Dr. Fűköh Levente szerk.: Malakológiai Tájékoztató 16. (Eger, 1997.)
FŰKÖH, L.: Holocene climate changes as model of global climate change
I. At the beginning of the Holocene age the extension of closed forests decreased at the territory of medium high mountain ranges. It is shown by the increasing of the number of species marking opened, bushy territories: Vallonia costata, Granaria frumentum, Cochlicopa lubrica, Cochlicopa lubricella, Chondnda tridens (Vallonia costa biozone/ It can be in close connection with warning of the climate or can be the sign of the decrease of precipitation and degree of humidity. There have been found great number of Pinns and Graminae pollens in the sediments containing the malacological material. This is the beginning of lacustrine sediment formation at the subsided zones, which can be characterized by the presence of wind-blown sand or loessy calcareous sediments at many places, mainly at the central part of the Carpathian Basin. While at the edge of the mediumhigh mountain ranges well-sorted gravel-deposits can be exposed, in which rheophyllous gastropod species (Lithoglyphus naticoides) occur. In the second phase of this sediment cycle the appearance of drift sand-free lime deposits can be observed (Litholyphus naticoides-Valvata piscinalis biozone). The age of this ecological phase is 8500-6500 B.P. according to the radiometric dating. There are experts (Krolopp, E.-Siimegi, P. 1995) who took the lower boundary to 11.000-10.000 B.P on the basis of more exact measurements. II. The first significant climate change took place at the boundary the Boreal and Atlantic phase. At the territory of medium high mountain ranges species characteristic for scrubby, grassy territories fall into the background. Empty places were occupied by species preferring closed forests: Clausula cruciata, Laciniaria plicata, Ruthenica filograna, Cochlodina cerrata, Cochlodina orthostoma (Clausiliidae biozonej. On the basis of principle of actualism these species mark warm (humid) climate. In pollen samples the dominancy of pollens can be observed which characteristic for the Central-European closed forests (Tilia, Fraxinus, Alnus, Betula, Fagus, Quercus, Ulmus). On the opened, xerotherm karstic-regions appear such Mediterranean immigrant species like Zebrina detrita. And this is the beginning of the first antropogenous environment modifier activity (Lozek, V. 1982, Fűköh, L. 1992). In lacustrine sediments appear the first signs of reeds, the water level is increased, and disappeared the rheophyllous elements of the fauna. Their place was occupied by characteristic lacustrine species. The dominancy of thermophyllous species can be observed in the sediments of the central part of the basin (Gyraulus albus, Bithynia tentaculata). This change is stressed by the malacofaunae of the lacustrine sediments (Gyraulus albus - Bithynia tentaculata biozone) of Great Hungarian Plain and Transdanubia (Fényes, J. 1983., Fűköh, L. 1988). Tracing the climate change actualpaleontological examinations have been carried out at Uppony-pass. This territory is the best examined region in the Carpathian-basin from malacological point of view. (One of the stream valley surrounded by the largest cliffs in the Carpathian basin can be found here.) There are numerous caves nowdays at this partly covered partly open karstic area. These caves contain different sediments ranging from the Middle-Pleistocene until Holocene in age (Jánossy, D. - Krolopp, E. - Brunacker, K. 1968, Fűköh, L. - Kordos, L. 1977, 1980). At the northern and southern cliffs of the pass climate examinations combined with malacological collecting of recent species have been carried out. Comparing the results of the analysis of the collected material and climate data with the malacological material of Holocene cave sediments the following conclusions can be drawn:
