tiszabökény) and of the towns Vinohragyiv (Виноградiв, Nagyszőlős) and Huszt (Хуст, Huszt). We collected our samples from 8 sites in the main channel, 2 sites in side channels and 3 sites in two dead channels. We collected 255 larvae and 1587 exuviae, from which 8 species of dragonflies were identified [Gomphus vulgatissimus (Linnaeus, 1758), Stylurus flavipes (Charpentier, 1825), Onychogomphus forcipatus (Linnaeus, 1758), Ophiogomphus cecilia (Fourcroy, 1785), Somatochlora metallica (van der Linden, 1825), Calopteryx splendens (Harris, 1782), Platycnemis pennipes (Pallas, 1771), and Sympecma fusca (van der Linden, 1820)]. We compared the species composition of dragonflies in the three habitats. In the case of larvae in the main channel G. vulgatissimus (48.0%), C. splendens (29.6%) and O. forcipatus (20.8%) dominated, while in the dead channels C. splendens (49.5%) and P. pennipes (23.7%) were found most frequently. In the side channels G. vulgatissimus, O. forcipatus and C. splendens were the most frequent species. S. flavipes appeared only in the main and side channels, while S. metallica and S. fusca were only detected in the dead channels.

Between 2019 and 2022, we studied the avifauna and environmental conditions of two wet-land habitats located in close proximity to each other in Transcarpathia (nearby to the village of Dyida, Zakarpatska Oblast, Ukraine)—one being a natural, currently protected but drying and highly degraded former bog (Tóvár Ornithological Reserve), whereas the other one being an ar-tificial pit lake (Lake Dyida). Lake Dyida is used as a beach and recreation area during the summer nesting season of birds. Both of these wetlands border with agricultural lands. Bird species that occur in both of the investigated habitats are affected by severe anthropogenic disturbances. A total of 27 795 individuals of 58 bird species from 34 families were observed in the two areas over the four study years. Results indicate that the species composition of the two study sites differed considerably, both on annual and seasonal basis. Seasonal precipitation totals strongly influence the current spatial ratios of terrestrial and waterbird species, and show a strong positive correlation with the seasonal total number of bird species. Maximum numbers of birds are recorded in spring and summer at Tóvár and in autumn and winter at Lake Dyida. In the case of Lake Dyida, these could partly be due to the autumn–winter appearance of migratory waterbirds and the end of the beach season. Despite the impact of numerous anthro-pogenic factors and habitat distrubances, the natural wetland is much more species-rich even in its degraded condition than the artificial wetland, which has been confirmed not only for bird species but also for plant species in the two areas. The obtained results revealed that duck spe-cies consider the deep-water pit lake as an alternative habitat during periods of drought, but for waders the great water depth makes this site less exploitable. In Europe, too, drying out due to seasonal precipitation shortages is an issue of increasing concern, especially for wetlands bea-cuse artificially maintained lakes and reservoirs cannot fully take over the role of natural lakes, marshes and bogs, which will have severe consequences for nature protection and species con-servation in the future.