Growth rate of cave ice based on 14 C dating of fossil bats as a palaeoenvironmental proxy for the last 1300 years in the Western Carpathians

Among various palaeoclimatic analyses of the Late-Holocene, assessing the cave ice growth rate offers valuable insights into past environmental conditions. Dobšiná Ice Cave (DIC; Carpathians, Slovakia) is an impressive ice cave, which hosts one of the most extensive subterranean perennial ice block. Thirteen organic macroremains were collected from a clearly layered ice section ca. 12 m thick. ¹⁴C dating of the samples enabled the construction of the precise age-depth model which revealed the ice growth rate. The obtained data proved that it was high during the Dark Ages (1.29 cm/year), significantly lower during the Medieval Climate Anomaly (0.58 cm/year), again high during the Little Ice Age (1.2 cm/year), and then decreased again (0.95 cm/year) during the Anthropogenic Recent Warmth. Among the collected organic macroremains, 10 were bats remains belonging to the species Myotis mystacinus, M. brandtii and Eptesicus nilssonii, which recently hibernate in the cold conditions of the cave. They group into two age clusters, which indicates higher bats mortality during colder periods, that is, the Dark Ages and Little Ice Age. This is consistent with episodes of faster ice growth in DIC. The continuous ice growth distinguishes DIC from several Alpine caves, where episodes of ice melting have been documented during the Medieval Climate Anomaly. This may result from local site-specific processes or geographically differentiated climatic conditions over Central Europe during the period under consideration.