Prehliadanie podľa Autor "Svitok, Marek"
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Položka Diversity and distribution of chironomids in Central European ponds(John Wiley & Sons : New York, 2024) Sedlačková Přidalová, Marcela; Hamerlík, Ladislav; Novikmec, Milan; Slobodníková, Veronika; Veselská, Marta; Bitušík, Peter; Svitok, MarekPonds are common freshwater habitats in the European landscape that substantially contribute to local and regional biodiversity. Chironomids often dominate invertebrate communities in ponds but are usually disregarded in ecological studies due to relatively complicated taxonomy and identification issues. We present a comprehensive overview of the chironomid diversity in 246 ponds spanning a wide range of conditions extending from the Pannonian Plain to the Carpathians. Altogether, we recorded 225 taxa including 192 species from six subfamilies (Podonominae, Tanypodinae, Diamesinae, Prodiamesinae, Orthocladiinae and Chironominae). However, the chironomid taxa inventory is far from complete and about 16% of the total diversity of pond-dwelling chironomids remains undetected. Chironomid alpha diversity showed a significant unimodal pattern along the elevation gradient with the highest number of taxa per pond expected around 790 m a.s.l. Gamma diversity also peaked in mid-elevations (600–800 m), and the common chironomid taxa partitioned the 2100-m long altitudinal gradient relatively evenly. The heterogeneity of chironomid communities among ponds measured as beta diversity was significantly higher in elevations below 800 m. Temperature and the proportion of surrounding forests significantly influenced alpha diversity of chironomid communities, while urban land cover and pond size had no significant effect. Ponds with a mean annual air temperature of approximately 4.8°C and a low proportion of surrounding forests are expected to harbour the most diverse chironomid communities. Our study showed that chironomids represent a very diverse and often exceptionally rich group of pond-dwelling macroinvertebrates. Given the high diversity and broad range of occupied niches, chironomids should not be overlooked in pond ecology studies. On the contrary, they should be considered a potential model group.Položka New faunistic records of chironomids and phantom midges (Diptera, Chironomidae and Chaoboridae) from Ukraine indicate recent climatic refugia in the Eastern Carpathians(Pensoft Publishers : Sofia, 2024) Bitušík, Peter; Novikmec, Milan; Svitok, Marek; Hamerlík, LadislavThe aquatic insect fauna of the Eastern Carpathians is poorly known, especially in Ukraine. To address this knowledge gap, we conducted faunistic surveys of Chironomidae and Chaoboridae in 2018 and 2021. The study involved sampling of 11 watercourses and 10 mountain lakes situated in the Ukrainian part of the Eastern Carpathians. A total of 101 taxa were identified, including 40 chironomid species and one genus that have been recorded for the first time from Ukraine. The occurrence of one species previously considered as “doubtfully present” in Ukraine was confirmed by this study. One of the two identified phantom midge species, Chaoborus (s. str.) obscuripes (van der Wulp, 1859), is recorded for the first time from Ukraine. The most intriguing records are chironomid species Cricotopus (s. str.) beckeri Hirvenoja, 1973, Eukiefferiella bedmari Vilchez-Quero & Laville, 1987, and Pseudorthocladius (s. str.) berthelemyi Moubayed, 1990. These species have Mediterranean distribution and their occurrence in the Eastern Carpathians could be remains of once-widespread populations that currently survive in the Carpathian refugia due to adverse climatic conditions in the former distribution area. The high number of first records from a relatively small number of sites indicates a great gap in the knowledge of the Ukrainian chironomid fauna.Položka Topographically shaded lakes may provide refugia for cold-adapted aquatic fauna threatened by climate change(Springer : Dordrecht, 2025) Novikmec, Milan; Bitušík, Peter; Kopáček, Jiří; Svitok, MarekUnderstanding the structure and diversity of high-altitude lake communities and the patterns of their altitudinal changes is important for predicting their response to ongoing climate change. We analysed littoral benthic communities of 18 mountain lakes of glacial origin distributed along a 500-m altitudinal gradient and characterized by differing topographic shading levels: unshaded lakes and shaded lakes with a substantially lower (by 1151 h) mean annual duration of direct solar radiation. We hypothesized that local topographic shading modifies diversity–altitude relationships and affects the pattern of community turnover along the altitudinal gradient. We found a decreasing trend in diversity with increasing altitude and a significant deviation from that pattern in shaded lakes. Investigated lake groups supported distinct communities in lower altitudes. However, their community composition converged towards higher altitudes in communities typical for a greater abundance of cold stenotherms. The proportion of cold-stenothermal species increased with increasing altitude in shaded lakes and was notably greater than that in unshaded lakes along the studied altitudinal gradient. The lower temperatures of shaded lakes and different temperature variabilities of the two groups of lakes likely explain the observed patterns. We hypothesize that topographically shaded lakes may provide refugia for cold-stenothermal communities threatened by ongoing global warming.Položka Unravelling some factors affecting sexual reproduction in rock-specialist shrub: Insight from an endemic Daphne arbuscula (Thymelaeaceae)(Public Library of Science : San Francisco, 2024) Gajdošová, Zuzana; Šlenker, Marek; Svitok, Marek; Šrámková, Gabriela; Blanár, Drahoš; Cetlová, Veronika; Kučera, Jaromír; Turisová, Ingrid; Turis, Peter; Slovák, MarekThe role of endemic species in global biodiversity is pivotal, and understanding their biology and ecology is imperative for their fitness and long-term survival, particularly in the face of ongoing climatic oscillations. Our primary goal was to investigate the sexual reproduction level of the endangered Western Carpathian endemic Daphne arbuscula (Thymelaeaceae), which inhabits extreme rocky habitats, and to comprehend the influence of specific factors on its reproductive success. We conducted the research across four populations, varying in size and environmental conditions. Over two years, we monitored flower and fruit production, analyzed genetic variability within and among populations, and studied pollination mechanisms. Daphne arbuscula proved to be strictly self-incompatible, with significant variations in flower and fruit production among populations and seasons. The average fruit production percentage consistently remained below 50% across populations, indicating challenges in sexual reproduction. Cold and harsh weather during the reproductive phase had a substantial negative impact on sexual reproduction efficacy, leading to decreased fruit production. Nevertheless, several individuals in sheltered microhabitats displayed significantly higher fruit production, ranging from 60% to 83%, emphasizing the critical role of microhabitat heterogeneity in sustaining sexual reproduction in this species. We found no pronounced differences in genetic diversity within or among populations, suggesting that genetic factors may not critically influence the reproductive success of this endemic species. The implications of our findings might be of paramount importance for the long-term survival of D. arbuscula and offer valuable insights for the development of effective conservation strategies for this species.