Vojen Ložek’s research while affiliated with Charles University in Prague and other places

The Alps are an important hotspot of species diversity and endemism, as well as a presumed glacial refugium of several species’ groups including land snails. The recent ranges of Alpine endemics are well known, but their fluctuations during the postglacial period mirroring local climate changes are understudied. By analysing five Late Glacial and Holocene mollusc successions from two areas in the southernmost part of the Bohemian Massif (Czech Republic) situated about 100 km north of the Alps, we reveal details of these fluctuations. The Alpine endemic rocky dweller Chilostoma achates had reached the southern part of the Bohemian Massif already in the Late Glacial and disappeared in the Mid-Holocene canopy forest optimum. On the contrary, the northern boundaries of Alpine canopy forest epigeic snails extended further north than today at the turn of the Middle and Late-Holocene, pointing to a more favourable forest microclimate. The earliest known occurrences of several temperate canopy forest central European species, especially Causa holosericea and Discus perspectivus, imply the role of different areas in the Alps as their glacial refugia.

The first long-term and detailed survey of terrestrial molluscs in the Blanský les protected landscape area (southern Bohemia) is presented. The survey took place in 1994–2013 and was carried out by standard collection of litter samples and hand picking. The geo- and phytoindications were used for site selection. Mostly forest and shrubbery and open habitats were examined to cover the entire habitat diversity of the monitored area. Altogether, 81 species of terrestrial molluscs were found in 443 localities. One of the most important is the alpine forest species Aegopis verticillus, which has the last continuous occurrence north of the Alps here. It occurs only in isolated populations more northerly. Macrogastra tumida, on the other hand, is a Carpathian forest element. Bulgarica cana indicates the best-preserved forests, Clausilia cruciata, Discus ruderatus, Vertigo substriata, and Vitrea subrimata are characteristic species of mountain forests, which represent the most valuable habitats in this area. This monograph provides an overview of all recorded species with brief comments on their local distribution and ecological requirements, and a list of their localities. The maps of distribution of all founded species are presented. The history of mollusc research and landscape development of the Blanský les Mts. is presented, an occurrence of endangered species is evaluated, and the relation of the mollusc fauna of the Blanský les Mts. to the Central European area is commented.

Total organic carbon XRF XRD Stable isotopes 13 C and 18 O OSL A B S T R A C T Loess-paleosol sequences preserve information that can be used to reconstruct paleoenvironments. A dense network of reliably analyzed sequences from different geographic locations is crucial to address ecological and climatic trends, which occurred during the Pleistocene. This paper focuses on a loess-paleosol sequence in Bůhzdař, situated 9 km NW of Prague, Czech Republic. Geochemical approaches (total organic carbon, XRF elemental analyses, XRD mineralogy, 13 C and 18 O stable isotopes) are combined with grain-size distributions and optically stimulated luminescence (OSL) to assess the climatic conditions at the time of formation of the strata. The oldest loess at this location was formed circa 200 ka ago (MIS 7), making it the oldest loess in Central Bohemia for now. The Bůhzdař loess-paleosol sequence was highly affected by several erosion events, Eemian paleosols (MIS 5e) being completely missing. The partly relocated paleosols situated at the lower part of the Bůhzdař sequence represent a period of increased humidity during late MIS 7 and MIS 6. Despite the fact that the Bůhzdař profile is not particularly thick (5 m), significant changes in paleoclimate reconstructions have been detected.

