**Acknowledgements**

(MIS 5), when this taxon expanded to almost all areas of Central Europe, including the Czech Basin [107], the Vienna Basin [108], as well as the Alps and the Carpathian Mts to a height of ca. 1000 m ASL [25, 26, 109]. All these indicate the expansion of temperate forest steppes to the foothill areas and the lower highlands during the drier periods of the last interglacial characterized by higher temperatures as well. After 60 ka, marking the onset of the last glacial, there is a gradual retreat in the distribution of *Granaria frumentum* to scattered habitats characterized by favorable microclimatic conditions. There is another major expansion of the referred taxon which can be dated between 40 and 30 ka. The highest dominances are recorded in the southern parts of the GHP with gradually decreasing northward trends. There is a major retreat between 30 and 24 ka to scattered refugia found in the southern part of the Carpathian Basin again, which hallmarked the start of the coldest phase of the last glacial. According to the findings of comprehensive studies done using our own mollusk data compiled into a database (Hungarian Quartermalacological Database), the southern part of the GHP, including the area of Vojvodina, Serbia, as well, was a transitional fluctuation zone between the refugia of the southern foothills of the Carpathians, the marginal area of the Dinarides and its northern island hills. This zone harbored an ecotone of temperate Pannonian grassland and forest steppe during the warmer, drier periods of the Late Pleistocene. Conversely, this vegetation complex was replaced by a boreal forest steppe during the cooler periods, similar to the taiga steppes of Southern Siberia today. This special evolution of the vegetation is utterly different from that of the northern parts of the Carpathian Basin as well as Northern, Western, and Central Europe. The difference is attributable to the regional and local higher temperatures of the ice age resulting in drier conditions in the former areas. Thus the most important ecological driver, regarding the evolution of both the vegetation and the mollusk fauna, in the southern areas of the basin was humidity. The higher aridity of this area during the Late Glacial is attributable partly to the high distance from the seas and oceans. In addition, the intensification of the so-called basin effect as a result of the uplift of the surrounding mountains.

The area of the Carpathian Basin is characterized by a large-scale environmental mosaicity present on the scale of the basin. This complexity increases downward to the regional and local scales. The major driving factor on the scale of the basin is the regional overlap of various climatic influences ranging from the Atlantic, Alpine, and Continental influences to the Sub-Mediterranean-Pontic climatic effects. According to our data, this type of mosaic-like complexity of the environment developed even during the ice age and controlled the evolution of the mollusk fauna both on the regional and local scales. Geomorphology, bedrock, groundwater table, exposition, as well as soil conditions further increased the macro-scale mosaicity on the regional and local scales. These regional environmental mosaics functioned as the ice age refugia for terrestrial and freshwater warmth-loving gastropods. Long-term conservation of these is the key to the preservation of the natural biota of the basin among

**6. Concluding remarks**

108 Biological Resources of Water

changing climatic conditions.

The research was supported by the European Union and the State of Hungary, cofinanced by the European Regional Development Fund in the project of GINOP-2.3.15-02-2016-00009 "ICER."
