The Little Ice Age and its Spatial Variability across the Balkans

Abstract:

Using biological proxies (pollen, spores, and charcoal), geochemical signals through X-ray fluorescence, and AMS ¹⁴C based chronology, we present a correlation between two new high resolution Little Ice Age (LIA) records from the Central Balkans that are part of one of the least studied regions of Europe. The sediments extracted from a western sinkhole and central Serbian oxbow lake are analyzed at 8-10-cm intervals to capture the nature and magnitude of the LIA at a resolution of 20 years. During the 15^th-19^th CE, indigenous tree (e.g. Quercus, Acer, Pinus) and herbaceous (e.g. Poaceae, Chenopodiaceae, Artemisia) pollen from these records demonstrate fluctuations in woodland-grassland dynamics. While tree populations from Central Serbia remain comparatively stable (40-60%), the trees of western Serbia vacillate drastically between 15% and 50%. Similarly, central Serbian grasses show variations of ~18-36% whereas the western Serbian grass populations exhibit abrupt oscillations between high (55%) and low (19%) percentages. As a proxy for surface erosion and clastic input into the lakes, the 1-cm resolution potassium and titanium counts are in strong agreement with varying herbaceous taxa. These variations in ecological signals across the cores can account for local factors including altitude, terrain exposure, soils etc., however, the dynamic human component of the landscape is evident through crop pollen (e.g. Cerealia, Juglans) and microscopic charcoal highlighting the dominant role of people in ecological changes. Although the two sites show certain differences in charcoal concentration, extremely high charcoal indicates accelerated land clearance between the 15^th and 17^th CE. Until the beginning of 18^th CE, the cultivars (e.g. Secale, Triticum) occur with very low percentages and then peak to suggest improved agriculture in the region. In the post-LIA era, the 20^th CE exhibits increased arboreal percentages and declining grasslands in both the two Central Balkan records.