We studied the transformation of a middle-to-late Holocene forested ecosystem using the highly indicative remains of land snails. The study areas were sandstone landscapes of northern Bohemia (Czech Republic) that provide extremely rich terrestrial fossil records. As far as we know, nowhere else in the world does such a type of sedimentary environment provide Holocene records of snail shells. Currently, these sandstone landscapes are covered by low productivity coniferous forests with very low species pools. In sharp contrast, in the middle Holocene, they were dominated by species-rich productive woodland communities. Such ecosystems were then supported by a favourable warm and wet climate and by nutrient-rich, calcareous substrata formed of late Pleistocene aeolian dust (loess). A radical transformation of this temporal ecological equilibrium began in the third millennium BC. Over the next millennia, the species-rich canopy forest mollusc assemblages almost completely disappeared, together with calciphilous rock dwellers. The main driving force of this transformation was gradual soil leaching that resulted in the loss of calcium carbonate and principal nutrients (like P and N) and subsequent ecosystem retrogression. Synergistically with this background trend, the unstable climatic regime of the late Holocene, along with long-term anthropogenic pressure that peaked for the first time during the late Bronze Age, accelerated the transformation.

Prehistoric settlements are usually perceived as being in opposition to the natural development of the landscape. Indeed, for woodland snail assemblages in anthropogenic landscapes in central Europe, considerable impoverishment is typical. However, it remains unclear whether this has been caused by humans only or also by climate effects. From an archaeological point of view, the Moravian Karst is one of the classic prehistorical locations in central Europe, but with a more humid climate than the previously studied anthropogenic areas. To learn more about coexistence of humans and natural forests during the Lateglacial and Holocene, we analysed 11 mollusc successions covering this entire area, a unique data set for such a relatively small area. These mollusc successions show several specific features compared to the standard development known from other mid‐European areas. One is that although the Moravian Karst is not far from the Western Carpathians, Carpathian species appeared relatively late, only during the second half of the Holocene climatic optimum. Similarly, some western European and Alpine elements appeared later than expected. In contrast to this, however, a number of forest species with central European range appeared relatively early during the Lateglacial or Early Holocene. Two even survived the Last Glacial Maximum in the Moravian Karst. This would suggest an early occurrence of forest patches in a mosaic landscape. Humans have apparently inhabited this area since the Lateglacial amongst islands of forests, which later changed during the Boreal and then the climatic optimum into humid canopy forests. Thus, a mosaic of anthropogenic and natural habitats persisting in close vicinity was possible in rugged and humid landscapes practically until the Industrial Revolution.

Although Holocene mollusc succession has been described from many temperate European sites, no attempt to analyse diversity patterns across the continent from east to west has yet been done. Here, we assembled and quantitatively analysed 54 most representative Holocene successions categorized into five climatic and geomorphological regions. These were defined along a longitudinal transect across temperate Europe, i.e. West Carpathians, Bohemian Massif, West Continental, Atlantic France, and Atlantic England. We found a clear east-west gradient in the Holocene dynamic of land snail assemblages, correlating mainly with the changes in strictly forest species richness. Representation of these species increased towards the east in accordance with known position of glacial refugia in the Carpathian Mountains. The West Carpathians acted as a unique refugium, expressing the highest temporal stability of Holocene snail assemblages, with a sharp increase in strictly forest species richness already in the Early Holocene. In contrast, Atlantic regions, characterized by low elevation and low topographical heterogeneity, were always poor in number of strictly forest species with no or only shallow increase of their richness in the Holocene climatic optimum. Further reduction in the second half of the Holocene, along with the increase of strictly open-country species richness correlates with higher human impact on mollusc faunas in lowland and flat regions. These factors can explain the previously reported impoverishment of modern western European forest fauna and have apparently also contributed to regional diversity patterns throughout the Holocene. Among the regions, we found three types of successional trajectories in the composition changes of Holocene molluscs, mirroring the above mentioned east-west gradient, with the West Carpathians having the most distinctive fauna. Our results show that distance from glacial refugia, landscape topography, and also human impact importantly shaped the species richness dynamic and successional pathways of Holocene land-snail fauna across temperate Europe.

History of research at an important Paleolithic site of central Europe. Excavation at sub-site Předmostí II in 1989-1992. Discovery of Middle Paleolithic layers below the Gravettian. Chronological and environmental contexts.