Climate and human impacts inferred from 2 a 1500-year multi-proxy record of an 3 alpine peat bog in the South-Eastern Alps

In the last decades, global warming and human activities significantly affected ecosystems, particularly in mountain areas. Whereas the Alps have been extensively studied for paleoclimatic reconstructions, few information is available about ecological changes, especially in the Southeastern Alps. This study aims at presenting a paleoclimatic and palaeoecological reconstruction from a 1500-years-old mountain peat bog record: Wölflmoor (Italy). Through physico-chemical, biological proxies, and environmental DNA (eDNA) we pursued a two-fold objective: 1) reconstructing the paleoenvironmental variations to identify the main dry/wet periods, and their correlations with climate and human activities; 2) testing the use of eDNA from peat bog. Through dating, a hiatus was detected at a depth of 50 cm of about 600 years. All proxies showed a shift towards drier environmental conditions starting from 920 cal. CE. This shift depends on the increase in temperature that occurred during the Medieval Warm Period, which may have caused the hiatus as a result of increased degradation of organic matter. However, a possible exploitation of the peatland by humans between the end of the 19th and the beginning of the 20th century cannot be excluded. The pollen analysis showed that high human pressure started around 720 cal. CE, characterized by the increased signal of Poaceae, Cerealia type and Secale cereale, and by the reduction of Fagus sylvatica and Quercus, more affected by deforestation. eDNA metabarcoding results showed similar trends as the other proxies This method presented some limitations such as the preferential amplification of the most abundant peatland species, leading to a relatively small number of detected taxa. This is one of the first studies of eDNA metabarcoding from peat bog; thus, we argue that ample room for improvement is expected in a short time, making eDNA metabarcoding a valuable complementary approach especially when both flora and fauna taxa are targeted.